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Sample records for mev si implantation

  1. High-dose MeV electron irradiation of Si-SiO2 structures implanted with high doses Si+

    Science.gov (United States)

    Kaschieva, S.; Angelov, Ch; Dmitriev, S. N.

    2018-03-01

    The influence was studied of 22-MeV electron irradiation on Si-SiO2 structures implanted with high-fluence Si+ ions. Our earlier works demonstrated that Si redistribution is observed in Si+-ion-implanted Si-SiO2 structures (after MeV electron irradiation) only in the case when ion implantation is carried out with a higher fluence (1016 cm-2). We focused our attention on the interaction of high-dose MeV electron irradiation (6.0×1016 cm-2) with n-Si-SiO2 structures implanted with Si+ ions (fluence 5.4×1016 cm-2 of the same order magnitude). The redistribution of both oxygen and silicon atoms in the implanted Si-SiO2 samples after MeV electron irradiation was studied by Rutherford back-scattering (RBS) spectroscopy in combination with a channeling technique (RBS/C). Our results demonstrated that the redistribution of oxygen and silicon atoms in the implanted samples reaches saturation after these high doses of MeV electron irradiation. The transformation of amorphous SiO2 surface into crystalline Si nanostructures (after MeV electron irradiation) was evidenced by atomic force microscopy (AFM). Silicon nanocrystals are formed on the SiO2 surface after MeV electron irradiation. The shape and number of the Si nanocrystals on the SiO2 surface depend on the MeV electron irradiation, while their size increases with the dose. The mean Si nanocrystals height is 16-20 nm after irradiation with MeV electrons at the dose of 6.0×1016 cm-2.

  2. Si exfoliation by MeV proton implantation

    International Nuclear Information System (INIS)

    Braley, Carole; Mazen, Frédéric; Tauzin, Aurélie; Rieutord, François; Deguet, Chrystel; Ntsoenzok, Esidor

    2012-01-01

    Proton implantation in silicon and subsequent annealing are widely used in the Smart Cut™ technology to transfer thin layers from a substrate to another. The low implantation energy range involved in this process is usually from a few ten to a few hundred of keV, which enables the separation of up to 2 μm thick layers. New applications in the fields of 3D integration and photovoltaic wafer manufacturing raise the demand for extending this technology to higher energy in order to separate thicker layer from a substrate. In this work, we propose to investigate the effect of proton implantation in single crystalline silicon in the 1–3 MeV range which corresponds to a 15–100 μm range for the hydrogen maximum concentration depth. We show that despites a considerably lower hydrogen concentration at R p , the layer separation is obtained with fluence close to the minimum fluence required for low energy implantation. It appears that the fracture propagation in Si and the resulting surface morphology is affected by the substrate orientation. Defects evolution is investigated with Fourier Transform Infrared Spectroscopy. The two orientations reveal similar type of defects but their evolution under annealing appears to be different.

  3. Effect of substrate temperature on the radiation damage from MeV Si implantation in Si

    International Nuclear Information System (INIS)

    Yu, X.K.; Shao Lin; Rusakova, Irene; Wang, X.M.; Ma, K.B.; Chen, H.; Liu, Jiarui; Chu, W.-K.

    2006-01-01

    We have investigated the radiation damage by MeV implantation of Si in Si and its evolution under thermal annealing. Si wafers were implanted with MeV Si at various substrate temperatures. Damages were characterized by Rutherford-backscattering (RBS) channeling and by transmission electron microscopy (TEM). Defect formation after post-implantation annealing is very sensitive to the substrate temperatures during implantation. When the substrate temperature was decreased to 200 K, TEM revealed two distinct bands of damage after annealing: one around the mean projected ion range and another at half the projected range. Our study indicates that the formation of defects at half range results from the solid phase epitaxy growth of initial buried amorphous layers

  4. Patterned microstructures formed with MeV Au implantation in Si(1 0 0)

    International Nuclear Information System (INIS)

    Rout, Bibhudutta; Greco, Richard R.; Zachry, Daniel P.; Dymnikov, Alexander D.; Glass, Gary A.

    2006-01-01

    Energetic (MeV) Au implantation in Si(1 0 0) (n-type) through masked micropatterns has been used to create layers resistant to KOH wet etching. Microscale patterns were produced in PMMA and SU(8) resist coatings on the silicon substrates using P-beam writing and developed. The silicon substrates were subsequently exposed using 1.5 MeV Au 3+ ions with fluences as high as 1 x 10 16 ions/cm 2 and additional patterns were exposed using copper scanning electron microscope calibration grids as masks on the silicon substrates. When wet etched with KOH microstructures were created in the silicon due to the resistance to KOH etching cause by the Au implantation. The process of combining the fabrication of masked patterns with P-beam writing with broad beam Au implantation through the masks can be a promising, cost-effective process for nanostructure engineering with Si

  5. Si-nanoparticle synthesis using ion implantation and MeV ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chulapakorn, T.; Wolff, M.; Primetzhofer, D.; Possnert, G. [Uppsala University, Department of Physics and Astronomy, P.O. Box 516, 751 20 Uppsala (Sweden); Sychugov, I.; Suvanam, S.S.; Linnros, J. [Royal Institute of Technology, School of Information and Communication Technology, P.O. Box Electrum 229, 164 40 Kista (Sweden); Hallen, A. [Uppsala University, Department of Physics and Astronomy, P.O. Box 516, 751 20 Uppsala (Sweden); Royal Institute of Technology, School of Information and Communication Technology, P.O. Box Electrum 229, 164 40 Kista (Sweden)

    2015-12-15

    A dielectric matrix with embedded Si-nanoparticles may show strong luminescence depending on nanoparticles size, surface properties, Si-excess concentration and matrix type. Ion implantation of Si ions with energies of a few tens to hundreds of keV in a SiO{sub 2} matrix followed by thermal annealing was identified as a powerful method to form such nanoparticles. The aim of the present work is to optimize the synthesis of Si-nanoparticles produced by ion implantation in SiO{sub 2} by employing MeV ion irradiation as an additional annealing process. The luminescence properties are measured by spectrally resolved photoluminescence including PL lifetime measurement, while X-ray reflectometry, atomic force microscopy and ion beam analysis are used to characterize the nanoparticle formation process. The results show that the samples implanted at 20%-Si excess atomic concentration display the highest luminescence and that irradiation of 36 MeV {sup 127}I ions affects the luminosity in terms of wavelength and intensity. It is also demonstrated that the nanoparticle luminescence lifetime decreases as a function of irradiation fluence. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Effect of 3.0 MeV helium implantation on electrical characteristics of 4H-SiC BJTs

    International Nuclear Information System (INIS)

    Usman, Muhammad; Hallen, Anders; Ghandi, Reza; Domeij, Martin

    2010-01-01

    Degradation of 4H-SiC power bipolar junction transistors (BJTs) under the influence of a high-energy helium ion beam was studied. Epitaxially grown npn BJTs were implanted with 3.0 MeV helium in the fluence range of 10 10 -10 11 cm -2 . The devices were characterized by their current-voltage (I-V) behaviour before and after the implantation, and the results showed a clear degradation of the output characteristics of the devices. Annealing these implanted devices increased the interface traps between passivation oxide and the semiconductor, resulting in an increase of base current in the low-voltage operation range.

  7. Ion beam synthesis of IrSi3 by implantation of 2 MeV Ir ions

    International Nuclear Information System (INIS)

    Sjoreen, T.P.; Chisholm, M.F.; Hinneberg, H.J.

    1992-11-01

    Formation of a buried IrSi 3 layer in (111) oriented Si by ion implantation and annealing has been studied at an implantation energy of 2 MeV for substrate temperatures of 450--550C. Rutherford backscattering (RBS), ion channeling and cross-sectional transmission electron microscopy showed that a buried epitaxial IrSi 3 layer is produced at 550C by implanting ≥ 3.4 x 10 17 Ir/cm 2 and subsequently annealing for 1 h at 1000C plus 5 h at 1100C. At a dose of 3.4 x 10 17 Ir/cm 2 , the thickness of the layer varied between 120 and 190 nm and many large IrSi 3 precipitates were present above and below the film. Increasing the dose to 4.4 x 10 17 Ir/cm 2 improved the layer uniformity at the expense of increased lattice damage in the overlying Si. RBS analysis of layer formation as a function of substrate temperature revealed the competition between the mechanisms for optimizing surface crystallinity vs. IrSi 3 layer formation. Little apparent substrate temperature dependence was evident in the as-implanted state but after annealing the crystallinity of the top Si layer was observed to deteriorate with increasing substrate temperature while the precipitate coarsening and coalescence improved

  8. MeV ion irradiation effects on the luminescence properties of Si-implanted SiO{sub 2}-thin films

    Energy Technology Data Exchange (ETDEWEB)

    Chulapakorn, T.; Primetzhofer, D. [Uppsala University, Department of Physics and Astronomy, P.O. Box 516, 751 20 Uppsala (Sweden); Sychugov, I.; Suvanam, S.S.; Linnros, J.; Hallen, A. [Royal Institute of Technology (KTH), School of Information and Communication Technology, P.O. Box Electrum 229, 164 40 Kista (Sweden)

    2016-12-15

    The effects of MeV heavy ion irradiation at varying fluence and flux on excess Si, introduced in SiO{sub 2} by keV ion implantation, are investigated by photoluminescence (PL). From the PL peak wavelength (λ) and decay lifetime (τ), two PL sources are distinguished: (i) quasi-direct recombination of excitons of Si-nanoparticles (SiNPs), appearing after thermal annealing (λ > 720 nm, τ ∝ μs), and (ii) fast-decay PL, possibly due to oxide-related defects (λ ∝ 575-690 nm, τ ∝ ns). The fast-decay PL (ii) observed before and after ion irradiation is induced by ion implantation. It is found that this fast-decay luminescence decreases for higher irradiation fluence of MeV heavy ions. After thermal annealing (forming SiNPs), the SiNP PL is reduced for samples irradiated by MeV heavy ions but found to stabilize at higher level for higher irradiation flux; the (ii) band vanishes as a result of annealing. The results are discussed in terms of the influence of electronic and nuclear stopping powers. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Effect of 3.0 MeV helium implantation on electrical characteristics of 4H-SiC BJTs

    Energy Technology Data Exchange (ETDEWEB)

    Usman, Muhammad; Hallen, Anders; Ghandi, Reza; Domeij, Martin, E-mail: musman@kth.s [Microelectronics and Applied Physics, School of Communication and Information Technology, Royal Institute of Technology (KTH), Electrum 229, 16440 Kista (Sweden)

    2010-11-01

    Degradation of 4H-SiC power bipolar junction transistors (BJTs) under the influence of a high-energy helium ion beam was studied. Epitaxially grown npn BJTs were implanted with 3.0 MeV helium in the fluence range of 10{sup 10}-10{sup 11} cm{sup -2}. The devices were characterized by their current-voltage (I-V) behaviour before and after the implantation, and the results showed a clear degradation of the output characteristics of the devices. Annealing these implanted devices increased the interface traps between passivation oxide and the semiconductor, resulting in an increase of base current in the low-voltage operation range.

  10. The studies of surface properties of 1.5 MeV Si-implanted silicon by multiphonon Raman spectrum

    International Nuclear Information System (INIS)

    Huang, X.

    1995-01-01

    The surface layer of crystalline silicon implanted by 1.5 MeV Si ions with doses ranging from 1 x 10 11 to 1 x 10 15 Si + cm -2 has been studied by two-phonon Raman spectra in both the acoustical overtone region and optical overtone region. Two-phonon Raman line intensities and shifts have been used to investigate the properties in the skin layer. The experimental two-phonon Raman spectra showed a decrease in intensity for both optical and acoustical two-phonon Raman peaks and also showed shifts by different amounts in different directions depending on the particular phonons. The stress values obtained by two-phonon Raman line shifts are compared with those obtained previously by one-phonon Raman shifts. The comparison shows that the surface defects make no contribution to two-phonon Raman line shifts. The two-phonon Raman line shifts show that the surface stress increases as a function of implantation doses. (author)

  11. Effect of Xe ion (167 MeV) irradiation on polycrystalline SiC implanted with Kr and Xe at room temperature

    International Nuclear Information System (INIS)

    Hlatshwayo, T T; Kuhudzai, R J; Njoroge, E G; Malherbe, J B; O’Connell, J H; Skuratov, V A; Msimanga, M

    2015-01-01

    The effect of swift heavy ion (Xe 167 MeV) irradiation on polycrystalline SiC individually implanted with 360 keV Kr and Xe ions at room temperature to fluences of 2  ×  10 16 cm −2 and 1  ×  10 16 cm −2 respectively, was investigated using transmission electron microscopy (TEM), Raman spectroscopy and Rutherford backscattering spectrometry (RBS). Implanted specimens were each irradiated with 167 MeV Xe +26 ions to a fluence of 8.3  ×  10 14 cm −2 at room temperature. It was observed that implantation of 360 keV Kr and Xe ions individually at room temperature amorphized the SiC from the surface up to a depth of 186 and 219 nm respectively. Swift heavy ion (SHI) irradiation reduced the amorphous layer by about 27 nm and 30 nm for the Kr and Xe samples respectively. Interestingly, the reduction in the amorphous layer was accompanied by the appearance of randomly oriented nanocrystals in the former amorphous layers after SHI irradiation in both samples. Previously, no similar nanocrystals were observed after SHI irradiations at electron stopping powers of 33 keV nm −1 and 20 keV nm −1 to fluences below 10 14 cm −2 . Therefore, our results suggest a fluence threshold for the formation of nanocrystals in the initial amorphous SiC after SHI irradiation. Raman results also indicated some annealing of radiation damage after swift heavy ion irradiation and the subsequent formation of small SiC crystals in the amorphous layers. No diffusion of implanted Kr and Xe was observed after swift heavy ion irradiation. (paper)

  12. Strain evolution in Si substrate due to implantation of MeV ion observed by extremely asymmetric x-ray diffraction

    International Nuclear Information System (INIS)

    Emoto, T.; Ghatak, J.; Satyam, P. V.; Akimoto, K.

    2009-01-01

    We studied the strain introduced in a Si(111) substrate due to MeV ion implantation using extremely asymmetric x-ray diffraction and measured the rocking curves of asymmetrical 113 diffraction for the Si substrates implanted with a 1.5 MeV Au 2+ ion at fluence values of 1x10 13 , 5x10 13 , and 1x10 14 /cm 2 . The measured curves consisted of a bulk peak and accompanying subpeak with an interference fringe. The positional relationship of the bulk peak to the subpeak and the intensity variation of those peaks with respect to the wavelengths of the x rays indicated that crystal lattices near the surface were strained; the lattice spacing of surface normal (111) planes near the surface was larger than that of the bulk. Detailed strain profiles along the depth direction were successfully estimated using a curve-fitting method based on Darwin's dynamical diffraction theory. Comparing the shapes of resultant strain profiles, we found that a strain evolution rapidly occurred within a depth of ∼300 nm at fluence values between 1x10 13 and 5x10 13 /cm 2 . This indicates that formation of the complex defects progressed near the surface when the fluence value went beyond a critical value between 1x10 13 and 5x10 13 /cm 2 and the defects brought a large strain to the substrate.

  13. Enhanced diffusion of dopants in vacancy supersaturation produced by MeV implantation

    International Nuclear Information System (INIS)

    Venezia, V.C.; Univ. of North Texas, Denton, TX; Haynes, T.E.; Agarwal, A.; Lucent Technologies, Murray Hill, NJ; Gossmann, H.J.; Eaglesham, D.J.

    1997-04-01

    The diffusion of Sb and B markers has been studied in vacancy supersaturations produced by MeV Si implantation in float zone (FZ) silicon and bonded etch-back silicon-on-insulator (BESOI) substrates. MeV Si implantation produces a vacancy supersaturated near-surface region and an interstitial-rich region at the projected ion range. Transient enhanced diffusion (TED) of Sb in the near surface layer was observed as a result of a 2 MeV Si + , 1 x 10 16 /cm 2 , implant. A 4x larger TED of Sb was observed in BESOI than in FZ silicon, demonstrating that the vacancy supersaturation persists longer in BESOI than in FZ. B markers in samples with MeV Si implant showed a factor of 10x smaller diffusion relative to markers without the MeV Si + implant. This data demonstrates that a 2 MeV Si + implant injects vacancies into the near surface region

  14. RBS studies of the lattice damage caused by 1 MeV Si+ implantation into Al0.3Ga0.7As/GaAs superlattices at elevated temperature

    International Nuclear Information System (INIS)

    Xu Tianbing; Zhu Peiran; Zhou Junsi; Li Daiqing; Gong Baoan; Wan Ya; Mu Shanming; Zhao Qingtai; Wang Zhonglie

    1994-01-01

    The lattice damage accumulation in GaAs and Al 0.3 Ga 0.7 As/GaAs superlattices by 1 MeV Si + irradiation at room temperature and 350 C has been studied. For irradiations at 350 C, at lower doses the samples were almost defect-free after irradiation, while a large density of accumulated defects was induced at a higher dose. The critical dose above which the damage accumulation is more efficient is estimated to be 2 x 10 15 Si/cm 2 for GaAs, and is 5 x 10 15 Si/cm 2 for Al 0.8 Ga 0.7 As/GaAs superlattice for implantation with 1.0 MeV Si ions at 350 C. The damage accumulation rate for 1 MeV Si ion implantation in Al 0.3 Ga 0.7 As/GaAs superlattice is less than that in GaAs. (orig.)

  15. Fluorescence lifetime studies of MeV erbium implanted silica glass

    International Nuclear Information System (INIS)

    Lidgard, A.; Polman, A.; Jacobsen, D.C.; Blonder, G.E.; Kistler, R.; Poate, J.M.; Becker, P.C.

    1991-01-01

    MeV erbium ion implantation into various SiO 2 glasses has been studied with the aim of incorporating the rare-earth dopant as an optically active ion in the silica network. The lifetime of the excited state ranges from 1.6 to 12.8 ms, depending on base material and implantation fluence. These results have positive implications for silica-based integrated optical technology. (Author)

  16. Fluorescence lifetime studies of MeV erbium implanted silica glass

    Energy Technology Data Exchange (ETDEWEB)

    Lidgard, A.; Polman, A.; Jacobsen, D.C.; Blonder, G.E.; Kistler, R.; Poate, J.M.; Becker, P.C. (AT and T Bell Labs., Murray Hill, NJ (USA))

    1991-05-23

    MeV erbium ion implantation into various SiO{sub 2} glasses has been studied with the aim of incorporating the rare-earth dopant as an optically active ion in the silica network. The lifetime of the excited state ranges from 1.6 to 12.8 ms, depending on base material and implantation fluence. These results have positive implications for silica-based integrated optical technology. (Author).

  17. Cavities at the Si projected range by high dose and energy Si ion implantation in Si

    International Nuclear Information System (INIS)

    Canino, M.; Regula, G.; Lancin, M.; Xu, M.; Pichaud, B.; Ntzoenzok, E.; Barthe, M.F.

    2009-01-01

    Two series of n-type Si samples α and β are implanted with Si ions at high dose (1 x 10 16 ) and high energies, 0.3 and 1.0 MeV, respectively. Both sort of samples are then implanted with 5 x 10 16 He cm -2 (at 10 or 50 keV) and eventually with B atoms. Some of the samples are annealed at temperatures ranging from 800 to 1000 deg. C to allow the thermal growth of He-cavities, located between sample surface and the projected range (R p ) of Si. After the triple ion implantation, which corresponds to defect engineering, samples were characterized by cross-section transmission electron microscopy (XTEM). Voids (or bubbles) are observed not only at the R p (He) on all annealed samples, but also at the R p (Si) on β samples implanted with He at 50 keV. The samples are also studied by positron annihilation spectroscopy (PAS) and the spectra confirm that as-implanted samples contain di-vacancies and that the annealed ones, even at high temperature have bigger open volumes, which are assumed to be the same voids observed by XTEM. It is demonstrated that a sole Si implantation at high energy and dose is efficient to create cavities which are thermally stable up to 1000 deg. C only in the presence of He.

  18. Improving Passivation Process of Si Nanocrystals Embedded in SiO2 Using Metal Ion Implantation

    Directory of Open Access Journals (Sweden)

    Jhovani Bornacelli

    2013-01-01

    Full Text Available We studied the photoluminescence (PL of Si nanocrystals (Si-NCs embedded in SiO2 obtained by ion implantation at MeV energy. The Si-NCs are formed at high depth (1-2 μm inside the SiO2 achieving a robust and better protected system. After metal ion implantation (Ag or Au, and a subsequent thermal annealing at 600°C under hydrogen-containing atmosphere, the PL signal exhibits a noticeable increase. The ion metal implantation was done at energies such that its distribution inside the silica does not overlap with the previously implanted Si ion . Under proper annealing Ag or Au nanoparticles (NPs could be nucleated, and the PL signal from Si-NCs could increase due to plasmonic interactions. However, the ion-metal-implantation-induced damage can enhance the amount of hydrogen, or nitrogen, that diffuses into the SiO2 matrix. As a result, the surface defects on Si-NCs can be better passivated, and consequently, the PL of the system is intensified. We have selected different atmospheres (air, H2/N2 and Ar to study the relevance of these annealing gases on the final PL from Si-NCs after metal ion implantation. Studies of PL and time-resolved PL indicate that passivation process of surface defects on Si-NCs is more effective when it is assisted by ion metal implantation.

  19. MeV Si ion modifications on the thermoelectric generators from Si/Si + Ge superlattice nano-layered films

    Science.gov (United States)

    Budak, S.; Heidary, K.; Johnson, R. B.; Colon, T.; Muntele, C.; Ila, D.

    2014-08-01

    The performance of thermoelectric materials and devices is characterized by a dimensionless figure of merit, ZT = S2σT/K, where, S and σ denote, respectively, the Seebeck coefficient and electrical conductivity, T is the absolute temperature in Kelvin and K represents the thermal conductivity. The figure of merit may be improved by means of raising either S or σ or by lowering K. In our laboratory, we have fabricated and characterized the performance of a large variety of thermoelectric generators (TEG). Two TEG groups comprised of 50 and 100 alternating layers of Si/Si + Ge multi-nanolayered superlattice films have been fabricated and thoroughly characterized. Ion beam assisted deposition (IBAD) was utilized to assemble the alternating sandwiched layers, resulting in total thickness of 300 nm and 317 nm for 50 and 100 layer devices, respectively. Rutherford Backscattering Spectroscopy (RBS) was employed in order to monitor the precise quantity of Si and Ge utilized in the construction of specific multilayer thin films. The material layers were subsequently impregnated with quantum dots and/or quantum clusters, in order to concurrently reduce the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and raise the cross plane electrical conductivity. The quantum dots/clusters were implanted via the 5 MeV Si ion bombardment which was performed using a Pelletron high energy ion beam accelerator. We have achieved remarkable results for the thermoelectric and optical properties of the Si/Si + Ge multilayer thin film TEG systems. We have demonstrated that with optimal setting of the 5 MeV Si ion beam bombardment fluences, one can fabricate TEG systems with figures of merits substantially higher than the values previously reported.

  20. MeV Si ion modifications on the thermoelectric generators from Si/Si + Ge superlattice nano-layered films

    Energy Technology Data Exchange (ETDEWEB)

    Budak, S., E-mail: satilmis.budak@aamu.edu [Department of Electrical Engineering and Computer Science, Alabama A and M University, Huntsville, AL (United States); Heidary, K. [Department of Electrical Engineering and Computer Science, Alabama A and M University, Huntsville, AL (United States); Johnson, R.B.; Colon, T. [Department of Physics, Alabama A and M University, Huntsville, AL (United States); Muntele, C. [Cygnus Scientific Services, Huntsville, AL (United States); Ila, D. [Department of Physics, Fayetteville St. University, Fayetteville, NC (United States)

    2014-08-15

    The performance of thermoelectric materials and devices is characterized by a dimensionless figure of merit, ZT = S{sup 2}σT/K, where, S and σ denote, respectively, the Seebeck coefficient and electrical conductivity, T is the absolute temperature in Kelvin and K represents the thermal conductivity. The figure of merit may be improved by means of raising either S or σ or by lowering K. In our laboratory, we have fabricated and characterized the performance of a large variety of thermoelectric generators (TEG). Two TEG groups comprised of 50 and 100 alternating layers of Si/Si + Ge multi-nanolayered superlattice films have been fabricated and thoroughly characterized. Ion beam assisted deposition (IBAD) was utilized to assemble the alternating sandwiched layers, resulting in total thickness of 300 nm and 317 nm for 50 and 100 layer devices, respectively. Rutherford Backscattering Spectroscopy (RBS) was employed in order to monitor the precise quantity of Si and Ge utilized in the construction of specific multilayer thin films. The material layers were subsequently impregnated with quantum dots and/or quantum clusters, in order to concurrently reduce the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and raise the cross plane electrical conductivity. The quantum dots/clusters were implanted via the 5 MeV Si ion bombardment which was performed using a Pelletron high energy ion beam accelerator. We have achieved remarkable results for the thermoelectric and optical properties of the Si/Si + Ge multilayer thin film TEG systems. We have demonstrated that with optimal setting of the 5 MeV Si ion beam bombardment fluences, one can fabricate TEG systems with figures of merits substantially higher than the values previously reported.

  1. Defects induced by helium implantation in SiC

    International Nuclear Information System (INIS)

    Oliviero, E.; Barbot, J.F.; Declemy, A.; Beaufort, M.F.; Oliviero, E.

    2008-01-01

    SiC is one of the considered materials for nuclear fuel conditioning and for the fabrication of some core structures in future nuclear generation reactors. For the development of this advance technology, a fundamental research on this material is of prime importance. In particular, the implantation/irradiation effects have to be understood and controlled. It is with this aim that the structural alterations induced by implantation/irradiation in SiC are studied by different experimental techniques as transmission electron microscopy, helium desorption, X-ray diffraction and Rutherford backscattering spectrometry. In this work, the different types of defects induced by helium implantation in SiC, point or primary defects (obtained at low energy (∼100 eV) until spread defects (obtained at higher energy (until ∼2 MeV)) are exposed. The amorphization/recrystallization and swelling phenomena are presented too. (O.M.)

  2. Annealing behaviour of MeV erbium implanted lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Gortmaker, P; McCallum, J C [Royal Melbourne Inst. of Tech., VIC (Australia)

    1994-12-31

    Lithium niobate (LiNbO{sub 3}) is a crystalline ceramic commonly used in the fabrication of optoelectronic devices. Recently, rare earth doping of LiNbO{sub 3} has become a topic of particular interest. The electronic configuration of rare earth elements such as Erbium (Er) and Neodymium (Nd) allows them to lase in nearly any host matrix making fabrication of a whole range of new optoelectronic devices possible. At present, the doping technique, for LiNbO{sub 3} are centred upon diffusion technology, but the diffusion profiles for the rare earths are not generally well-matched to the optical modes of the device. The aim of this research is to develop MeV implantation and annealing conditions of rare earth doped LiNbO{sub 3} that would be compatible with optoelectronic device fabrication. To determine the characteristics of the rare earth elements in the LiNbO{sub 3} host material over the depth range of interest in optoelectronic device applications, high energy Rutherford backscattering spectrometry and ion channeling (RBS-C) must be used. Presented here are the Er depth profile and lattice damage results obtained from 5 MeV RBS-C measurements on samples of LiNbO{sub 3} implanted with various doses of MeV Erbium and subsequently thermally annealed at a temperature of 1000 deg C. It was found that there is a peak implant concentration (2 x 10{sup 16} Er/cm{sup 2}) for which erbium no longer goes substitutional in the lattice, and the implantation damage is not fully removed by annealing. 8 refs., 3 figs.

  3. Annealing behaviour of MeV erbium implanted lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Gortmaker, P.; McCallum, J.C. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1993-12-31

    Lithium niobate (LiNbO{sub 3}) is a crystalline ceramic commonly used in the fabrication of optoelectronic devices. Recently, rare earth doping of LiNbO{sub 3} has become a topic of particular interest. The electronic configuration of rare earth elements such as Erbium (Er) and Neodymium (Nd) allows them to lase in nearly any host matrix making fabrication of a whole range of new optoelectronic devices possible. At present, the doping technique, for LiNbO{sub 3} are centred upon diffusion technology, but the diffusion profiles for the rare earths are not generally well-matched to the optical modes of the device. The aim of this research is to develop MeV implantation and annealing conditions of rare earth doped LiNbO{sub 3} that would be compatible with optoelectronic device fabrication. To determine the characteristics of the rare earth elements in the LiNbO{sub 3} host material over the depth range of interest in optoelectronic device applications, high energy Rutherford backscattering spectrometry and ion channeling (RBS-C) must be used. Presented here are the Er depth profile and lattice damage results obtained from 5 MeV RBS-C measurements on samples of LiNbO{sub 3} implanted with various doses of MeV Erbium and subsequently thermally annealed at a temperature of 1000 deg C. It was found that there is a peak implant concentration (2 x 10{sup 16} Er/cm{sup 2}) for which erbium no longer goes substitutional in the lattice, and the implantation damage is not fully removed by annealing. 8 refs., 3 figs.

  4. Improving Passivation Process of Si Nano crystals Embedded in SiO2 Using Metal Ion Implantation

    International Nuclear Information System (INIS)

    Bornacelli, J.; Esqueda, J.A.R.; Fernandez, L.R.; Oliver, A.

    2013-01-01

    We studied the photoluminescence (PL) of Si nano crystals (Si-NCs) embedded in SiO 2 obtained by ion implantation at MeV energy. The Si-NCs are formed at high depth (1-2 μm) inside the SiO 2 achieving a robust and better protected system. After metal ion implantation (Ag or Au), and a subsequent thermal annealing at 600°C under hydrogen-containing atmosphere, the PL signal exhibits a noticeable increase. The ion metal implantation was done at energies such that its distribution inside the silica does not overlap with the previously implanted Si ion . Under proper annealing Ag or Au nanoparticles (NPs) could be nucleated, and the PL signal from Si-NCs could increase due to plasmonic interactions. However, the ion-metal-implantation-induced damage can enhance the amount of hydrogen, or nitrogen, that diffuses into the SiO 2 matrix. As a result, the surface defects on Si-NCs can be better passivated, and consequently, the PL of the system is intensified. We have selected different atmospheres (air, H 2 /N 2 and Ar) to study the relevance of these annealing gases on the final PL from Si-NCs after metal ion implantation. Studies of PL and time-resolved PL indicate that passivation process of surface defects on Si-NCs is more effective when it is assisted by ion metal implantation.

  5. INCLUSIVE SYSTEMATICS FOR SI-28+SI-28 REACTIONS BETWEEN 20 AND 35 MEV PER NUCLEON

    NARCIS (Netherlands)

    BOX, PF; GRIFFIOEN, KA; DECOWSKI, P; BOOTSMA, T; GIERLIK, E; VANNIEUWENHUIZEN, GJ; TWENHOFEL, C; KAMERMANS, R; WILSCHUT, HW; GIORNI, A; MORAND, C; DEMEYER, A; GUINET, D

    Inclusive velocity spectra of heavy ions produced in the Si-28 + Si-28 reaction at 22, 26, 30, and 35 MeV per nucleon were measured and decomposed into peripheral and central components using an analytical moving-source parametrization. The persistence of incomplete fusion followed by evaporation

  6. Annealing Behavior of Al-Implantation-Induced Disorder in 4H-SiC

    International Nuclear Information System (INIS)

    Zhang, Yanwen; Weber, William J.; Jiang, Weilin; Shutthanandan, V.; Thevuthasan, Suntharampillai; Janson, Martin; Hallen, Anders

    2004-01-01

    Single crystal 4H-SiC films were implanted at 150 K with 1.1 MeV Al 2 2+ and subsequently annealed at elevated temperatures. Rutherford backscattering spectrometry (RBS) results indicate that the relative Si disorder at the damage peak recovers significantly as the annealing temperature increases. However, the residual Si disorder is more resistant to high-temperature annealing in the region of the implanted Al. The maximum concentration of Al profile measured by secondary ion mass spectroscopy (SIMS) is a factor of 1000 lower than the level of the residual Si disorder at the same region. Analysis of these results indicates that the excess residual Si disorder around the implanted Al projected range cannot be accounted for by just the Al interstitials; instead, it appears that each implanted Al stabilizes or inhibits recovery for an equivalent of a few hundred Si interstitials under the current experimental conditions

  7. Highly Stripped Ion Sources for MeV Ion Implantation

    Energy Technology Data Exchange (ETDEWEB)

    Hershcovitch, Ady

    2009-06-30

    Original technical objectives of CRADA number PVI C-03-09 between BNL and Poole Ventura, Inc. (PVI) were to develop an intense, high charge state, ion source for MeV ion implanters. Present day high-energy ion implanters utilize low charge state (usually single charge) ion sources in combination with rf accelerators. Usually, a MV LINAC is used for acceleration of a few rnA. It is desirable to have instead an intense, high charge state ion source on a relatively low energy platform (de acceleration) to generate high-energy ion beams for implantation. This de acceleration of ions will be far more efficient (in energy utilization). The resultant implanter will be smaller in size. It will generate higher quality ion beams (with lower emittance) for fabrication of superior semiconductor products. In addition to energy and cost savings, the implanter will operate at a lower level of health risks associated with ion implantation. An additional aim of the project was to producing a product that can lead to long­ term job creation in Russia and/or in the US. R&D was conducted in two Russian Centers (one in Tomsk and Seversk, the other in Moscow) under the guidance ofPVI personnel and the BNL PI. Multiple approaches were pursued, developed, and tested at various locations with the best candidate for commercialization delivered and tested at on an implanter at the PVI client Axcelis. Technical developments were exciting: record output currents of high charge state phosphorus and antimony were achieved; a Calutron-Bemas ion source with a 70% output of boron ion current (compared to 25% in present state-of-the-art). Record steady state output currents of higher charge state phosphorous and antimony and P ions: P{sup 2+} (8.6 pmA), P{sup 3+} (1.9 pmA), and P{sup 4+} (0.12 pmA) and 16.2, 7.6, 3.3, and 2.2 pmA of Sb{sup 3+} Sb {sup 4 +}, Sb{sup 5+}, and Sb{sup 6+} respectively. Ultimate commercialization goals did not succeed (even though a number of the products like high

  8. Focussed MeV ion beam implanted waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Von Bibra, M L; Roberts, A; Nugent, K; Jamieson, D N [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1997-12-31

    Single mode buried optical waveguides have been fabricated in fused silica by MeV proton implantation using a focussed hydrogen ion beam. The technique has the potential to direct write waveguide devices and produce multi-layered structures, without the need for intermediate steps such as mask fabrication or layered depositions. A micron resolution Confocal Raman Spectrometer has been used to map the distribution of atomic vacancies that forms the waveguiding region. The results are compared with theoretical calculations. Losses of 3 dB cm{sup -1} have been measured in unannealed samples, which decreases to less than 0.5 dB cm{sup -1} after annealing at 500 degrees Celsius. We describe methods for determining the refractive index distribution of single mode buried waveguides from their output intensity distributions via an inversion of the scalar wave equation. (authors). 5 figs.

  9. Focussed MeV ion beam implanted waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Von Bibra, M.L.; Roberts, A.; Nugent, K.; Jamieson, D.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    Single mode buried optical waveguides have been fabricated in fused silica by MeV proton implantation using a focussed hydrogen ion beam. The technique has the potential to direct write waveguide devices and produce multi-layered structures, without the need for intermediate steps such as mask fabrication or layered depositions. A micron resolution Confocal Raman Spectrometer has been used to map the distribution of atomic vacancies that forms the waveguiding region. The results are compared with theoretical calculations. Losses of 3 dB cm{sup -1} have been measured in unannealed samples, which decreases to less than 0.5 dB cm{sup -1} after annealing at 500 degrees Celsius. We describe methods for determining the refractive index distribution of single mode buried waveguides from their output intensity distributions via an inversion of the scalar wave equation. (authors). 5 figs.

  10. Properties of tribology for Si implanted PET

    International Nuclear Information System (INIS)

    Wu Yuguang; Zhang Tonghe; Zhang Xu; Liu Andong; Xie Mengxia; Zhang Aimin; Chen Jianmin

    2002-01-01

    Polyethylene terephthalate (PET) has been modified with Si ions from a metal vapor arc source (MEVVA). After implantation, the surface structure has been greatly changed. The experimental results of infrared absorption indicated that the particles are referred to rich carbon and SiC particles. The PET has been strengthened by these dispersed particles. The measurement results using nanometer hardness tester reveal that both surface hardness and modulus increase obviously. Therefore the surface wear resistance improved extremely. Finally the modification mechanism of Si implanted PET was discussed

  11. He implantation induced nanovoids in crystalline Si

    International Nuclear Information System (INIS)

    Kilpelaeinen, S.; Kuitunen, K.; Slotte, J.; Tuomisto, F.; Bruno, E.; Mirabella, S.; Priolo, F.

    2009-01-01

    Positron annihilation spectroscopy (PAS) in Doppler broadening mode was used to study the vacancy profile of crystalline Si after He and B implantation and subsequent annealing. In the He-implanted samples two different void layers were observed, one consisting of large voids at the projected range of He and another containing 'nanovoids' slightly larger than divacancies at roughly halfway between R p of He and the surface. The nanovoid layer was shown to be absent from samples co-implanted with B, implying that interstitials created during B implantation get trapped in the nanovoids and fill them, thus hindering interstitial-mediated B diffusion.

  12. Simulations of Proton Implantation in Silicon Carbide (SiC)

    Science.gov (United States)

    2016-03-31

    Simulations of Proton Implantation in Silicon Carbide (SiC) Jonathan P. McCandless, Hailong Chen, Philip X.-L. Feng Electrical Engineering, Case...of implanting protons (hydrogen ions, H+) into SiC thin layers on silicon (Si) substrate, and explore the ion implantation conditions that are...relevant to experimental radiation of SiC layers. Keywords: silicon carbide (SiC); radiation effects; ion implantation ; proton; stopping and range of

  13. Amorphization and the effect of implanted ions in SiC

    International Nuclear Information System (INIS)

    Snead, L.L.; Zinkle, S.J.

    1994-01-01

    The effects of implanted ion chemistry and displacement damage on the amorphization threshold dose of SiC were studied using cross-section transmission electron microscopy. Room temperature as well as 200 and 400 C irradiations were carried out with 3.6 MeV Fe, 1.8 MeV Cl, 1 MeV He or 0.56 MeV Si ions. The room temperature amorphization threshold dose in irradiated regions well separated from the implanted ions was found to range from 0.3 to 0.5 dpa for the four different ion species. The threshold dose for amorphization in the He, Si and Fe ion-implanted regions was also ∼0.3 to 0.5 dpa. On the other hand, the amorphization threshold in the Cl-implanted region was only about 0.1 dpa. The volume change associated with amorphization was ∼17%. No evidence for amorphization was obtained in specimens irradiated at 200 or 400 C. An understanding of the microstructural evolution of SiC under irradiation is critical to the application of these materials in fusion energy systems

  14. Carbon redistribution and precipitation in high temperature ion-implanted strained Si/SiGe/Si multi-layered structures

    DEFF Research Database (Denmark)

    Gaiduk, Peter; Hansen, John Lundsgaard; Nylandsted Larsen, Arne

    2014-01-01

    Graphical abstract Carbon depth profiles after high temperature implantation in strained Si/SiGe/Si multilayered system and induced structural defects.......Graphical abstract Carbon depth profiles after high temperature implantation in strained Si/SiGe/Si multilayered system and induced structural defects....

  15. Amorphization and recrystallization in MeV ion implanted InP crystals

    International Nuclear Information System (INIS)

    Xiong, F.; Nieh, C.W.; Jamieson, D.N.; Vreeland, T. Jr.; Tombrello, T.A.

    1988-01-01

    A comprehensive study of MeV- 15 N-ion-implanted InP by a variety of analytical techniques has revealed the physical processes involved in MeV ion implantation into III-V compound semiconductors as well as the influence of post-implantation annealing. It provides a coherent picture of implant distribution, structural transition, crystalline damage, and lattice strain in InP crystals induced by ion implantation and thermal annealing. The experimental results from the different measurements are summarized in this report. Mechanisms of amorphization by implantation and recrystallization through annealing in MeV-ion-implanted InP are proposed and discussed in light of the results obtained

  16. Bond formation in hafnium atom implantation into SiC induced by high-energy electron irradiation

    International Nuclear Information System (INIS)

    Yasuda, H.; Mori, H.; Sakata, T.; Naka, M.; Fujita, H.

    1992-01-01

    Bilayer films of Hf (target atoms)/α-SiC (substrate) were irradiated with 2 MeV electrons in an ultra-high voltage electron microscope (UHVEM), with the electron beam incident on the hafnium layer. As a result of the irradiation, hafnium atoms were implanted into the SiC substrate. Changes in the microstructure and valence electronic states associated with the implantation were studied by a combination of UHVEM and Auger valence electron spectroscopy. The implantation process is summarized as follows. (1) Irradiation with 2 MeV electrons first induces a crystalline-to-amorphous transition in α-SiC. (2) Hafnium atoms which have been knocked-off from the hafnium layer by collision with the 2 MeV electrons are implanted into the resultant amorphous SiC. (3) The implanted hafnium atoms make preferential bonding to carbon atoms. (4) With continued irradiation, the hafnium atoms repeat the displacement along the beam direction and the subsequent bonding with the dangling hybrids of carbon and silicon. The repetition of the displacement and subsequent bonding lead to the deep implantation of hafnium atoms into the SiC substrate. It is concluded that implantation successfully occurs when the bond strength between a constituent atom of a substrate and an injected atom is stronger than that between constituent atoms of a substrate. (Author)

  17. Scanning probe microscopy of single Au ion implants in Si

    International Nuclear Information System (INIS)

    Vines, L.; Monakhov, E.; Maknys, K.; Svensson, B.G.; Jensen, J.; Hallen, A.; Kuznetsov, A. Yu.

    2006-01-01

    We have studied 5 MeV Au 2+ ion implantation with fluences between 7 x 10 7 and 2 x 10 8 cm -2 in Si by deep level transient spectroscopy (DLTS) and scanning capacitance microscopy (SCM). The DLTS measurements show formation of electrically active defects such as the two negative charge states of the divacancy (V 2 (=/-) and V 2 (-/0)) and the vacancy-oxygen (VO) center. It is observed that the intensity of the V 2 (=/-) peak is lower compared to that of V 2 (-/0) by a factor of 5. This has been attributed to a highly localized distribution of the defects along the ion tracks, which results in trapping of the carriers at V 2 (-/0) and incomplete occupancy of V 2 (=/-). The SCM measurements obtained in a plan view show a random pattern of regions with a reduced SCM signal for the samples implanted with fluence above 2 x 10 8 cm -2 . The reduced SCM signal is attributed to extra charges associated with acceptor states, such as V 2 (-/0), formed along the ion tracks in the bulk Si. Indeed, the electron emission rate from the V 2 (-/0) state is in the range of 10 kHz at room temperature, which is well below the probing frequency of the SCM measurements, resulting in 'freezing' of electrons at V 2 (-/0)

  18. Electronic states at Si-SiO2 interface introduced by implantation of Si in thermal SiO2

    International Nuclear Information System (INIS)

    Kalnitsky, A.; Poindexter, E.H.; Caplan, P.J.

    1990-01-01

    Interface traps due to excess Si introduced into the Si-SiO 2 system by ion implantation are investigated. Implanted oxides are shown to have interface traps at or slightly above the Si conduction band edge with densities proportional to the density of off-stoichiometric Si at the Si-SiO 2 interface. Diluted oxygen annealing is shown to result in physical separation of interface traps and equilibrium substrate electrons, demonstrating that ''interface'' states are located within a 0.5 nm thick layer of SiO 2 . Possible charge trapping mechanisms are discussed and the effect of these traps on MOS transistor characteristics is described using a sheet charge model. (author)

  19. Elastic and inelastic scattering of α particles at 41MeV and elastic scattering of 3He at 46MeV on 27Al, 28Si, 29Si, and 30Si

    International Nuclear Information System (INIS)

    Mariolopoulos, Georges.

    1976-01-01

    Elastic and inelastic scattering of α particles at 41MeV has been studied on 27 Al, 28 Si, 29 Si and 30 Si between 30 and 160deg c.m. The elastic cross section for α particles on 28 Si shows more oscillation than that for the other targets in the region between 80 and 160deg c.m. The data have been analyzed using both a 9 parameters optical model potential and a coupled channel code. In order to investigate the assumption that the abnormal cross section of 28 Si is due to a cluster effect, the 27 Al, 28 Si, 29 Si, 30 Si( 3 He, 3 He) reaction have been studied between 30 and 110deg c.m., using a 46MeV beam. In this case the angular distributions of the three Si isotopes are similar. An optical model analysis of the data reveals no anomaly [fr

  20. Effect of MeV energy He and N pre-implantation on the formation of porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Manuaba, A. E-mail: manu@rmki.kfki.hu; Paszti, F.; Ortega, C.; Grosman, A.; Horvath, Z.E.; Szilagyi, E.; Khanh, N.Q.; Vickridge, I

    2001-06-01

    The effects of MeV energy He and N pre-implantation of Si substrate on the structure of porous silicon formed by anodic etching were studied by measuring the depth profiles of {sup 15}N decorating the pores walls. Radiation damage was recovered by annealing after the implantation. It was found that the He implant accelerates the etching process, probably due to the bubbles or the remaining lattice damage. At a dose of 8x10{sup 16} ions/cm{sup 2} the He containing layer was formed with a significantly enhanced porosity due to the contribution of the large-sized bubbles. At the highest dose of 32.5x10{sup 16} ions/cm{sup 2} flaking took place during the anodic etching. In contrast to He, N stopped the anodic etching at a depth of critical N concentration of {approx}0.9 at.%. For the lowest implantation dose, where the peak concentration was below this limit, the pores propagate through the implanted layer with an enhanced speed.

  1. Effect of MeV energy He and N pre-implantation on the formation of porous silicon

    International Nuclear Information System (INIS)

    Manuaba, A.; Paszti, F.; Ortega, C.; Grosman, A.; Horvath, Z.E.; Szilagyi, E.; Khanh, N.Q.; Vickridge, I.

    2001-01-01

    The effects of MeV energy He and N pre-implantation of Si substrate on the structure of porous silicon formed by anodic etching were studied by measuring the depth profiles of 15 N decorating the pores walls. Radiation damage was recovered by annealing after the implantation. It was found that the He implant accelerates the etching process, probably due to the bubbles or the remaining lattice damage. At a dose of 8x10 16 ions/cm 2 the He containing layer was formed with a significantly enhanced porosity due to the contribution of the large-sized bubbles. At the highest dose of 32.5x10 16 ions/cm 2 flaking took place during the anodic etching. In contrast to He, N stopped the anodic etching at a depth of critical N concentration of ∼0.9 at.%. For the lowest implantation dose, where the peak concentration was below this limit, the pores propagate through the implanted layer with an enhanced speed

  2. Formation of Si/SiC multilayers by low-energy ion implantation and thermal annealing

    NARCIS (Netherlands)

    Dobrovolskiy, S.; Yakshin, Andrey; Tichelaar, F.D.; Verhoeven, J.; Louis, Eric; Bijkerk, Frederik

    2010-01-01

    Si/SiC multilayer systems for XUV reflection optics with a periodicity of 10–20 nm were produced by sequential deposition of Si and implantation of 1 keV View the MathML source ions. Only about 3% of the implanted carbon was transferred into the SiC, with a thin, 0.5–1 nm, buried SiC layer being

  3. Formation of Si/SiC multilayers by low-energy ion implantation and thermal annealing

    NARCIS (Netherlands)

    Dobrovolskiy, S.; Yakshin, A. E.; Tichelaar, F. D.; Verhoeven, J.; E. Louis,; F. Bijkerk,

    2010-01-01

    Si/SiC multilayer systems for XUV reflection optics with a periodicity of 10-20 nm were produced by sequential deposition of Si and implantation of 1 key CHx+ ions. Only about 3% of the implanted carbon was transferred into the SIC, with a thin, 0.5-1 nm, buried SIC layer being formed. We

  4. Effects of C+ ion implantation on electrical properties of NiSiGe/SiGe contacts

    International Nuclear Information System (INIS)

    Zhang, B.; Yu, W.; Zhao, Q.T.; Buca, D.; Breuer, U.; Hartmann, J.-M.; Holländer, B.; Mantl, S.; Zhang, M.; Wang, X.

    2013-01-01

    We have investigated the morphology and electrical properties of NiSiGe/SiGe contact by C + ions pre-implanted into relaxed Si 0.8 Ge 0.2 layers. Cross-section transmission electron microscopy revealed that both the surface and interface of NiSiGe were improved by C + ions implantation. In addition, the effective hole Schottky barrier heights (Φ Bp ) of NiSiGe/SiGe were extracted. Φ Bp was observed to decrease substantially with an increase in C + ion implantation dose

  5. Modelling of ion implantation in SiC crystals

    Energy Technology Data Exchange (ETDEWEB)

    Chakarov, Ivan [SILVACO International, 4701 Patrick Henry Drive, Building 2, Santa Clara, CA 95054 (United States)]. E-mail: ivan.chakarov@silvaco.com; Temkin, Misha [SILVACO International, 4701 Patrick Henry Drive, Building 2, Santa Clara, CA 95054 (United States)

    2006-01-15

    An advanced electronic stopping model for ion implantation in SiC has been implemented within the binary collision approximation. The model has been thoroughly tested and validated for Al implantation into 4H-, 6H-SiC under different initial implant conditions. A very good agreement between calculated and experimental profiles has been achieved. The model has been integrated in an industrial technology CAD process simulator.

  6. Modelling of ion implantation in SiC crystals

    International Nuclear Information System (INIS)

    Chakarov, Ivan; Temkin, Misha

    2006-01-01

    An advanced electronic stopping model for ion implantation in SiC has been implemented within the binary collision approximation. The model has been thoroughly tested and validated for Al implantation into 4H-, 6H-SiC under different initial implant conditions. A very good agreement between calculated and experimental profiles has been achieved. The model has been integrated in an industrial technology CAD process simulator

  7. Mechanical properties of MeV ion-irradiated SiC/SiC composites characterized by indentation technique

    International Nuclear Information System (INIS)

    Park, J.Y.; Park, K.H.; Kim, W.; Kishimoto, H.; Kohyama, A.

    2007-01-01

    Full text of publication follows: SiC/SiC composites have been considered as a structural material for advanced fusion concepts. In the core of fusion reactor, those SiC/SiC composites are experienced the complex attacks such as strong neutron, high temperature and transmuted gases. One of the vital data for designing the SiC/SiC composites to the fusion reactor is mechanical properties under the severe neutron irradiation. In this work, various SiC/SiC composites were prepared by the different fabrication processes like CVI (chemical vapor infiltration), WA-CVI (SiC whisker assisted CVI) and hot-pressed method. The expected neutron irradiation was simulated by a silicon self-ion irradiation at a DuET facility; Dual-beam for Energy Technologies, Kyoto University. The irradiation temperature were 600 deg. C and 1200 deg. C, and the irradiation does were 5 dpa and 20 dpa, respectively. The 5.1 MeV Si ions were irradiated to the intrinsic CVI-SiC, SiC whisker reinforced SiC and SiC composites produced by hot-press method. The mechanical properties like hardness, elastic modulus and fracture toughness were characterized by an indentation technique. The ion irradiation caused the increase of the hardness and fracture toughness, which was dependent on the irradiation temperature. SiC whisker reinforcement in the SiC matrix accelerated the increase of the fracture toughness by the ion irradiation. For SiC/SiC composites after the ion irradiation, this work will provide the additional data for the mechanical properties as well as the effect of SiC whisker reinforcement. (authors)

  8. Accelerator based synthesis of hydroxyapatite by MeV ion implantation

    International Nuclear Information System (INIS)

    Rautray, Tapash R.; Narayanan, R.; Kwon, Tae-Yub; Kim, Kyo-Han

    2010-01-01

    Accelerator based MeV ion implantation of Ca 2+ and P 2+ into the titanium substrate to form hydroxyapatite (HA) has been carried out. Calcium hydroxide was formed after heating the calcium implanted titanium in air at 80 o C for 3 h. Upon subsequent annealing for 5 min at 600 o C HA was formed on the surface. Penetration depth of the HA layer in this method is much higher as compared to keV ion implantation. By elemental analysis, Ca/P ratio of the HA was found to be 1.76 which is higher than the ideal 1.67. This higher Ca/P ratio is attributed to the higher penetration depth of the MeV technique used.

  9. 120 MeV Ag ion induced effects in Au/HfO2/Si MOSCAPs

    Science.gov (United States)

    Manikanthababu, N.; Prajna, K.; Pathak, A. P.; Rao, S. V. S. Nageswara

    2018-05-01

    HfO2/Si thinfilms were deposited by RF sputtering technique. 120 MeV Ag ion irradiation has been used to study the electrical properties of Au/HfO2/Si MOSCAPs. SHI (120 MeV Ag) induced annealing, defects creation and intermixing effects on the electrical properties of these systems have been studied. Here, we have observed that the high electronic excitation can cause a significant reduction of leakage currents in these MOSCAP devices. Various quantum mechanical tunneling phenomenon has been observed from the I-V characteristics.

  10. High-temperature Au implantation into Ni-Be and Ni-Si alloys

    Science.gov (United States)

    James, M. R.; Lam, N. Q.; Rehn, L. E.; Baldo, P. M.; Funk, L.; Stubbins, J. F.

    1992-12-01

    Effects of implantation temperature and target composition on depth distribution of implanted species were investigated. Au+ ions were implanted at 300 keV into polycrystalline Ni-Be and Ni-Si alloys between 25 and 700C to a dose of 10(exp 16) cm(exp -2). Depth distributions of Au were analyzed with RBS using He+ at both 1.7 and 3.0 MeV, and those of the other alloying elements by SIMS. Theoretical modeling of compositional redistribution during implantation at elevated temperatures was also carried out with the aid of a comprehensive kinetic model. The analysis indicated that below approximately 250C, the primary controlling processes were preferential sputtering and displacement mixing, while between 250 and 600C radiation-induced segregation was dominant. Above 600C, thermal-diffusion effects were most important. Fitting of model calculations to experimental measurements provided values for various defect migration and formation parameters.

  11. Dopant profile engineering of advanced Si MOSFET's using ion implantation

    International Nuclear Information System (INIS)

    Stolk, P.A.; Ponomarev, Y.V.; Schmitz, J.; Brandenburg, A.C.M.C. van; Roes, R.; Montree, A.H.; Woerlee, P.H.

    1999-01-01

    Ion implantation has been used to realize non-uniform, steep retrograde (SR) dopant profiles in the active channel region of advanced Si MOSFET's. After defining the transistor configuration, SR profiles were formed by dopant implantation through the polycrystalline Si gate and the gate oxide (through-the-gate, TG, implantation). The steep nature of the as-implanted profile was retained by applying rapid thermal annealing for dopant activation and implantation damage removal. For NMOS transistors, TG implantation of B yields improved transistor performance through increased carrier mobility, reduced junction capacitances, and reduced susceptibility to short-channel effects. Electrical measurements show that the gate oxide quality is not deteriorated by the ion-induced damage, demonstrating that transistor reliability is preserved. For PMOS transistors, TG implantation of P or As leads to unacceptable source/drain junction broadening as a result of transient enhanced dopant diffusion during thermal activation

  12. POSITRON-ELECTRON DECAY OF SI-28, AT AN EXCITATION-ENERGY OF 50-MEV

    NARCIS (Netherlands)

    BUDA, A; BACELAR, JC; BALANDA, A; VANDERPLOEG, H; SUJKOWSKI, Z; VANDERWOUDE, A

    1993-01-01

    The electron-positron pair decay of Si-28 at 50 MeV excitation produced by the isospin T=0 (alpha + Mg-24) and the mixed isospin T=0,1 (He-3 + Mg-25) reactions has been studied using a special designed Positron-Electron pair spectrometer PEPSI.

  13. Positron-electron decay of 28Si at an excitation energy of 50 MeV

    International Nuclear Information System (INIS)

    Buda, A.; Bacelar, J.C.; Balanda, A.; Ploeg, H. van der; Sujkowski, Z.; Woude, A. van der

    1993-01-01

    The electron-positron pair decay of 28 Si at 50 MeV excitation produced by the isospin T=0 (α+ 24 Mg) and the mixed isospin T=0, 1 ( 3 He+ 25 Mg) reactions has been studied using a special designed Positron-Electron pair spectrometer PEPSI. (orig.)

  14. Anomalous defect processes in Si implanted amorphous SiO2, II

    International Nuclear Information System (INIS)

    Fujita, Tetsuo; Fukui, Minoru; Okada, Syunji; Shimizu-Iwayama, Tsutomu; Hioki, Tatsumi; Itoh, Noriaki

    1994-01-01

    Aanomalous features of the defects in Si implanted amorphous SiO 2 are reported. The numbers of E 1 prime centers and B 2 centers are found to increase monotonically with implanted Si dose, in contrast to the saturating feature of these numbers in Ar implanted samples. Moreover, when H ions are implanted in amorphous SiO 2 predamaged by Si implantation, both of the density and the number of E 1 prime centers increase and they reach a constant value at a small H dose. We point out that these anomalies can be explained in terms of the difference in the cross-section for defect annihilation in the specimens implanted with Si ions and other ions, in accordance with the homogeneous model proposed by Devine and Golanski. We consider that the main mechanism of defect annihilation is the recombination of an E 1 prime center and an interstitial O, which is stabilized by an implanted Si, reducing the cross-section in Si-implanted specimens. ((orig.))

  15. Elastic scattering of 16O on 28Si between 45.0 and 73.5 MeV

    International Nuclear Information System (INIS)

    Shkolnik, V.; Dehnhard, D.; Kubono, S.; Franey, M.A.; Tripp, S.; Artz, J.L.; Weber, D.J.

    1977-01-01

    Angular distributions of 16 O elastically scattering by Si isotopes were analyzed by the optical model. Differential cross sections are shown for all isotopes at 60 MeV, and for 28 Si at energies from 45 to 63 MeV. The potentials found are discussed in some detail; the best fits were produced by surface-transparent potentials. 3 figures, 2 tables

  16. Structural and magnetic properties of Mn-implanted Si

    International Nuclear Information System (INIS)

    Zhou Shengqiang; Potzger, K.; Zhang Gufei; Muecklich, A.; Eichhorn, F.; Schell, N.; Groetzschel, R.; Schmidt, B.; Skorupa, W.; Helm, M.; Fassbender, J.; Geiger, D.

    2007-01-01

    Structural and magnetic properties in Mn-implanted, p-type Si were investigated. High resolution structural analysis techniques such as synchrotron x-ray diffraction revealed the formation of MnSi 1.7 nanoparticles already in the as-implanted samples. Depending on the Mn fluence, the size increases from 5 nm to 20 nm upon rapid thermal annealing. No significant evidence is found for Mn substituting Si sites either in the as-implanted or annealed samples. The observed ferromagnetism yields a saturation moment of 0.21μ B per implanted Mn at 10 K, which could be assigned to MnSi 1.7 nanoparticles as revealed by a temperature-dependent magnetization measurement

  17. Electrical activation of nitrogen heavily implanted 3C-SiC(1 0 0)

    Energy Technology Data Exchange (ETDEWEB)

    Li, Fan, E-mail: f.li.1@warwick.ac.uk [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom); Sharma, Yogesh; Shah, Vishal; Jennings, Mike [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom); Pérez-Tomás, Amador [ICN2 – Institut Catala de Nanociència i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona (Spain); Myronov, Maksym [Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom); Fisher, Craig [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom); Leadley, David [Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom); Mawby, Phil [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2015-10-30

    Highlights: • Nitrogen is fully activated by 1175 °C annealing for 1.5 × 10{sup 19} cm{sup −3} doped 3C-SiC. • Free donor concentration is found to readily saturate in 3C-SiC at ∼7 × 10{sup 19} cm{sup −3}. • 3C-SiC is found to have complete donor thermal ionization above 150 K. • Donor in 1.5 × 10{sup 19} cm{sup −3} nitrogen implanted 3C-SiC has an energy level ∼15 meV. • The SiO{sub 2} cap is found to have a bigger influence on low and medium doped samples. - Abstract: A degenerated wide bandgap semiconductor is a rare system. In general, implant levels lie deeper in the band-gap and carrier freeze-out usually takes place at room temperature. Nevertheless, we have observed that heavily doped n-type degenerated 3C-SiC films are achieved by nitrogen implantation level of ∼6 × 10{sup 20} cm{sup −3} at 20 K. According to temperature dependent Hall measurements, nitrogen activation rates decrease with the doping level from almost 100% (1.5 × 10{sup 19} cm{sup −3}, donor level 15 meV) to ∼12% for 6 × 10{sup 20} cm{sup −3}. Free donors are found to saturate in 3C-SiC at ∼7 × 10{sup 19} cm{sup −3}. The implanted film electrical performances are characterized as a function of the dopant doses and post implantation annealing (PIA) conditions by fabricating Van der Pauw structures. A deposited SiO{sub 2} layer was used as the surface capping layer during the PIA process to study its effect on the resultant film properties. From the device design point of view, the lowest sheet resistivity (∼1.4 mΩ cm) has been observed for medium doped (4 × 10{sup 19} cm{sup −3}) sample with PIA 1375 °C 2 h without a SiO{sub 2} cap.

  18. TEM studies of P+ implanted and subsequently laser annealed Si

    International Nuclear Information System (INIS)

    Sadana, D.K.; Wilson, M.C.; Booker, G.R.; Washburn, J.

    1979-05-01

    The present investigation is concerned with laser annealing of P + implanted Si. The aim of the work was to study the crystallization behavior of damage structure occurring due to high dose rate implantation using transmission electron microscopy (TEM) as the method of examination

  19. On formation of silicon nanocrystals under annealing SiO2 layers implanted with Si ions

    International Nuclear Information System (INIS)

    Kachurin, G.A.; Yanovskaya, S.G.; Volodin, V.A.; Kesler, V.G.; Lejer, A.F.; Ruault, M.-O.

    2002-01-01

    Raman scattering, X-ray photoelectron spectroscopy, and photoluminescence have been used to study the formation of silicon nanocrystals in SiO 2 implanted with Si ions. Si clusters have been formed at once in the postimplanted layers, providing the excessive Si concentration more ∼ 3 at. %. Si segregation with Si-Si 4 bonds formation is enhanced as following annealing temperature increase, however, the Raman scattering by Si clusters diminishes. The effect is explained by a transformation of the chain-like Si clusters into compact phase nondimensional structures. Segregation of Si nanoprecipitates had ended about 1000 deg C, but the strong photoluminescence typical for Si nanocrystals manifested itself only after 1100 deg C [ru

  20. Nonlinear optical waveguides produced by MeV ion implantation in LiNbO3

    International Nuclear Information System (INIS)

    Sarkisov, S.S.; Curley, M.J.; Williams, E.K.; Ila, D.; Svetchnikov, V.L.; Zandbergen, H.W.; Zykov, G.A.; Banks, C.; Wang, J.-C.; Poker, D.B.; Hensley, D.K.

    2000-01-01

    We analyze microstructure, linear and nonlinear optical properties of planar waveguides produced by implantation of MeV Ag ions into LiNbO 3 . Linear optical properties are described by the parameters of waveguide propagation modes and optical absorption spectra. Nonlinear properties are described by the nonlinear refractive index. Operation of the implanted crystal as an optical waveguide is due to modification of the linear refractive index of the implanted region. The samples as implanted do not show any light-guiding. The implanted region has amorphous and porous microstructure with the refractive index lower than the substrate. Heat treatment of the implanted samples produces planar light-guiding layer near the implanted surface. High-resolution electron microscopy reveals re-crystallization of the host between the surface and the nuclear stopping region in the form of randomly oriented crystalline grains. They make up a light-guiding layer isolated from the bulk crystal by the nuclear stopping layer with low refractive index. Optical absorption of the sample as implanted has a peak at 430 nm. This peak is due to the surface plasmon resonance in nano-clusters of metallic silver. Heat treatment of the samples shifts the absorption peak to 545 nm. This is more likely due to the increase of the refractive index back to the value for the crystalline LiNbO 3 . The nonlinear refractive index of the samples at 532 nm (of the order of 10 -10 cm 2 W -1 ) was measured with the Z-scan technique using a picosecond laser source. Possible applications of the waveguides include ultra-fast photonic switches and modulators

  1. 29Si(d,3He)28Al reaction at 29 MeV

    International Nuclear Information System (INIS)

    Vernotte, J.; Berrier-Ronsin, G.; Fortier, S.; Hourani, E.; Kalifa, J.; Khendriche, A.; Maison, J.M.; Rosier, L.H.; Rotbard, G.

    1994-01-01

    The 29 Si(d, 3 He) 28 Al reaction has been investigated at 29 MeV incident energy. Observations using a split-pole magnetic spectrograph have been made of 55 levels of 28 Al in the range of excitation energy between 0 and 6.7 MeV. Most of them have been identified with 28 Al levels which have been previously observed by other techniques. The spectroscopic factors have been obtained for 23 of these levels through distorted-wave Born approximation analyses of measured angular distributions. The levels at E x =3.105 and 3.762 MeV have been definitely assigned J π =1 + and 0 + , respectively. Four levels which are populated through the pickup of a l p =1 proton have been observed at E x =4.998, 5.406, 6.021, and 6.652 MeV. The excitation energies and spectroscopic factors for positive-parity states were compared with the results of a recent, complete sd-shell space, shell-model calculation. This comparison led to the identification of 21 shell-model levels with experimental levels. This comparison seems accurate enough to make very likely the J π =3 + assignment for the levels at E x =2.988 and 4.597 MeV which were previously assigned J π =(1,3) +

  2. Surface sputtering in high-dose Fe ion implanted Si

    International Nuclear Information System (INIS)

    Ishimaru, Manabu

    2007-01-01

    Microstructures and elemental distributions in high-dose Fe ion implanted Si were characterized by means of transmission electron microscopy and Rutherford backscattering spectroscopy. Single crystalline Si(0 0 1) substrates were implanted at 350 deg. C with 120 keV Fe ions to fluences ranging from 0.1 x 10 17 to 4.0 x 10 17 /cm 2 . Extensive damage induced by ion implantation was observed inside the substrate below 1.0 x 10 17 /cm 2 , while a continuous iron silicide layer was formed at 4.0 x 10 17 /cm 2 . It was found that the spatial distribution of Fe projectiles drastically changes at the fluence between 1.0 x 10 17 and 4.0 x 10 17 /cm 2 due to surface sputtering during implantation

  3. Implantation of P ions in SiO{sub 2} layers with embedded Si nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Kachurin, G.A. E-mail: kachurin@isp.nsc.ru; Cherkova, S.G.; Volodin, V.A.; Kesler, V.G.; Gutakovsky, A.K.; Cherkov, A.G.; Bublikov, A.V.; Tetelbaum, D.I

    2004-08-01

    The effect of 10{sup 13}-10{sup 16} cm{sup -2} P ions implantation and of subsequent annealing on Si nanocrystals (Si-ncs), formed preliminarily in SiO{sub 2} layers by the ion-beam synthesis, has been studied. Photoluminescence (PL), Raman spectroscopy, high resolution electron microscopy (HREM), X-Ray Photoelectron Spectroscopy (XPS) and optical absorption were used for characterizations. The low fluence implantations have shown even individual displacements in Si-ncs quench their PL. Restoration of PL from partly damaged Si-ncs proceeds at annealing less than 1000 deg. C. In the low fluence implanted and annealed samples an increased Si-ncs PL has been found and ascribed to the radiation-induced shock crystallization of stressed Si nanoprecipitates. Annealing at temperatures under 1000 deg. C are inefficient when P ion fluences exceed 10{sup 14} cm{sup -2}, thus becoming capable to amorphize Si-ncs. High crystallization temperature of the amorphized Si-ncs is attributed to a counteraction of their shell layers. After implantation of the highest P fluences an enhanced recovery of PL was found from P concentration over 0.1 at.%. Raman spectroscopy and HREM showed an increased Si-ncs number in such layers. The effect resembles the impurity-enhanced crystallization, known for heavily doped bulk Si. This effect, along with the data obtained by XPS, is considered as an indication P atoms are really present inside the Si-ncs. However, no evidence of free electrons appearance has been observed. The fact is explained by an increased interaction of electrons with the donor nuclei in Si-ncs.

  4. Implantation of P ions in SiO2 layers with embedded Si nanocrystals

    International Nuclear Information System (INIS)

    Kachurin, G.A.; Cherkova, S.G.; Volodin, V.A.; Kesler, V.G.; Gutakovsky, A.K.; Cherkov, A.G.; Bublikov, A.V.; Tetelbaum, D.I.

    2004-01-01

    The effect of 10 13 -10 16 cm -2 P ions implantation and of subsequent annealing on Si nanocrystals (Si-ncs), formed preliminarily in SiO 2 layers by the ion-beam synthesis, has been studied. Photoluminescence (PL), Raman spectroscopy, high resolution electron microscopy (HREM), X-Ray Photoelectron Spectroscopy (XPS) and optical absorption were used for characterizations. The low fluence implantations have shown even individual displacements in Si-ncs quench their PL. Restoration of PL from partly damaged Si-ncs proceeds at annealing less than 1000 deg. C. In the low fluence implanted and annealed samples an increased Si-ncs PL has been found and ascribed to the radiation-induced shock crystallization of stressed Si nanoprecipitates. Annealing at temperatures under 1000 deg. C are inefficient when P ion fluences exceed 10 14 cm -2 , thus becoming capable to amorphize Si-ncs. High crystallization temperature of the amorphized Si-ncs is attributed to a counteraction of their shell layers. After implantation of the highest P fluences an enhanced recovery of PL was found from P concentration over 0.1 at.%. Raman spectroscopy and HREM showed an increased Si-ncs number in such layers. The effect resembles the impurity-enhanced crystallization, known for heavily doped bulk Si. This effect, along with the data obtained by XPS, is considered as an indication P atoms are really present inside the Si-ncs. However, no evidence of free electrons appearance has been observed. The fact is explained by an increased interaction of electrons with the donor nuclei in Si-ncs

  5. A comparative study of 30MeV boron4+ and 60MeV oxygen8+ ion irradiated Si NPN BJTs

    International Nuclear Information System (INIS)

    Kumar, M. Vinay; Krishnaveni, S.; Yashoda, T.; Dinesh, C. M.; Krishnakumar, K. S.; Jayashree, B.; Ramani

    2015-01-01

    The impact of 30MeV boron 4+ and 60MeV oxygen 8+ ion irradiation on electrical characteristics of 2N3773 Si NPN Bipolar junction transistors (BJTs) is reported in the present study. The transistors were decapped and irradiated at room temperature. Gummel characteristics, DC current gain and Capacitance-voltage (C-V) characteristics were studied before and after irradiation at different fluences. DC current gain has decreased significantly in both boron and oxygen ion irradiation. Also the value of capacitance decreased 3-4 times with increase in fluence. Both 30MeV boron ion and 60MeV oxygen ion induced similar extent of degradation in electrical characteristics of the transistor

  6. Implantation activation annealing of Si-implanted gallium nitride at temperatures > 1,100 C

    International Nuclear Information System (INIS)

    Zolper, J.C.; Han, J.; Biefeld, R.M.

    1997-01-01

    The activation annealing of Si-implanted GaN is reported for temperatures from 1,100 to 1,400 C. Although previous work has shown that Si-implanted GaN can be activated by a rapid thermal annealing at ∼1,100 C, it was also shown that significant damage remained in the crystal. Therefore, both AlN-encapsulated and uncapped Si-implanted GaN samples were annealed in a metal organic chemical vapor deposition system in a N 2 /NH 3 ambient to further assess the annealing process. Electrical Hall characterization shows increases in carrier density and mobility for annealing up to 1,300 C before degrading at 1,400 C due to decomposition of the GaN epilayer. Rutherford backscattering spectra show that the high annealing temperatures reduce the implantation induced damage profile but do not completely restore the as-grown crystallinity

  7. Channeling effect for low energy ion implantation in Si

    International Nuclear Information System (INIS)

    Cho, K.; Allen, W.R.; Finstad, T.G.; Chu, W.K.; Liu, J.; Wortman, J.J.

    1985-01-01

    Ion implantation is one of the most important processes in semiconductor device fabrication. Due to the crystalline nature of Si, channeling of implanted ions occurs during this process. Modern devices become smaller and shallower and therefore require ion implantation at lower energies. The effect of channeling on ion implantation becomes a significant problem for low energy ion implantation. The critical angle for axial and planar channeling increases with decreasing energy. This corresponds to an increased probability for channeling with lowering of ion energy. The industry approach to avoid the channeling problem is to employ a tilt angle of 7 0 between the ion implantation direction and the surface normal. We approach the problem by mapping major crystalline axes and planes near the [100] surface normal. Our analysis indicates that a 7 0 tilt is not an optimum selection in channeling reduction. Tilt angles in the range 5 0 to 6 0 combined with 7 0 +- 0.5 0 rotation from the (100) plane are better selections for the reduction of the channeling effect. The range of suitable angles is a function of the implantation energy. Implantations of boron along well specified crystallographic directions have been carried out by careful alignment and the resulting boron profiles measured by SIMS. (orig.)

  8. Microscopic analysis of alpha scattering from sup 28 Si at 40 and 45 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Roy, S.; Dey, T.; Goswami, A. (Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Calcutta 700064 (India)); Chintalapudi, S.N.; Banerjee, S.R. (Variable Energy Cyclotron Centre, 1/AF, Bidhannagar, Calcutta 700064 (India))

    1992-06-01

    Angular distributions for the elastic and inelastic alpha scattering from {sup 28}Si at {ital E}{sub {alpha}}=40 and 45 MeV are analyzed in the framework of microscopic folding model. Transition densities are calculated from improved {ital s}-{ital d} shell-model wave functions and are also compared with those extracted from inelastic electron scattering data. The density-dependent Jeukenne-Lejeune-Mahaux interaction is used, besides the M3Y interaction, in an attempt to fit the large-angle data. Fairly good agreement with the data is obtained. The extracted {ital M}{sub {ital n}}/{ital M}{sub {ital p}} value for the 2{sup +} excited state of {sup 28}Si also compares well with the shell-model prediction.

  9. Microscopic analysis of alpha scattering from 28Si at 40 and 45 MeV

    International Nuclear Information System (INIS)

    Roy, S.; Dey, T.; Goswami, A.; Chintalapudi, S.N.; Banerjee, S.R.

    1992-01-01

    Angular distributions for the elastic and inelastic alpha scattering from 28 Si at E α =40 and 45 MeV are analyzed in the framework of microscopic folding model. Transition densities are calculated from improved s-d shell-model wave functions and are also compared with those extracted from inelastic electron scattering data. The density-dependent Jeukenne-Lejeune-Mahaux interaction is used, besides the M3Y interaction, in an attempt to fit the large-angle data. Fairly good agreement with the data is obtained. The extracted M n /M p value for the 2 + excited state of 28 Si also compares well with the shell-model prediction

  10. Interface strength of SiC/SiC composites with and without helium implantation using micro-indentation test

    International Nuclear Information System (INIS)

    Saito, M.; Ohtsuka, S.

    1998-01-01

    Helium implantation effects on interface strength of SiC/SiC composite were studied using the micro-indentation fiber push-out method. Helium implantation was carried out with an accelerator at about 400 K. Total amount of implanted helium was approximately 10000 appm. Increase of the fiber push-in load was observed in as-implanted specimen. After post-implantation-annealing at 1673 K for 1 h, the change of the fiber push-in load by helium implantation was not observed. Effects of helium implantation on the interface are discussed. (orig.)

  11. 75 MeV boron ion irradiation studies on Si PIN photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakara Rao, Y.P.; Praveen, K.C. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570006 (India); Rejeena Rani, Y. [Integrated Circuits Division, Bharat Electronics Limited, Bangalore 560013, Karnataka (India); Tripathi, Ambuj [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Gnana Prakash, A.P., E-mail: gnanap@hotmail.com [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570006 (India)

    2013-12-01

    The highly sensitive silicon PIN photodiodes were fabricated to use in radiation environments. The Si PIN photodiodes are coated with 150 nm silicon dioxide (SiO{sub 2}) as anti-reflective (AR) coating. The presence of AR coating on the performance of irradiated PIN photodiodes is studied up to a total dose of 10 Mrad. The effects of 75 MeV boron (B{sup 5+}) ions and {sup 60}Co gamma radiation on the I–V, C–V and spectral responses of PIN photodiodes were studied systematically to understand the radiation tolerance of the devices. The 75 MeV B{sup 5+} irradiation results are compared with {sup 60}Co gamma irradiated results in the same dose range for 1 mm × 1 mm and 10 mm × 10 mm active area PIN photodiodes. The irradiation results show that the ion irradiated PIN photodiodes show more degradation when compared {sup 60}Co gamma irradiated devices. The irradiation results are presented in this paper and the possible mechanism behind the degradation of photodiodes is also discussed in the paper.

  12. Effects of high-energy (MeV) ion implantation of polyester films

    International Nuclear Information System (INIS)

    Ueno, Keiji; Matsumoto, Yasuyo; Nishimiya, Nobuyuki; Noshiro, Mitsuru; Satou, Mamoru

    1991-01-01

    The effects of high-energy ion beam irradiation on polyester (PET) films using a 3 MeV tandem-type ion beam accelerator were studied. O, Ni, Pt, and Au as ion species were irradiated at 10 14 -10 15 ions/cm 2 on 50 μm thick PET films. Physical properties and molecular structure changes were studied by the surface resistivity measurements and RBS. The surface resistivity decreases with an increase in irradiation dose. At 10 15 ions/cm 2 irradiation, the surface resistivity is 10 8 Ω/□. According to RBS and XPS analyses, some carbon and oxygen atoms in the PET are replaced by implanted ions and the -C=O bonds are destroyed easily by the ion beam. (orig.)

  13. Restoration of an electrical breakdown Terahertz emitter by 2 MeV He+ ion implantation

    International Nuclear Information System (INIS)

    Yang kang; Ma Mingwang; Chen Xiliang; Zhu Zhiyong

    2009-01-01

    The irradiation of solids by energetic particles may cause extensive displacement cascades and point defects (vacancies and interstitials), and can be widely used for material modification. In order to repair an electrical breakdown photoconductive antenna (PCA), we irradiated the (100)-oriented, low-temperature (LT) grown GaAs substrate with 10 16 /cm 2 of 2 MeV helium ions. After being implanted, electric resistance of the PCA has increased from 800 Ω to 60 ΜΩ. The irradiated PCA exhibits improvements in the output power in comparison with the electrical breakdown PCA and its signal intensity has increased from 2 nA to 8 nA. Accordingly, its output power has become more than one order of magnitude higher than that before irradiation. The frequency range of PCA has obviously improvement. (authors)

  14. Study of ({alpha}, {sup 3}He) and ({alpha}, t) reactions on {sup 28}Si at 45 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Darshan, V.P.; Sathyavathiamma, M.P.; Ramaswamy, C.R.; Raja Rao, M.; Puttaswamy, N.G.; Banerjee, S.R.; Chintalapudi, S.N. [Dept. of Phys., Bangalore Univ. (India)

    1995-03-01

    The {sup 28}Si({alpha}, {sup 3}He){sup 29}Si, {sup 28}Si({alpha}, t){sup 29}P and Si({alpha}, {alpha})Si reactions were studied at E{sub {alpha}} = 45 MeV. Exact finite-range (EFR) DWBA analysis was carried out for the transitions to the ground state and to five excited states in {sup 29}Si and {sup 29}P. Spectroscopic strengths G were extracted for all the states and were compared with the predictions from shell-model and quasi-particle core-coupling calculations. Similar EFR-DWBA analyses were carried out from available (unpublished) data for the {sup 28}Si({alpha}, {sup 3}He){sup 29}Si reaction at E{sub {alpha}} = 64.9 and 120 MeV, and for the {sup 28}Si({alpha}, t){sup 29}P reaction at E{sub {alpha}} = 50 and 64.9 MeV. The comparison of experimental and theoretical values of G are provided. (author)

  15. Operation of low-energy ion implanters for Si, N, C ion implantation into silicon and glassy carbon

    International Nuclear Information System (INIS)

    Carder, D.A.; Markwitz, A.

    2009-01-01

    This report details the operation of the low-energy ion implanters at GNS Science for C, N and Si implantations. Two implanters are presented, from a description of the components through to instructions for operation. Historically the implanters have been identified with the labels 'industrial' and 'experimental'. However, the machines only differ significantly in the species of ions available for implantation and sample temperature during implantation. Both machines have been custom designed for research purposes, with a wide range of ion species available for ion implantation and the ability to implant two ions into the same sample at the same time from two different ion sources. A fast sample transfer capability and homogenous scanning profiles are featured in both cases. Samples up to 13 mm 2 can be implanted, with the ability to implant at temperatures down to liquid nitrogen temperatures. The implanters have been used to implant 28 Si + , 14 N + and 12 C + into silicon and glassy carbon substrates. Rutherford backscattering spectroscopy has been used to analyse the implanted material. From the data a Si 30 C 61 N 9 layer was measured extending from the surface to a depth of about 77 ± 2 nm for (100) silicon implanted with 12 C + and 14 N + at multiple energies. Silicon and nitrogen ion implantation into glassy carbon produced a Si (40.5 %), C (38 %), N (19.5 %) and O (2%) layer centred around a depth of 50 ± 2 nm from the surface. (author). 8 refs., 20 figs

  16. Behavior of PET implanted by Ti, Ag, Si and C ion using MEVVA implantation

    International Nuclear Information System (INIS)

    Wu Yuguang; Zhang Tonghe; Zhang Yanwen; Zhang Huixing; Zhang Xiaoji; Zhou Gu

    2001-01-01

    Polyethylene terephthalane (PET) has been modified with Ti, Ag, Si and C ions from a metal vapor arc source (MEVVA). Ti, Ag, Si and C ions were implanted with acceleration voltage 40 kV to fluences ranging from 1x10 16 to 2x10 17 cm -2 . The surface of implanted PET darkened with increasing ion dose, when the metal ion dose was greater than 1x10 17 cm -2 the color changed to metallic bright. The surface resistance decreases by 5-6 orders of magnitude with increasing dose. The resistivity is stable after long-term storage. The depth of Ti- and Ag-implanted layer is approximately 150 and 80 nm measured by Rutherford backscattering (RBS), respectively. TEM photos revealed the presence of Ti and Ag nano-meter particles on the surface resulting from the high-dose implantation. Ti and Ag ion implantations improved conductivity and wear resistance significantly. The phase and structural changes were obtained by X-ray diffraction (XRD). It can be seen that nano-meter particles of Ti precipitation, TiO 2 and Ti-carbides have been formed in implanted layer. Nano-hardness of implanted PET has been measured by a nano-indenter. The results show that the surface hardness, modulus and wear resistance could be increased

  17. Effects of MeV Si ions bombardment on the thermoelectric generator from SiO{sub 2}/SiO{sub 2} + Cu and SiO{sub 2}/SiO{sub 2} + Au nanolayered multilayer films

    Energy Technology Data Exchange (ETDEWEB)

    Budak, S., E-mail: satilmis.budak@aamu.edu [Department of Electrical Engineering, Alabama A and M University, Normal, AL (United States); Chacha, J., E-mail: chacha_john79@hotmail.com [Department of Electrical Engineering, Alabama A and M University, Normal, AL (United States); Smith, C., E-mail: cydale@cim.aamu.edu [Center for Irradiation of Materials, Alabama A and M University, Normal, AL (United States); Department of Physics, Alabama A and M University, Normal, AL (United States); Pugh, M., E-mail: marcuspughp@yahoo.com [Department of Electrical Engineering, Alabama A and M University, Normal, AL (United States); Colon, T. [Department of Mechanical Engineering, Alabama A and M University, Normal, AL (United States); Heidary, K., E-mail: kaveh.heidary@aamu.edu [Department of Electrical Engineering, Alabama A and M University, Normal, AL (United States); Johnson, R.B., E-mail: barry@w4wb.com [Department of Physics, Alabama A and M University, Normal, AL (United States); Ila, D., E-mail: ila@cim.aamu.edu [Center for Irradiation of Materials, Alabama A and M University, Normal, AL (United States); Department of Physics, Alabama A and M University, Normal, AL (United States)

    2011-12-15

    The defects and disorder in the thin films caused by MeV ions bombardment and the grain boundaries of these nanoscale clusters increase phonon scattering and increase the chance of an inelastic interaction and phonon annihilation. We prepared the thermoelectric generator devices from 100 alternating layers of SiO{sub 2}/SiO{sub 2} + Cu multi-nano layered superlattice films at the total thickness of 382 nm and 50 alternating layers of SiO{sub 2}/SiO{sub 2} + Au multi-nano layered superlattice films at the total thickness of 147 nm using the physical vapor deposition (PVD). Rutherford Backscattering Spectrometry (RBS) and RUMP simulation have been used to determine the stoichiometry of the elements of SiO{sub 2}, Cu and Au in the multilayer films and the thickness of the grown multi-layer films. The 5 MeV Si ions bombardments have been performed using the AAMU-Center for Irradiation of Materials (CIM) Pelletron ion beam accelerator to make quantum (nano) dots and/or quantum (quantum) clusters in the multilayered superlattice thin films to decrease the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and cross plane electrical conductivity. To characterize the thermoelectric generator devices before and after Si ion bombardments we have measured Seebeck coefficient, cross-plane electrical conductivity, and thermal conductivity in the cross-plane geometry for different fluences.

  18. Amorphization threshold in Si-implanted strained SiGe alloy layers

    International Nuclear Information System (INIS)

    Simpson, T.W.; Love, D.; Endisch, E.; Goldberg, R.D.; Mitchell, I.V.; Haynes, T.E.; Baribeau, J.M.

    1994-12-01

    The authors have examined the damage produced by Si-ion implantation into strained Si 1-x Ge x epilayers. Damage accumulation in the implanted layers was monitored in situ by time-resolved reflectivity and measured by ion channeling techniques to determine the amorphization threshold in strained Si 1-x Ge x (x = 0.16 and 0.29) over the temperature range 30--110 C. The results are compared with previously reported measurements on unstrained Si 1-x Ge x , and with the simple model used to describe those results. They report here data which lend support to this model and which indicate that pre-existing strain does not enhance damage accumulation in the alloy layer

  19. Correlation between the structure modification and conductivity of 3 MeV Si ion-irradiated polyimide

    International Nuclear Information System (INIS)

    Sun Youmei; Zhu Zhiyong; Li Changlin

    2002-01-01

    The surface modification of the polyimide (PI/Kapton) films was carried out by 3 MeV Si + implantation to fluences ranging from 1x10 12 to 1.25x10 15 ions/cm 2 . Fourier transform infrared (FTIR), Raman and ultraviolet/visible (UV/Vis) spectroscopes were employed to investigate the chemical degradation of function groups in the irradiated layer. FTIR results show that the absorbance of typical function group decreases exponentially as a function of fluence. The damage cross-section of typical bonds of PI was evaluated from the FTIR spectra. Raman analysis shows the absorbed dose for destruction of all function groups is above 218 MGy. The red shifting of the absorption edge from UV to visible reveals the band gap closing which results from increase of the cluster size. The production efficiency of the chromophores was discussed according to UV/Vis analysis. Irradiation dramatically enhances the electrical conductivity and the sheet resistivity in our experiment descends nearly 10 orders of magnitude compared with its intrinsic value

  20. Relaxation of mechanical stresses in Si-Ge/Si structures implanted by carbon ions. Study with optical methods

    International Nuclear Information System (INIS)

    Klyuj, M.Yi.

    1998-01-01

    Optical properties of Si-Ge/Si structures implanted by carbon ions with the energy of 20 keV and at the doses of 5 centre dot 10 15 - 1- 16 cm -2 are studied by spectro ellipsometry and Raman scattering techniques. From the comparison of experimental data with the results of theoretical calculations, it is shown that, as a result of implantation, a partial relaxation of mechanical stresses in the Si 1-x Ge x film due to introduction of carbon atoms with a small covalent radius into the Si-Ge lattice takes place. An elevated implantation temperature allows one to maintain a high structural perfection of the implanted film

  1. The eight modes observation in LiNbO3 induced by 3.0 MeV He+ implantation

    International Nuclear Information System (INIS)

    Wang Keming; Shi Borong; Zhou Zhuang; Wang Wei; Ding Peijun; Wang Zhonglie.

    1994-01-01

    The y-cut LiNbO 3 was implanted by 3.0 MeV He + to a dose of 2 x10 16 ions/cm 2 at liquid nitrogen temperature. The eight black and bright modes from He implanted LiNbO 3 waveguide were observed before and after rapid annealing. The refractive index profile is obtained by means of a non-stationary mode index calculation. The comparison of refractive index profile with damage profile is given. The result shows that the peak position of the refractive index profile is found to be in good agreement with the peak position of damage profile induced by 3.0 MeV He + implanted in LiNbO 3 based on transport of ions in matter (TRIM'92).(author)

  2. Effect of pre-implanted oxygen in Si on the retention of implanted He

    Energy Technology Data Exchange (ETDEWEB)

    Manuaba, A. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary); Paszti, F. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary)]. E-mail: paszti@rmki.kfki.hu; Ramos, A.R. [ITN - Instituto Tecnologico e Nuclear, Estrada Nacional 10, P-2686-953, Sacavem (Portugal); Khanh, N.Q. [MTA Research Institute for Technical Physics and Materials Science, P.O. Box 49, H-1525 Budapest (Hungary); Pecz, B. [MTA Research Institute for Technical Physics and Materials Science, P.O. Box 49, H-1525 Budapest (Hungary); Zolnai, Z. [MTA Research Institute for Technical Physics and Materials Science, P.O. Box 49, H-1525 Budapest (Hungary); Tunyogi, A. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary); Szilagyi, E. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary)

    2006-08-15

    Buried SiO {sub x} layers, with different x values, were formed by implanting 80 keV O{sup +} ions with different fluences into single crystal Si samples at room temperature. Into each of these O pre-implanted layers, 20 keV He{sup +} was implanted up to the fluence of 1 x 10{sup 17} ion/cm{sup 2}. The He distribution profiles were determined by 2045 keV proton backscattering spectrometry. It was found that as the O content increases, the retained He gradually decreases at the beginning, then rapidly falls at x = 0.6 till it disappears at x = 1.3. The process that leads to this phenomenon is discussed.

  3. Low temperature intermediate band metallic behavior in Ti implanted Si

    Energy Technology Data Exchange (ETDEWEB)

    Olea, Javier, E-mail: oleaariza@fis.ucm.es; Pastor, David; Garcia-Hemme, Eric; Garcia-Hernansanz, Rodrigo; Prado, Alvaro del; Martil, Ignacio; Gonzalez-Diaz, German

    2012-08-31

    Si samples implanted with very high Ti doses and subjected to Pulsed-Laser Melting (PLM) have been electrically analyzed in the scope of a two-layer model previously reported based on the Intermediate Band (IB) theory. Conductivity and Hall effect measurements using the van der Pauw technique suggest that the insulator-metal transition takes place for implantation doses in the 10{sup 14}-10{sup 16} cm{sup -2} range. Results of the sample implanted with the 10{sup 16} cm{sup -2} dose show a metallic behavior at low temperature that is explained by the formation of a p-type IB out of the Ti deep levels. This suggests that the IB would be semi-filled, which is essential for IB photovoltaic devices. - Highlights: Black-Right-Pointing-Pointer We fabricated high dose Ti implanted Si samples for intermediate band research. Black-Right-Pointing-Pointer We measured the electronic transport properties in the 7-300 K range. Black-Right-Pointing-Pointer We show an insulator to metallic transition when the intermediate band is formed. Black-Right-Pointing-Pointer The intermediate band is semi-filled and populated by holes. Black-Right-Pointing-Pointer We satisfactorily explain the electrical behavior by an intermediate band model.

  4. Polarized triton scattering from 26Mg, 27Al and 28Si at 17 MeV

    International Nuclear Information System (INIS)

    Hardekopf, R.A.; Brown, R.E.; Correll, F.D.; Ohlsen, G.G.

    1980-01-01

    Differential-cross-section and analyzing-power angular distributions were measured for 17 MeV tritons elastically scattered from targets of 26 Mg, 27 Al, and 28 Si in the angular range 20 to 160 0 . The experiment was performed at the Los Alamos Scientific Laboratory Van de Graaff facility using the Lamb-shift polarized triton source and the supercube scattering chamber. A pair of detector telescopes with angular resolutions of +-0.4 0 detected the reaction products, with mass identification and storage performed by an on-line computer. The triton beam intensity available at the target was about 70 nA with a polarization of 0.77. The target thicknesses were about 3 mg/cm 2 , although thinner targets were used for the 27 Al forward-angle data

  5. Structure Characterization of Modified Polyimide Films Irradiated by 2 MeV Si Ions

    International Nuclear Information System (INIS)

    Tian-Xiang, Chen; Shu-De, Yao; Kun, Wang; Huan, Wang; Zhi-Bo, Ding; Di, Chen

    2009-01-01

    Structures of polyimide (6051) films modified by irradiation of 2.0 MeV Si ions with different fluences are studied in detail. Variations of the functional groups in polyimide are investigated by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and Raman spectroscopy. The results indicate that the functional groups can be destroyed gradually with the increasing ion fluence. The variations of structure and element contents are characterized by x-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS) and x-ray photoelectron spectroscopy (XPS). The results indicate that the contents of N and O decrease significantly compared with the original samples, some graphite-like and carbon-rich phases are formed in the process of irradiation

  6. Semimicroscopic analysis of 6Li+28Si elastic scattering at 76 to 318 MeV

    Science.gov (United States)

    Hassanain, M. A.; Anwar, M.; Behairy, Kassem O.

    2018-04-01

    Using the α-cluster structure of colliding nuclei, the elastic scattering of 6Li+28Si at energies from 76 to 318 MeV has been investigated by the use of the real folding cluster approach. The results of the cluster analysis are compared with those obtained by the CDM3Y6 effective density- and energy-dependent nucleon-nucleon (NN) interaction based upon G -matrix elements of the M3Y-Paris potential. A Woods-Saxon (WS) form was used for the imaginary potential. For all energies and derived potentials, the diffraction region was well reproduced, except at Elab=135 and 154 MeV at large angle. These results suggest that the addition of the surface (DWS) imaginary potential term to the volume imaginary potential is essential for a correct description of the refractive structure of the 6Li elastic scattering distribution at these energies. The energy dependence of the total reaction cross sections and that of the real and imaginary volume integrals is also discussed.

  7. Enhanced photoelectrochemical properties of 100 MeV Si8+ ion irradiated barium titanate thin films

    International Nuclear Information System (INIS)

    Solanki, Anjana; Choudhary, Surbhi; Satsangi, Vibha R.; Shrivastav, Rohit; Dass, Sahab

    2013-01-01

    Highlights: ► Effect of 100 MeV Si 8+ ion irradiation on photoelectrochemical (PEC) properties of BaTiO 3 thin films was studied. ► Films were deposited on Indium doped Tin Oxide (ITO) coated glass by sol–gel spin coating technique. ► Optimal irradiation fluence for best PEC response was 5 × 10 11 ion cm −2 . ► Maximum photocurrent density was observed to be 0.7 mA cm −2 at 0.4 V/SCE. ► Enhanced photo-conversion efficiency was due to maximum negative flatband potential, donor density and lowest resistivity. -- Abstract: Effects of high electronic energy deposition on the structure, surface topography, optical property and photoelectrochemical behavior of barium titanate (BaTiO 3 ) thin films were investigated by irradiating films with 100 MeV Si 8+ ions at different ion fluences in the range of 1 × 10 11 –2 × 10 13 ions cm −2 . BaTiO 3 thin films were deposited on indium tin oxide coated glass substrate by sol gel spin coating method. Irradiation induced modifications in the films were analyzed using the results from XRD, SEM, cross sectional SEM, AFM and UV–Vis spectrometry. Maximum photocurrent density of 0.7 mA cm −2 at 0.4 V/SCE and applied bias hydrogen conversion efficiency (ABPE) of 0.73% was observed for BaTiO 3 film irradiated at 5 × 10 11 ions cm −2 , which can be attributed to maximum negative value of the flatband potential and donor density and lowest resistivity

  8. Synthesis and characterization of ion-implanted Pt nanocrystals in SiO2

    International Nuclear Information System (INIS)

    Giulian, R.; Kluth, P.; Johannessen, B.; Araujo, L.L.; Llewellyn, D.J.; Cookson, D.J.; Ridgway, M.C.

    2007-01-01

    Pt nanocrystals (NCs) produced by ion implantation in SiO 2 films were investigated by Rutherford backscattering spectroscopy (RBS), transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). The implantations were performed at liquid nitrogen temperature using energies between 3.4 and 5.6 MeV and an ion fluence range of 2-30 x 10 16 cm -2 and were followed by annealing in forming gas (95% N 2 , 5% H 2 ) for one hour at temperatures between 500 and 1100 deg. C. TEM analysis revealed that the NCs are spherical in shape. The mean size of the NCs annealed at 1100 deg. C varied between 2.8 and 3.6 nm for the highest and lowest fluences, respectively, as determined with both TEM and SAXS. In contrast to previous studies on ion implanted metal NCs, larger Pt NCs are located far beyond the Pt peak concentration, potentially the result of a strongly defect mediated NC nucleation

  9. Effects of He implantation on radiation induced segregation in Cu-Au and Ni-Si alloys

    Science.gov (United States)

    Iwase, A.; Rehn, L. E.; Baldo, P. M.; Funk, L.

    Effects of He implantation on radiation induced segregation (RIS) in Cu-Au and Ni-Si alloys were investigated using in situ Rutherford backscattering spectrometry during simultaneous irradiation with 1.5-MeV He and low-energy (100 or 400-keV) He ions at elevated temperatures. RIS during single He ion irradiation, and the effects of pre-implantation with low-energy He ions, were also studied. RIS near the specimen surface, which was pronounced during 1.5-MeV He single-ion irradiation, was strongly reduced under low-energy He single-ion irradiation, and during simultaneous irradiation with 1.5-MeV He and low-energy He ions. A similar RIS reduction was also observed in the specimens pre-implanted with low-energy He ions. The experimental results indicate that the accumulated He atoms cause the formation of small bubbles, which provide additional recombination sites for freely migrating defects.

  10. Ion implantation enhanced metal-Si-metal photodetectors

    Science.gov (United States)

    Sharma, A. K.; Scott, K. A. M.; Brueck, S. R. J.; Zolper, J. C.; Myers, D. R.

    1994-05-01

    The quantum efficiency and frequency response of simple Ni-Si-Ni metal-semiconductor-metal (MSM) photodetectors at long wavelengths are significantly enhanced with a simple, ion-implantation step to create a highly absorbing region approx. 1 micron below the Si surface. The internal quantum efficiency is improved by a factor of approx. 3 at 860 nm (to 64%) and a full factor of ten at 1.06 microns (to 23%) as compared with otherwise identical unimplanted devices. Dark currents are only slightly affected by the implantation process and are as low as 630 pA for a 4.5-micron gap device at 10-V bias. Dramatic improvement in the impulse response is observed, 100 ps vs. 600 ps, also at 10-V bias and 4.5-micron gap, due to the elimination of carrier diffusion tails in the implanted devices. Due to its planar structure, this device is fully VLSI compatible. Potential applications include optical interconnections for local area networks and multi-chip modules.

  11. Effect of Si implantation on the microstructure of silicon nanocrystals and surrounding SiO2 layer

    International Nuclear Information System (INIS)

    Ross, G.G.; Smirani, R.; Levitcharsky, V.; Wang, Y.Q.; Veilleux, G.; Saint-Jacques, R.G.

    2005-01-01

    Si nanocrystals (Si-nc) embedded in a SiO 2 layer have been characterized by means of transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). For local Si concentration in excess 8 x 10 21 Si + /cm 3 , the size of the Si-nc was found to be ∼3 nm and comparatively homogeneous throughout the whole implanted layer. For local Si concentration in excess of ∼2.4 x 10 22 Si + /cm 3 , the Si-nc diameter ranges from ∼2 to ∼12 nm in the sample, the Si-nc in the middle region of the implanted layer being bigger than those near the surface and the bottom of the layer. Also, Si-nc are visible deeper than the implanted depth. Characterization by XPS shows that a large quantity of oxygen was depleted from the first ∼25 nm in this sample (also visible on TEM image) and most of the SiO 2 bonds have been replaced by Si-O bonds. Experimental and simulation results suggest that a local Si concentration in excess of ∼3 x 10 21 Si/cm 3 is required for the production of Si-nc

  12. Nanocrystalline diamond in carbon implanted SiO{sub 2}.

    Energy Technology Data Exchange (ETDEWEB)

    Tsoi, K.A.; Prawer, S.; Nugent, K.W.; Walker, R. J.; Weiser, P.S. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    Recently, it was reported that nanocrystalline diamond can be produced via laser annealing of a high dose C implanted fused quartz (SiO{sub 2}) substrate. The aim of this investigation is to reproduce this result on higher C{sup +} dose samples and the non-implanted silicon sample, as well as optimise the power range and annealing time for the production of these nanocrystals of diamond. In order to provide a wide range of laser powers the samples were annealed using an Ar ion Raman laser. The resulting annealed spots were analysed using scanning electron microscopy (SEM) and Raman analysis. These techniques are employed to determine the type of bonding produced after laser annealing has occurred. 4 refs., 5 figs.

  13. Nanocrystalline diamond in carbon implanted SiO{sub 2}.

    Energy Technology Data Exchange (ETDEWEB)

    Tsoi, K A; Prawer, S; Nugent, K W; Walker, R J; Weiser, P S [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1997-12-31

    Recently, it was reported that nanocrystalline diamond can be produced via laser annealing of a high dose C implanted fused quartz (SiO{sub 2}) substrate. The aim of this investigation is to reproduce this result on higher C{sup +} dose samples and the non-implanted silicon sample, as well as optimise the power range and annealing time for the production of these nanocrystals of diamond. In order to provide a wide range of laser powers the samples were annealed using an Ar ion Raman laser. The resulting annealed spots were analysed using scanning electron microscopy (SEM) and Raman analysis. These techniques are employed to determine the type of bonding produced after laser annealing has occurred. 4 refs., 5 figs.

  14. Fluence dependence of disorder depth profiles in Pb implanted Si

    International Nuclear Information System (INIS)

    Christodoulides, C.E.; Kadhim, N.J.; Carter, G.

    1980-01-01

    The total, depth integrated disorder, induced by Pb implantation into Si at room temperature, initially increases rapidly with implantation fluence and then reaches a quasi saturation level where the increase with fluence is slow. Measurements of the depth distributions of the disorder, using high resolution low angle exit Rutherford Backscattering/Channelling analysis, suggest that the quasi saturation results from overlapping of disordered zones generated deep in the tail of the disorder-depth profiles. The depth of the disordered solid-crystal boundary, xsub(D), increases with ion fluence PHI, according to the relation xsub(D) = x bar + f(PHI).σ, where x bar is the most probable projected depth and σ the projected standard deviation of disorder generation. It is shown that this relationship is consistent with an approximately Gaussian depth distribution of disorder production. (author)

  15. Activation characteristics of ion-implanted Si+ in AlGaN

    International Nuclear Information System (INIS)

    Irokawa, Y.; Fujishima, O.; Kachi, T.; Pearton, S.J.; Ren, F.

    2005-01-01

    Multiple-energy Si + implantation in the range 30-360 keV into Al 0.13 Ga 0.87 N for n-type doping was carried out at room temperature, followed by annealing at 1150-1375 deg. C for 5 min. Activation efficiencies close to 100% were obtained for ion doses of 1.0x10 15 cm -2 after annealing at 1375 deg. C, with a resulting sheet resistance of 74 Ω/square. By sharp contrast, the activation efficiency at 1150 deg. C was only 4% for this dose, with a sheet resistance of 1.63x10 4 Ω/square. The activation efficiency was also a function of dose, with a maximum activation percentage of only 55% for lower doses of 1.0x10 14 cm -2 annealed at 1375 deg. C. This is due to the comparatively larger effect of compensating acceptors at the lower dose and is also lower than the corresponding activation of Si in pure GaN under these conditions (78%). The measurement temperature dependence of sheet carrier density showed an activation energy of 23 meV, consistent with the ionization energy of Si in AlGaN

  16. Evaluation of neutron and proton nuclear data of {sup 28}Si for energies up to 200 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Weili [Kyushu Univ., Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka (Japan); Watanabe, Y. [Kyushu Univ., Department of Advanced Energy Engineering Science, Fukuoka (Japan); Sukhovitskii, E. Sh. [Radiation Physics and Chemistry Problems Institute, Minsk-Sosny (Belarus); Iwamoto, O.; Chiba, S. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-03-01

    The neutron and proton nuclear data of {sup 28}Si up to 200 MeV are evaluated for various nuclear engineering applications. The soft rotator model and the coupled-channel method are used to perform a consistent analysis of the collective band structure of {sup 28}Si and nucleon scattering from {sup 28}Si. The GNASH nuclear model code is used for compound and preequilibrium particle emission calculations, where the emission of {sup 3}He is also included. Comparisons show overall good agreement with various experimental data. (author)

  17. Evaluation of neutron and proton nuclear data of 28Si for energies up to 200 MeV

    International Nuclear Information System (INIS)

    Sun, Weili; Watanabe, Y.; Sukhovitskii, E. Sh.; Iwamoto, O.; Chiba, S.

    2001-01-01

    The neutron and proton nuclear data of 28 Si up to 200 MeV are evaluated for various nuclear engineering applications. The soft rotator model and the coupled-channel method are used to perform a consistent analysis of the collective band structure of 28 Si and nucleon scattering from 28 Si. The GNASH nuclear model code is used for compound and preequilibrium particle emission calculations, where the emission of 3 He is also included. Comparisons show overall good agreement with various experimental data. (author)

  18. Studies of phase formation in CoSi2 buried layers fabricated using ion implantation

    International Nuclear Information System (INIS)

    Galaev, A.A.; Parkhomenko, Yu.N.; Podgornyi, D.A.; Shcherbachev, K.D.

    1998-01-01

    The processes of the formation of cobalt disilicide buried layers in silicon are studied under different conditions of implantation with Co. In particular, the effects of the implantation dose and the postimplantation annealing temperature on the state of the Co-implanted layer are considered. Two types of heteroepitaxial Si/CoSi 2 /Si structures are obtained with the conducting layers of thicknesses 70 and 90 nm buried at the depths 80 and 10 nm, respectively

  19. Simulation studies of the n{sup +}n{sup -} Si sensors having p-spray/p-stop implant for the SiD experiment

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, Pooja; Ranjan, Kirti [Centre for Detector and Related Software Technology, Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Bhardwaj, Ashutosh, E-mail: abhardwaj@physics.du.ac.in [Centre for Detector and Related Software Technology, Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Shivpuri, R.K.; Bhattacharya, Satyaki [Centre for Detector and Related Software Technology, Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

    2011-12-01

    Silicon Detector (SiD) is one of the proposed detectors for the future International Linear Collider (ILC). In the innermost vertex of the ILC, Si micro-strip sensors will be exposed to the neutron background of around 1-1.6 Multiplication-Sign 10{sup 10} 1 MeV equivalent neutrons cm{sup -2} year{sup -1}. The p{sup +}n{sup -}n{sup +} double-sided Si strip sensors are supposed to be used as position sensitive sensors for SiD. The shortening due to electron accumulation on the n{sup +}n{sup -} side of these sensors leads to uniform spreading of signal over all the n{sup +} strips and thus ensuring good isolation between the n{sup +} strips becomes one of the major issues in these sensors. One of the possible solutions is the use of floating p-type implants introduced between the n{sup +} strips (p-stops) and another alternative is the use of uniform layer of p-type implant on the entire n-side (p-spray). However, pre-breakdown micro-discharge is reported because of the high electric field at the edge of the p-stop/p-spray. An optimization of the implant dose profile of the p-stop and p-spray is required to achieve good electrical isolation while ensuring satisfactory breakdown performance of the Si sensors. Preliminary results of the simulation study performed on the n{sup +}n{sup -} Si sensors having p-stop and p-spray using device simulation program, ATLAS, are presented.

  20. Scaling of ion implanted Si:P single electron devices

    International Nuclear Information System (INIS)

    Escott, C C; Hudson, F E; Chan, V C; Petersson, K D; Clark, R G; Dzurak, A S

    2007-01-01

    We present a modelling study on the scaling prospects for phosphorus in silicon (Si:P) single electron devices using readily available commercial and free-to-use software. The devices comprise phosphorus ion implanted, metallically doped (n + ) dots (size range 50-500 nm) with source and drain reservoirs. Modelling results are compared to measurements on fabricated devices and discussed in the context of scaling down to few-electron structures. Given current fabrication constraints, we find that devices with 70-75 donors per dot should be realizable. We comment on methods for further reducing this number

  1. Thermal stability of intermediate band behavior in Ti implanted Si

    Energy Technology Data Exchange (ETDEWEB)

    Olea, J.; Pastor, D.; Martil, I.; Gonzalez-Diaz, G. [Dpto. De Fisica Aplicada III (Electricidad y Electronica), Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain)

    2010-11-15

    Ti implantation in Si with very high doses has been performed. Subsequent Pulsed Laser Melting (PLM) annealing produces good crystalline lattice with electrical transport properties that are well explained by the Intermediate Band (IB) theory. Thermal stability of this new material is analyzed by means of isochronal annealing in thermodynamic equilibrium conditions at increasing temperature. A progressive deactivation of the IB behavior is shown during thermal annealing, and structural and electrical measurements are reported in order to find out the origin of this result. (author)

  2. Scaling of ion implanted Si:P single electron devices

    Energy Technology Data Exchange (ETDEWEB)

    Escott, C C [Centre for Quantum Computer Technology, School of Electrical Engineering and Telecommunications, UNSW, Sydney, NSW 2052 (Australia); Hudson, F E [Centre for Quantum Computer Technology, School of Electrical Engineering and Telecommunications, UNSW, Sydney, NSW 2052 (Australia); Chan, V C [Centre for Quantum Computer Technology, School of Electrical Engineering and Telecommunications, UNSW, Sydney, NSW 2052 (Australia); Petersson, K D [Centre for Quantum Computer Technology, School of Electrical Engineering and Telecommunications, UNSW, Sydney, NSW 2052 (Australia); Clark, R G [Centre for Quantum Computer Technology, School of Physics, UNSW, Sydney, 2052 (Australia); Dzurak, A S [Centre for Quantum Computer Technology, School of Electrical Engineering and Telecommunications, UNSW, Sydney, NSW 2052 (Australia)

    2007-06-13

    We present a modelling study on the scaling prospects for phosphorus in silicon (Si:P) single electron devices using readily available commercial and free-to-use software. The devices comprise phosphorus ion implanted, metallically doped (n{sup +}) dots (size range 50-500 nm) with source and drain reservoirs. Modelling results are compared to measurements on fabricated devices and discussed in the context of scaling down to few-electron structures. Given current fabrication constraints, we find that devices with 70-75 donors per dot should be realizable. We comment on methods for further reducing this number.

  3. Implantation damage in heavy gas implanted 4H-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, C. [Institut Pprime, CNRS, Université de Poitiers, ENSMA, UPR 3346, Département Physique et Mécanique des Matériaux, Bd Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex (France); Nicolaï, J., E-mail: julien.nicolai@univ-poitiers.fr [Institut Pprime, CNRS, Université de Poitiers, ENSMA, UPR 3346, Département Physique et Mécanique des Matériaux, Bd Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex (France); Declémy, A. [Institut Pprime, CNRS, Université de Poitiers, ENSMA, UPR 3346, Département Physique et Mécanique des Matériaux, Bd Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex (France); Gilabert, E. [Centre d’Etude Nucléaire de Bordeaux-Gradignan, 33175 Gradignan Cedex (France); Beaufort, M.-F.; Barbot, J.-F. [Institut Pprime, CNRS, Université de Poitiers, ENSMA, UPR 3346, Département Physique et Mécanique des Matériaux, Bd Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex (France)

    2016-05-01

    Single crystals of SiC were implanted with heavy inert gases (Xe, Ar) at elevated temperatures (300–800 °C) and for a large range of fluence (1 × 10{sup 12}–1 × 10{sup 15} ions cm{sup −2}). Thermodesorption measurements suggest that gas is trapped by implantation-induced vacancy-type defects impeding any gas diffusion. The damage accumulation versus dose was studied through the tensile elastic strain determined by using X-ray diffraction. Results show that at low dose the strain is predictable via a thermally activated direct impact model. The low thermal activation energy at saturation suggests a dynamic recovery process dominated by the migration of interstitial-type defects as its relaxation during post thermal annealing. As compared with light-gas implantation the heavy-gas to defect ratio is low enhancing the formation of strongly perturbed zones rather than the formation of bubble precursors.

  4. Metallization of ion beam synthesized Si/3C-SiC/Si layer systems by high-dose implantation of transition metal ions

    International Nuclear Information System (INIS)

    Lindner, J.K.N.; Wenzel, S.; Stritzker, B.

    2001-01-01

    The formation of metal silicide layers contacting an ion beam synthesized buried 3C-SiC layer in silicon by means of high-dose titanium and molybdenum implantations is reported. Two different strategies to form such contact layers are explored. The titanium implantation aims to convert the Si top layer of an epitaxial Si/SiC/Si layer sequence into TiSi 2 , while Mo implantations were performed directly into the SiC layer after selectively etching off all capping layers. Textured and high-temperature stable C54-TiSi 2 layers with small additions of more metal-rich silicides are obtained in the case of the Ti implantations. Mo implantations result in the formation of the high-temperature phase β-MoSi 2 , which also grows textured on the substrate. The formation of cavities in the silicon substrate at the lower SiC/Si interface due to the Si consumption by the growing silicide phase is observed in both cases. It probably constitutes a problem, occurring whenever thin SiC films on silicon have to be contacted by silicide forming metals independent of the deposition technique used. It is shown that this problem can be solved with ion beam synthesized contact layers by proper adjustment of the metal ion dose

  5. Boron lattice location in room temperature ion implanted Si crystal

    International Nuclear Information System (INIS)

    Piro, A.M.; Romano, L.; Mirabella, S.; Grimaldi, M.G.

    2005-01-01

    The B lattice location in presence of a Si-self-interstitial (I Si ) supersaturation, controlled by energetic proton bombardment, has been studied by means of ion channelling and massive Monte Carlo simulations. B-doped layers of Si crystals with a B concentration of 1 x 10 2 B/cm 3 were grown by Molecular Beam Epitaxy. Point defect engineering techniques, with light energetic ion implants, have been applied to generate an I Si uniform injection in the electrically active layer. The displacement of B atoms out of substitutional lattice sites was induced by 650 keV proton irradiations at room temperature (R.T.) and the resultant defect configuration was investigated by ion channelling and Nuclear Reaction Analysis (NRA) techniques. Angular scans were measured both through and axes along the (1 0 0) plane using the 11 B(p,α) 8 Be nuclear reaction at 650 keV proton energy. Monte Carlo simulated angular scans were calculated considering a variety of theoretical defect configurations, supported by literature, and compared with experimental data. Our experimental scans can be fitted by a linear combination of small (0.3 A) and large B displacements (1.25 A) along the direction, compatible with the B-dumbbell oriented along as proposed by ab initio calculations

  6. Effects of Mev Si Ions and Thermal Annealing on Thermoelectric and Optical Properties of SiO2/SiO2+Ge Multi-nanolayer thin Films

    Science.gov (United States)

    Budak, S.; Alim, M. A.; Bhattacharjee, S.; Muntele, C.

    Thermoelectric generator devices have been prepared from 200 alternating layers of SiO2/SiO2+Ge superlattice films using DC/RF magnetron sputtering. The 5 MeV Si ionsbombardmenthasbeen performed using the AAMU Pelletron ion beam accelerator to formquantum dots and / or quantum clusters in the multi-layer superlattice thin films to decrease the cross-plane thermal conductivity, increase the cross-plane Seebeck coefficient and increase the cross-plane electrical conductivity to increase the figure of merit, ZT. The fabricated devices have been annealed at the different temperatures to tailor the thermoelectric and optical properties of the superlattice thin film systems. While the temperature increased, the Seebeck coefficient continued to increase and reached the maximum value of -25 μV/K at the fluenceof 5x1013 ions/cm2. The decrease in resistivity has been seen between the fluence of 1x1013 ions/cm2 and 5x1013 ions/cm2. Transport properties like Hall coefficient, density and mobility did not change at all fluences. Impedance spectroscopy has been used to characterize the multi-junction thermoelectric devices. The loci obtained in the C*-plane for these data indicate non-Debye type relaxation displaying the presence of the depression parameter.

  7. Implantation temperature and thermal annealing behavior in H{sub 2}{sup +}-implanted 6H-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Li, B.S., E-mail: b.s.li@impcas.ac.cn; Wang, Z.G.; Jin, J.F.

    2013-12-01

    The effects of hydrogen implantation temperature and annealing temperature in 6H-SiC are studied by the combination of Rutherford backscattering in channeling geometry (RBS/C), high-resolution X-ray diffraction (HRXRD) and scanning electron microscopy (SEM). 6H-SiC wafers were implanted with 100 keV H{sub 2}{sup +} ions to a fluence of 2.5 × 10{sup 16} H{sub 2}{sup +} cm{sup −2} at room temperature (RT), 573 K and 773 K. Post-implantation, the samples were annealing under argon gas flow at different temperatures from 973 K to 1373 K for isochronal annealing (15 min). The relative Si disorder at the damage peak for the sample implanted at RT decreases gradually with increasing annealing temperature. However, the reverse annealing effect is found for the samples implanted at 573 K and 773 K. As-implantation, the intensity of in-plane compressive stress is the maximum as the sample was implanted at RT, and is the minimum as the sample was implanted at 573 K. The intensity of in-plane compressive stress for the sample implanted at RT decreases gradually with increasing annealing temperature, while the intensities of in-plane compressive stress for the sample implanted at 573 K and 773 K show oscillatory changes with increasing annealing temperature. After annealing at 1373 K, blisters and craters occur on the sample surface and their average sizes increase with increasing implantation temperature.

  8. Alpha-heavy-ion angular correlations from /sup 28/Si + /sup 12/C. [84 to 91. 5 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Ost, R; Cole, A J [Institut des Sciences Nucleaires, 38 - Grenoble (France); Clover, M R; Fulton, B R; Sikora, B [Rochester Univ., NY (USA). Nuclear Structure Research Lab.

    1980-06-01

    Alpha particles have been measured in coincidence with heavy recoil nuclei from the /sup 28/Si + /sup 12/C reaction. At Esub(lab) = 87 MeV angular correlations for alphas between 15/sup 0/ and 55/sup 0/ and heavy ions at angles -9/sup 0/, -12/sup 0/ and -15/sup 0/ have been taken. An excitation function of coincidence events with THETAsub(..cap alpha..) = 30/sup 0/ and THETAsub(HI) = -12/sup 0/ has been measured for 84 MeV < Esub(lab) < 91.5 MeV. The results are well described by a statistical-model calculation for compound nucleus decay. No evidence is found for additional processes.

  9. RBS-study of GexSi1-x Compounds Formed by Variable Dose Ge Implantation into Si Wafers

    Directory of Open Access Journals (Sweden)

    Ramírez A.

    2002-01-01

    Full Text Available Amorphous and relaxed epitaxial GeSi films are prepared by Ge-implantation into Si(111 wafers of both 60 keV and 200 keV energetic Ge+-ions with appropriate dose, followed by post-implantation thermal annealing, comprising a single final annealing at a temperature of 900 °C. The implantation dose was varied between 10(14 and 10(17 atoms cm-2. Rutherford backscattering (RBS and channeling analysis was applied in order to explore the formation of a single crystalline Si-Ge compound layer, both prior and after the thermal treatment. The depth and the thickness of the implanted layer, as well as their molar composition and crystalline quality was determined, and it was found that a single crystalline Si-Ge alloy layer was created, with both depth and mole fraction depending on the ion energy and the ion dose.

  10. Study of elastic pion scattering from 9Be, 28Si, 58Ni, and 208Pb at 162 MeV

    International Nuclear Information System (INIS)

    Devereux, M.J.

    1979-05-01

    Elastic pion scattering from 9 Be, 28 Si, 58 Ni, and 208 Pb at 162 MeV is analyzed and compared with an optical model theory which incorporates a pion--nucleon range. Excellent fits to the data are obtained in all but one case. The fitted values of the pion--nucleon range, as well as other fitted values are listed. 108 references

  11. Variation of carrier concentration and interface trap density in 8MeV electron irradiated c-Si solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, Sathyanarayana, E-mail: asharao76@gmail.com; Rao, Asha, E-mail: asharao76@gmail.com [Department of Physics, Mangalore Institute of Technology and Engineering, Moodabidri, Mangalore-574225 (India); Krishnan, Sheeja [Department of Physics, Sri Devi Institute of Technology, Kenjar, Mangalore-574142 (India); Sanjeev, Ganesh [Microtron Centre, Department of Physics, Mangalore University, Mangalagangothri-574199 (India); Suresh, E. P. [Solar Panel Division, ISRO Satellite Centre, Bangalore-560017 (India)

    2014-04-24

    The capacitance and conductance measurements were carried out for c-Si solar cells, irradiated with 8 MeV electrons with doses ranging from 5kGy – 100kGy in order to investigate the anomalous degradation of the cells in the radiation harsh environments. Capacitance – Voltage measurements indicate that there is a slight reduction in the carrier concentration upon electron irradiation due to the creation of radiation induced defects. The conductance measurement results reveal that the interface state densities and the trap time constant increases with electron dose due to displacement damages in c-Si solar cells.

  12. Monte Carlo simulation of channeled and random profiles of heavy ions implanted in silicon at high energy (1.2 MeV)

    International Nuclear Information System (INIS)

    Mazzone, A.M.

    1987-01-01

    In order to study channeling effects and implants of heavy ions with energy of few MeV in silicon, ion distributions are calculated with a Monte Carlo method for axial [(001) axis], planar, and nominally random directions for As + and P + ions implanted into silicon with energies in the range 100 keV to 2 MeV. The calculation indicates an appreciable channeling at the higher energy only for the (001) axis and the (110) planes. For heavy ions with energy in the MeV range the subsidence of channeling into major channels and the disappearance of minor channels are shown

  13. Formation of radiative centers in SiO2 by tin high-dose implantation

    International Nuclear Information System (INIS)

    Komarov, F.F.; Parkhomenko, I.N.; Vlasukova, L.A.; Mil'chanin, O.V.; Mokhovikov, M.A.; Wendler, E.; Wesch, W.

    2013-01-01

    The structural transformations in SiO 2 layers implanted with high fluence of Sn ions have been investigated. It has been found that post-implantation annealing results in the β-Sn precipitation as well as the formation of SnO 2 -enriched regions in SiO 2 :Sn matrix. The intensive emission in the range of photon energies 1.5 – 3.5 eV is registered for the implanted and annealed samples. We attribute it to the oxygen deficiency centers created in the SiO 2 :Sn matrix and at the 'nanocluster/SiO 2 ' interfaces. (authors)

  14. Comparison of thermally and mechanically induced Si layer transfer in hydrogen-implanted Si wafers

    International Nuclear Information System (INIS)

    Hoechbauer, T.; Misra, A.; Nastasi, M.; Henttinen, K.; Suni, T.; Suni, I.; Lau, S.S.; Ensinger, W.

    2004-01-01

    Hydrogen ion-implantation into Si and subsequent heat treatment has been shown to be an effective means of cleaving thin layer of Si from its parent wafer. This process has been called Smart Cut TM or ion-cut. We investigated the cleavage process in H-implanted silicon samples, in which the ion-cut was provoked thermally and mechanically, respectively. A oriented p-type silicon wafer was irradiated at room temperature with 100 keV H 2 + -ions to a dose of 5 x 10 16 H 2 /cm 2 and subsequently joined to a handle wafer. Ion-cutting was achieved by two different methods: (1) thermally by annealing to 350 deg. C and (2) mechanically by insertion of a razor blade sidewise into the bonded wafers near the bond interface. The H-concentration and the crystal damage depth profiles before and after the ion-cut were investigated through the combined use of elastic recoil detection analysis and Rutherford backscattering spectroscopy (RBS). The location at which the ion-cut occurred was determined by RBS in channeling mode and cross-section transmission electron spectroscopy. The ion-cut depth was found to be independent on the cutting method. The gained knowledge was correlated to the depth distribution of the H-platelet density in the as-implanted sample, which contains two separate peaks in the implantation zone. The obtained results suggest that the ion-cut location coincides with the depth of the H-platelet density peak located at a larger depth

  15. Synergistic effects of iodine and silver ions co-implanted in 6H-SiC

    Science.gov (United States)

    Kuhudzai, R. J.; Malherbe, J. B.; Hlatshwayo, T. T.; van der Berg, N. G.; Devaraj, A.; Zhu, Z.; Nandasiri, M.

    2015-12-01

    Motivated by the aim of understanding the release of fission products through the SiC coating of fuel kernels in modern high temperature nuclear reactors, a fundamental investigation is conducted to understand the synergistic effects of implanted silver (Ag) and iodine (I) in 6H-SiC. The implantation of the individual species, as well as the co-implantation of 360 keV ions of I and Ag at room temperature in 6H-SiC and their subsequent annealing behaviour has been investigated by Secondary Ion Mass Spectrometry (SIMS), Atom Probe Tomography (APT) and X-ray Photoelectron Spectroscopy (XPS). SIMS and APT measurements indicated the presence of Ag in the co-implanted samples after annealing at 1500 °C for 30 h in sharp contrast to the samples implanted with Ag only. In samples implanted with Ag only, complete loss of the implanted Ag was observed. However, for I only implanted samples, some iodine was retained. APT of annealed co-implanted 6H-SiC showed clear spatial association of Ag and I clusters in SiC, which can be attributed to the observed I assisted retention of Ag after annealing. Such detailed studies will be necessary to identify the fundamental mechanism of fission products migration through SiC coatings.

  16. A HRXRD and nano-indentation study on Ne-implanted 6H–SiC

    International Nuclear Information System (INIS)

    Xu, C.L.; Zhang, C.H.; Li, J.J.; Zhang, L.Q.; Yang, Y.T.; Song, Y.; Jia, X.J.; Li, J.Y.; Chen, K.Q.

    2012-01-01

    Specimens of 6H–SiC single crystal were irradiated at room temperature with 2.3 MeV neon ions to three successively increasing fluences of 2 × 10 14 , 1.1 × 10 15 and 3.8 × 10 15 ions/cm 2 and then annealed at room temperature, 500, 700 and 1000 °C, respectively. The strain in the specimens was investigated with a high resolution XRD spectrometer with an ω-2θ scanning. And the mechanical properties were investigated with the nano-indentation in the continuous stiffness measurement (CSM) mode with a diamond Berkovich indenter. The XRD curves of specimens after irradiation show the diffraction peaks arising at lower angles aside of the main Bragg peak Θ Bragg , indicating that a positive strain is produced in the implanted layer. In the as-implanted specimens, the strain increases with the increase of the ion fluence or energy deposition. Recovery of the strain occurs on subsequent thermal annealing treatment and two stages of defects evolution process are displayed. An interpretation of defects migration, annihilation and evolution is given to explain the strain variations of the specimens after annealing. The nano-indentation measurements show that the hardness in as-implanted specimens first increases with the increase of the ion fluence, and a degradation of hardness occurs when the ion fluence exceeds a threshold. On the subsequent annealing, the hardness variations are regarded to be a combined effect of the covalent bonding and the pinning effect of defect clusters.

  17. Recrystallization of implanted amorphous silicon layers. I. Electrical properties of silicon implanted with BF+2 or Si++B+

    International Nuclear Information System (INIS)

    Tsai, M.Y.; Streetman, B.G.

    1979-01-01

    Electrical properties of recrystallized amorphous silicon layers, formed by BF + 2 implants or Si + +B + implants, have been studied by differential resistivity and Hall-effect measurements. Electrical carrier distribution profiles show that boron atoms inside the amorphized Si layers can be fully activated during recrystallization at 550 0 C. The mobility is also recovered. However, the tail of the B distribution, located inside a damaged region near the original amorphous-crystalline interface, remains inactive. This inactive tail has been observed for all samples implanted with BF + 2 . Only in a thicker amorphous layer, formed for example by Si + predamage implants, can the entire B profile be activated. The etch rate of amorphous silicon in HF and the effect of fluorine on the recrystallization rate are also reported

  18. Post-annealing recrystallization and damage recovery process in Fe ion implanted Si

    International Nuclear Information System (INIS)

    Naito, Muneyuki; Hirata, Akihiko; Ishimaru, Manabu; Hirotsu, Yoshihiko

    2007-01-01

    We have investigated ion-beam-induced and thermal annealing-induced microstructures in high fluence Fe implanted Si using transmission electron microscopy. Si(1 1 1) substrates were irradiated with 120 keV Fe ions at 120 K to fluences of 0.4 x 10 17 and 4.0 x 10 17 cm -2 . A continuous amorphous layer was formed on Si substrates in both as-implanted samples. After thermal annealing at 1073 K for 2 h, β-FeSi 2 fine particles buried in a polycrystalline Si layer were observed in the low fluence sample, while a continuous β-FeSi 2 layer was formed in the high fluence sample. We discuss the relationship between ion fluence and defects recovery process in Fe ion implanted Si

  19. IBC c-Si solar cells based on ion-implanted poly-silicon passivating contacts

    NARCIS (Netherlands)

    Yang, G.; Ingenito, A.; Isabella, O.; Zeman, M.

    2016-01-01

    Ion-implanted poly-crystalline silicon (poly-Si), in combination with a tunnel oxide layer, is investigated as a carrier-selective passivating contact in c-Si solar cells based on an interdigitated back contact (IBC) architecture. The optimized poly-Si passivating contacts enable low interface

  20. Synergistic effects of iodine and silver ions co-implanted in 6H–SiC

    International Nuclear Information System (INIS)

    Kuhudzai, R.J.; Malherbe, J.B.; Hlatshwayo, T.T.; Berg, N.G. van der; Devaraj, A.; Zhu, Z.; Nandasiri, M.

    2015-01-01

    Motivated by the aim of understanding the release of fission products through the SiC coating of fuel kernels in modern high temperature nuclear reactors, a fundamental investigation is conducted to understand the synergistic effects of implanted silver (Ag) and iodine (I) in 6H–SiC. The implantation of the individual species, as well as the co-implantation of 360 keV ions of I and Ag at room temperature in 6H–SiC and their subsequent annealing behaviour has been investigated by Secondary Ion Mass Spectrometry (SIMS), Atom Probe Tomography (APT) and X-ray Photoelectron Spectroscopy (XPS). SIMS and APT measurements indicated the presence of Ag in the co-implanted samples after annealing at 1500 °C for 30 h in sharp contrast to the samples implanted with Ag only. In samples implanted with Ag only, complete loss of the implanted Ag was observed. However, for I only implanted samples, some iodine was retained. APT of annealed co-implanted 6H–SiC showed clear spatial association of Ag and I clusters in SiC, which can be attributed to the observed I assisted retention of Ag after annealing. Such detailed studies will be necessary to identify the fundamental mechanism of fission products migration through SiC coatings. - Highlights: • Co-implantation of Ag and I ions in 6H–SiC was performed. • Clear spatial association of Ag and I clusters observed after annealing. • Complete loss of Ag after high temperature annealing of silver only sample. • Iodine was retained in iodine only sample after high temperature annealing. • Iodine was found to play a role in the retention of Ag in the co-implanted samples.

  1. Study of thermal treated a-Si implanted with Er and O ions

    CERN Document Server

    Plugaru, R; Piqueras, J; Tate, T J

    2002-01-01

    Visible luminescence of amorphous silicon layers either implanted with Er or co-implanted with Er and O and subsequently annealed in nitrogen has been investigated by cathodoluminescence (CL) in a scanning electron microscope. Co-implanted samples show a more intense luminescence, which is revealed by annealing at lower temperatures than the samples implanted only with erbium. Thermal treatments cause the formation of erbium oxide as well as Er-Si complexes or precipitates. Violet-blue luminescence has been found from CL images and spectra to be related to Er-Si precipitates. Emission in the green-red range is attributed to oxide species.

  2. Semiconductor nanocrystals formed in SiO2 by ion implantation

    International Nuclear Information System (INIS)

    Zhu, J.G.; White, C.W.; Budai, J.D.; Withrow, S.P.; Chen, Y.

    1994-11-01

    Nanocrystals of group IV (Si, Ge and SiGe), III-V (GaAs), and II-VI (CdSe) semiconductor materials have been fabricated inside SiO 2 by ion implantation and subsequent thermal annealing. The microstructure of these nanocrystalline semiconductor materials has been studied by transmission electron microscopy (TEM). The nanocrystals form in near-spherical shape with random crystal orientations in amorphous SiO 2 . Extensive studies on the nanocrystal size distributions have been carried out for the Ge nanocrystals by changing the implantation doses and the annealing temperatures. Remarkable roughening of the nanocrystals occurs when the annealing temperature is raised over the melting temperature of the implanted semiconductor material. Strong red photoluminescence peaked around 1.67 eV has been achieved in samples with Si nanocrystals in SiO 2

  3. TEM investigation of the microstructural evolution in nickel during MeV helium implantation

    International Nuclear Information System (INIS)

    Gadalla, A.A.; Jaeger, W.; Ehrhart, P.

    1986-01-01

    In a recent TEM investigation of high energy He-implanted copper the low average helium density could be understood by the observation of the coexistence of two types of vacancy agglomerates i.e. relaxed vacancy agglomerates in the form of stacking fault tetrahedra (SFT) and small bubbles. In order to arrive at a more systematic understanding of the evolution of the microstructure during high energy helium implantation we extended these TEM investigations to nickel. Of particular interest was also the minimum implantation dose necessary to precipitate bubbles that are large enough to be visible in the TEM. (orig./RK)

  4. Exceptional cracking behavior in H-implanted Si/B-doped Si0.70Ge0.30/Si heterostructures

    Science.gov (United States)

    Chen, Da; Wang, Dadi; Chang, Yongwei; Li, Ya; Ding, Rui; Li, Jiurong; Chen, Xiao; Wang, Gang; Guo, Qinglei

    2018-01-01

    The cracking behavior in H-implanted Si/B-doped Si0.70Ge0.30/Si structures after thermal annealing was investigated. The crack formation position is found to closely correlate with the thickness of the buried Si0.70Ge0.30 layer. For H-implanted Si containing a buried 3-nm-thick B-doped Si0.70Ge0.30 layer, localized continuous cracking occurs at the interfaces on both sides of the Si0.70Ge0.30 interlayer. Once the thickness of the buried Si0.70Ge0.30 layer increases to 15 and 70 nm, however, a continuous sharp crack is individually observed along the interface between the Si substrate and the B-doped Si0.70Ge0.30 interlayer. We attribute this exceptional cracking behavior to the existence of shear stress on both sides of the buried Si0.70Ge0.30 layer and the subsequent trapping of hydrogen, which leads to a crack in a well-controlled manner. This work may pave the way for high-quality Si or SiGe membrane transfer in a feasible manner, thus expediting its potential applications to ultrathin silicon-on-insulator (SOI) or silicon-germanium-on-insulator (SGOI) production.

  5. The reactivity of ion-implanted SiC

    International Nuclear Information System (INIS)

    McHargue, C.J.; Lewis, M.B.; Williams, J.M.; Appleton, B.R.

    1985-01-01

    Implantation of chromium into single crystal or polycrystalline α-SiC produces a surface amorphous layer for displacement damage greater than about 0.2 displacements per atom at room temperature. The enhanced chemical reactivity of such specimens was studied by two methods: chemical etching rate and oxidation rate. The chemical etching rates in a saturated solution of 50% K 3 Fe(CN) 6 plus 50% KOH were measured. The etching rate for the amorphous layer was 2.4-3.7 times that of the polycrystalline samples and 3.0-4.1 times that of the single-crystal samples. Polycrystalline specimens were exposed to flowing oxygen for 1 h at 1300 0 C. Rutherford backscattering and the nuclear reaction 16 O(d,p) 17 O* were used to determine the amount of oxygen on the surface. The amount of oxygen (and the thickness of oxide) over the amorphous region was 1.67 times that over the crystalline region. The relative thicknesses of the oxide on the amorphous and crystalline regions were confirmed by measuring the sputtering time required to remove the oxygen signal in an Auger spectrometer. (Auth.)

  6. Ion implantation into amorphous Si layers to form carrier-selective contacts for Si solar cells

    International Nuclear Information System (INIS)

    Feldmann, Frank; Mueller, Ralph; Reichel, Christian; Hermle, Martin

    2014-01-01

    This paper reports our findings on the boron and phosphorus doping of very thin amorphous silicon layers by low energy ion implantation. These doped layers are implemented into a so-called tunnel oxide passivated contact structure for Si solar cells. They act as carrier-selective contacts and, thereby, lead to a significant reduction of the cell's recombination current. In this paper we address the influence of ion energy and ion dose in conjunction with the obligatory high-temperature anneal needed for the realization of the passivation quality of the carrier-selective contacts. The good results on the phosphorus-doped (implied V oc = 725 mV) and boron-doped passivated contacts (iV oc = 694 mV) open a promising route to a simplified interdigitated back contact (IBC) solar cell featuring passivated contacts. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Formation of SiC using low energy CO2 ion implantation in silicon

    International Nuclear Information System (INIS)

    Sari, A.H.; Ghorbani, S.; Dorranian, D.; Azadfar, P.; Hojabri, A.R.; Ghoranneviss, M.

    2008-01-01

    Carbon dioxide ions with 29 keV energy were implanted into (4 0 0) high-purity p-type silicon wafers at nearly room temperature and doses in the range between 1 x 10 16 and 3 x 10 18 ions/cm 2 . X-ray diffraction analysis (XRD) was used to characterize the formation of SiC in implanted Si substrate. The formation of SiC and its crystalline structure obtained from above mentioned technique. Topographical changes induced on silicon surface, grains and evaluation of them at different doses observed by atomic force microscopy (AFM). Infrared reflectance (IR) and Raman scattering measurements were used to reconfirm the formation of SiC in implanted Si substrate. The electrical properties of implanted samples measured by four point probe technique. The results show that implantation of carbon dioxide ions directly leads to formation of 15R-SiC. By increasing the implantation dose a significant changes were also observed on roughness and sheet resistivity properties.

  8. MOS memory structures by very-low-energy-implanted Si in thin SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Dimitrakis, P.; Kapetanakis, E.; Normand, P.; Skarlatos, D.; Tsoukalas, D.; Beltsios, K.; Claverie, A.; Benassayag, G.; Bonafos, C.; Chassaing, D.; Carrada, M.; Soncini, V

    2003-08-15

    The electrical characteristics of thin silicon dioxide layers with embedded Si nanocrystals obtained by low-energy ion beam implantation and subsequent annealing have been investigated through capacitance and current-voltage measurements of MOS capacitors. The effects of the implantation energy (range: 0.65-2 keV), annealing temperature (950-1050 deg. C) and injection oxide characteristics on charge injection and storage are reported. It is shown that the implantation energy allows for a fine control of the memory window characteristics, and various device options are possible including memory operation with charge injection at low gate voltages.

  9. Properties of ion implanted epitaxial CoSi2/Si(1 0 0) after rapid thermal oxidation

    International Nuclear Information System (INIS)

    Zhao, Q.T.; Kluth, P.; Xu, J.; Kappius, L.; Zastrow, U.; Wang, Z.L.; Mantl, S.

    2000-01-01

    Epitaxial CoSi 2 layers were grown on Si(1 0 0) using molecular beam allotaxy. Boron ion implantations and rapid thermal oxidation (RTO) were performed. During oxidation, SiO 2 formed on the surface of the CoSi 2 layers, and the silicides was pushed into the substrate. The diffusion of boron was slightly retarded during oxidation for the specimen with a 20 nm epitaxial CoSi 2 capping layer as compared to the specimen without CoSi 2 capping layer. The electrical measurements showed that the silicide has good Schottky contacts with the boron doped silicon layer after RTO. A nanometer silicide patterning process, based on local oxidation of silicide (LOCOSI) layer, was also investigated. It shows two back-to-back Schottky diodes between the two separated parts of the silicide

  10. Beam-envelope calculations of space-charge loaded beams in MeV dc ion-implantation facilities

    International Nuclear Information System (INIS)

    Urbanus, W.H.; Bannenberg, J.G.; Doorn, S.; Saris, F.W.; Koudijs, R.; Dubbelman, P.; Koelewijn, W.

    1989-01-01

    MeV dc ion accelerators are being developed that can deliver a beam current up to several hundred micro-amperes. At the low-energy part of the accelerator, the beam transport is space-charge dominated rather than emittance dominated. A system of differential equations has been derived, based on the Kapchinski-Vladimirski equations, which describe the envelope of a space-charge loaded ion beam, taking a longitudinal electrical field in an accelerating tube into account. The equations have been used to design the accelerator of a high-current 1 MV heavy-ion implantation facility. Furthermore, the design of a 2 MV accelerator is presented, which is used for analyzing techniques such as RBS and PIXE. Both facilities are based on single-ended Van de Graaff accelerators. (orig.)

  11. The emittance and brightness characteristics of negative ion sources suitable for MeV ion implantation

    International Nuclear Information System (INIS)

    Alton, G.D.

    1987-01-01

    This paper provides the description and beam properties of ion sources suitable for use with ion implantation devices. Particular emphasis is placed on the emittance and brightness properties of state-of-the-art, high intensity, negative ion sources based on the cesium ion sputter principle

  12. Decrease of Staphylococcal adhesion on surgical stainless steel after Si ion implantation

    International Nuclear Information System (INIS)

    Braceras, Iñigo; Pacha-Olivenza, Miguel A.; Calzado-Martín, Alicia; Multigner, Marta; Vera, Carolina; Broncano, Luis Labajos-; Gallardo-Moreno, Amparo M.; González-Carrasco, José Luis; Vilaboa, Nuria

    2014-01-01

    Highlights: • Si ion implantation of AISI 316LVM medical grade alloy might reduce bacterial adhesion and colonization. • Si ion implantation does not impair the attachment, viability and matrix maturation of human mesenchymal stem cells. • Nano-topography and surface chemistry changes account for the Si ion implantation induced effects. - Abstract: 316LVM austenitic stainless steel is often the material of choice on temporal musculoskeletal implants and surgical tools as it combines good mechanical properties and acceptable corrosion resistance to the physiologic media, being additionally relatively inexpensive. This study has aimed at improving the resistance to bacterial colonization of this surgical stainless steel, without compromising its biocompatibility and resistance. To achieve this aim, the effect of Si ion implantation on 316LVM has been studied. First, the effect of the ion implantation parameters (50 keV; fluence: 2.5–5 × 10 16 ions/cm 2 ; angle of incidence: 45–90°) has been assessed in terms of depth profiling of chemical composition by XPS and nano-topography evaluation by AFM. The in vitro biocompatibility of the alloy has been evaluated with human mesenchymal stem cells. Finally, bacterial adhesion of Staphylococcus epidermidis and Staphylococcus aureus on these surfaces has been assessed. Reduction of bacterial adhesion on Si implanted 316LVM is dependent on the implantation conditions as well as the features of the bacterial strains, offering a promising implantable biomaterial in terms of biocompatibility, mechanical properties and resistance to bacterial colonization. The effects of surface composition and nano-topography on bacterial adhesion, directly related to ion implantation conditions, are also discussed

  13. Decrease of Staphylococcal adhesion on surgical stainless steel after Si ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Braceras, Iñigo, E-mail: inigo.braceras@tecnalia.com [Tecnalia, Mikeletegi Pasealekua 2, 20009 Donostia-San Sebastian (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Pacha-Olivenza, Miguel A. [CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Universidad de Extremadura, Departamento de Física Aplicada, Facultad de Ciencias, Av. Elvas s/n, 06006 Badajoz (Spain); Calzado-Martín, Alicia [Hospital Universitario La Paz-IdiPAZ, Paseo de la Castellana 261, 28046 Madrid (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Multigner, Marta [Centro Nacional de Investigaciones Metalúrgicas, CENIM-CSIC, Avda Gregorio del Amo 8, 28040 Madrid (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Vera, Carolina [Tecnalia, Mikeletegi Pasealekua 2, 20009 Donostia-San Sebastian (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Broncano, Luis Labajos-; Gallardo-Moreno, Amparo M. [Universidad de Extremadura, Departamento de Física Aplicada, Facultad de Ciencias, Av. Elvas s/n, 06006 Badajoz (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); González-Carrasco, José Luis [Centro Nacional de Investigaciones Metalúrgicas, CENIM-CSIC, Avda Gregorio del Amo 8, 28040 Madrid (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Vilaboa, Nuria [Hospital Universitario La Paz-IdiPAZ, Paseo de la Castellana 261, 28046 Madrid (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); and others

    2014-08-15

    Highlights: • Si ion implantation of AISI 316LVM medical grade alloy might reduce bacterial adhesion and colonization. • Si ion implantation does not impair the attachment, viability and matrix maturation of human mesenchymal stem cells. • Nano-topography and surface chemistry changes account for the Si ion implantation induced effects. - Abstract: 316LVM austenitic stainless steel is often the material of choice on temporal musculoskeletal implants and surgical tools as it combines good mechanical properties and acceptable corrosion resistance to the physiologic media, being additionally relatively inexpensive. This study has aimed at improving the resistance to bacterial colonization of this surgical stainless steel, without compromising its biocompatibility and resistance. To achieve this aim, the effect of Si ion implantation on 316LVM has been studied. First, the effect of the ion implantation parameters (50 keV; fluence: 2.5–5 × 10{sup 16} ions/cm{sup 2}; angle of incidence: 45–90°) has been assessed in terms of depth profiling of chemical composition by XPS and nano-topography evaluation by AFM. The in vitro biocompatibility of the alloy has been evaluated with human mesenchymal stem cells. Finally, bacterial adhesion of Staphylococcus epidermidis and Staphylococcus aureus on these surfaces has been assessed. Reduction of bacterial adhesion on Si implanted 316LVM is dependent on the implantation conditions as well as the features of the bacterial strains, offering a promising implantable biomaterial in terms of biocompatibility, mechanical properties and resistance to bacterial colonization. The effects of surface composition and nano-topography on bacterial adhesion, directly related to ion implantation conditions, are also discussed.

  14. Characterization of Si(1 1 1) crystals implanted with Sb{sup +} ions and annealed by rapid thermal processing

    Energy Technology Data Exchange (ETDEWEB)

    Labbani, R.; Halimi, R.; Laoui, T.; Vantomme, A.; Pipeleers, B.; Roebben, G

    2003-09-15

    Monocrystalline Si(1 1 1) targets are implanted (at room temperature) with antimony ions at 120 keV energy to 5x10{sup 14} or 5x10{sup 15} Sb{sup +} cm{sup -2} dose. The samples are heat treated by means of rapid thermal processing (RTP) at 1000 deg. C during 60 s, under nitrogen atmosphere. In this work, we report the measured evolution of the silicon surface damage and the radiation damage recovery in relation to antimony dose and RTP processing. We also study the behavior of antimony dopant into Si(1 1 1) specimens. The investigation is carried out by He{sup +} Rutherford backscattering spectrometry (RBS; operating at 1.57 MeV energy in both random and channeling modes), X-ray diffraction (XRD) and atomic force microscopy (AFM) techniques. It is shown that a good surface damage recovery is obtained for all the annealed samples. However, after RTP, a significant loss of antimony has occurred for the specimens which are implanted with 5x10{sup 15} Sb{sup +} cm{sup -2} dose. This suggests an antimony out-diffusion. Finally, a good morphological characterization of the specimens is provided by AFM.

  15. Elastic scattering of 28Si + 40Ca system at Elab = 225 MeV

    International Nuclear Information System (INIS)

    Ashok Kumar; Srivastava, Amita; Kumar, Sarita; Seth, Madhup; Srivastava, B.B.; Mishra, R.C.

    1996-01-01

    The real part of nucleus-nucleus interaction for 28 Si + 40 Ca system was microscopically calculated in terms of antisymmetrised shell model wave functions using equivalence relation between RGM and GCM

  16. Fusion evaporation-residue cross sections for 28Si+40Ca at E(28Si)=309, 397, and 452 MeV

    International Nuclear Information System (INIS)

    Vineyard, M.F.; Bauer, J.S.; Crum, J.F.; Gosdin, C.H.; Trotter, R.S.; Kovar, D.G.; Beck, C.; Henderson, D.J.; Janssens, R.V.F.; Wilkins, B.D.; Maguire, C.F.; Mateja, J.F.; Prosser, F.W.; Stephans, G.S.F.

    1992-01-01

    Velocity distributions of mass-identified evaporation residues produced in the 28 Si+ 40 Ca reaction have been measured at bombarding energies of 309, 397, and 452 MeV using time-of-flight techniques. These distributions were used to identify evaporation residues and to separate the complete-fusion and incomplete-fusion components. Angular distributions and upper limits for the total evaporation-residue and complete-fusion evaporation-residue cross sections were extracted at all three bombarding energies. The complete-fusion evaporation-residue cross sections and the deduced critical angular momenta are compared with earlier measurements and the predictions of existing models. The ratios of the complete-fusion evaporation-residue cross section to the total evaporation-residue cross section, along with those measured for the 28 Si+ 12 C and 28 Si+ 28 Si systems at the same energies, support the entrance-channel mass-asymmetry dependence of the incomplete-fusion evaporation-residue process reported earlier

  17. Shift in room-temperature photoluminescence of low-fluence Si+-implanted SiO2 films subjected to rapid thermal annealing

    International Nuclear Information System (INIS)

    Fu Mingyue; Tsai, J.-H.; Yang, C.-F.; Liao, C.-H.

    2008-01-01

    We experimentally demonstrate the effect of the rapid thermal annealing (RTA) in nitrogen flow on photoluminescence (PL) of SiO 2 films implanted by different doses of Si + ions. Room-temperature PL from 400-nm-thick SiO 2 films implanted to a dose of 3x10 16 cm -2 shifted from 2.1 to 1.7 eV upon increasing RTA temperature (950-1150 deg. C) and duration (5-20 s). The reported approach of implanting silicon into SiO 2 films followed by RTA may be effective for tuning Si-based photonic devices.

  18. Inhibitive formation of nanocavities by introduction of Si atoms in Ge nanocrystals produced by ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Cai, R. S.; Shang, L.; Liu, X. H.; Zhang, Y. J. [The Cultivation Base for State Key Laboratory, Qingdao University, No. 308 Ningxia Road, Qingdao 266071 (China); Wang, Y. Q., E-mail: yqwang@qdu.edu.cn, E-mail: barba@emt.inrs.ca [The Cultivation Base for State Key Laboratory, Qingdao University, No. 308 Ningxia Road, Qingdao 266071 (China); College of Physics Science, Qingdao University, No. 308 Ningxia Road, Qingdao 266071 (China); Ross, G. G.; Barba, D., E-mail: yqwang@qdu.edu.cn, E-mail: barba@emt.inrs.ca [INRS-Énergie, Matériaux et Télécommunications, 1650 boulevard Lionel-Boulet, Varennes Québec J3X 1S2 (Canada)

    2014-05-28

    Germanium nanocrystals (Ge-nc) were successfully synthesized by co-implantation of Si and Ge ions into a SiO{sub 2} film thermally grown on (100) Si substrate and fused silica (pure SiO{sub 2}), respectively, followed by subsequent annealing at 1150 °C for 1 h. Transmission electron microscopy (TEM) examinations show that nanocavities only exist in the fused silica sample but not in the SiO{sub 2} film on a Si substrate. From the analysis of the high-resolution TEM images and electron energy-loss spectroscopy spectra, it is revealed that the absence of nanocavities in the SiO{sub 2} film/Si substrate is attributed to the presence of Si atoms inside the formed Ge-nc. Because the energy of Si-Ge bonds (301 kJ·mol{sup −1}) are greater than that of Ge-Ge bonds (264 kJ·mol{sup −1}), the introduction of the Si-Ge bonds inside the Ge-nc can inhibit the diffusion of Ge from the Ge-nc during the annealing process. However, for the fused silica sample, no crystalline Si-Ge bonds are detected within the Ge-nc, where strong Ge outdiffusion effects produce a great number of nanocavities. Our results can shed light on the formation mechanism of nanocavities and provide a good way to avoid nanocavities during the process of ion implantation.

  19. Poly-Si gate engineering for advanced CMOS transistors by germanium implantation

    International Nuclear Information System (INIS)

    Bourdon, H.; Juhel, M.; Oudet, B.; Breil, N.; Lenoble, D.

    2005-01-01

    Standard gate materials are compared to Ge implanted poly-Si and deposited poly-SiGe. It is demonstrated in this paper that the electrical resistance of the gate is significantly reduced via the use of poly-SiGe (from 30% to 40% decrease in resistance). Similarly, we show via specific optimization that localized Ge implantation is also suitable to reduce gate resistance. Physical characterizations are performed to determine the 'root' causes at the origin of these improvements. In line with future publications showing strong benefits on CMOS device performance, grain size effects seem to be the main mechanisms explaining the measured improvement

  20. Segregation gettering by implantation-formed cavities and B-Si precipitates in silicon

    International Nuclear Information System (INIS)

    Myers, S.M.; Petersen, G.A.; Follstaedt, D.M.

    1998-01-01

    The authors show that Fe, Co, Cu, and Au in Si undergo strong segregation gettering to cavities and B-Si precipitates formed by He or B ion implantation and annealing. The respective mechanisms are argued to be chemisorption on the cavity walls and occupation of solution sites within the disordered, B-rich, B-Si phase. The strengths of the reactions are evaluated, enabling prediction of gettering performance

  1. Influence of implantation energy on the electrical properties of ultrathin gate oxides grown on nitrogen implanted Si substrates

    International Nuclear Information System (INIS)

    Kapetanakis, E.; Skarlatos, D.; Tsamis, C.; Normand, P.; Tsoukalas, D.

    2003-01-01

    Metal-oxide-semiconductor tunnel diodes with gate oxides, in the range of 2.5-3.5 nm, grown either on 25 or 3 keV nitrogen-implanted Si substrates at (0.3 or 1) x10 15 cm -2 dose, respectively, are investigated. The dependence of N 2 + ion implant energy on the electrical quality of the growing oxide layers is studied through capacitance, equivalent parallel conductance, and gate current measurements. Superior electrical characteristics in terms of interface state trap density, leakage current, and breakdown fields are found for oxides obtained through 3 keV nitrogen implants. These findings together with the full absence of any extended defect in the silicon substrate make the low-energy nitrogen implantation technique an attractive option for reproducible low-cost growth of nanometer-thick gate oxides

  2. Characterization of the implantation damage in SiO2 with x-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Ajioka, T.; Ushio, S.

    1986-01-01

    X-ray photoelectron spectroscopy (XPS) has been applied to characterize the damage introduced into SiO 2 by ion implantation. By measuring the peak width of Si/sub 2p/ from SiO 2 which corresponds to perturbation of the SiO 2 network, good depth profiles of the damage have been obtained for implanted samples and subsequently annealed samples. The results show that the damage distributed more widely than that calculated from energy deposition and that the perturbation of the network is caused not only by radiation damage but also by the existence of impurities in the network. It has been found that the XPS method is effective to understand the atomic structure, and thus, electrical properties of SiO 2

  3. XPS studies of SiO2 surface layers formed by oxygen ion implantation into silicon

    International Nuclear Information System (INIS)

    Schulze, D.; Finster, J.

    1983-01-01

    SiO 2 surface layers of 160 nm thickness formed by 16 O + ion implantation into silicon are examined by X-ray photoelectron spectroscopy measurements into the depth after a step-by-step chemical etching. The chemical nature and the thickness of the transition layer were determined. The results of the XPS measurements show that the outer surface and the bulk of the layers formed by oxygen implantation and subsequent high temperature annealing consist of SiO 2 . There is no evidence for Si or SiO/sub x/ (0 2 and Si is similar to that of thin grown oxide layers. Only its thickness is somewhat larger than in thermal oxide

  4. Controlled fabrication of Si nanocrystal delta-layers in thin SiO{sub 2} layers by plasma immersion ion implantation for nonvolatile memories

    Energy Technology Data Exchange (ETDEWEB)

    Bonafos, C.; Ben-Assayag, G.; Groenen, J.; Carrada, M. [CEMES-CNRS and Université de Toulouse, 29 rue J. Marvig, 31055 Toulouse Cedex 04 (France); Spiegel, Y.; Torregrosa, F. [IBS, Rue G Imbert Prolongée, ZI Peynier-Rousset, 13790 Peynier (France); Normand, P.; Dimitrakis, P.; Kapetanakis, E. [NCSRD, Terma Patriarchou Gregoriou, 15310 Aghia Paraskevi (Greece); Sahu, B. S.; Slaoui, A. [ICube, 23 Rue du Loess, 67037 Strasbourg Cedex 2 (France)

    2013-12-16

    Plasma Immersion Ion Implantation (PIII) is a promising alternative to beam line implantation to produce a single layer of nanocrystals (NCs) in the gate insulator of metal-oxide semiconductor devices. We report herein the fabrication of two-dimensional Si-NCs arrays in thin SiO{sub 2} films using PIII and rapid thermal annealing. The effect of plasma and implantation conditions on the structural properties of the NC layers is examined by transmission electron microscopy. A fine tuning of the NCs characteristics is possible by optimizing the oxide thickness, implantation energy, and dose. Electrical characterization revealed that the PIII-produced-Si NC structures are appealing for nonvolatile memories.

  5. Controlled fabrication of Si nanocrystal delta-layers in thin SiO2 layers by plasma immersion ion implantation for nonvolatile memories

    International Nuclear Information System (INIS)

    Bonafos, C.; Ben-Assayag, G.; Groenen, J.; Carrada, M.; Spiegel, Y.; Torregrosa, F.; Normand, P.; Dimitrakis, P.; Kapetanakis, E.; Sahu, B. S.; Slaoui, A.

    2013-01-01

    Plasma Immersion Ion Implantation (PIII) is a promising alternative to beam line implantation to produce a single layer of nanocrystals (NCs) in the gate insulator of metal-oxide semiconductor devices. We report herein the fabrication of two-dimensional Si-NCs arrays in thin SiO 2 films using PIII and rapid thermal annealing. The effect of plasma and implantation conditions on the structural properties of the NC layers is examined by transmission electron microscopy. A fine tuning of the NCs characteristics is possible by optimizing the oxide thickness, implantation energy, and dose. Electrical characterization revealed that the PIII-produced-Si NC structures are appealing for nonvolatile memories

  6. Ion implantation damage annealing in 4H-SiC monitored by scanning spreading resistance microscopy

    International Nuclear Information System (INIS)

    Suchodolskis, A.; Hallen, A.; Linnarsson, M.K.; Osterman, J.; Karlsson, U.O.

    2006-01-01

    To obtain a better understanding of the damage annealing process and dopant defect incorporation and activation we have implanted epitaxially grown 4H-SiC layers with high doses of Al + ions. Cross-sections of the samples are investigated by scanning spreading resistance microscopy (SSRM) using a commercial atomic force microscopy (AFM). The defects caused by the implanted ions compensate for the doping and decrease the charge carrier mobility. This causes the resistivity to increase in the as-implanted regions. The calculated profile of implanted ions is in good agreement with the measured ones and shows a skewed Gaussian shape. Implanted samples are annealed up to 400 deg. C. Despite these low annealing temperatures we observe a clear improvement of the sample conductivity in the as-implanted region

  7. Amorphous Ge quantum dots embedded in SiO2 formed by low energy ion implantation

    International Nuclear Information System (INIS)

    Zhao, J. P.; Huang, D. X.; Jacobson, A. J.; Chen, Z. Y.; Makarenkov, B.; Chu, W. K.; Bahrim, B.; Rabalais, J. W.

    2008-01-01

    Under ultrahigh vacuum conditions, extremely small Ge nanodots embedded in SiO 2 , i.e., Ge-SiO 2 quantum dot composites, have been formed by ion implantation of 74 Ge + isotope into (0001) Z-cut quartz at a low kinetic energy of 9 keV using varying implantation temperatures. Transmission electron microscopy (TEM) images and micro-Raman scattering show that amorphous Ge nanodots are formed at all temperatures. The formation of amorphous Ge nanodots is different from reported crystalline Ge nanodot formation by high energy ion implantation followed by a necessary high temperature annealing process. At room temperature, a confined spatial distribution of the amorphous Ge nanodots can be obtained. Ge inward diffusion was found to be significantly enhanced by a synergetic effect of high implantation temperature and preferential sputtering of surface oxygen, which induced a much wider and deeper Ge nanodot distribution at elevated implantation temperature. The bimodal size distribution that is often observed in high energy implantation was not observed in the present study. Cross-sectional TEM observation and the depth profile of Ge atoms in SiO 2 obtained from x-ray photoelectron spectra revealed a critical Ge concentration for observable amorphous nanodot formation. The mechanism of formation of amorphous Ge nanodots and the change in spatial distribution with implantation temperature are discussed

  8. Synthesis of SiC microstructures in Si technology by high dose carbon implantation: Etch-stop properties

    International Nuclear Information System (INIS)

    Serre, C.; Perez-Rodriguez, A.; Romano-Rodriguez, A.; Calvo-Barrio, L.; Morante, J.R.; Esteve, J.; Acero, M.C.; Skorupa, W.; Koegler, R.

    1997-01-01

    The use of high dose carbon ion implantation in Si for the production of membranes and microstructures is investigated. Si wafers were implanted with carbon doses of 10 17 and 5 x 10 17 cm -2 , at an energy of 300 keV and a temperature of 500 C. The structural analysis of these samples revealed the formation of a highly stable buried layer of crystalline β-SiC precipitates aligned with the Si matrix. The etch-stop properties of this layer have been investigated using tetramethyl-ammonium hydroxide as etchant solution. Secondary ion mass spectrometry measurements performed on the etched samples have allowed an estimate of the minimum dose needed for obtaining an etch-stop layer to a value in the range 2 to 3 x 10 17 ions/cm 2 . This behavior has been explained assuming the existence of a percolation process in a SiC/Si binary system. Finally, very thin crystalline membranes and self-standing structures with average surface roughness in the range 6 to 7 nm have been obtained

  9. Origin and behavior of main electron traps in Si-implanted GaAs

    International Nuclear Information System (INIS)

    Fang, Z.Q.; Yamamoto, H.; Look, D.C.

    1990-01-01

    The electron traps in Si-implanted active layers (n ∼ 10 17 cm -3 ) have been studied by capacitance and conductance DLTS techniques in conjunction with different anneal conditions, which include rapid thermal anneals at different temperatures and furnace anneals with Si 3 N 4 cap or capless in an AsH 3 atmosphere. As compared to the electron traps in as-grown bulk n-GaAs (n ∼ 4 x 10 16 cm -3 ), nearly the same electron traps, i.e. EL2, EL3, EL4, EL5, EL6, and EL9 can be observed in the Si-implanted layers. Through a comparison with the annealing behavior of the main electron traps in bulk n-GaAs, the processing associated origins of some of the traps (EL2, EL3, EL4, EL5 and EL9) observed in Si-implanted GaAs layers have been determined. For some Si-implanted capped with Si 3 N 4 and furnace annealed, traps EL3 and EL4 dominate the trap EL2. In such layers it is found that emission due to EL3 is reduced while emission from EL12 is augmented by increasing the filling pulse width from 10 μs to 5 x 10 3 μs. In this paper phenomenon is explained in terms of a defect reaction enhanced by electron capture, showing a metastability or bistability

  10. Effects of recoil-implanted oxygen on depth profiles of defects and annealing processes in P{sup +}-implanted Si studied using monoenergetic positron beams

    Energy Technology Data Exchange (ETDEWEB)

    Uedono, Akira; Moriya, Tsuyoshi; Tanigawa, Shoichiro [Tsukuba Univ., Ibaraki (Japan). Inst. of Materials Science; Kitano, Tomohisa; Watanabe, Masahito; Kawano, Takao; Suzuki, Ryoichi; Ohdaira, Toshiyuki; Mikado, Tomohisa

    1996-04-01

    Effects of oxygen atoms recoiled from SiO{sub 2} films on depth profiles of defects and annealing processes in P{sup +}-implanted Si were studied using monoenergetic positron beams. For an epitaxial Si specimen, the depth profile of defects was found to be shifted toward the surface by recoil implantation of oxygen atoms. This was attributed to the formation of vacancy-oxygen complexes and a resultant decrease in the diffusion length of vacancy-type defects. The recoiled oxygen atoms stabilized amorphous regions introduced by P{sup +}-implantation, and the annealing of these regions was observed after rapid thermal annealing (RTA) at 700degC. For a Czochralski-grown Si specimen fabricated by through-oxide implantation, the recoiled oxygen atoms introduced interstitial-type defects upon RTA below the SiO{sub 2}/Si interface, and such defects were dissociated by annealing at 1000degC. (author)

  11. Lattice site of helium implanted in Si and diamond

    International Nuclear Information System (INIS)

    Allen, W.R.

    1993-01-01

    Single crystals of silicon and diamond were implanted at 300K with 70 keV 3 He. Ion channeling analyses were executed by application of Rutherford backscattering spectrometry and nuclear reaction analysis. Helium exhibits a non-random lattice site in the channeling angular distributions for silicon and diamond. A major fraction of the implanted He was qualitatively identified to be near to the tetrahedral interstice in both materials

  12. Damage accumulation in nitrogen implanted 6H-SiC: Dependence on the direction of ion incidence and on the ion fluence

    International Nuclear Information System (INIS)

    Zolnai, Z.; Ster, A.; Khanh, N. Q.; Battistig, G.; Lohner, T.; Gyulai, J.; Kotai, E.; Posselt, M.

    2007-01-01

    The influence of crystallographic orientation and ion fluence on the shape of damage distributions induced by 500 keV N + implantation at room temperature into 6H-SiC is investigated. The irradiation was performed at different tilt angles between 0 degree sign and 4 degree sign with respect to the crystallographic axis in order to consider the whole range of beam alignment from channeling to random conditions. The applied implantation fluence range was 2.5x10 14 -3x10 15 cm -2 . A special analytical method, 3.55 MeV 4 He + ion backscattering analysis in combination with channeling technique (BS/C), was employed to measure the disorder accumulation simultaneously in the Si and C sublattices of SiC with good depth resolution. For correct energy to depth conversion in the BS/C spectra, the average electronic energy loss per analyzing He ion for the axial channeling direction was determined. It was found that the tilt angle of nitrogen implantation has strong influence on the shape of the induced disorder profiles. Significantly lower disorder was found for channeling than for random irradiation. Computer simulation of the measured BS/C spectra showed the presence of a simple defect structure in weakly damaged samples and suggested the formation of a complex disorder state for higher disorder levels. Full-cascade atomistic computer simulation of the ion implantation process was performed to explain the differences in disorder accumulation on the Si and C sublattices. The damage buildup mechanism was interpreted with the direct-impact, defect-stimulated amorphization model in order to understand damage formation and to describe the composition of structural disorder versus the ion fluence and the implantation tilt angle

  13. Formation of slab waveguides in eulytine type BGO and CaF{sub 2} crystals by implantation of MeV nitrogen ions

    Energy Technology Data Exchange (ETDEWEB)

    Banyasz, I., E-mail: bakonyjako@yahoo.es [Department of Crystal Physics, Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Berneschi, S. [Centro Studi e Ricerche ' Enrico Fermi' , Piazza del Viminale 2, 00184 Roma (Italy); MDF-Lab, ' ' Nello Carrara' ' Institute of Applied Physics, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Khanh, N.Q.; Lohner, T. [Research Institute for Technical Physics and Materials Science of the Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Lengyel, K. [Department of Crystal Physics, Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Fried, M. [Research Institute for Technical Physics and Materials Science of the Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Peter, A. [Department of Crystal Physics, Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Petrik, P.; Zolnai, Z. [Research Institute for Technical Physics and Materials Science of the Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Watterich, A. [Department of Crystal Physics, Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Nunzi-Conti, G.; Pelli, S.; Righini, G.C. [MDF-Lab, ' ' Nello Carrara' ' Institute of Applied Physics, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy)

    2012-09-01

    Ion implantation, compared with other waveguide fabrication methods, has some unique advantages. It has proved to be a universal technique for producing waveguides in most optical materials. The authors of the present article reported fabrication of channel and slab waveguides in an Erbium-doped tungsten tellurite glass by implantation of MeV energy N{sup +} ions. The present article reports successful adaptation of the same technique to the fabrication of slab waveguides in eulytine type bismuth germanate (BGO) and CaF{sub 2} crystals. This is the first report on successful waveguide fabrication in these materials using 3.5 MeV N{sup +} ions at implanted fluences between 5 Multiplication-Sign 10{sup 15} and 4 Multiplication-Sign 10{sup 16} ions/cm{sup 2}. Spectroscopic ellipsometric measurements revealed the existence of guiding structures in both materials. M-line spectroscopic measurements indicated guiding effect in the as-implanted BGO up to 1550 nm and up to 980 nm in the as-implanted CaF{sub 2}. Ion implantation induced the appearance of three peaks in the UV/Vis absorption spectrum of CaF{sub 2}, that can be attributed to colour centres.

  14. Submicron confinement effect on electrical activation of B implanted in Si

    International Nuclear Information System (INIS)

    Bruno, E.; Mirabella, S.; Impellizzeri, G.; Priolo, F.; Giannazzo, F.; Raineri, V.; Napolitani, E.

    2005-01-01

    In this work we studied the effect of B implantation in Si through submicron laterally confined area on B clustering and its electrical activation. For this study, we implanted B 3 keV into a Si wafer grown by Molecular Beam Epitaxy (MBE) through a patterned oxide mask with opening widths down to 0.38 μm. Then, we annealed the sample at 800 deg. C for several times up to 120 min and monitored the 2D carrier profile by quantitative high resolution Scanning Capacitance Microscopy (SCM). We show that by reducing the opening widths, not only the B clustering is strongly reduced, but also the B cluster dissolution is accelerated. This demonstrates the beneficial role of implanted B confinement on the B electrical activation. The above results have a significant impact in the modern Si based electronic device engineering

  15. AlN metal-semiconductor field-effect transistors using Si-ion implantation

    Science.gov (United States)

    Okumura, Hironori; Suihkonen, Sami; Lemettinen, Jori; Uedono, Akira; Zhang, Yuhao; Piedra, Daniel; Palacios, Tomás

    2018-04-01

    We report on the electrical characterization of Si-ion implanted AlN layers and the first demonstration of metal-semiconductor field-effect transistors (MESFETs) with an ion-implanted AlN channel. The ion-implanted AlN layers with Si dose of 5 × 1014 cm-2 exhibit n-type characteristics after thermal annealing at 1230 °C. The ion-implanted AlN MESFETs provide good drain current saturation and stable pinch-off operation even at 250 °C. The off-state breakdown voltage is 2370 V for drain-to-gate spacing of 25 µm. These results show the great potential of AlN-channel transistors for high-temperature and high-power applications.

  16. Solid-state microwave annealing of ion-implanted 4H-SiC

    International Nuclear Information System (INIS)

    Sundaresan, Siddarth G.; Tian, Yong-lai; Ridgway, Mark C.; Mahadik, Nadeemullah A.; Qadri, Syed B.; Rao, Mulpuri V.

    2007-01-01

    Solid-state microwave annealing was performed at temperatures up to 2120 deg, C for 30 s on ion-implanted 4H-SiC in N 2 ambient. The surface roughness in the samples annealed without a surface cap at 1950 deg, C is 2.65 nm for 10 μm x 10 μm atomic force microscopy scans. The sheet resistances measured on Al + - and P + -implanted 4H-SiC, annealed by microwaves, are lower than the best conventional furnace annealing results reported in literature. X-ray diffraction spectra indicate alleviation of the lattice damage induced by the ion-implantation and also incorporation of most of the implanted species into substitutional lattice sites

  17. Charge accumulation in the buried oxide of SOI structures with the bonded Si/SiO2 interface under γ-irradiation: effect of preliminary ion implantation

    International Nuclear Information System (INIS)

    Naumova, O V; Fomin, B I; Ilnitsky, M A; Popov, V P

    2012-01-01

    In this study, we examined the effect of preliminary boron or phosphorous implantation on charge accumulation in the buried oxide of SOI-MOSFETs irradiated with γ-rays in the total dose range (D) of 10 5 –5 × 10 7 rad. The buried oxide was obtained by high-temperature thermal oxidation of Si, and it was not subjected to any implantation during the fabrication process of SOI structures. It was found that implantation with boron or phosphorous ions, used in fabrication technologies of SOI-MOSFETs, increases the concentration of precursor traps in the buried oxide of SOI structures. Unlike in the case of boron implantation, phosphorous implantation leads to an increased density of states at the Si/buried SiO 2 interface during subsequent γ-irradiation. In the γ-irradiated SOI-MOSFETs, the accumulated charge density and the density of surface states in the Si/buried oxide layer systems both vary in proportion to k i ln D. The coefficients k i for as-fabricated and ion-implanted Si/buried SiO 2 systems were evaluated. From the data obtained, it was concluded that a low density of precursor hole traps was a factor limiting the positive charge accumulation in the buried oxide of as-fabricated (non-implanted) SOI structures with the bonded Si/buried SiO 2 interface. (paper)

  18. The annealing behavior of hydrogen implanted into Al-Si alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ogura, Masahiko; Yamaji, Norisuke; Imai, Makoto; Itoh, Akio; Imanishi, Nobutsugu [Kyoto Univ. (Japan). Faculty of Engineering

    1997-03-01

    We have studied effects of not only defects but also an added elements on trap-sites of hydrogen in metals. For the purpose, we observed depth profiles and thermal behaviors of hydrogen implanted into Al-1.5at.%Si alloy samples in an implantation-temperature range of liquid nitrogen temperature (LNT) to 373K at different doses. The results were compared with those for pure aluminum samples. It was found that hydrogen is trapped as molecules in grain boundaries of Al/Si. (author)

  19. Boron diffusion in Ge+ premorphized and BF2 implanted Si(001)

    International Nuclear Information System (INIS)

    Zou, L.F.; Acosta-Ortiz, S.E.; Zou, L.X.; Regalado, L.E.; Sun, D.Z.; Wang, Z.G.

    1998-01-01

    The annealing behavior of Si implanted with Ge and then BF 2 has been characterized by double crystal X-ray diffraction (DCXRD) and secondary ion mass spectroscopy (SIMS). The results show that annealing at 600 Centigrade for 60 minutes can only remove a little damage induced by implantation and nearly no redistribution of Ge and B atoms has occurred during the annealing. The initial crystallinity of Si is fully recovered after annealing at 950 Centigrade for 60 minutes and accompanied by Ge diffusion. Very shallow boron junction depth has been formed. When annealing temperature rises to 1050 Centigrade, B diffusion enhances, which leads to a deep diffusion and good distribution of B atoms into the Si substrate. The X-ray diffraction (004) rocking curves from the samples annealed at 1050 Centigrade for 60 minutes display two Si Ge peaks, which may be related to the B concentration profiles. (Author)

  20. Diffusion of Ag, Au and Cs implants in MAX phase Ti3SiC2

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Weilin; Henager, Charles H.; Varga, Tamas; Jung, Hee Joon; Overman, Nicole R.; Zhang, Chonghong; Gou, Jie

    2015-05-16

    MAX phases (M: early transition metal; A: elements in group 13 or 14; X: C or N), such as titanium silicon carbide (Ti3SiC2), have a unique combination of both metallic and ceramic properties, which make them attractive for potential nuclear applications. Ti3SiC2 has been considered as a possible fuel cladding material. This study reports on the diffusivities of fission product surrogates (Ag and Cs) and a noble metal Au (with diffusion behavior similar to Ag) in this ternary compound at elevated temperatures, as well as in dual-phase nanocomposite of Ti3SiC2/3C-SiC and polycrystalline CVD 3C-SiC for behavior comparisons. Samples were implanted with Ag, Au or Cs ions and characterized with various methods, including x-ray diffraction, electron backscatter diffraction, energy dispersive x-ray spectroscopy, Rutherford backscattering spectrometry, helium ion microscopy, and transmission electron microscopy. The results show that in contrast to immobile Ag in 3C-SiC, there is a significant outward diffusion of Ag in Ti3SiC2 within the dual-phase nanocomposite during Ag ion implantation at 873 K. Similar behavior of Au in polycrystalline Ti3SiC2 was also observed. Cs out-diffusion and release from Ti3SiC2 occurred during post-implantation thermal annealing at 973 K. This study suggests caution and further studies in consideration of Ti3SiC2 as a fuel cladding material for advanced nuclear reactors operating at very high temperatures.

  1. Selective CVD tungsten on silicon implanted SiO/sub 2/

    International Nuclear Information System (INIS)

    Hennessy, W.A.; Ghezzo, M.; Wilson, R.H.; Bakhru, H.

    1988-01-01

    The application range of selective CVD tungsten is extended by its coupling to the ion implantation of insulating materials. This article documents the results of selective CVD tungsten using silicon implanted into SiO/sub 2/ to nucleate the tungsten growth. The role of implant does, energy, and surface preparation in achieving nucleation are described. SEM micrographs are presented to demonstrate the selectivity of this process. Measurements of the tungsten film thickness and sheet resistance are provided for each of the experimental variants corresponding to successful deposition. RBS and XPS analysis are discussed in terms of characterizing the tungsten/oxide interface and to evaluate the role of the silicon implant in the CVD tungsten mechanism. Utilizing this method a desired metallization pattern can be readily defined with lithography and ion implantation, and accurately replicated with a layer of CVD tungsten. This approach avoids problems usually associated with blanket deposition and pattern transfer, which are particularly troublesome for submicron VLSI technology

  2. Nano-SiC region formation in (100) Si-on-insulator substrate: Optimization of hot-C+-ion implantation process to improve photoluminescence intensity

    Science.gov (United States)

    Mizuno, Tomohisa; Omata, Yuhsuke; Kanazawa, Rikito; Iguchi, Yusuke; Nakada, Shinji; Aoki, Takashi; Sasaki, Tomokazu

    2018-04-01

    We experimentally studied the optimization of the hot-C+-ion implantation process for forming nano-SiC (silicon carbide) regions in a (100) Si-on-insulator substrate at various hot-C+-ion implantation temperatures and C+ ion doses to improve photoluminescence (PL) intensity for future Si-based photonic devices. We successfully optimized the process by hot-C+-ion implantation at a temperature of about 700 °C and a C+ ion dose of approximately 4 × 1016 cm-2 to realize a high intensity of PL emitted from an approximately 1.5-nm-thick C atom segregation layer near the surface-oxide/Si interface. Moreover, atom probe tomography showed that implanted C atoms cluster in the Si layer and near the oxide/Si interface; thus, the C content locally condenses even in the C atom segregation layer, which leads to SiC formation. Corrector-spherical aberration transmission electron microscopy also showed that both 4H-SiC and 3C-SiC nanoareas near both the surface-oxide/Si and buried-oxide/Si interfaces partially grow into the oxide layer, and the observed PL photons are mainly emitted from the surface SiC nano areas.

  3. Energy loss and straggling of MeV Si ions in gases

    Energy Technology Data Exchange (ETDEWEB)

    Vockenhuber, C., E-mail: vockenhuber@phys.ethz.ch [Laboratory of Ion Beam Physics, ETH Zurich, Otto-Stern-Weg 5, 8093 Zurich (Switzerland); Arstila, K. [Department of Physics, University of Jyväskylä, 40014 Jyväskylä (Finland); Jensen, J. [Department of Physics, Chemistry and Biology, Linköping University, 581 83 Linköping (Sweden); Julin, J.; Kettunen, H.; Laitinen, M.; Rossi, M.; Sajavaara, T. [Department of Physics, University of Jyväskylä, 40014 Jyväskylä (Finland); Thöni, M. [Laboratory of Ion Beam Physics, ETH Zurich, Otto-Stern-Weg 5, 8093 Zurich (Switzerland); Whitlow, H.J. [Institut des Microtechnologies Appliquées Arc, Haute Ecole Arc Ingénierie, 2300 La Chaux-de-Fonds (Switzerland)

    2017-01-15

    We present measurements of energy loss and straggling of Si ions in gases. An energy range from 0.5 to 12 MeV/u was covered using the 6 MV EN tandem accelerator at ETH Zurich, Switzerland, and the K130 cyclotron accelerator facility at the University of Jyväskylä, Finland. Our energy-loss data compare well with calculation based on the SRIM and PASS code. The new straggling measurements support a pronounced peak in He gas at around 4 MeV/u predicted by recent theoretical calculations. The straggling curve structure in the other gases (N{sub 2}, Ne, Ar, Kr) is relatively flat in the covered energy range. Although there is a general agreement between the straggling data and the theoretical calculations, the experimental uncertainties are too large to confirm or exclude the predicted weak multi-peak structure in the energy-loss straggling.

  4. Carbon nanotube growth from catalytic nano-clusters formed by hot-ion-implantation into the SiO{sub 2}/Si interface

    Energy Technology Data Exchange (ETDEWEB)

    Hoshino, Yasushi, E-mail: yhoshino@kanagawa-u.ac.jp [Department of Information Sciences, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293 (Japan); Arima, Hiroki; Yokoyama, Ai; Saito, Yasunao; Nakata, Jyoji [Department of Information Sciences, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293 (Japan)

    2012-07-01

    We have studied growth of chirality-controlled carbon nanotubes (CNTs) from hot-implantation-formed catalytic nano-clusters in a thermally grown SiO{sub 2}/Si substrate. This procedure has the advantage of high controllability of the diameter and the number of clusters by optimizing the conditions of the ion implantation. In the present study, Co{sup +} ions with ion dose of 8 Multiplication-Sign 10{sup 16} cm{sup -2} are implanted in the vicinity of the SiO{sub 2}/Si interface at 300 Degree-Sign C temperature. The implanted Co atoms located in the SiO{sub 2} layer has an amorphous-like structure with a cluster diameter of several nm. In contrast, implanted Co atoms in the Si substrate are found to take a cobalt silicide structure, confirmed by the high-resolution image of transmission electron microscope. CNTs are grown by microwave-plasma-enhanced chemical vapor deposition. We have confirmed a large amount of vertically-aligned multi-walled CNTs from the Co nano-clusters formed by the hot-ion-implantation near the SiO{sub 2}/Si interface.

  5. Defect engineering via ion implantation to control B diffusion in Si

    International Nuclear Information System (INIS)

    Canino, M.; Regula, G.; Xu, M.; Ntzoenzok, E.; Pichaud, B.

    2009-01-01

    The processes which are currently studied in the fabrication of B-doped ultra shallow junctions (USJ) usually involve a preamorphization step to reduce B channelling effect during implantation and to improve B electrical activation. At this stage a high amount of Si interstitial atoms (Is), which dramatically increases the B diffusivity, is introduced. The introduction of voids in Si is a promising tool to control B transient enhanced diffusion (TED), because of their ability to capture Is. In this work the efficiency of a cavity band to reduce B TED is checked in silicon interstitial supersaturation conditions, obtained by high dose Si implantation. He is implanted either at 10 keV or at 50 keV with a fluence of 5 x 10 16 cm -2 . Conventional techniques to introduce and activate the B (conventional ion implantation and rapid thermal annealing (RTA)) are applied in order to have a better control of the technological process to focus on the benefit of the cavity layer. The samples were characterized by cross section transmission electron microscopy (XTEM), secondary ion mass spectroscopy (SIMS) and Hall Effect (HE). The latter shows that good activation of the B is achieved only after 1000 deg. C RTA, though a 900 deg. C RTA is sufficient for implantation-damage recovery, as it is confirmed by XTEM observations. B SIMS profiles show that the band of cavities plays its best effect in reducing B TED when it is located near the surface.

  6. Microstructure of buried CoSi2 layers formed by high-dose Co implantation into (100) and (111) Si substrates

    International Nuclear Information System (INIS)

    Bulle-Lieuwma, C.W.T.; Van Ommen, A.H.; Vandenhoudt, D.E.W.; Ottenheim, J.J.M.; de Jong, A.F.

    1991-01-01

    Heteroepitaxial Si/CoSi 2 /Si structures have been synthesized by implanting 170-keV Co + with doses in the range 1--3x10 17 Co + ions/cm 2 into (100) and (111) Si substrates and subsequent annealing. The microstructure of both the as-implanted and annealed structures is investigated in great detail by transmission electron microscopy, high-resolution electron microscopy, and x-ray diffraction. In the as-implanted samples, the Co is present as CoSi 2 precipitates, occurring both in aligned (A-type) and twinned (B-type) orientation. For the highest dose, a continuous layer of stoichiometric CoSi 2 is already formed during implantation. It is found that the formation of a connected layer, already during implantation, is crucial for the formation of a buried CoSi 2 layer upon subsequent annealing. Particular attention is given to the coordination of the interfacial Co atoms at the Si/CoSi 2 (111) interfaces of both types of precipitates. We find that the interfacial Co atoms at the A-type interfaces are fully sevenfold coordinated, whereas at the B-type interfaces they appear to be eightfold coordinated

  7. Atomic mixing effects on high fluence Ge implantation into Si at 40 keV

    International Nuclear Information System (INIS)

    Gras-Marti, A.; Jimenez-Rodriguez, J.J.; Peon-Fernandez, J.; Rodriguez-Vidal, M.; Tognetti, N.P.; Carter, G.; Nobes, M.J.; Armour, D.G.

    1982-01-01

    Ion implanted profiles of 40 keV Ge + into Si at fluences ranging from approx. equal to 10 15 ions/cm 2 up to saturation have been measured using the RBS technique. The profiles compare well with the predictions of an analytical model encompasing sputter erosion plus atomic relocation. (orig.)

  8. Co-delivery of siRNA and doxorubicin to cancer cells from additively manufactured implants

    DEFF Research Database (Denmark)

    Chen, Muwan; Andersen, Morten Østergaard; Dillschneider, Philipp

    2015-01-01

    , capable of physically supporting the void while killing residual cancer cells, would be an attractive solution. Here we describe a novel additively manufactured implant that can be functionalized with chitosan/siRNA nanoparticles. These induce long term gene silencing in adjacent cancer cells without...

  9. Si+ and N+ ion implantation for improving blood compatibility of medical poly(methyl methacrylate)

    International Nuclear Information System (INIS)

    Li, D.J.; Cui, F.Z; Cui, F.Z.

    1998-01-01

    Si + and N + ion implantation into medical poly(methyl methacrylate) (PMMA) were performed at an energy of 80 keV with fluences ranging from 5x10 12 to 5x10 15 ions/cm 2 at room temperature to improve blood compatibility. The results of the blood contacting measurements in vitro showed that the anticoagulability and anticalcific behaviour on the surface morphology were enhanced after ion implantation. No appreciable change in the surface morphology was detected by scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS) analysis indicated that ion implantation broke some original chemical bonds on the surface to form some new Si- and N-containing groups. These results were considered responsible for the enhancement in the blood compatibility of PMMA. (author)

  10. Lattice sites and stability of implanted Er in FZ and CZ Si

    CERN Document Server

    Wahl, U; Langouche, G; Vantomme, A

    1998-01-01

    We report on the lattice location of $^{167}$Er in Si measured by conversion electron emission channeling. In both FZ and CZ Si, a high fraction of Er (>65%) occupies near-tetrahedral interstitial (T) sites directly following 60 keV room temperature implantation at doses of 6 $\\times 10^{12}$ cm$^{-2}$. For higher doses, the as-implanted near-T fractions of Er visible by emission channeling are smaller, due to the beginning of amorphization. Following the recovery of implantation damage at 600°C, more than 70% of Er is found on near-T sites in both FZ and CZ Si. In FZ Si, Er exhibits a remarkable thermal stability and only prolonged annealing for several hours reduces the near-T fraction. On the other hand, annealing of CZ Si at 900°C for more than 10 minutes results in the majority of Er probes in sites of very low symmetry or disordered surroundings.

  11. 125 MeV Si 9+ ion irradiation of calcium phosphate thin film coated by rf-magnetron sputtering technique

    Science.gov (United States)

    Elayaraja, K.; Joshy, M. I. Ahymah; Suganthi, R. V.; Kalkura, S. Narayana; Palanichamy, M.; Ashok, M.; Sivakumar, V. V.; Kulriya, P. K.; Sulania, I.; Kanjilal, D.; Asokan, K.

    2011-01-01

    Titanium substrate was coated with hydroxyapatite by radiofrequency magnetron sputtering (rf-magnetron sputtering) technique and subjected to swift heavy ion (SHI) irradiation of 125 MeV with Si 9+ at fluences of 1 × 10 10, 1 × 10 11 and 1 × 10 12 ions/cm 2. The glancing incidence X-ray diffraction (GIXRD) analysis confirmed the HAp phase of the irradiated film. There was a considerable decrease in crystallinity and particle size after irradiation. In addition, DRS-UV reflectance spectra revealed a decrease in optical band gap ( Eg) from 5.2 to 4.6 eV. Wettability of biocompatible materials plays an important role in biological cells proliferation for tissue engineering, drug delivery, gene transfer and bone growth. HAp thin films irradiated with 1 × 10 11 ions/cm 2 fluence showed significant increase in wettability. While the SHI irradiated samples exhibited enhanced bioactivity, there was no significant variation in cell viability. Surface roughness, pores and average particle size were analyzed by atomic force microscopy (AFM).

  12. Gamma-ray multiplicity measurements in the 28Si + 64Ni reaction at 163.8 MeV

    International Nuclear Information System (INIS)

    Di Pietro, A.; Cardella, G.; Musumarra, A.; Papa, M.; Pappalardo, G.; Rizzo, F.; De Rosa, A.; D'Onofrio, A.; Inglima, G.; Roca, V.; Romano, M.; Romoli, M.; Sandoli, M.; Terrasi, F.; Fioretto, E.

    1994-01-01

    The 28 Si+ 64 Ni reaction at 163.8 MeV incident energy is studied by measuring in coincidence γ-rays and charged particles identified from Z 2 to Z = 16. The transition from quasi-elastic to more damped reactions is observed when the difference between the detected charge and the projectile one is increased. The strong influence of the particle decay on the measured γ-ray multiplicity is evidenced with the help of the statistical model computer code CASCADE. Dissipative events are well described in the rolling limit with excitation energy equally shared between the fragments. The overall agreement is lost for the fragments with the projectile charge which show a small value of the γ-multiplicity even for dissipative events. This is probably connected with the previously observed non statistical behavior of gamma rays emitted in coincidence with projectile-like fragments. In the alpha-spectrum measured in coincidence with gamma-rays, the deexcitation of fused systems is clearly separated from in flight emission of deep inelastic fragments. The low measured gamma-ray multiplicity for fusion events is qualitatively explained taking into account the effect of alpha-emission in the statistical decay. (orig.)

  13. Lateral spread of P+ ions implanted in silicon through the SiO2 mask window

    International Nuclear Information System (INIS)

    Sakurai, T.; Kawata, H.; Sato, T.; Hisatsugu, T.; Hashimoto, H.; Furuya, T.

    1979-01-01

    The lateral spread of implanted P + ions and the shape of the mask window have been observed simultaneously using the technique of staining the cleaved surface and scanning electron microscopy for the Si samples with the SiO 2 mask window with a tapered edge. The mask edge with a gradient of 45 0 or 78 0 to the Si surface and the implanted n-type region with a carrier concentration higher than 2 x 10 17 /cm 3 are observed in the same photograph. The observed maximum lateral spread when the gradient of the mask edge is 45 0 is about 1.6 times larger than that when the gradient is 78 0 . The calculated results of the lateral spread agree relatively well with the experimental data although the precise analysis based on the definite basis is necessary

  14. Optical, structural, and chemical properties of CR-39 implanted with 5.2 MeV doubly charged carbon ions

    Science.gov (United States)

    Ali, Dilawar; Butt, M. Z.; Ishtiaq, Mohsin; Waqas Khaliq, M.; Bashir, Farooq

    2016-11-01

    Poly-allyl-diglycol-carbonate (CR-39) specimens were irradiated with 5.2 MeV doubly charged carbon ions using Pelletron accelerator. Ion dose was varied from 5 × 1013 to 5 × 1015 ions cm-2. Optical, structural, and chemical properties were investigated by UV-vis spectroscopy, x-ray diffractometer, and FTIR/Raman spectroscopy, respectively. It was found that optical absorption increases with increasing ion dose. Absorption edge shifts from UV region to visible region. The measured opacity values of pristine and ion implanted CR-39 range from 0.0519 to 4.7959 mm-1 following an exponential growth (9141%) with the increase in ion dose. The values of direct and indirect band gap energy decrease exponentially with an increase in ion dose by 59% and 71%, respectively. However, average refractive index in the visible region increases from 1.443 to 2.864 with an increase in ion dose, by 98%. A linear relation between band gap energy and crystallite size was observed. Both the number of carbon atoms in conjugation length and the number of carbon atoms per cluster increase linearly with the increase in ion dose. FTIR spectra showed that on C+2 ions irradiation, the intensity of all bands decreases gradually without appearance of any new band, indicating degradation of polymer after irradiation. Raman spectra revealed that the density of -CH2- group decreases on C+2 ions irradiation. However, the structure of CR-39 is completely destroyed on irradiation with ion dose 1 × 1015 and 5 × 1015 ions cm-2.

  15. Implantation processing of Si: A unified approach to understanding ion-induced defects and their impact

    International Nuclear Information System (INIS)

    Holland, O.W.; Roth, E.G.

    1997-05-01

    A model is presented to account for the effects of ion-induced defects during implantation processing of Si. It will be shown that processing is quite generally affected by the presence of defect excesses rather than the total number of defects. a defect is considered excess if it represents a surplus locally of one defect type over its compliment. Processing spanning a wide range of implantation conditions will be presented to demonstrate that the majority of the total defects played little or no role in the process. This is a direct result of the ease with which the spatially correlated Frenkel pairs recombine either dynamically or during a post-implantation annealing. Based upon this model, a method will be demonstrated for manipulating or engineering the excess defects to modify their effects. In particular high-energy, self-ions are shown to inject vacancies into a boron implanted region resulting in suppression of transient enhanced diffusion of the dopant

  16. The formation of magnetic silicide Fe{sub 3}Si clusters during ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Balakirev, N. [Kazan National Research Technological University, K.Marx st. 68, Kazan 420015 (Russian Federation); Zhikharev, V., E-mail: valzhik@mail.ru [Kazan National Research Technological University, K.Marx st. 68, Kazan 420015 (Russian Federation); Gumarov, G. [Zavoiskii Physico-Technical Institute of Russian Academy of Sciences, 10/7 Sibirskii trakt st., Kazan 420029 (Russian Federation)

    2014-05-01

    A simple two-dimensional model of the formation of magnetic silicide Fe{sub 3}Si clusters during high-dose Fe ion implantation into silicon has been proposed and the cluster growth process has been computer simulated. The model takes into account the interaction between the cluster magnetization and magnetic moments of Fe atoms random walking in the implanted layer. If the clusters are formed in the presence of the external magnetic field parallel to the implanted layer, the model predicts the elongation of the growing cluster in the field direction. It has been proposed that the cluster elongation results in the uniaxial magnetic anisotropy in the plane of the implanted layer, which is observed in iron silicide films ion-beam synthesized in the external magnetic field.

  17. The formation of magnetic silicide Fe3Si clusters during ion implantation

    Science.gov (United States)

    Balakirev, N.; Zhikharev, V.; Gumarov, G.

    2014-05-01

    A simple two-dimensional model of the formation of magnetic silicide Fe3Si clusters during high-dose Fe ion implantation into silicon has been proposed and the cluster growth process has been computer simulated. The model takes into account the interaction between the cluster magnetization and magnetic moments of Fe atoms random walking in the implanted layer. If the clusters are formed in the presence of the external magnetic field parallel to the implanted layer, the model predicts the elongation of the growing cluster in the field direction. It has been proposed that the cluster elongation results in the uniaxial magnetic anisotropy in the plane of the implanted layer, which is observed in iron silicide films ion-beam synthesized in the external magnetic field.

  18. The formation of magnetic silicide Fe3Si clusters during ion implantation

    International Nuclear Information System (INIS)

    Balakirev, N.; Zhikharev, V.; Gumarov, G.

    2014-01-01

    A simple two-dimensional model of the formation of magnetic silicide Fe 3 Si clusters during high-dose Fe ion implantation into silicon has been proposed and the cluster growth process has been computer simulated. The model takes into account the interaction between the cluster magnetization and magnetic moments of Fe atoms random walking in the implanted layer. If the clusters are formed in the presence of the external magnetic field parallel to the implanted layer, the model predicts the elongation of the growing cluster in the field direction. It has been proposed that the cluster elongation results in the uniaxial magnetic anisotropy in the plane of the implanted layer, which is observed in iron silicide films ion-beam synthesized in the external magnetic field

  19. Si-O compound formation by oxygen ion implantation into silicon

    International Nuclear Information System (INIS)

    Hensel, E.; Wollschlaeger, K.; Kreissig, U.; Skorupa, W.; Schulze, D.; Finster, J.

    1985-01-01

    High dose oxygen ion implantation into silicon at 30 keV was performed to produce understoichiometric and stoichiometric surface oxide layers of approx. 160 nm thickness. The oxygen depth profile and oxide stoichiometry was determined by RBS and XPS. Si-O compound formation was found by IR spectroscopy and XPS in the unannealed samples as well as after target heating, furnace or flash lamp annealing. As implanted understoichiometric layers consist of random bonding like SiOsub(x) (O 2 after annealing. Unannealed stoichiometric layers are bond strained SiO 2 . The activation energies of demixing and of the annealing of bond strains are determined to 0.19 and 0.13 eV, respectively. The removing of bond strains occurs at temperatures >= 800 C in a time shorter than 1 s. The SiO 2 /Si transition region of unannealed stoichiometric layers consists of SiOsub(x) with an extent of about 10 nm. After annealing this extent diminishes to 0.8 to 1 nm in consequence of oxidation by excess oxygen from the overstoichiometric oxide region. This thickness is comparable with that of thermal oxide. (author)

  20. Exfoliation of GaAs caused by MeV 1H and 4He ion implantation at left angle 100 right angle , left angle 110 right angle axial and random orientations

    International Nuclear Information System (INIS)

    Rauhala, E.; Raeisaenen, J.

    1994-01-01

    The exfoliation procedure of the ion range determination of gaseous implants in single crystal GaAs is investigated. The correlation of the observed crater depth with the ion range is studied for random, left angle 100 right angle and left angle 110 right angle axial orientation high dose implantations of 1.5-2.5 MeV 1 H and 4 He ions. Depending on the experimental conditions, the crater depths corresponded to range values between the modal range and the range maximum. The observed crater depths could be related to the actual He concentration depth distributions by determining the profiles of the 4 He implants by 2.7 MeV proton backscattering. The implantation parameters affecting the exfoliation process, and especially the increase rate of the sample temperature, are investigated. The range distribution parameters for the 1.5 MeV 4 He implants are presented. ((orig.))

  1. Resistivity and morphology of TiSi2 formed on Xe+-implanted polycrystalline silicon

    International Nuclear Information System (INIS)

    Kuwano, H.; Phillips, J.R.; Mayer, J.W.

    1990-01-01

    Xe ion irradiation of polycrystalline silicon before Ti deposition is found to affect subsequent silicide formation. Silicide films were prepared by implanting 60, 100, or 240 keV Xe + ions into 500-nm-thick undoped polycrystalline silicon before depositing Ti and annealing in vacuum. Preimplantation altered the subsequent silicide resistivity, x-ray diffraction patterns, and morphology as compared to films prepared on unimplanted polycrystalline Si substrates. We found that minimal TiSi 2 resistivities were achieved at lower temperatures with preimplantation, indicating that the Xe-implanted substrate promotes a lower temperature transition from the metastable C49 phase to the low-resistivity equilibrium C54 phase of TiSi 2 . X-ray diffraction results confirmed the lower temperature formation of the C54 phase with preimplantation. Low-temperature annealing (650 degree C, 30 min) of 6x10 16 cm -2 , 240 keV Xe + -implanted samples yielded low-resistivity (∼22 μΩ cm) silicide films, while simultaneously annealed samples without preimplantation had resistivity five times higher. Lower doses were effective at lower implant energies, with low resistivity achieved after 725 degree C, 30 min annealing for 2x10 15 cm -2 , 60 keV Xe + preimplantation

  2. Shift in room-temperature photoluminescence of low-fluence Si{sup +}-implanted SiO{sub 2} films subjected to rapid thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Mingyue, Fu [Department of Avionics Engineering, Air Force Academy, Kangshan, Kaohsiung 820, Taiwan (China); Tsai, J -H [Department of Mathematics and Physics, Air Force Academy, Kangshan, Kaohsiung 820, Taiwan (China); Yang, C -F [Department of Chemical and Materials Engineering, National Kaohsiung University, Nan-Tzu District, Kaohsiung 811, Taiwan (China); Liao, C.-H. [Department of Physics, Chinese Military Academy, Fengshan, Kaohsiung 830, Taiwan (China)], E-mail: fumy@cc.cafa.edu.tw

    2008-12-15

    We experimentally demonstrate the effect of the rapid thermal annealing (RTA) in nitrogen flow on photoluminescence (PL) of SiO{sub 2} films implanted by different doses of Si{sup +} ions. Room-temperature PL from 400-nm-thick SiO{sub 2} films implanted to a dose of 3x10{sup 16} cm{sup -2} shifted from 2.1 to 1.7 eV upon increasing RTA temperature (950-1150 deg. C) and duration (5-20 s). The reported approach of implanting silicon into SiO{sub 2} films followed by RTA may be effective for tuning Si-based photonic devices.

  3. Effect of recoiled O on damage regrowth and electrical properties of through-oxide implanted Si

    International Nuclear Information System (INIS)

    Sadana, D.K.; Wu, N.R.; Washburn, J.; Current, M.; Morgan, A.; Reed, D.; Maenpaa, M.

    1982-10-01

    High dose (4 to 7.5 x 10 15 cm -2 ) As implantations into p-type (100) Si have been carried out through a screen-oxide of thicknesses less than or equal to 775A and without screen oxide. The effect of recoiled O on damage annealing and electrical properties of the implanted layers has been investigated using a combination of the following techniques: TEM, RBS/MeV He + channeling, SIMS and Hall measurements in conjunction with chemical stripping and sheet resistivity measurements. The TEM results show that there is a dramatically different annealing behavior of the implantation damage for the through oxide implants (Case I) as compared to implants into bare silicon (Case II). Comparison of the structural defect profiles with O distributions obtained by SIMS demonstrated that retardation in the secondary damage growth in Case I can be directly related with the presence of O. Weak-beam TEM showed that a high density of fine defect clusters (less than or equal to 50A) were present both in Case I and Case II. The electrical profiles showed only 30% of the total As to be electrically active. The structural and electrical results have been explained by a model that entails As-O, Si-O and As-As complex formation and their interaction with the dislocations

  4. Ion implantation effects in single crystal Si investigated by Raman spectroscopy

    International Nuclear Information System (INIS)

    Harriman, T.A.; Lucca, D.A.; Lee, J.-K.; Klopfstein, M.J.; Herrmann, K.; Nastasi, M.

    2009-01-01

    A study of the effects of Ar ion implantation on the structural transformation of single crystal Si investigated by confocal Raman spectroscopy is presented. Implantation was performed at 77 K using 150 keV Ar ++ with fluences ranging from 2 x 10 13 to 1 x 10 15 ions/cm 2 . The Raman spectra showed a progression from crystalline to highly disordered structure with increasing fluence. The 520 cm -1 c-Si peak was seen to decrease in intensity, broaden and exhibit spectral shifts indicating an increase in lattice disorder and changes in the residual stress state. In addition, an amorphous Si band first appeared as a shoulder on the 520 cm -1 peak and then shifted to lower wavenumbers as a single broadband peak with a spectral center of 465 cm -1 . Additionally, the emergence of the a-Si TA phonon band and the decrease of the c-Si 2TA and 2TO phonon bands also indicated the same structural transition from crystalline to highly disordered. The Raman results were compared to those obtained by channeling RBS.

  5. Surface morphologies of excimer-laser annealed BF2+ implanted Si diodes

    International Nuclear Information System (INIS)

    Burtsev, A.; Schut, H.; Nanver, L.K.; Veen, A. van; Slabbekoorn, J.; Scholtes, T.L.M.

    2004-01-01

    Laser-induced surface roughness and damage formation in ultra-shallow n + -p and p + -n junctions, formed by low energy (5 keV) As + and BF 2 + implantations in Si, respectively, with a dose of 1 x 10 15 cm -2 have been investigated by atomic force microscopy (AFM) and Positron Annihilation Doppler Broadening (PADB) technique. The Si surface roughness is found to increase with laser energy density, and reaches a value of 3.5 nm after excimer-laser annealing (ELA) at 1100 mJ/cm 2 . However, anomalous behavior is witnessed for BF 2 + -implanted Si sample at 800 mJ/cm 2 , at which energy very high surface protrusions up to 9 nm high are observed. By PADB this behavior is correlated to extensive deep microcavity formation in the Si whereby the volatile F 2 fraction can accumulate and evaporate/out-diffuse, leading to Si surface roughening. The consequences for the diode characteristics and contact resistivity are examined

  6. Radiation-induced effects in MgO single crystal by 200 keV and 1 MeV Ni ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Ryohei; Nakai, Yoshihiro; Hamaguchi, Dai [Kyoto Inst. of Tech. (Japan); and others

    1997-03-01

    MgO(100) single crystals were implanted with 1.0 MeV and 200 keV Ni ions between 10{sup 15} and 10{sup 17} ions/cm{sup 2} at room temperature. Before and after thermal annealing the radiation damage and the lattice location of implanted Ni ions were analyzed by using Rutherford backscattering spectrometry with channeling and optical absorption measurements. For 1.0 MeV Ni ions, the disorder of Mg atoms increased slowly with ion dose near surface region, while it increased sharply and saturated with ion dose from 2x10{sup 16} ions/cm{sup 2} near ion range. The radiation damage was recovered and implanted Ni ions diffused to the whole of crystal and occupied substitutional positions after 1400degC annealing. For 200 keV Ni ions, the disorder of Mg atoms increased with dose near ion range and had a maximum at about 5x10{sup 16} ions/cm{sup 2}. This tendency agrees with the behavior of color centers obtained from optical measurements. For thermal annealing the radiation damage did not change during 500degC annealing, but the aggregate centers appeared after 300degC annealing. (author)

  7. Oxygen recoil implant from SiO2 layers into single-crystalline silicon

    International Nuclear Information System (INIS)

    Wang, G.; Chen, Y.; Li, D.; Oak, S.; Srivastav, G.; Banerjee, S.; Tasch, A.; Merrill, P.; Bleiler, R.

    2001-01-01

    It is important to understand the distribution of recoil-implanted atoms and the impact on device performance when ion implantation is performed at a high dose through surface materials into single crystalline silicon. For example, in ultralarge scale integration impurity ions are often implanted through a thin layer of screen oxide and some of the oxygen atoms are inevitably recoil implanted into single-crystalline silicon. Theoretical and experimental studies have been performed to investigate this phenomenon. We have modified the Monte Carlo ion implant simulator, UT-Marlowe (B. Obradovic, G. Wang, Y. Chen, D. Li, C. Snell, and A. F. Tasch, UT-MARLOWE Manual, 1999), which is based on the binary collision approximation, to follow the full cascade and to dynamically modify the stoichiometry of the Si layer as oxygen atoms are knocked into it. CPU reduction techniques are used to relieve the demand on computational power when such a full cascade simulation is involved. Secondary ion mass spectrometry (SIMS) profiles of oxygen have been carefully obtained for high dose As and BF 2 implants at different energies through oxide layers of various thicknesses, and the simulated oxygen profiles are found to agree very well with the SIMS data. [copyright] 2001 American Institute of Physics

  8. Bond length contraction in Au nanocrystals formed by ion implantation into thin SiO2

    International Nuclear Information System (INIS)

    Kluth, P.; Johannessen, B.; Giraud, V.; Cheung, A.; Glover, C.J.; Azevedo, G. de M; Foran, G.J.; Ridgway, M.C.

    2004-01-01

    Au nanocrystals (NCs) fabricated by ion implantation into thin SiO 2 and annealing were investigated by means of extended x-ray absorption fine structure (EXAFS) spectroscopy and transmission electron microscopy. A bond length contraction was observed and can be explained by surface tension effects in a simple liquid-drop model. Such results are consistent with previous reports on nonembedded NCs implying a negligible influence of the SiO 2 matrix. Cumulant analysis of the EXAFS data suggests surface reconstruction or relaxation involving a further shortened bond length. A deviation from the octahedral closed shell structure is apparent for NCs of size 25 A

  9. Positron annihilation studies of silicon-rich SiO2 produced by high dose ion implantation

    International Nuclear Information System (INIS)

    Ghislotti, G.; Nielsen, B.; Asoka-Kumar, P.; Lynn, K.G.; Di Mauro, L.F.; Corni, F.; Tonini, R.

    1997-01-01

    Positron annihilation spectroscopy (PAS) is used to study Si-rich SiO 2 samples prepared by implantation of Si (160 keV) ions at doses in the range 3x10 16 endash 3x10 17 cm -2 and subsequent thermal annealing at high temperature (up to 1100 degree C). Samples implanted at doses higher than 5x10 16 cm -2 and annealed above 1000 degree C showed a PAS spectrum with an annihilation peak broader than the unimplanted sample. We discuss how these results are related to the process of silicon precipitation inside SiO 2 . copyright 1997 American Institute of Physics

  10. Si diffusion in compositional disordering of Si-implanted GaAs/AlGaAs superlattices induced by rapid thermal annealing

    International Nuclear Information System (INIS)

    Uematsu, Masashi; Yanagawa, Fumihiko

    1988-01-01

    The Si diffusion in Si-implanted GaAs/Al 0.5 Ga 0.5 As superlattices intermixed in the disrodering process induced by rapid thermal annealing (RTA), is investigated by means of secondary ion mass spectroscopy (SIMS). The SIMS profiles indicate that no fast Si diffusion occurs during the disordering, and the disordering occurs when the Si concentration exceeds 1 x 10 19 cm -3 , which is about three times larger than the threshold value for the disordering by furnace annealing (FA). The number of Si atoms which are allowed to pass through the heterointerface is considered to be essential for disordering. (author)

  11. Effects of synchrotron x-rays on PVD deposited and ion implanted α-Si

    International Nuclear Information System (INIS)

    Yu, K.M.; Wang, L.; Walukiewicz, W.; Muto, S.; McCormick, S.; Abelson, J.R.

    1997-01-01

    The authors have studied the effects of intense X-ray irradiation on the structure of amorphous Si films. The films were obtained by either physical vapor deposition or by implantation of high energy ions into crystalline Si. They were exposed to different total doses of synchrotron X-rays. From the EXAFS and EXELFS measurements they find that an exposure to X-rays increases the Si coordination number. Also in the PVD films a prolonged X-ray exposure enlarges, by about 2%, the Si-Si bond length. Raman spectroscopy shows that Si amorphized with high energy ions contains small residual amounts of crystalline material. Irradiation of such films with X-rays annihilates those crystallites resulting in homogeneously amorphous layer with a close to four-fold coordination of Si atoms. This rearrangement of the local structure has a pronounced effect on the crystallization process of the amorphous films. Thermal annealing of X-ray irradiated ion amorphized films leads to nearly defect free solid phase epitaxy at 500 C. Also they observe a delay in the onset of the crystallization process in X-ray irradiated PVD films. They associate this with a reduced concentration of nucleation centers in the x-ray treated materials

  12. On the use of thin ion implanted Si detectors in heavy ion experiments

    International Nuclear Information System (INIS)

    Lavergne-Gosselin, L.; Stab, L.; Lampert, M.O.

    1988-10-01

    We present test results on the use of thin ion implanted epitaxial Si detectors for registration of low- and medium energy heavy fragments in nuclear reactions. A linear energy response for very low energy nuclei has been observed. A test of 10 μm + 300 μm telescopes under realistic experimental conditions for heavy ion experiments exhibits the possibilities to use these detectors for the measurements of multifragmentation products. (authors)

  13. The mechanisms of surface exfoliation in H and He implanted Si crystals

    International Nuclear Information System (INIS)

    Reboh, S.; Mattos, A.A.D. de; Schaurich, F.; Fichtner, P.F.P.; Beaufort, M.F.; Barbot, J.F.

    2011-01-01

    We report on the exfoliation mechanisms in light gas implanted Si. Microstructure characterization, extensive statistical analysis and solid mechanics theory show that exfoliation is caused by microcracks growing close to equilibrium pressure for high fluences. For lower fluences, cracks evolve at under-equilibrium pressure and exfoliation relies on a coalescence mechanism assisted by cleavage. This provides long-range, collective and efficient stress relief for clusters of cracks, causing enhancement of the exfoliation. The physical processes are independent of the irradiation energy.

  14. Si+ ion implantation reduces the bacterial accumulation on the Ti6Al4V surface

    International Nuclear Information System (INIS)

    Gallardo-Moreno, A M; Pacha-Olivenza, M A; Perera-Nunez, J; Gonzalez-Carrasco, J L; Gonzalez-Martin, M L

    2010-01-01

    Ti6Al4V is one of the most commonly used biomaterials in orthopedic applications due to its interesting mechanical properties and reasonable biocompatibility. Nevertheless, after the implantation, microbial adhesion to its surface can provoke severe health problems associated to the development of biofilms and subsequent infectious processes. This work shows a modification of the Ti6Al4V surface by Si+ ion implantation which reduces the bacterial accumulation under shear forces. Results have shown that the number of bacteria remaining on the surface at the end of the adhesion experiments decreased for silicon-treated surface. In general, the new surface also behaved as less adhesive under in vitro flow conditions. Since no changes are observed in the electrical characteristics between the control and implanted samples, differences are likely related to small changes observed in hydrophobicity.

  15. Visible light emission from silicon implanted and annealed SiO2layers

    International Nuclear Information System (INIS)

    Ghislotti, G.; Nielsen, B.; Asoka-Kumar, P.; Lynn, K.G.; Di Mauro, L.F.; Bottani, C.E.; Corni, F.; Tonini, R.; Ottaviani, G.P.

    1997-01-01

    Silicon implanted and annealed SiO 2 layers are studied using photoluminescence (PL) and positron annihilation spectroscopy (PAS). Two PL emission bands are observed. A band centered at 560 nm is present in as-implanted samples and it is still observed after 1,000 C annealing. The emission time is fast. A second band centered at 780 nm is detected after 1,000 C annealing. The intensity of the 780 nm band further increased when hydrogen annealing was performed. The emission time is long (1 micros to 0.2 ms). PAS results show that defects produced by implantation anneal at 600 C. Based on the annealing behavior and on the emission times, the origin of the two bands is discussed

  16. Dual-Functionalized Graphene Oxide Based siRNA Delivery System for Implant Surface Biomodification with Enhanced Osteogenesis.

    Science.gov (United States)

    Zhang, Li; Zhou, Qing; Song, Wen; Wu, Kaimin; Zhang, Yumei; Zhao, Yimin

    2017-10-11

    Surface functionalization by small interfering RNA (siRNA) is a novel strategy for improved implant osseointegration. A gene delivery system with safety and high transfection activity is a crucial factor for an siRNA-functionalized implant to exert its biological function. To this end, polyethylene glycol (PEG) and polyethylenimine (PEI) dual-functionalized graphene oxide (GO; nGO-PEG-PEI) may present a promising siRNA vector. In this study, nanosized nGO-PEG-PEI was prepared and optimized for siRNA delivery. Titania nanotubes (NTs) fabricated by anodic oxidation were biomodified with nGO-PEG-PEI/siRNA by cathodic electrodeposition, designated as NT-GPP/siRNA. NT-GPP/siRNA possessed benign cytocompatibility, as evaluated by cell adhesion and proliferation. Cellular uptake and knockdown efficiency of the NT-GPP/siRNA were assessed by MC3T3-E1 cells, which exhibited high siRNA delivery efficiency and sustained target gene silencing. Casein kinase-2 interacting protein-1 (Ckip-1) is a negative regulator of bone formation. siRNA-targeting Ckip-1 (siCkip-1) was introduced to the implant, and a series of in vitro and in vivo experiments were carried out to evaluate the osteogenic capacity of NT-GPP/siCkip-1. NT-GPP/siCkip-1 dramatically improved the in vitro osteogenic differentiation of MC3T3-E1 cells in terms of improved osteogenesis-related gene expression, and increased alkaline phosphatase (ALP) production, collagen secretion, and extracellular matrix (ECM) mineralization. Moreover, NT-GPP/siCkip-1 led to apparently enhanced in vivo osseointegration, as indicated by histological staining and EDX line scanning. Collectively, these findings suggest that NT-GPP/siRNA represents a practicable and promising approach for implant functionalization, showing clinical potential for dental and orthopedic applications.

  17. Spatially Controlled Delivery of siRNAs to Stem Cells in Implants Generated by Multi-Component Additive Manufacturing

    DEFF Research Database (Denmark)

    Andersen, Morten Østergaard; Le, Dang Quang Svend; Chen, Muwan

    2013-01-01

    Additive manufacturing is a promising technique in tissue engineering, as it enables truly individualized implants to be made to fit a particular defect. As previously shown, a feasible strategy to produce complex multicellular tissues is to deposit different small interfering RNA (siRNA) in porous...... implants that are subsequently sutured together. In this study, an additive manufacturing strategy to deposit carbohydrate hydrogels containing different siRNAs is applied into an implant, in a spatially controlled manner. When the obtained structures are seeded with mesenchymal stem (stromal) cells......, the selected siRNAs are delivered to the cells and induces specific and localized gene silencing. Here, it is demonstrated how to replicate part of a patient's spinal cord from a computed tomography scan, using an additive manufacturing technique to produce an implant with compartmentalized si...

  18. Room-temperature annealing of Si implantation damage in InP

    International Nuclear Information System (INIS)

    Akano, U.G.; Mitchell, I.V.

    1991-01-01

    Spontaneous recovery at 295 K of Si implant damage in InP is reported. InP(Zn) and InP(S) wafers of (100) orientation have been implanted at room temperature with 600 keV Si + ions to doses ranging from 3.6x10 11 to 2x10 14 cm -2 . Room-temperature annealing of the resultant damage has been monitored by the Rutherford backscattering/channeling technique. For Si doses ≤4x10 13 cm -2 , up to 70% of the initial damage (displaced atoms) annealed out over a period of ∼85 days. The degree of recovery was found to depend on the initial level of damage. Recovery is characterized by at least two time constants t 1 2 ∼100 days. Anneal rates observed between 295 and 375 K are consistent with an activation energy of 1.2 eV, suggesting that the migration of implant-induced vacancies is associated with the reordering of the InP lattice

  19. Location of trapped charge in aluminum-implanted SiO2

    International Nuclear Information System (INIS)

    DiMaria, D.J.; Young, D.R.; Hunter, W.R.; Serrano, C.M.

    1978-01-01

    The position of the centroid of electrons trapped on sites resulting from aluminum implantation into SiO 2 is measured by using the photo I-V technique for energies from 15 to 40 keV, oxide thicknesses from 49 to 140 nm, and post-implant annealing temperature from 600 to 1050 0 C in N 2 for 30 min. The centroid of the trapped electrons is found to be identical to that of the implanted aluminum from SIMS measurements, regardless of annealing temperature from 600 to 1050 0 C, and located closer (by less than 9 nm) to the Al--SiO 2 interface than predicted from the Lindhard-Scharff-Schott (LSS) calculations of Gibbons, Johnson, and Mylroie. Comparison of centroids determined from photo I-V and SIMS measurements as a function of SiO 2 thickness also implies that the distributions of the ions and negative trapped charge are the same. The trapping behavior of these sites is discussed in the accompanying paper by Young et al

  20. Nucleation, growth and dissolution of extended defects in implanted Si: impact on dopant diffusion

    International Nuclear Information System (INIS)

    Claverie, A.; Giles, L.F.; Omri, M.; Mauduit, B. de; Ben Assayag, G.; Mathiot, D.

    1999-01-01

    Transient Enhanced Diffusion (TED) of boron in silicon is driven by the large supersaturations of self-interstitial silicon atoms left after implantation which also often lead to the nucleation and subsequent growth, upon annealing, of extended defects. In this paper we review selected experimental results and concepts concerning boron diffusion and/or defect behavior which have recently emerged with the ion implantation community and briefly indicate how they are, or will be, currently used to improve 'predictive simulations' softwares aimed at predicting TED. In a first part, we focus our attention on TED and on the formation of defects in the case of 'direct' implantation of boron in silicon. In a second part, we review our current knowledge of the defects and of the diffusion behavior of boron when annealing preamorphised Si. In a last part, we try to compare these two cases and to find out what are the reasons for some similarities and many differences in defect types and thermal evolution depending on whether boron is implanted in crystalline or amorphous silicon. While rising many more questions, we propose a 'thermodynamical' vision of the nucleation and growth of clusters and extended defects and stress the interactions between these defects and the free Si self-interstitial atoms which surround them and are the source for TED in all cases. A pragmatic approach to the simulation of TED for various experimental conditions is proposed

  1. XPS studies of SiO/sub 2/ surface layers formed by oxygen ion implantation into silicon

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, D.; Finster, J. (Karl-Marx-Universitaet, Leipzig (German Democratic Republic). Sektion Chemie); Hensel, E.; Skorupa, W.; Kreissig, U. (Zentralinstitut fuer Kernforschung, Rossendorf bei Dresden (German Democratic Republic))

    1983-03-16

    SiO/sub 2/ surface layers of 160 nm thickness formed by /sup 16/O/sup +/ ion implantation into silicon are examined by X-ray photoelectron spectroscopy measurements into the depth after a step-by-step chemical etching. The chemical nature and the thickness of the transition layer were determined. The results of the XPS measurements show that the outer surface and the bulk of the layers formed by oxygen implantation and subsequent high temperature annealing consist of SiO/sub 2/. There is no evidence for Si or SiO/sub x/ (0SiO/sub x/ transition region between SiO/sub 2/ and Si is similar to that of thin grown oxide layers. Only its thickness is somewhat larger than in thermal oxide.

  2. Graphene synthesis on SiC: Reduced graphitization temperature by C-cluster and Ar-ion implantation

    International Nuclear Information System (INIS)

    Zhang, R.; Li, H.; Zhang, Z.D.; Wang, Z.S.; Zhou, S.Y.; Wang, Z.; Li, T.C.; Liu, J.R.; Fu, D.J.

    2015-01-01

    Thermal decomposition of SiC is a promising method for high quality production of wafer-scale graphene layers, when the high decomposition temperature of SiC is substantially reduced. The high decomposition temperature of SiC around 1400 °C is a technical obstacle. In this work, we report on graphene synthesis on 6H–SiC with reduced graphitization temperature via ion implantation. When energetic Ar, C 1 and C 6 -cluster ions implanted into 6H–SiC substrates, some of the Si–C bonds have been broken due to the electronic and nuclear collisions. Owing to the radiation damage induced bond breaking and the implanted C atoms as an additional C source the graphitization temperature was reduced by up to 200 °C

  3. Fabrication of planar optical waveguides by 6.0 MeV silicon ion implantation in Nd-doped phosphate glasses

    Science.gov (United States)

    Shen, Xiao-Liang; Dai, Han-Qing; Zhang, Liao-Lin; Wang, Yue; Zhu, Qi-Feng; Guo, Hai-Tao; Li, Wei-Nan; Liu, Chun-Xiao

    2018-04-01

    We report the fabrication of a planar optical waveguide by silicon ion implantation into Nd-doped phosphate glass at an energy of 6.0 MeV and a dose of 5.0 × 1014 ions/cm2. The change in the surface morphology of the glass after the implantation can be clearly observed by scanning electron microscopy. The measurement of the dark mode spectrum of the waveguide is conducted using a prism coupler at 632.8 nm. The refractive index distribution of the waveguide is reconstructed by the reflectivity calculation method. The near-field optical intensity profile of the waveguide is measured using an end-face coupling system. The waveguide with good optical properties on the glass matrix may be valuable for the application of the Nd-doped phosphate glass in integrated optical devices.

  4. Optical waveguide formed in Yb:GdCOB and Yb:YCOB crystals by 3.0MeV O{sup +} implantation

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Yang, E-mail: sdujy@163.com [College of Physics and Electronics, Shandong Normal University, Jinan 250014 (China)

    2013-07-15

    Planar optical waveguides were formed in Yb:GdCOB and Yb:YCOB crystals by 3.0 MeV O{sup +} ion implantation at fluence of 2 × 10{sup 15} ions/cm{sup 2} at room temperature, respectively. The prism coupling method was performed to characterize the dark-mode property of the waveguides. The refractive index profiles in the waveguides were reconstructed by reflectivity calculation method (RCM). The results show that after the implantation, a 1.5 μm-wide region with enhanced refractive-index was formed beneath the sample surfaces to act as waveguide structures for both Yb:GdCOB and Yb:YCOB.

  5. Lattice location of implanted transition metals in 3C–SiC

    CERN Document Server

    AUTHOR|(CDS)2085259; Wahl, Ulrich; Martins Correia, Joao; David Bosne, Eric; Amorim, Lígia; Silva, Daniel; Castro Ribeiro Da Silva, Manuel; Bharuth-Ram, Krishanlal; Da Costa Pereira, Lino Miguel

    2017-01-01

    We have investigated the lattice location of implanted transition metal (TM) 56Mn, 59Fe and 65Ni ions in undoped single-crystalline cubic 3C–SiC by means of the emission channeling technique using radioactive isotopes produced at the CERN-ISOLDE facility. We find that in the room temperature as-implanted state, most Mn, Fe and Ni atoms occupy carbon-coordinated tetrahedral interstitial sites (TC). Smaller TM fractions were also found on Si substitutional (SSi) sites. The TM atoms partially disappear from ideal-TC positions during annealing at temperatures between 500 °C and 700 °C, which is accompanied by an increase in the TM fraction occupying both SSi sites and random sites. An explanation is given according to what is known about the annealing mechanisms of silicon vacancies in silicon carbide. The origin of the observed lattice sites and their changes with thermal annealing are discussed and compared to the case of Si, highlighting the feature that the interstitial migration of TMs in SiC is much slo...

  6. Elastic scattering of lithium by 9Be, 10B, 12C, 13C, 16O, and 28Si from 4 to 63 MeV

    International Nuclear Information System (INIS)

    Poling, J.E.; Norbeck, E.; Carlson, R.R.

    1976-01-01

    Elastic scattering angular distributions have been measured at energies between 4.0 and 13.0 MeV for 6 Li and 7 Li beams and targets of 10 B, 12 C, 13 C, 16 O, and 28 Si. Yield curves have been measured for energies from 3.0 to 13.0 MeV for 6 Li beams and targets of 9 Be, 12 C, 13 C, 16 O, and 28 Si, and for 7 Li and 12 C. The angular distributions, supplemented by published angular distributions, have been fitted with optical-model potentials. For 6 Li+ 12 C, angular distributions were available at energies from 4.5 to 63.0 MeV. Potentials which gave fits to the data across the entire available energy range were obtained for each elastic scattering reaction. The usual ambiguities were observed in the optical-model potentials. In certain cases the back angles were not well fitted by parameter sets which were useful for all energies. The quality of the fits did not seem to be limited by experimental errors, which were generally better than 10% for our data; compound nucleus effects are presumed to be the cause of rapid energy variations in the angular distributions

  7. Incorporating Si3 N4 into PEEK to Produce Antibacterial, Osteocondutive, and Radiolucent Spinal Implants.

    Science.gov (United States)

    Pezzotti, Giuseppe; Marin, Elia; Adachi, Tetsuya; Lerussi, Federica; Rondinella, Alfredo; Boschetto, Francesco; Zhu, Wenliang; Kitajima, Takashi; Inada, Kosuke; McEntire, Bryan J; Bock, Ryan M; Bal, B Sonny; Mazda, Osam

    2018-04-24

    Polyetheretherketone (PEEK) is a popular polymeric biomaterial which is primarily used as an intervertebral spacer in spinal fusion surgery; but it is developed for trauma, prosthodontics, maxillofacial, and cranial implants. It has the purported advantages of an elastic modulus which is similar to native bone and it can be easily formed into custom 3D shapes. Nevertheless, PEEK's disadvantages include its poor antibacterial resistance, lack of bioactivity, and radiographic transparency. This study presents a simple approach to correcting these three shortcomings while preserving the base polymer's biocompatibility, chemical stability, and elastic modulus. The proposed strategy consists of preparing a PEEK composite by dispersing a minor fraction (i.e., 15 vol%) of a silicon nitride (Si 3 N 4 ) powder within its matrix. In vitro tests of PEEK composites with three Si 3 N 4 variants-β-Si 3 N 4 , α-Si 3 N 4 , and β-SiYAlON-demonstrate significant improvements in the polymer's osteoconductive versus SaOS-2 cells and bacteriostatic properties versus gram-positive Staphylococcus epidermidis bacteria. These properties are clearly a consequence of adding the bioceramic dispersoids, according to chemistry similar to that previously demonstrated for bulk Si 3 N 4 ceramics in terms of osteogenic behavior (vs both osteosarcoma and mesenchymal progenitor cells) and antibacterial properties (vs both gram-positive and gram-negative bacteria). © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Copper diffusion in Ti-Si-N layers formed by inductively coupled plasma implantation

    International Nuclear Information System (INIS)

    Ee, Y.C.; Chen, Z.; Law, S.B.; Xu, S.; Yakovlev, N.L.; Lai, M.Y.

    2006-01-01

    Ternary Ti-Si-N refractory barrier films of 15 nm thick was prepared by low frequency, high density, inductively coupled plasma implantation of N into Ti x Si y substrate. This leads to the formation of Ti-N and Si-N compounds in the ternary film. Diffusion of copper in the barrier layer after annealing treatment at various temperatures was investigated using time-of-flight secondary ion mass spectrometer (ToF-SIMS) depth profiling, X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and sheet resistance measurement. The current study found that barrier failure did not occur until 650 deg. C annealing for 30 min. The failure occurs by the diffusion of copper into the Ti-Si-N film to form Cu-Ti and Cu-N compounds. FESEM surface morphology and EDX show that copper compounds were formed on the ridge areas of the Ti-Si-N film. The sheet resistance verifies the diffusion of Cu into the Ti-Si-N film; there is a sudden drop in the resistance with Cu compound formation. This finding provides a simple and effective method of monitoring Cu diffusion in TiN-based diffusion barriers

  9. Optical and electronic properties of sub-surface conducting layers in diamond created by MeV B-implantation at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Willems van Beveren, L. H., E-mail: laurensw@unimelb.edu.au; Bowers, H.; Ganesan, K.; Johnson, B. C.; McCallum, J. C.; Prawer, S. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Liu, R. [SIMS Facility, Office of the Deputy-Vice Chancellor (Research and Development) Western Sydney University, Locked Bag 1797, Penrith, New South Wales 2751 (Australia)

    2016-06-14

    Boron implantation with in-situ dynamic annealing is used to produce highly conductive sub-surface layers in type IIa (100) diamond plates for the search of a superconducting phase transition. Here, we demonstrate that high-fluence MeV ion-implantation, at elevated temperatures avoids graphitization and can be used to achieve doping densities of 6 at. %. In order to quantify the diamond crystal damage associated with implantation Raman spectroscopy was performed, demonstrating high temperature annealing recovers the lattice. Additionally, low-temperature electronic transport measurements show evidence of charge carrier densities close to the metal-insulator-transition. After electronic characterization, secondary ion mass spectrometry was performed to map out the ion profile of the implanted plates. The analysis shows close agreement with the simulated ion-profile assuming scaling factors that take into account an average change in diamond density due to device fabrication. Finally, the data show that boron diffusion is negligible during the high temperature annealing process.

  10. The role of nitrogen in luminescent Si nanoprecipitate formation during annealing of Si ion-implanted SiO sub 2 layers

    CERN Document Server

    Kachurin, G A; Zhuravlev, K S; Ruault, M O

    2001-01-01

    SiO sub 2 layers were implanted with 25 keV Si sup + and 13 keV N sup + ions with the doses of (1-4) x 10 sup 1 sup 6 cm sup - sup 2 and (0.2-2) x 10 sup 1 sup 6 cm sup - sup 2 , respectively. Then the samples were annealed at 900-1100 deg C to form luminescent silicon nanoprecipitates. The nitrogen effect on the process is controlled by photoluminescence spectra. It is found out that the photoluminescence intensity increases considerably at the appropriate ratio between silicon and nitrogen. It has been concluded that the interaction of nitrogen with excessive silicon results in increasing the number of precipitation centers. This raises the nanocrystals number and reduces their mean size

  11. Energy dependence of isovector and isoscalar 1+ excitations in 28Si(p,p/sup '/) between 200 and 400 MeV

    International Nuclear Information System (INIS)

    Haeusser, O.; Sawafta, R.; Jeppesen, R.G.

    1988-01-01

    Forward-angle cross sections for 1 + , T = 1 and 1 + , T = 0 states in 28 Si excited by the (p,p') reaction have been measured to determine the energy dependence of important pieces of the effective nucleon-nucleus interaction. The isovector spin-transfer transitions depend on energy as expected from distorted-wave impulse approximation calculations based on the dominant V/sub Σ//sub tau/ part of the Franey-Love interaction. The parts of this interaction responsible for exciting the 9.5 MeV isosca- lar spin-flip transition predict a weaker energy dependence than is observed experimentally. The summed Gamow-Teller strength for isovector transitions below 14.5 MeV is found to be (0.89 +- 0.09) times the result of large-scale shell model calculations

  12. Fe and Cu in Si: Lattice sites and trapping at implantation-related defects

    International Nuclear Information System (INIS)

    Wahl, U.; Correia, J.G.; Rita, E.; Araujo, J.P.; Soares, J.C.

    2006-01-01

    We have used the emission channeling technique in order to study the lattice sites of radioactive 59 Fe and 67 Cu following 60 keV ion implantation into Si single crystals at fluences around 10 12 -10 14 cm -2 . We find that in the room temperature as-implanted state in high-resistivity Si both Fe and Cu occupy mainly lattice sites displaced around 0.05 nm (0.5 A) from substitutional positions. Both are released from these positions during annealing at temperatures between 300 deg. C and 600 deg. C. Fe is then found mainly on near-tetrahedral interstitial sites and further annealing causes it to be increasingly incorporated on ideal substitutional sites, on which it is stable to around 800 deg. C. We have strong indications that during annealing around 600 deg. C, along with the dominance of interstitial Fe, a redistribution towards the surface takes place, suggesting that the subsequent formation of ideal substitutional Fe may be related to the trapping of Fe at R p /2, half of its implanted depth. Possible R p /2 trapping might also have taken place in our Cu experiments but appears to be less efficient since Cu tended to escape to the bulk of the samples

  13. Stress in ion-implanted CVD Si3N4 films

    International Nuclear Information System (INIS)

    EerNisse, E.P.

    1977-01-01

    The compressive stress buildup caused in chemical-vapor-deposited (CVD) Si 3 N 4 films by ion implantation is shown to be caused entirely by atomic collision effects, ionization effects being unimportant. The stress introduction rate is shown to be independent of CVD processing variables and O content of the film. The maximum attainable compressive stress change is 3.5 x 10 10 dyn/cm 2 , resulting in a maximum net compressive stress of 2 x 10 10 dyn/cm 2 for films on Si where the as-deposited films inherently have 1.5 x 10 10 dyn/cm 2 tensile stress before ion implantation. Results are presented which show that O in the films inhibits thermal annealing of the ion-implantation-induced compressive stress. Results for introduction rate and annealing effects are presented in normalized form so that workers can use the effects for intentional stress level adjustment in the films to reduce probability of cracking and detachment

  14. Characteristic electron energy loss spectra in SiC buried layers formed by C+ implantation into crystalline silicon

    International Nuclear Information System (INIS)

    Yan Hui; Chen Guanghua; Kwok, R.W.M.

    1998-01-01

    SiC buried layers were synthesized by a metal vapor vacuum arc ion source, with C + ions implanted into crystalline Si substrates. According to X-ray photoelectron spectroscopy, the characteristic electron energy loss spectra of the SiC buried layers were studied. It was found that the characteristic electron energy loss spectra depend on the profiles of the carbon content, and correlate well with the order of the buried layers

  15. Synthesis of metastable A-15 ''Nb3Si'' by ion implantation and on its superconducting transition temperature

    International Nuclear Information System (INIS)

    Clapp, M.T.; Rose, R.M.

    1980-01-01

    The authors have found a new technique for the synthesis of metastable compounds of well-defined composition: namely, ion implantation of a selected element into the desired crystal structure. [M.T. Clapp and R.M. Rose, Appl. Phys. Lett. 33, 205 (1978)]. Starting with a substrate material of A-15 Nb 3 Al/sub 0.9/Si/sub 0.1/, two basic approaches were tried towards the formation of A-15 Nb 3 Si by Si implantation: (1) direct replacement of the Al by Si and (2) implantation into a surface layer depleted of Al. This latter approach proved to be the most successful. It consisted of removing the Al by a diffusion anneal and replacing the Al deficiency by sequential Si implantations. Upon subsequent heat treatment a surface layer of A-15 Nb 3 Al/sub 0.2/Si/sub 0.8/ was produced. Details of the experimental procedure and a discussion of the superconducting transition temperature measurements of the implanted surfaces are presented

  16. Amorphous-crystalline interface evolution during Solid Phase Epitaxy Regrowth of SiGe films amorphized by ion implantation

    International Nuclear Information System (INIS)

    D'Angelo, D.; Piro, A.M.; Mirabella, S.; Bongiorno, C.; Romano, L.; Terrasi, A.; Grimaldi, M.G.

    2007-01-01

    Transmission Electron Microscopy was combined with Time Resolved Reflectivity to study the amorphous-crystalline (a-c) interface evolution during Solid Phase Epitaxy Regrowth (SPER) of Si 0.83 Ge 0.17 films deposited on Si by Molecular Beam Epitaxy and amorphized with Ge + ion implantation. Starting from the Si/SiGe interface, a 20 nm thick layer regrows free of defects with the same SPER rate of pure Si. The remaining SiGe regrows with planar defects and dislocations, accompanied by a decrease of the SPER velocity. The sample was also studied after implantation with B or P. In these cases, the SPER rate raises following the doping concentration profile, but no difference in the defect-free layer thickness was observed compared to the un-implanted sample. On the other hand, B or P introduction reduces the a-c interface roughness, while B-P co-implantation produces roughness comparable to the un-implanted sample

  17. Influence of n$^{+}$ and p$^{+}$ doping on the lattice sites of implanted Fe in Si

    CERN Document Server

    Silva, Daniel José; Correia, João Guilherme; Araújo, João Pedro

    2013-01-01

    We report on the lattice location of implanted $^{59}$Fe in n$^{+}$ and p$^{+}$ type Si by means of emission channeling. We found clear evidence that the preferred lattice location of Fe changes with the doping of the material. While in n$^{+}$ type Si Fe prefers displaced bond-centered (BC) sites for annealing temperatures up to 600°C, changing to ideal substitutional sites above 700°C, in p$^{+}$ type Si, Fe prefers to be in displaced tetrahedral interstitial positions after all annealing steps. The dominant lattice sites of Fe in n$^{+}$ type Si therefore seem to be well characterized for all annealing temperatures by the incorporation of Fe into vacancy-related complexes, either into single vacancies which leads to Fe on ideal substitutional sites, or multiple vacancies, which leads to its incorporation near BC sites. In contrast, in p$^{+}$ type Si, the major fraction of Fe is clearly interstitial (near-T or ideal T) for all annealing temperatures. The formation and possible lattice sites of Fe in FeB...

  18. Irradiation effects of 6 MeV electron on electrical properties of Al/Al2O3/n-Si MOS capacitors

    International Nuclear Information System (INIS)

    Laha, P.; Banerjee, I.; Bajaj, A.; Chakraborty, P.; Barhai, P.K.; Dahiwale, S.S.; Das, A.K.; Bhoraskar, V.N.; Kim, D.; Mahapatra, S.K.

    2012-01-01

    The influence of 6 MeV electron irradiation on the electrical properties of Al/Al 2 O 3 /n-Si metal–oxide–semiconductor (MOS) capacitors has been investigated. Using rf magnetron sputtering deposition technique, Al/Al 2 O 3 /n-Si MOS capacitors were fabricated and such twelve capacitors were divided into four groups. The first group of MOS capacitors was not irradiated with 6 MeV electrons and treated as virgin. The second group, third group and fourth group of MOS capacitors were irradiated with 6 MeV electrons at 10 kGy, 20 kGy, and 30 kGy doses, respectively, keeping the dose rate ∼1 kGy/min. The variations in crystallinity of the virgin and irradiated MOS capacitors have been compared from GIXRD (Grazing Incidence X-ray Diffraction) spectra. Thickness and in-depth elemental distributions of individual layers were performed using Secondary Ion Mass Spectrometry (SIMS). The device parameters like flat band voltage (V FB ) and interface trap density (D it ) of virgin and irradiated MOS capacitors have been calculated from C vs V and G/ω vs V curve, respectively. The electrical properties of the capacitors were investigated from the tan δ vs V graph. The device parameters were estimated using C–V and G/ω–V measurements. Poole–Frenkel coefficient (β PF ) of the MOS capacitors was determined from leakage current (I)–voltage (V) measurement. The leakage current mechanism was proposed from the β PF value. - Highlights: ► The electron irradiation effects make variation in the device parameters. ► The device parameters changes due to percentage of defects and charge trapping. ► Leakage current of Al/Al 2 O 3 /n-Si changes due to interface dangling bonds. ► The leakage current mechanism of MOS structures is due to Poole-Frenkel effect.

  19. Investigation of states in 30P via the 30Si(3He,t)30P reaction at 30 MeV

    International Nuclear Information System (INIS)

    Ramstein, B.; Rosier, L.H.; Paris-11 Univ., 91 - Orsay; Meijer, R.J. de

    1981-01-01

    The 30 Si( 3 He,t) 30 P reaction has been measured for about 100 levels in 30 P with Esub(x)<8.8 MeV. Little selectivity in the population of states has been observed. For 75 levels angular distributions have been analysed using a 'fingerprint method' by determining the L-value from a comparison in shape with transition to states with known Jsup(π). For possible mixed L-transitions a dominance of the higher L-value is observed for almost all cases. Coulomb displacement energy calculations utilizing shell-model wave functions have been used to identify T=1 states

  20. Spectroscopy of the {sup 29}Si(p,{gamma}) reaction for E{sub p}=1.00{endash}1.75 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Vavrina, G.A.; Bybee, C.R.; Mitchell, G.E.; Moore, E.F.; Shriner, J.D. [North Carolina State University, Raleigh, North Carolina 27695 (United States); Bilpuch, E.G.; Wallace, P.M.; Westerfeldt, C.R. [Duke University, Durham, North Carolina 27708 (United States); Shriner, J.F. , Jr. [Tennessee Technological University, Cookeville, Tennessee 38505 (United States)

    1997-03-01

    The {sup 29}Si(p,{gamma}) reaction has been studied in the range E{sub p}=1.00{endash}1.75 MeV. Three previously unknown states in {sup 30}P were identified, and one state previously assigned to {sup 30}P was identified as a state in {sup 14}N. Gamma-ray strengths were determined for the three new levels, and branching ratios were measured for 17 resonances. Revised J{sup {pi}};T assignments were made for nine of these states. {copyright} {ital 1997} {ital The American Physical Society}

  1. Cross sections measurements for the forward elastic scattering of 13 MeV 6,7 Li and 24 MeV 16 O by 9 Be, 12 C, 16 O and 28 Si

    International Nuclear Information System (INIS)

    Liendo, J.A.; Gonzalez, A.C.; Fletcher, N.R.; Caussyn, D.D.

    2001-01-01

    Full text: Absolute elastic cross sections have been measured for targets of 9 Be, 12 C 16 O, 28 Si and 197 Au being bombarded by beams of 13 MeV 6 7 Li and 24 MeV 16 O. The relevant yields were collected simultaneously at 12.450, 16.450, 20.450 and 280. The confidence of a forward elastic scattering method proposed previously to carry out multi-elemental analysis of evaporated liquid samples depends on the precision and accuracy of the cross sections reported in this work.The 24 MeV 16 0 + 197 Au reaction was used to determine the detector solid angles with uncertainties of approximately 3%. Some of the 16 O-beam reactions Some of the 16 O beam reactions have been shown to be consistent with the Rutherford formula predictions at several angles. This allowed us to obtain target thickness independent cross sections for the lithium beam initiated reactions with uncertainties close to 7%. In general, the 6 7 Li-beam reaction cross sections were found not to be consistent with the Coulomb scattering formula. In order to test the internal consistency of our measured cross sections, they were used to determine the elemental densities of several selected targets containing beryllium, carbon, oxygen and silicon. These targets were bombarded with the same beam types and energies used to measure the cross sections and, for every element of interest contained in each target, elemental density values were obtained at some of the scattering angles quoted above. Agreements between some of our results and those of a previous work support the validity of our measurements. (Author)

  2. Damage formation and recovery in Fe implanted 6H–SiC

    CERN Document Server

    Miranda, Pedro; Catarino, Norberto; Lorenz, Katharina; Correia, João Guilherme; Alves, Eduardo

    2012-01-01

    Silicon carbide doped with magnetic ions such as Fe, Mn, Ni or Co could make this wide band gap semiconductor part of the diluted magnetic semiconductor family. In this study, we report the implantation of 6H-SiC single crystals with magnetic $^{56}$Fe$^{+}$ ions with an energy of 150 keV. The samples were implanted with 5E14 Fe$^+$/cm$^{2}$ and 1E16 Fe$^+$/cm$^{2}$ at different temperatures to study the damage formation and lattice site location. The samples were subsequently annealed up to 1500°C in vacuum in order to remove the implantation damage. The effect of the annealing was followed by Rutherford Backscattering/Channeling (RBS/C) measurements. The results show that samples implanted above the critical amorphization temperature reveal a high fraction of Fe incorporated into regular sites along the [0001] axis. After the annealing at 1000°C, a maximum fraction of 75%, corresponding to a total of 3.8E14 Fe$^{+}$/cm$^{2}$, was measured in regular sites along the [0001] axis. A comparison is made betwee...

  3. Hyperfine electric parameters calculation in Si samples implanted with {sup 57}Mn→{sup 57}Fe

    Energy Technology Data Exchange (ETDEWEB)

    Abreu, Y., E-mail: yabreu@ceaden.edu.cu [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Calle 30 No. 502 e/5ta y 7ma Ave., 11300 Miramar, Playa, La Habana (Cuba); Cruz, C.M.; Piñera, I.; Leyva, A.; Cabal, A.E. [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Calle 30 No. 502 e/5ta y 7ma Ave., 11300 Miramar, Playa, La Habana (Cuba); Van Espen, P. [Departement Chemie, Universiteit Antwerpen, Middelheimcampus, G.V.130, Groenenborgerlaan 171, 2020 Antwerpen (Belgium); Van Remortel, N. [Departement Fysica, Universiteit Antwerpen, Middelheimcampus, G.U.236, Groenenborgerlaan 171, 2020 Antwerpen (Belgium)

    2014-07-15

    Nowadays the electronic structure calculations allow the study of complex systems determining the hyperfine parameters measured at a probe atom, including the presence of crystalline defects. The hyperfine electric parameters have been measured by Mössbauer spectroscopy in silicon materials implanted with {sup 57}Mn→{sup 57}Fe ions, observing four main contributions to the spectra. Nevertheless, some ambiguities still remain in the {sup 57}Fe Mössbauer spectra interpretation in this case, regarding the damage configurations and its evolution with annealing. In the present work several implantation environments are evaluated and the {sup 57}Fe hyperfine parameters are calculated. The observed correlation among the studied local environments and the experimental observations is presented, and a tentative microscopic description of the behavior and thermal evolution of the characteristic defects local environments of the probe atoms concerning the location of vacancies and interstitial Si in the neighborhood of {sup 57}Fe ions in substitutional and interstitial sites is proposed.

  4. Exploring of defects in He+ implanted Si(100) by slow positron beam

    International Nuclear Information System (INIS)

    Zhang Tianhao; Weng Huimin; Fan Yangmei; Du Jiangfeng; Zhou Xianyi; Han Rongdian; Zhang Miao; Lin Chenglu

    2001-01-01

    Si(100) crystal implanted by 5 x 10 16 cm -2 , 140 keV He + was probed by slow positron beam, and defect distribution along depth was obtained from the relation between S parameter and positron incidence energy. The near surface region of implanted sample was only slightly damaged. Small vacancies and vacancy clusters less than 1 nm in diameter were the dominant defects, while the deeper region around the He + projected range was heavily damaged and had dense larger helium micro-bubbles and microvoids. Thermal anneal study at different temperatures showed that low temperature annealing could remove most vacancy-type defects effectively. However, annealing at high temperature enlarged the diameters of micro-bubbles and microvoids

  5. Space charge limitation of the current in implanted SiO2 layers

    International Nuclear Information System (INIS)

    Szydlo, N.; Poirier, R.

    1974-01-01

    Metal-oxide-semiconductor capacitors were studied where the metal is a semitransparent gold layer of 5mm diameter, the oxide is thermal silica whose, thickness depends on the nature of the implant, and the semiconductor is N-type silicon of 5 ohms/cm. The SiO 2 thickness was chosen in such a way that the maximum of the profile of the implanted substance is in the medium of the oxide layer. In the case of virgin silica, the oscillations in the photocurrent versus energy and exponential variations versus the applied voltage show that the photoconduction obeys the model of injection limited current. In the case of the oxide after ion bombardment, the photocurrent similarity, independent of the direction of the electric field in silica, shows that volume transport phenomena become preponderent [fr

  6. A study of vacancy-type defects in B+-implanted SiO2/Si by a slow positron beam

    International Nuclear Information System (INIS)

    Uedono, Akira; Tanigawa, Shoichiro; Sugiura, Jun; Ogasawara, Makoto.

    1989-01-01

    Variable-energy (0∼30 keV) positron beam studies have been carried out on 80 keV B + -implanted SiO 2 (43 nm)/Si specimens. Doppler broadening profiles of the positron annihilation as a function of the incident positron energy were shown to be quite sensitive for the detection of vacancy-type defects introduced by B + -implantation. The average depth of the defected regions was found to shift towards the surface of the specimen with increasing the dose of B + ions. This effect is attributed to the accumulation of vacancy-type defects at the SiO 2 /Si interface. Dominant defect species were identified as vacancy clusters by their annealing stage. (author)

  7. Damage accumulation and dopant migration during shallow As and Sb implantation into Si

    Energy Technology Data Exchange (ETDEWEB)

    Werner, M.; Berg, J.A. van den E-mail: j.a.vandenberg@salford.ac.uk; Armour, D.G.; Vandervorst, W.; Collart, E.H.J.; Goldberg, R.D.; Bailey, P.; Noakes, T.C.Q

    2004-02-01

    The damage evolution and concomitant dopant redistribution as a function of ion fluence during ultra shallow, heavy ion implants into Si have been investigated using medium energy ion scattering (MEIS) and secondary ion mass spectrometry (SIMS). These studies involved As and Sb ions implanted at room temperature, at energies of 2.5 and 2 keV to doses from 3 x 10{sup 13} to 5 x 10{sup 15} cm{sup -2}. MEIS is capable of detecting both the displaced atom and implant profiles with sub-nanometre depth resolution. These studies show that for doses up to 1 x 10{sup 14} cm{sup -2} (at which an amorphous layer is formed) the damage build up does not follow the energy deposition function. Instead it proceeds through the initial formation of a {approx}4 nm wide amorphous layer immediately under the oxide, that grows inwards into the bulk with increasing dose. This behaviour is explained in terms of the migration of some of the interstitials produced along the length of the collision cascade to the oxide or amorphous/crystal Si interface, where their trapping nucleates the growth of a shallow amorphous layer and the subsequent planar growth inwards of the damage layer. Although for doses {>=}4 x 10{sup 14} cm{sup -2} the As depth profiles agreed well with TRIM calculations, for lower doses As was observed to have a shallower profile, {approx}2 nm nearer to the surface. This behaviour is related the growth of the amorphous layer and ascribed to the movement of As into the near-surface amorphous layer (probably mediated by point defect migration) in which the larger dopant is accommodated more easily. SIMS studies have confirmed this dopant segregation effect. Shallow Sb implants also exhibit this novel dopant movement effect for low doses in combination with a damage evolution similar to As.

  8. Damage accumulation and dopant migration during shallow As and Sb implantation into Si

    International Nuclear Information System (INIS)

    Werner, M.; Berg, J.A. van den; Armour, D.G.; Vandervorst, W.; Collart, E.H.J.; Goldberg, R.D.; Bailey, P.; Noakes, T.C.Q.

    2004-01-01

    The damage evolution and concomitant dopant redistribution as a function of ion fluence during ultra shallow, heavy ion implants into Si have been investigated using medium energy ion scattering (MEIS) and secondary ion mass spectrometry (SIMS). These studies involved As and Sb ions implanted at room temperature, at energies of 2.5 and 2 keV to doses from 3 x 10 13 to 5 x 10 15 cm -2 . MEIS is capable of detecting both the displaced atom and implant profiles with sub-nanometre depth resolution. These studies show that for doses up to 1 x 10 14 cm -2 (at which an amorphous layer is formed) the damage build up does not follow the energy deposition function. Instead it proceeds through the initial formation of a ∼4 nm wide amorphous layer immediately under the oxide, that grows inwards into the bulk with increasing dose. This behaviour is explained in terms of the migration of some of the interstitials produced along the length of the collision cascade to the oxide or amorphous/crystal Si interface, where their trapping nucleates the growth of a shallow amorphous layer and the subsequent planar growth inwards of the damage layer. Although for doses ≥4 x 10 14 cm -2 the As depth profiles agreed well with TRIM calculations, for lower doses As was observed to have a shallower profile, ∼2 nm nearer to the surface. This behaviour is related the growth of the amorphous layer and ascribed to the movement of As into the near-surface amorphous layer (probably mediated by point defect migration) in which the larger dopant is accommodated more easily. SIMS studies have confirmed this dopant segregation effect. Shallow Sb implants also exhibit this novel dopant movement effect for low doses in combination with a damage evolution similar to As

  9. Fabrication of SGOI material by oxidation of an epitaxial SiGe layer on an SOI wafer with H ions implantation

    International Nuclear Information System (INIS)

    Cheng Xinli; Chen Zhijun; Wang Yongjin; Jin Bo; Zhang Feng; Zou Shichang

    2005-01-01

    SGOI materials were fabricated by thermal dry oxidation of epitaxial H-ion implanted SiGe layers on SOI wafers. The hydrogen implantation was found to delay the oxidation rate of SiGe layer and to decrease the loss of Ge atoms during oxidation. Further, the H implantation did not degrade the crystallinity of SiGe layer during fabrication of the SGOI

  10. Pulsed Q-switched ruby laser annealing of Bi implanted Si crystals investigated by channeling

    International Nuclear Information System (INIS)

    Deutch, B.I.; Shih-Chang, T.; Shang-Hwai, L.; Zu-Yao, Z.; Jia-Zeng, H.; Ren-Zhi, D.; Te-Chang, C.; De-Xin, C.

    1979-01-01

    Channeling was used to investigate pulsed, Q switched ruby-laser annealed and thermally annealed Si single crystals implanted with 40-keV Bi ions to a dose of 10 15 atoms/cm 2 . After thermal annealing, residual damage decreased with increasing annealing temperature to a minimum value of 30% at 900 0 C. The Bi atoms in substitutional sites reached a maximum value (50%) after annealing at 750 0 C but decreased with increasing annealing temperature. Out diffusion of Bi atoms occurred at temperatures higher than 625 0 C. For comparison, the residual damage disappeared almost completely after pulsed-laser annealing (30 ns pulse width, Energy, E = 3J/cm 2 ). The concentration of Bi in Si exceeded its solid solubility by an order of magnitude; 95% of Bi atoms were annealed to substitutional sites. Laser pulses of different energies were used to investigate the efficiency of annealing. (author)

  11. Micro-Raman depth profile investigations of beveled Al+-ion implanted 6H-SiC samples

    International Nuclear Information System (INIS)

    Zuk, J.; Romanek, J.; Skorupa, W.

    2009-01-01

    6H-SiC single crystals were implanted with 450 keV Al + -ions to a fluence of 3.4 x 10 15 cm -2 , and in a separate experiment subjected to multiple Al + implantations with the four energies: 450, 240, 115 and 50 keV and different fluences to obtain rectangular-like depth distributions of Al in SiC. The implantations were performed along [0 0 0 1] channeling and non-channeling ('random') directions. Subsequently, the samples were annealed for 10 min at 1650 deg. C in an argon atmosphere. The depth profiles of the implanted Al atoms were obtained by secondary ion mass spectrometry (SIMS). Following implantation and annealing, the samples were beveled by mechanical polishing. Confocal micro-Raman spectroscopic investigations were performed with a 532 nm wavelength laser beam of a 1 μm focus diameter. The technique was used to determine precisely the depth profiles of TO and LO phonon lines intensity in the beveled samples to a depth of about 2000 nm. Micro-Raman spectroscopy was also found to be useful in monitoring very low levels of disorder remaining in the Al + implanted and annealed 6H-SiC samples. The micro-Raman technique combined with sample beveling also made it possible the determination of optical absorption coefficient profiles in implanted subsurface layers.

  12. A pulse synthesis of beta-FeSi sub 2 layers on silicon implanted with Fe sup + ions

    CERN Document Server

    Batalov, R I; Terukov, E I; Kudoyarova, V K; Weiser, G; Kuehne, H

    2001-01-01

    The synthesis of thin beta-FeSi sub 2 films was performed by means of the Fe sup + ion implantation into Si (100) and the following nanosecond pulsed ion treatment of implanted layer. Using the beta-FeSi sub 2 beta-FeSi sub 2 e X-ray diffraction it is shown that the pulsed ion treatment results in the generation of the mixture of two phases: FeSi and beta-FeSi sub 2 with stressed crystal lattices. The following short-time annealing leads to the total transformation of the FeSi phase into the beta-FeSi sub 2 one. The Raman scattering data prove the generation of the beta-FeSi sub 2 at the high degree of the silicon crystallinity. The experimental results of the optical absorption testify to the formation of beta-FeSi sub 2 layers and precipitates with the straight-band structure. The photoluminescence signal at lambda approx = 1.56 mu m observes up to 210 K

  13. In Vitro and In Vivo Evaluation of Zinc-Modified Ca–Si-Based Ceramic Coating for Bone Implants

    Science.gov (United States)

    Zheng, Xuebin; He, Dannong; Ye, Xiaojian; Wang, Meiyan

    2013-01-01

    The host response to calcium silicate ceramic coatings is not always favorable because of their high dissolution rates, leading to high pH within the surrounding physiological environment. Recently, a zinc-incorporated calcium silicate-based ceramic Ca2ZnSi2O7 coating, developed on a Ti-6Al-4V substrate using plasma-spray technology, was found to exhibit improved chemical stability and biocompatibility. This study aimed to investigate and compare the in vitro response of osteoblastic MC3T3-E1 cells cultured on Ca2ZnSi2O7 coating, CaSiO3 coating, and uncoated Ti-6Al-4V titanium control at cellular and molecular level. Our results showed Ca2ZnSi2O7 coating enhanced MC3T3-E1 cell attachment, proliferation, and differentiation compared to CaSiO3 coating and control. In addition, Ca2ZnSi2O7 coating increased mRNA levels of osteoblast-related genes (alkaline phosphatase, procollagen α1(I), osteocalcin), insulin-like growth factor-I (IGF-I), and transforming growth factor-β1 (TGF-β1). The in vivo osteoconductive properties of Ca2ZnSi2O7 coating, compared to CaSiO3 coating and control, was investigated using a rabbit femur defect model. Histological and histomorphometrical analysis demonstrated new bone formation in direct contact with the Ca2ZnSi2O7 coating surface in absence of fibrous tissue and higher bone-implant contact rate (BIC) in the Ca2ZnSi2O7 coating group, indicating better biocompatibility and faster osseointegration than CaSiO3 coated and control implants. These results indicate Ca2ZnSi2O7 coated implants have applications in bone tissue regeneration, since they are biocompatible and able to osseointegrate with host bone. PMID:23483914

  14. In vitro and in vivo evaluation of zinc-modified ca-si-based ceramic coating for bone implants.

    Science.gov (United States)

    Yu, Jiangming; Li, Kai; Zheng, Xuebin; He, Dannong; Ye, Xiaojian; Wang, Meiyan

    2013-01-01

    The host response to calcium silicate ceramic coatings is not always favorable because of their high dissolution rates, leading to high pH within the surrounding physiological environment. Recently, a zinc-incorporated calcium silicate-based ceramic Ca2ZnSi2O7 coating, developed on a Ti-6Al-4V substrate using plasma-spray technology, was found to exhibit improved chemical stability and biocompatibility. This study aimed to investigate and compare the in vitro response of osteoblastic MC3T3-E1 cells cultured on Ca2ZnSi2O7 coating, CaSiO3 coating, and uncoated Ti-6Al-4V titanium control at cellular and molecular level. Our results showed Ca2ZnSi2O7 coating enhanced MC3T3-E1 cell attachment, proliferation, and differentiation compared to CaSiO3 coating and control. In addition, Ca2ZnSi2O7 coating increased mRNA levels of osteoblast-related genes (alkaline phosphatase, procollagen α1(I), osteocalcin), insulin-like growth factor-I (IGF-I), and transforming growth factor-β1 (TGF-β1). The in vivo osteoconductive properties of Ca2ZnSi2O7 coating, compared to CaSiO3 coating and control, was investigated using a rabbit femur defect model. Histological and histomorphometrical analysis demonstrated new bone formation in direct contact with the Ca2ZnSi2O7 coating surface in absence of fibrous tissue and higher bone-implant contact rate (BIC) in the Ca2ZnSi2O7 coating group, indicating better biocompatibility and faster osseointegration than CaSiO3 coated and control implants. These results indicate Ca2ZnSi2O7 coated implants have applications in bone tissue regeneration, since they are biocompatible and able to osseointegrate with host bone.

  15. The effects of irradiation and proton implantation on the density of mobile protons in SiO2 films

    International Nuclear Information System (INIS)

    Vanheusden, K.

    1998-04-01

    Proton implantation into the buried oxide of Si/SiO 2 /Si structures does not introduce mobile protons. The cross section for capture of radiation-induced electrons by mobile protons is two orders of magnitude smaller than for electron capture by trapped holes. The data provide new insights into the atomic mechanisms governing the generation and radiation tolerance of mobile protons in SiO 2 . This can lead to improved techniques for production and radiation hardening of radiation tolerant memory devices

  16. Formation of 2-D arrays of semiconductor nanocrystals or semiconductor-rich nanolayers by very low-energy Si or Ge ion implantation in silicon oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Normand, P. E-mail: p.normand@imel.demokritos.gr; Beltsios, K.; Kapetanakis, E.; Tsoukalas, D.; Travlos, T.; Stoemenos, J.; Berg, J. van den; Zhang, S.; Vieu, C.; Launois, H.; Gautier, J.; Jourdan, F.; Palun, L

    2001-05-01

    The structure evolution of annealed low-energy Si- or Ge-implanted thin and thick SiO{sub 2} layers is studied. The majority of Si (or Ge) species is restricted within a 3-4 nm thick layer. Si is able to separate and crystallize more easily than Ge. The glass transition temperature of the as-implanted structure has a significant effect on the progress of phase transformations accompanying annealing.

  17. Formation of 2-D arrays of semiconductor nanocrystals or semiconductor-rich nanolayers by very low-energy Si or Ge ion implantation in silicon oxide films

    International Nuclear Information System (INIS)

    Normand, P.; Beltsios, K.; Kapetanakis, E.; Tsoukalas, D.; Travlos, T.; Stoemenos, J.; Berg, J. van den; Zhang, S.; Vieu, C.; Launois, H.; Gautier, J.; Jourdan, F.; Palun, L.

    2001-01-01

    The structure evolution of annealed low-energy Si- or Ge-implanted thin and thick SiO 2 layers is studied. The majority of Si (or Ge) species is restricted within a 3-4 nm thick layer. Si is able to separate and crystallize more easily than Ge. The glass transition temperature of the as-implanted structure has a significant effect on the progress of phase transformations accompanying annealing

  18. Design and application of ion-implanted polySi passivating contacts for interdigitated back contact c-Si solar cells

    International Nuclear Information System (INIS)

    Yang, Guangtao; Ingenito, Andrea; Hameren, Nienke van; Isabella, Olindo; Zeman, Miro

    2016-01-01

    Ion-implanted passivating contacts based on poly-crystalline silicon (polySi) are enabled by tunneling oxide, optimized, and used to fabricate interdigitated back contact (IBC) solar cells. Both n-type (phosphorous doped) and p-type (boron doped) passivating contacts are fabricated by ion-implantation of intrinsic polySi layers deposited via low-pressure chemical vapor deposition and subsequently annealed. The impact of doping profile on the passivation quality of the polySi doped contacts is studied for both polarities. It was found that an excellent surface passivation could be obtained by confining as much as possible the implanted-and-activated dopants within the polySi layers. The doping profile in the polySi was controlled by modifying the polySi thickness, the energy and dose of ion-implantation, and the temperature and time of annealing. An implied open-circuit voltage of 721 mV for n-type and 692 mV for p-type passivating contacts was achieved. Besides the high passivating quality, the developed passivating contacts exhibit reasonable high conductivity (R sh n-type  = 95 Ω/□ and R sh p-type  = 120 Ω/□). An efficiency of 19.2% (V oc  = 673 mV, J sc  = 38.0 mA/cm 2 , FF = 75.2%, and pseudo-FF = 83.2%) was achieved on a front-textured IBC solar cell with polySi passivating contacts as both back surface field and emitter. By improving the front-side passivation, a V OC of 696 mV was also measured

  19. Specific features of the current–voltage characteristics of SiO{sub 2}/4H-SiC MIS structures with phosphorus implanted into silicon carbide

    Energy Technology Data Exchange (ETDEWEB)

    Mikhaylova, A. I., E-mail: m.aleksey.spb@gmail.com; Afanasyev, A. V.; Ilyin, V. A.; Luchinin, V. V. [St. Petersburg State Electrotechnical University LETI (Russian Federation); Sledziewski, T. [Friedrich–Alexander–Universität Erlangen–Nürnberg (Germany); Reshanov, S. A.; Schöner, A. [Ascatron AB (Sweden); Krieger, M. [Friedrich–Alexander–Universität Erlangen–Nürnberg (Germany)

    2016-01-15

    The effect of phosphorus implantation into a 4H-SiC epitaxial layer immediately before the thermal growth of a gate insulator in an atmosphere of dry oxygen on the reliability of the gate insulator is studied. It is found that, together with passivating surface states, the introduction of phosphorus ions leads to insignificant weakening of the dielectric breakdown field and to a decrease in the height of the energy barrier between silicon carbide and the insulator, which is due to the presence of phosphorus atoms at the 4H-SiC/SiO{sub 2} interface and in the bulk of silicon dioxide.

  20. High Power Self-Aligned, Trench-Implanted 4H-SiC JFETs

    Directory of Open Access Journals (Sweden)

    Vamvoukakis K.

    2017-01-01

    Full Text Available The process technology for the fabrication of 4H-SiC trenched-implanted-gate 4H–SiC vertical-channel JFET (TI-VJFET has been developed. The optimized TIVJFETs have been fabricated with self-aligned nickel silicide source and gate contacts using a process sequence that greatly reduces process complexity as it includes only four lithography steps. A source-pillars sidewall oxidation and subsequent removal of the metallization from the top of the sidewall oxide ensured isolation between gate and source. Optimum planarization of the source pillars top has been performed by cyclotene spin coating and etch back. The effect of the channel geometry on the electrical characteristics has been studied by varying its length (0.3 and 1.2μm and its width (1.5-5μm. The voltage blocking exhibits a triode shape, which is typical for a static-induction transistor (SIT operation. The transistors exhibited high ON current handling capabilities (Direct Current density >1kA/cm2 and values of RON ranging from 6 - 12 mΩ•cm2 depending on the channel length. Maximum voltage blocking was 800V limited by the edge termination. The maximum voltage gain was 51. Most transistors were normally-on. Normally-off operation has been observed for transistors lower than 2μm channel width (mask level and deep implantation.

  1. Martensitic Transformations and Mechanical and Corrosion Properties of Fe-Mn-Si Alloys for Biodegradable Medical Implants

    Science.gov (United States)

    Drevet, Richard; Zhukova, Yulia; Malikova, Polina; Dubinskiy, Sergey; Korotitskiy, Andrey; Pustov, Yury; Prokoshkin, Sergey

    2018-03-01

    The Fe-Mn-Si alloys are promising materials for biodegradable metallic implants for temporary healing process in the human body. In this study, three different compositions are considered (Fe23Mn5Si, Fe26Mn5Si, and Fe30Mn5Si, all in wt pct). The phase composition analysis by XRD reveals ɛ-martensite, α-martensite, and γ-austenite in various proportions depending on the manganese amount. The DSC study shows that the starting temperature of the martensitic transformation ( M s) of the alloys decreases when the manganese content increases (416 K, 401 K, and 323 K (143 °C, 128 °C, and 50 °C) for the Fe23Mn5Si, Fe26Mn5Si, and Fe30Mn5Si alloys, respectively). Moreover, mechanical compression tests indicate that these alloys have a much lower Young's modulus ( E) than pure iron (220 GPa), i.e., 145, 133, and 118 GPa for the Fe23Mn5Si, Fe26Mn5Si, and Fe30Mn5Si alloys, respectively. The corrosion behavior of the alloys is studied in Hank's solution at 310 K (37 °C) using electrochemical experiments and weight loss measurements. The corrosion kinetics of the Fe-Mn-Si increases with the manganese content (0.48, 0.59, and 0.80 mm/year for the Fe23Mn5Si, Fe26Mn5Si, and Fe30Mn5Si alloys, respectively). The alloy with the highest manganese content shows the most promising properties for biomedical applications as a biodegradable and biomechanically compatible implant material.

  2. Vacancy-type defects and their annealing processes in ion-implanted Si studied by a variable-energy positron beam

    International Nuclear Information System (INIS)

    Uedono, A.; Wei, L.; Tanigawa, S.; Sugiura, J.; Ogasawara, M.

    1992-01-01

    Vacancy-type defects in B + -, P + - and Si + -ion implanted SiO 2 (43 nm)/Si(100) and Si(100) were studied by a variable-energy positron beam. Depth distributions of vacancy-type defects were obtained from measurements of Doppler broadening profiles of the positron annihilation as a function of incident positron energy. For 200-keV P + -implanted specimen with a dose of 5 x 10 13 P/cm 2 , the damaged layers induced by ion-implantation were found to extend far beyond the stopping range of P-atoms. For 80-keV B + -implanted SiO 2 (43 nm)/Si(100) specimens with different ion-currents, an increase of the ion-current introduced a homogeneous amorphous layer in the subsurface region. Dominant defect species in B + - and P + -implanted specimen were identified as vacancy clusters from their annealing behavior. (author)

  3. Atomic scale Monte Carlo simulations of BF3 plasma immersion ion implantation in Si

    International Nuclear Information System (INIS)

    La Magna, Antonino; Fisicaro, Giuseppe; Nicotra, Giuseppe; Spiegel, Yohann; Torregrosa, Frank

    2014-01-01

    We present a numerical model aimed to accurately simulate the plasma immersion ion implantation (PIII) process in micro and nano-patterned Si samples. The code, based on the Monte Carlo approach, is designed to reproduce all the relevant physical phenomena involved in the process. The particle based simulation technique is fundamental to efficiently compute the material modifications promoted by the plasma implantation at the atomic resolution. The accuracy in the description of the process kinetic is achieved linking (one to one) each virtual Monte Carlo event to each possible atomic phenomenon (e.g. ion penetration, neutral absorption, ion induced surface modification, etc.). The code is designed to be coupled with a generic plasma status, characterized by the particle types (ions and neutrals), their flow rates and their energy/angle distributions. The coupling with a Poisson solver allows the simulation of the correct trajectories of charged particles in the void regions of the micro-structures. The implemented model is able to predict the implantation 2D profiles and significantly support the process design. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. The effect of ions on the magnetic moment of vacancy for ion-implanted 4H-SiC

    Science.gov (United States)

    Peng, B.; Zhang, Y. M.; Dong, L. P.; Wang, Y. T.; Jia, R. X.

    2017-04-01

    The structural properties and the spin states of vacancies in ion implanted silicon carbide samples are analyzed by experimental measurements along with first-principles calculations. Different types and dosages of ions (N+, O+, and B+) were implanted in the 4H-silicon carbide single crystal. The Raman spectra, positron annihilation spectroscopy, and magnetization-magnetic field curves of the implanted samples were measured. The fitting results of magnetization-magnetic field curves reveal that samples implanted with 1 × 1016 cm-2 N+ and O+ ions generate paramagnetic centers with various spin states of J = 1 and J = 0.7, respectively. While for other implanted specimens, the spin states of the paramagnetic centers remain unchanged compared with the pristine sample. According to the positron annihilation spectroscopy and first-principles calculations, the change in spin states originates from the silicon vacancy carrying a magnetic moment of 3.0 μB in the high dosage N-implanted system and 2.0 μB in the O-doped system. In addition, the ratio of the concentration of implanted N ions and silicon vacancies will affect the magnetic moment of VSi. The formation of carbon vacancy which does not carry a local magnetic moment in B-implanted SiC can explain the invariability in the spin states of the paramagnetic centers. These results will help to understand the magnetic moments of vacancies in ion implanted 4H-SiC and provide a possible routine to induce vacancies with high spin states in SiC for the application in quantum technologies and spintronics.

  5. Rapid capless annealing of28Si,64Zn, and9Be implants in GaAs

    Science.gov (United States)

    Liu, S. G.; Narayan, S. Y.

    1984-11-01

    We report the use of tungsten-halogen lamps for rapid (-10 s) thermal annealing of ion-implanted (100) GaAs under AsH3/Ar and N2 atmospheres. Annealing under flowing AsH3/Ar was carried out without wafer encapsulation. Rapid capless annealing activated implants in GaAs with good mobility and surface morphology. Typical mobilities were 3700 4500 cm2/V-s for n-layers with about 2×1017cm-3 carrier concentration and 50 150 cm2/v-s for 0.1 5xl019 cm-3 doped p-layers. Rapid thermal annealing was performed in a vertical quartz tube where different gases (N2, AsH3/H2, AsH3/Ar) can be introduced. Samples were encapsulated with SiO when N2 was used. Tungsten-halogen lamps of 600 or 1000 W were utilized for annealing GaAs wafers ranging from 1 to 10 cm2 in area and 0.025 to 0.040 cm in thickness. The transient temperature at the wafer position was monitored using a fine thermocouple. We carried out experiments for energies of 30 to 200 keV, doses of 2×1012 to 1×1015 cm-2, and peak temperatures ranging from 600 to 1000‡C. Most results quoted are in the 700 to 870‡C temperature range. Data on implant conditions, optimum anneal conditions, electrical characteristics, carrier concentration profiles, and atomic profiles of the implanted layers are described.

  6. Compositional, structural, and optical changes of polyimide implanted by 1.0 MeV Ni+ ions

    Czech Academy of Sciences Publication Activity Database

    Mikšová, Romana; Macková, Anna; Pupíková, Hana; Malinský, Petr; Slepička, P.; Švorčík, V.

    2017-01-01

    Roč. 406, SEP (2017), s. 199-204 ISSN 0168-583X R&D Projects: GA MŠk LM2015056; GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:61389005 Keywords : Ni ion implantation * polyimide * polymer degradation Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders OBOR OECD: Nuclear physics Impact factor: 1.109, year: 2016

  7. Broad and focused ion beams Ga+ implantation damage in the fabrication of p+-n Si shallow junctions

    International Nuclear Information System (INIS)

    Steckl, A.J.; Lin, C.M.; Patrizio, D.; Rai, A.K.; Pronko, P.P.

    1989-01-01

    The use of focused and broad beam Ga + implantation for the fabrication of p + -n Si shallow junctions is explored. In particular, the issue of ion induced damage and its effect on diode electrical properties is explored. FIB-fabricated junctions exhibit a deeper junction with lower sheet resistance and higher leakage current than the BB-implanted diodes. TEM analysis exhibits similar amorphization and recrystallization behavior for both implantation techniques with the BB case generating a higher dislocation loop density after a 900 degree C anneal. 6 refs., 5 figs., 1 tab

  8. Diffusion of Ag, Au and Cs implants in MAX phase Ti{sub 3}SiC{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Weilin, E-mail: weilin.jiang@pnnl.gov [Pacific Northwest National Laboratory, Richland, WA (United States); Henager, Charles H.; Varga, Tamas; Jung, Hee Joon; Overman, Nicole R. [Pacific Northwest National Laboratory, Richland, WA (United States); Zhang, Chonghong; Gou, Jie [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China)

    2015-07-15

    MAX phases (M: early transition metal; A: elements in group 13 or 14; X: C or N), such as titanium silicon carbide (Ti{sub 3}SiC{sub 2}), have a unique combination of both metallic and ceramic properties, which make them attractive for potential nuclear applications. Ti{sub 3}SiC{sub 2} has been considered as a possible fuel cladding material. This study reports on the diffusivities of fission product surrogates (Ag and Cs) and a noble metal Au (with diffusion behavior similar to Ag) in this ternary compound at elevated temperatures, as well as in dual-phase nanocomposite of Ti{sub 3}SiC{sub 2}/3C-SiC and polycrystalline CVD 3C-SiC for behavior comparisons. Samples were implanted with Ag, Au or Cs ions and characterized with various methods, including X-ray diffraction, electron backscatter diffraction, energy dispersive X-ray spectroscopy, Rutherford backscattering spectrometry, helium ion microscopy, and transmission electron microscopy. The results show that in contrast to immobile Ag in 3C-SiC, there is a significant outward diffusion of Ag in Ti{sub 3}SiC{sub 2} within the dual-phase nanocomposite during Ag ion implantation at 873 K. Similar behavior of Au in polycrystalline Ti{sub 3}SiC{sub 2} was also observed. Cs out-diffusion and release from Ti{sub 3}SiC{sub 2} occurred during post-implantation thermal annealing at 973 K. This study suggests caution and further studies in consideration of Ti{sub 3}SiC{sub 2} as a fuel cladding material for advanced nuclear reactors operating at very high temperatures.

  9. Formation and characterization of nanoparticles formed by sequential ion implantation of Au and Co into SiO2

    International Nuclear Information System (INIS)

    Kluth, P.; Hoy, B.; Johannessen, B.; Dunn, S.G.; Foran, G.J.; Ridgway, M.C.

    2007-01-01

    Nanoparticles (NPs) were formed by sequential ion implantation of Au and Co into thin SiO 2 . After Au implantation and annealing, Co implantations were carried out at room temperature (RT) and 400 deg. C, respectively, with no subsequent annealing. The NPs were investigated by means of Rutherford backscattering spectroscopy (RBS), transmission electron microscopy (TEM) and extended X-ray absorption fine structure spectroscopy (EXAFS). TEM shows the formation of Co-Au core-shell NPs for the Co implantation at 400 deg. C. EXAFS measurements indicate significant strain in the NPs and a bond-length expansion of the Co-Co bonds in the NP core with a concomitant contraction of the Au-Au bonds in the Au shells. NPs are also observed by TEM for the Co implantation performed at RT, however, a lack of crystallinity is apparent from electron diffraction and EXAFS measurements

  10. Measurement of proton induced thick target γ-ray yields on B, N, Na, Al and Si from 2.5 to 4.1 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Chiari, M., E-mail: chiari@fi.infn.it [INFN-Florence and Department of Physics and Astronomy, University of Florence, via G. Sansone 1, 50019 Sesto Fiorentino (Italy); Ferraccioli, G.; Melon, B.; Nannini, A.; Perego, A.; Salvestrini, L. [INFN-Florence and Department of Physics and Astronomy, University of Florence, via G. Sansone 1, 50019 Sesto Fiorentino (Italy); Lagoyannis, A.; Preketes-Sigalas, K. [Tandem Accelerator Laboratory, Institute of Nuclear and Particle Physics, NCSR “Demokritos”, 153.10 Aghia Paraskevi, Athens (Greece)

    2016-01-01

    Thick target yields for proton induced γ-ray emission (PIGE) on low-Z nuclei, namely B, N, Na, Al and Si, were measured for proton energies from 2.5 to 4.1 MeV and emission angles of 0°, 45° and 90°, at the 3 MV Tandetron laboratory of INFN-LABEC in Florence. The studied reactions were: {sup 10}B(p,α′γ){sup 7}Be (E{sub γ} = 429 keV), {sup 10}B(p,p′γ){sup 10}B (E{sub γ} = 718 keV) and {sup 11}B(p,p′γ){sup 11}B (E{sub γ} = 2125 keV) for boron; {sup 14}N(p,p′γ){sup 14}N (E{sub γ} = 2313 keV) for nitrogen; {sup 23}Na(p,p′γ){sup 23}Na (E{sub γ} = 441 and 1636 keV) and {sup 23}Na(p,α′γ){sup 20}Ne (E{sub γ} = 1634 keV) for sodium; {sup 27}Al(p,p′γ){sup 27}Al (E{sub γ} = 844 and 1014 keV) and {sup 27}Al(p,α′γ){sup 24}Mg (E{sub γ} = 1369 keV) for aluminum; {sup 28}Si(p,p′γ){sup 28}Si (E{sub γ} = 1779 keV) and {sup 29}Si(p,p′γ){sup 29}Si (E{sub γ} = 1273 keV) for silicon. The PIGE thick target yields have been measured with an overall uncertainty typically better than 10%. The use of the measured thick target yield to benchmark and validate experimental cross sections available in the literature is demonstrated.

  11. Study of surface exfoliation on 6H-SiC induced by H{sub 2}{sup +} implantation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, L. [Department of Physics, School of Science, Lanzhou University of Technology, Lanzhou 730050 (China); Li, B.S., E-mail: b.s.li@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2017-03-01

    The effect of lattice damage generated by the H{sub 2}{sup +}-implantation on exfoliation efficiency in 6H-SiC wafers is investigated. <0001> 6H-SiC wafers were implanted with 134 keV H{sub 2}{sup +} ions to ion fluences from 1.5×10{sup 16} to 5×10{sup 16} H{sub 2}{sup +} cm{sup −2} and subsequently annealed at temperatures from 973 K to 1373 K. The samples were studied by a combination of optical microscopy and transmission electron microscopy. Only after 1373 K annealing for 15 min, blisters and exfoliation occur on the H{sub 2}{sup +}-implanted sample surface. With increasing the implantation fluences from 1.5×10{sup 16} to 3.75×10{sup 16} H{sub 2}{sup +} cm{sup −2}, the exfoliation mean size decreases, while the exfoliation density increases. For the highest fluence of 5×10{sup 16} H{sub 2}{sup +} cm{sup −2}, seldom exfoliations occur on the sample surface. Microstructure analysis shows that exfoliation efficiency is largely controlled by the H{sub 2}{sup +}-implantation-induced lattice damage. The depth of the microcrack is related to the implantation fluence. The effect of implantation fluence on dislocation loops, platelet nucleation and growth is investigated.

  12. Detection of 14 MeV neutrons in high temperature environment up to 500 deg. C using 4H-SiC based diode detector

    Energy Technology Data Exchange (ETDEWEB)

    Szalkai, D.; Klix, A. [KIT- Karlsruhe Institute of Technology, Institute of Neutron Physics and Reactor Technology Karlsruhe 76344 (Germany); Ferone, R.; Issa, F.; Ottaviani, L.; Vervisch, V. [IM2NP, UMR CNRS 7334, Aix-Marseille University, Case 231 -13397 Marseille Cedex 20 (France); Gehre, D. [Inst. for Nucl.- and Particle-Phys., Dresden University of Technology, Dresden 01069 (Germany); Lyoussi, A. [CEA, DEN, Departement d' Etudes des Reacteurs, Service de Physique Experimentale, Laboratoire Dosimetrie Capteurs Instrumentation, 13108 Saint-Paul-lez-Durance (France)

    2015-07-01

    In reactor technology and industrial applications detection of fast and thermal neutrons plays a crucial role in getting relevant information about the reactor environment and neutron yield. The inevitable elevated temperatures make neutron yield measurements problematic. Out of the currently available semiconductors 4H-SiC seems to be the most suitable neutron detector material under extreme conditions due to its high heat and radiation resistance, large band-gap and lower cost of production than in case of competing diamond detectors. In the framework of the European I-Smart project, optimal {sup 4}H-SiC diode geometries were developed for high temperature neutron detection and have been tested with 14 MeV fast neutrons supplied by a deuterium-tritium neutron generator with an average neutron flux of 10{sup 10}-10{sup 11} n/(s*cm{sup 2}) at Neutron Laboratory of the Technical University of Dresden in Germany from room temperatures up to several hundred degrees Celsius. Based on the results of the diode measurements, detector geometries appear to play a crucial role for high temperature measurements up to 500 deg. C. Experimental set-ups using SiC detectors were constructed to simulate operation in the harsh environmental conditions found in the tritium breeding blanket of the ITER fusion reactor, which is planned to be the location of neutron flux characterization measurements in the near future. (authors)

  13. Central collisions between 28Si nuclei at 12.4, 19.7 and 30.0 MeV per nucleon

    International Nuclear Information System (INIS)

    Meijer, R.J.

    1989-01-01

    The formation and decay of nuclei in central collisions of the 28 Si + 28 Si system at bombarding energies of 12.4, 19.7 and 30.0 MeV per nucleon is studied by analysis of the light particle (LP) spectra measured in coincidence with evaporation residues (ER) and measurements of the inclusive velocity distribution of ER's. From the last set of measurements a strong reduction of the ER cross section at increasing incident energy was observed and especially the relation to a possible vanishing fusion cross section is discussed. The coincidence measurements determines the LP pre-equilibrium contribution and the LP decay modes of highly excited systems. The ER's produced in fusion reactions between 28 Si nuclei were detected with a simple ionization chamber ΔE detector and a surface barrier E detector. For the LP detection multidetector systems consisting of CsI(TL) detectors were used. In this thesis the developments that have led to the construction of a CsI(TL) charged particle detector and of the Utrecht multidetector system, the experimental setup and the methods used in the acquisition, processing and analysis of the data, are described. The results of the heavy-ion velocity measurements are presented and conclusions are drawn about equilibrium and pre-equilibrium processes from the analysis. (H.W.). 124 refs.; 44 figs.; 24 tabs

  14. Extended deep level defects in Ge-condensed SiGe-on-Insulator structures fabricated using proton and helium implantations

    International Nuclear Information System (INIS)

    Kwak, D.W.; Lee, D.W.; Oh, J.S.; Lee, Y.H.; Cho, H.Y.

    2012-01-01

    SiGe-on-Insulator (SGOI) structures were created using the Ge condensation method, where an oxidation process is performed on the SiGe/Si structure. This method involves rapid thermal chemical vapor deposition and H + /He + ion-implantations. Deep level defects in these structures were investigated using deep level transient spectroscopy (DLTS) by varying the pulse injection time. According to the DLTS measurements, a deep level defect induced during the Ge condensation process was found at 0.28 eV above the valence band with a capture cross section of 2.67 × 10 −17 cm 2 , two extended deep levels were also found at 0.54 eV and 0.42 eV above the valence band with capture cross sections of 3.17 × 10 −14 cm 2 and 0.96 × 10 −15 cm 2 , respectively. In the SGOI samples with ion-implantation, the densities of the newly generated defects as well as the existing defects were decreased effectively. Furthermore, the Coulomb barrier heights of the extended deep level defects were drastically reduced. Thus, we suggest that the Ge condensation method with H + ion implantation could reduce deep level defects generated from the condensation and control the electrical properties of the condensed SiGe layers. - Highlights: ► We have fabricated low-defective SiGe-on-Insulator (SGOI) with implantation method. ► H + and He + -ions are used for ion-implantation method. ► We have investigated the deep level defects of SGOI layers. ► Ge condensation method using H + ion implantation could reduce extended defects. ► They could enhance electrical properties.

  15. Study of transfer induced fission and fusion-fission reactions for 28 Si + 232 Th system at 340 MeV

    International Nuclear Information System (INIS)

    Prete, G.; Rizzi, V.; Fioretto, E.; Cinausero, M.; Shetty, D.V.; Pesente, S.; Brondi, A.; La Rana, G.; Moro, R.; Vardaci, E.; Boiano, A.; Ordine, A.; Gelli, N.; Lucarelli, F.; Bortignon, P.F.; Saxena, A.; Nayak, B.K.; Biswas, D.C.; Choudhury, R.K.; Kapoor, R.S.

    2001-01-01

    Full text: Fission induced by nucleons transfer has been investigated in the reaction 28 Si + 232 Th at 340 MeV. Looking at the projectile-like-fragments (PLF), the fission yield increases as the transfer increases, but a decreases is observed for transfers with DZ . Light charged particles in coincidence with PLF and Fission have been detected with large solid angle and show an increasing multiplicity as the Z of PLF is reduced and a constant value when fission is requested. The present results indicate inhibition of transfer induced fission reaction for higher Z transfer and increasing probability for decay through charged particle evaporation. Fission is the dominant decay process in heavy reactions involving fissile systems but the dynamical evolution of the composite system is largely governed by the formation and decay mechanisms. Important insight into the formation and the survival probability of the heavy composite nuclei formed in heavy ion collisions can be gained by simultaneously investigate the fission process and light particle emission over a continuous range of excitation energy, angular momentum and fissility. This can be achieved by studying fission induced by transfer of nucleons between the interacting projectile and the target nucleus. In the present work, we have carried out measurements on multinucleon transfer induced fission reactions in 28 Si + 232 Th system at Elab = 340 MeV. The experiment has been performed at the Laboratori Nazionale di Legnaro (LNL) using the 8pLP detector in its final configuration with 257 DE-E telescopes. The backward detectors were used to measure both light charged particles and fission fragments. The projectile-like fragments were detected using separate DE-E telescopes around the grazing angle. Two neutron detectors were placed at a distance of 115.5 cm from the target to measure neutrons emitted in coincidence with fission fragments. Here we present the results of the data analysis of transfer induced fission

  16. Surface damage versus defect microstructures in He and H ion co-implanted Si{sub 3}N{sub 4}/Si

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, F. [School of Science, Tianjin University, Tianjin 300072 (China); Liu, C.L., E-mail: liuchanglong@tju.edu.cn [School of Science, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Institute of Advanced Materials Physics Faculty of Science, Tianjin 300072 (China); Gao, Y.J.; Wang, Z.; Wang, J. [School of Science, Tianjin University, Tianjin 300072 (China)

    2012-09-01

    Cz n-type Si (1 0 0) wafers with a top Si{sub 3}N{sub 4} layer of about 170 nm in thickness were sequentially implanted with 40 keV He ions at a fluence of 5 Multiplication-Sign 10{sup 16}/cm{sup 2} and 35 keV H ions at fluences of 1 Multiplication-Sign 10{sup 15}, 5 Multiplication-Sign 10{sup 15} and 1 Multiplication-Sign 10{sup 16}/cm{sup 2}, respectively. Creation and evolution of surface damage as well as micro-defects have been studied. Our results clearly show that production of surface damage depends strongly on both the H implant fluence and annealing temperature. Only blistering or localized exfoliation of the top Si{sub 3}N{sub 4} layer has been observed for post H implantation at fluences of 1 Multiplication-Sign 10{sup 15} and 5 Multiplication-Sign 10{sup 15}/cm{sup 2} upon 800 Degree-Sign C annealing. However, serious surface exfoliation has been found for the 1 Multiplication-Sign 10{sup 16}/cm{sup 2} H co-implanted samples after annealing at 450 Degree-Sign C and above. The exfoliation occurs at a depth of about 360 nm from the surface, which is obviously larger than the He or H ion range. Moreover, the exfoliated craters show clear two-step structures. Cross-sectional transmission electron microscopy (XTEM) observations reveal formation of micro-cracks in Si bulk and along the original interface, which is mainly responsible for the observed surface phenomena. The formation mechanism of micro-cracks has been discussed in combination of He and H implant-induced defects, impurities as well as their interactions upon annealing.

  17. Tuning of Schottky Barrier Height at NiSi/Si Contact by Combining Dual Implantation of Boron and Aluminum and Microwave Annealing

    Directory of Open Access Journals (Sweden)

    Feng Sun

    2018-03-01

    Full Text Available Dopant-segregated source/drain contacts in a p-channel Schottky-barrier metal-oxide semiconductor field-effect transistor (SB-MOSFET require further hole Schottky barrier height (SBH regulation toward sub-0.1 eV levels to improve their competitiveness with conventional field-effect transistors. Because of the solubility limits of dopants in silicon, the requirements for effective hole SBH reduction with dopant segregation cannot be satisfied using mono-implantation. In this study, we demonstrate a potential solution for further SBH tuning by implementing the dual implantation of boron (B and aluminum (Al in combination with microwave annealing (MWA. By using such a method, not only has the lowest hole SBH ever with 0.07 eV in NiSi/n-Si contacts been realized, but also the annealing duration of MWA was sharply reduced to 60 s. Moreover, we investigated the SBH tuning mechanisms of the dual-implanted diodes with microwave annealing, including the dopant segregation, activation effect, and dual-barrier tuning effect of Al. With the selection of appropriate implantation conditions, the dual implantation of B and Al combined with the MWA technique shows promise for the fabrication of future p-channel SB-MOSFETs with a lower thermal budget.

  18. Contribution estimate of the 2+(1.78 MeV) level excitation in silicon nucleus to the cross section of the 28Si(π, 3π)28Si * reaction

    International Nuclear Information System (INIS)

    Ermekov, N.T.; Korotkikh, V.L.; Starkov, N.I.

    1981-01-01

    For the purpose of studying the channel contribution with low-lying level excitation in silicon nucleus into the differential cross section of the reaction the π - + 28 Si→π - +π - +π + + 28 Si reaction is investigated at the bombarding 16 GeV/c pion momentum. The calculation of differential cross sections on the basis of the Glauber model with a factorizing nucleus density is performed. The found parameters of nuclear densities are tabulated. The investigated reaction differential cross sections are calculated with account of coherent production as well as the channel with 2 + (1.78 MeV) level excitation. The calculated differential cross sections values integrated by the effective mass of the produced three-pion system (0.9 GeV + , 1.78 MeV)=0.25 mb are obtained. It is shown that filling the diffraction minimum in three-pion production differential cross section for ''alive'' silicon target is due to contribution from events with the excitation of the low-lying level 2 + (1.78 MeV) [ru

  19. Quantitative approach to relate dielectric constant studies with TSDC studies of 50 MeV Si ion irradiated kapton-H polymide

    International Nuclear Information System (INIS)

    Quamara, J.K.; Garg, Maneesha; Sridharbabu, Y.; Prabhavathi, T.

    2003-01-01

    Temperature and frequency dependent dielectric behaviour has been investigated for pristine and swift heavy ion irradiated (Si ion, 50 MeV energy) kapton-H polyimide in the temperature range of 30 to 250 deg C at frequencies 120 Hz, 1 kHz, 10 kHz and 100 kHz respectively. The dielectric relaxation behaviour of the same samples was also studied using thermally stimulated discharge current (TSDC) technique. A quantitative approach is developed using a well-known Clausius Mossotti equation to relate the TSDC findings to the dielectric constant studies. An overall increase in the dielectric constant of the irradiated samples are also in conformity to the TSDC findings. (author)

  20. Effect of radiation damage on luminescence of erbium-implanted SiO sub 2 /Si studied by slow positron beam

    CERN Document Server

    Kawasuso, A; Hirata, K; Sekiguchi, T; Kobayashi, Y; Okada, S

    2000-01-01

    The effect of damage on 1.54 mu m luminescence for 30 keV-Er-implanted SiO sub 2 films has been studied by positron annihilation and cathodoluminescence. It was found that S-parameter in the films decreased after implantation, indicating the suppression of positronium formation. The luminescence appeared with the recovery of the S-parameter after 600 deg. C annealing. The intensity reached a maximum at 900 deg. C annealing whereas the S-parameter did not change significantly. It seems that most damages recover at 600 deg. C and thereafter Er ions transform to an optically active state at 900 deg. C.

  1. Raman study of damage processes in Si+-implanted GaAs

    International Nuclear Information System (INIS)

    Ivanda, M.; Desnica, U.V.; Haynes, T.E.; Hartmann, I.; Kiefer, W.

    1994-09-01

    Ion-induced damage in GaAs as a function of ion dose following 100 keV Si + implants has been investigated by Raman spectroscopy. A new approach for decomposition of Raman scattering intensity on to the crystalline and amorphous phase components has been used in analysis of Raman spectra. With increasing ion dose the following was observed: (a) the widths of vibrational bands of a-phase significantly increase, while the width of the LO(Γ) phonon band of c-phase remains unchanged; (b) the longitudinal optical phonon band of c-phase completely dissappears, while the transverse optical phonon mode evolves in to a new band of a-phase; (c) the wavenumbers of all vibrational bands of a- and c-phase shift to lower values by ∼ 10--15 cm -1 . A number of mechanisms possibly accountable for these shifts were analysed and evaluated

  2. Laser induced recrystallisation and defects in ion implanted hexagonal SiC

    International Nuclear Information System (INIS)

    Makarov, V.V.; Tuomi, T.; Naukkarinen, K.; Luomajaervi, M.; Riihonen, M.

    1979-10-01

    SiC(6H) crystals amorphized with 14 N + -ion implantation were annealed with CO 2 laser pulses at intensities of 20 to 100 MW/cm 2 . Laser produced crystallisation due to residual ray absorption was studied by means of optical spectroscopy, 4 He + -ion backscattering spectrometry and channeling as well as Cu Kα 1 and synchrotron x-ray diffraction topography. At low laser intensities topographs revealed linear and planar defects which contributed to increased dechanneling independent of analyzing beam energy. Minimum of lattice disorder, which was in some regions of the laser impact area smaller than that obtained in thermal annealing, was attained at the peak laser intensities of about 50 MW/cm 2 . (orig.)

  3. Activation behavior of boron implanted poly-Si on glass substrate

    International Nuclear Information System (INIS)

    Furuta, M.; Shimamura, K.; Tsubokawa, H.; Tokushige, K.; Furuta, H.; Hirao, T.

    2010-01-01

    The activation behavior of boron (B) implanted poly-Si films on glass substrates has been investigated. The effect of B dose and annealing temperature on crystal defects and electrical properties of the films were evaluated by Raman spectroscopy and Hall measurement. It was found that the maximum activation ratio of the film with B dose of 1 x 10 15 cm -2 was obtained when Raman peak associated with disordered amorphous silicon disappeared. However, reverse anneal was observed in the film when the annealing temperature further increased. The results from secondary ion mass spectrometry and Hall measurement revealed that B segregation at the top and bottom interface and deactivation of B substitutional occurred simultaneously in the high-dose specimens when the annealing temperature increased from 600 to 750 o C.

  4. Ion implantation induced structural changes in reactively sputtered Cr-N layers on Si substrates

    International Nuclear Information System (INIS)

    Novakovic, M.; Popovic, M.; Perusko, D.; Milinovic, V.; Radovic, I.; Bibic, N.; Mitric, M.; Milosavljevic, M.

    2007-01-01

    This paper presents a study of the structure and composition of reactively sputtered Cr-N layers as a function of deposition parameters, and the effects of ion implantation on these structures. The layers were deposited on (1 0 0) Si substrates to a thickness of 240-280 nm, at different nitrogen partial pressure, and subsequently irradiated with 120 keV Ar ions. Structural characterisation of the samples was performed with Rutherford backscattering spectroscopy, transmission electron microscopy and X-ray diffraction analysis. We also measured their electrical resistivity with a four point probe. It was found that the layers grow in form of columnar structures, and their composition, Cr 2 N or CrN, strongly depends on the nitrogen partial pressure during deposition. Ion irradiation induces local micro-structural changes, formation of nano-particles and defects, which can be nicely correlated to the measured electrical resistivity

  5. Studies of light charged particle emission from fission and ER reactions in the system 344 MeV {sup 28}Si+{sup 121}Sb{yields}{sup 149}Tb (E{sup *}=240 MeV)

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, Morton E-mail: kaplan@cmchem.chem.cmu.edu; Copi, Craig J.; DeYoung, Paul A.; Gilfoyle, G.J.; Karol, Paul J.; Moses, David J.; Parker, W.E.; Rehm, K. Ernst; Sarafa, John; Vardaci, Emanuele

    2001-04-09

    Light charged particles (LCP) have been measured for the reaction 344 MeV {sup 28}Si+{sup 121}Sb in singles and in coincidence with evaporation residues (ER), fusion-fission fragments (FF), and other LCP. A major feature of this experiment was the use of a gas-filled magnetic spectrometer in the forward direction to separate ER from the much more abundant yield of elastically scattered projectiles and projectile-like fragments. The dominant sources of evaporative {sup 1}H and {sup 4}He emission are the ER (approximately 75%), with the remainder being largely associated with fission reactions. For these latter reactions, most of the {sup 1}H and {sup 4}He can be well accounted for by evaporation from the composite system prior to fission and by evaporation from the postfission fragments. LCP emission cross sections were determined for each identified source, and a comparison has been made to previous studies. From this comparison, indications were found for significant entrance channel effects, with the more asymmetric channels exhibiting much larger LCP cross sections. Statistical model predictions for ER emissions are in good agreement with observed LCP energy spectra, angular distributions, and integrated inclusive and exclusive cross sections, with all calculations using the same unique set of model parameters. This result contrasts strongly with recent reports for light mass systems, where model calculations were unable to simultaneously reproduce all observables.

  6. Negative differential resistance effect induced by metal ion implantation in SiO2 film for multilevel RRAM application

    Science.gov (United States)

    Wu, Facai; Si, Shuyao; Shi, Tuo; Zhao, Xiaolong; Liu, Qi; Liao, Lei; Lv, Hangbing; Long, Shibing; Liu, Ming

    2018-02-01

    Pt/SiO2:metal nanoparticles/Pt sandwich structure is fabricated with the method of metal ion (Ag) implantation. The device exhibits multilevel storage with appropriate R off/R on ratio, good endurance and retention properties. Based on transmission electron microscopy and energy dispersive spectrometer analysis, we confirm that Pt nanoparticles are spurted into SiO2 film from Pt bottom electrode by Ag implantation; during electroforming, the local electric field can be enhanced by these Pt nanoparticles, meanwhile the Ag nanoparticles constantly migrate toward the Pt nanoparticles. The implantation induced nanoparticles act as trap sites in the resistive switching layer and play critical roles in the multilevel storage, which is evidenced by the negative differential resistance effect in the current-voltage (I-V) measurements.

  7. Investigation of electric fields in B-implanted Si by positron beam spectroscopy

    International Nuclear Information System (INIS)

    Abdulmalik, D.A.; Coleman, P.G.

    2007-01-01

    Besides its conventional applications in defect characterization, variable-energy positron annihilation spectroscopy can be employed to monitor internal electric fields in the depletion regions in semiconductor structures. In this work, electric fields were studied in pre-amorphized Cz Si wafers (background dopant level ∝10 15 cm -3 ) implanted with 0.5 keV B ions at a dose of 10 15 cm -2 , and then annealed isothermally at 800 C for times ranging from 1 to 2700 s. Differences in the S parameter with annealing time were observed in samples implanted (a) with B ions only and (b) with B followed by F ions at 10 keV; these were attributed to different electric fields, which drift positrons back (a) to the surface, or (b) to a vacancy-like defected layer. Fitting of the data revealed depletion regions of widths between 150-350 nm centered at depths between 250-350 nm, with electric field values in the range -9 x 10 6 to -3 x 10 6 Vm -1 . The depth and width of the depletion regions increase significantly for annealing times greater than 100 s, attributed to B diffusion. The results are consistent with simple theoretical estimates, but the uncertainties on the latter are large. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Effect of 100 MeV Ag{sup +7} ion irradiation on the bulk and surface magnetic properties of Co–Fe–Si thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hysen, T., E-mail: hysenthomas@gmail.com [Department of Physics, Cochin University of Science and Technology, Cochin 682 022, Kerala (India); Department of Physics, Christian College, Chengannur, Kerala 689 122 (India); Geetha, P. [Department of Physics, Cochin University of Science and Technology, Cochin 682 022, Kerala (India); Al-Harthi, Salim; Al-Omari, I.A. [Department of Physics, College of Science, Sultan Qaboos University, Al Khod 123 (Oman); Lisha, R. [Department of Physics, Cochin University of Science and Technology, Cochin 682 022, Kerala (India); Ramanujan, R.V. [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639 798 (Singapore); Sakthikumar, D. [Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe (Japan); Avasthi, D.K. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Anantharaman, M.R., E-mail: mra@cusat.ac.in [Department of Physics, Cochin University of Science and Technology, Cochin 682 022, Kerala (India)

    2014-12-15

    Thin films of Co–Fe–Si were vacuum evaporated on pre-cleaned float glass substrates employing thermal evaporation. The films were subsequently irradiated with 100 MeV Ag{sup +7} ions at fluences of 1×10{sup 11}, 1×10{sup 12} and 1×10{sup 13} ions/cm{sup 2}. The pristine and irradiated samples were subjected to surface analysis using Atomic Force Microscopy (AFM), Vibrating Sample Magnetometry (VSM) and Magneto Optic Kerr Effect (MOKE) measurements. The as deposited film has a root mean square roughness (Rq) of 8.9 nm and an average roughness of (Ra) 5.6 nm. Irradiation of the as deposited films with 100 MeV Ag{sup 7+} ions modifies the surface morphology. Irradiating with ions at fluences of 1×10{sup 11} ions/cm{sup 2} smoothens the mesoscopic hill-like structures, and then, at 1×10{sup 12} ions/cm{sup 2} new surface structures are created. When the fluence is further increased to 1×10{sup 13} ions/cm{sup 2} an increase in the surface roughness is observed. The MOKE loop of as prepared film indicated a squareness ratio of 0.62. As the film is irradiated with fluences of 1×10{sup 11} ions/cm{sup 2}, 1×10{sup 12} ions/cm{sup 2} and 1×10{sup 13} ions/cm{sup 2} the squareness ratio changes to 0.76, 0.8 and 0.86 respectively. This enhancement in squareness ratio towards 1 is a typical feature when the exchange interaction starts to dominates the inherent anisotropies in the system. The variation in surface magnetisation is explained based on the variations in surface roughness with swift heavy ion (SHI) irradiation. - Highlights: • We have irradiated thermally evaporated Co–Fe–Si thin films on glass substrate with 100 MeV Ag{sup +7} ions using the 15 UD Pelletron Accelerator at IUAC, New Delhi, India. • Surface morphology and magnetic characteristics of the films can be altered with ion irradiation. • It was observed that the variation in surface magnetic properties correlates well with the changes in surface morphology, further reiterating the

  9. Current transport studies of ZnO/p-Si heterostructures grown by plasma immersion ion implantation and deposition

    International Nuclear Information System (INIS)

    Chen, X.D.; Ling, C.C.; Fung, S.; Beling, C.D.; Mei, Y.F.; Fu, Ricky K.Y.; Siu, G.G.; Chu, Paul K.

    2006-01-01

    Rectifying undoped and nitrogen-doped ZnO/p-Si heterojunctions were fabricated by plasma immersion ion implantation and deposition. The undoped and nitrogen-doped ZnO films were n type (n∼10 19 cm -3 ) and highly resistive (resistivity ∼10 5 Ω cm), respectively. While forward biasing the undoped-ZnO/p-Si, the current follows Ohmic behavior if the applied bias V forward is larger than ∼0.4 V. However, for the nitrogen-doped-ZnO/p-Si sample, the current is Ohmic for V forward 2 for V forward >2.5 V. The transport properties of the undoped-ZnO/p-Si and the N-doped-ZnO/p-Si diodes were explained in terms of the Anderson model and the space charge limited current model, respectively

  10. Comparative study of SOI/Si hybrid substrates fabricated using high-dose and low-dose oxygen implantation

    International Nuclear Information System (INIS)

    Dong Yemin; Chen Meng; Chen Jing; Wang Xiang; Wang Xi

    2004-01-01

    Hybrid substrates comprising both silicon-on-insulator (SOI) and bulk Si regions have been fabricated using the technique of patterned separation by implantation of oxygen (SIMOX) with high-dose (1.5 x 10 18 cm -2 ) and low-dose ((1.5-3.5) x 10 17 cm -2 ) oxygen ions, respectively. Cross-sectional transmission electron microscopy (XTEM) was employed to examine the microstructures of the resulting materials. Experimental results indicate that the SOI/Si hybrid substrate fabricated using high-dose SIMOX is of inferior quality with very large surface height step and heavily damaged transitions between the SOI and bulk regions. However, the quality of the SOI/Si hybrid substrate is enhanced dramatically by reducing the implant dose. The defect density in transitions is reduced considerably. Moreover, the expected surface height difference does not exist and the surface is exceptionally flat. The possible mechanisms responsible for the improvements in quality are discussed

  11. B implanted at room temperature in crystalline Si: B defect formation and dissolution

    International Nuclear Information System (INIS)

    Romano, L.; Piro, A.M.; Mirabella, S.; Grimaldi, M.G.

    2005-01-01

    The B lattice location of B implanted into crystalline Si at room temperature has been investigated using the nuclear reaction 11 B(p,α) 8 Be induced by 650 keV proton beam and channelling analyses. The angular scans along the and axes indicate the formation of a particular B complex with B atoms non-randomly located. The same defect has been observed also for B doped Si where the B atoms, initially substitutional and electrically active, have been displaced as consequence of the interaction with the point defects generated by proton irradiation. The angular scans were compatible with the B-B pairs aligned along the axis predicted by theoretical calculations. The thermal evolution in the 400-950 deg. C range of the B complexes has been inferred both by B lattice location measurements and electrical activation. At low temperature (<700 deg. C) only 10% of the total B dose is active and a significant increase of randomly located B occurs. A significant electrical activation consistent with the concentration of substitutional B occurs at temperature higher than 800 deg. C. The data are interpreted in terms of a formation and dissolution of the B complexes

  12. Growth of surface structures correlated with structural and mechanical modifications of brass by laser-induced Si plasma ions implantation

    Science.gov (United States)

    Ahmad, Shahbaz; Bashir, Shazia; Rafique, M. Shahid; Yousaf, Daniel

    2017-04-01

    Laser-produced Si plasma is employed as an ion source for implantation on the brass substrate for its surface, structural, and mechanical modifications. Thomson parabola technique is employed for the measurement of energy and flux of Si ions using CR-39. In response to stepwise increase in number of laser pulses from 3000 to 12000, four brass substrates were implanted by laser-induced Si plasma ions of energy 290 keV at different fluxes ranging from 45 × 1012 to 75 × 1015 ions/cm2. SEM analysis reveals the formation of nano/micro-sized irregular shaped cavities and pores for the various ion fluxes for varying numbers of laser pulses from 3000 to 9000. At the maximum ion flux for 12,000 pulses, distinct and organized grains with hexagonal and irregular shaped morphology are revealed. X-ray diffractometer (XRD) analysis exhibits that a new phase of CuSi (311) is identified which confirms the implantation of Si ions in brass substrate. A significant decrease in mechanical properties of implanted brass, such as Yield Stress (YS), Ultimate Tensile Strength (UTS), and hardness, with increasing laser pulses from 3000 to 6000 is observed. However, with increasing laser pulses from 9000 to a maximum value of 12,000, an increase in mechanical properties like hardness, YS, and UTS is observed. The generation as well as annihilation of defects, recrystallization, and intermixing of Si precipitates with brass matrix is considered to be responsible for variations in surface, structural, and mechanical modifications of brass.

  13. Investigation of the atomic interface structure of mesotaxial Si/CoSi2(100) layers formed by high-dose implantation

    International Nuclear Information System (INIS)

    Bulle-Lieuwma, C.W.T.; Jong, A.F. de; Vandenhoudt, D.E.W.

    1991-01-01

    Aligned mesotaxial films of CoSi 2 in monocrystalline (100) oriented Si substrates have been formed by high-dose ion implantation of Co, followed by a high temperature treatment. The atomic structures of both the lower and upper Si/CoSi 2 (100) interfaces of the buried CoSi 2 layer have been investigated by high-resolution electron microscopy (HREM) combined with image simulations. A domain-like structure is observed consisting of areas with different interfaces. In order to derive the atomic configuration, image simulations of different proposed models are presented. By comparing simulated images and HREM images, two different atomic structure models for the Si/CoSi 2 (100) interface have been found. In the first model the interfacial Co atoms are six-fold coordinated and the tetrahedral coordination and bond lengths of silicon atoms are everywhere maintained. In the second model we found evidence for a 2 x 1 interface reconstruction, involving a difference in composition. The interfacial Co atoms are seven-fold coordinated. It is shown that the boundaries between the domains are associated with interfacial dislocations of edge-type with Burgers vectors b a/4 inclined and b = a/2 parallel to the interfacial plane. (author)

  14. Gamma-ray production cross-sections for the interactions of 14.9 MeV neutrons with Si, Cu, Nb and Pb

    International Nuclear Information System (INIS)

    Fan Guoying

    1991-12-01

    Gamma rays produced in the interactions of 14.9 MeV neutrons with Si, Cu, Nb and Pb targets were studied. The neutron beam was produced with the T(d,n)He reaction using 300 KeV Cockroft-Walton accelerator. Absolute neutron flux was determined by the associated particle technique. The time-of-flight technique was used to reduce the background. The FWHM of neutron pulses was 1.5 ns. A Ge(Li) detector was used for gamma-ray detection. 39 gamma lines for Si, 39 gamma lines for Cu, 79 for Nb and 39 for Pb were detected. Most of these gamma rays were emitted in (n,γ), (n,n') and (n,2n) reactions. The measurements were made at 40 deg. C, 55 deg. C, 125 deg. C and 140 deg. C relative to the incident neutron beam. The results are presented in the form of the data tables. 9 refs, 11 figs, 19 tabs

  15. Cadaveric feasibility study of da Vinci Si-assisted cochlear implant with augmented visual navigation for otologic surgery.

    Science.gov (United States)

    Liu, Wen P; Azizian, Mahdi; Sorger, Jonathan; Taylor, Russell H; Reilly, Brian K; Cleary, Kevin; Preciado, Diego

    2014-03-01

    To our knowledge, this is the first reported cadaveric feasibility study of a master-slave-assisted cochlear implant procedure in the otolaryngology-head and neck surgery field using the da Vinci Si system (da Vinci Surgical System; Intuitive Surgical, Inc). We describe the surgical workflow adaptations using a minimally invasive system and image guidance integrating intraoperative cone beam computed tomography through augmented reality. To test the feasibility of da Vinci Si-assisted cochlear implant surgery with augmented reality, with visualization of critical structures and facilitation with precise cochleostomy for electrode insertion. Cadaveric case study of bilateral cochlear implant approaches conducted at Intuitive Surgical Inc, Sunnyvale, California. Bilateral cadaveric mastoidectomies, posterior tympanostomies, and cochleostomies were performed using the da Vinci Si system on a single adult human donor cadaveric specimen. Radiographic confirmation of successful cochleostomies, placement of a phantom cochlear implant wire, and visual confirmation of critical anatomic structures (facial nerve, cochlea, and round window) in augmented stereoendoscopy. With a surgical mean time of 160 minutes per side, complete bilateral cochlear implant procedures were successfully performed with no violation of critical structures, notably the facial nerve, chorda tympani, sigmoid sinus, dura, or ossicles. Augmented reality image overlay of the facial nerve, round window position, and basal turn of the cochlea was precise. Postoperative cone beam computed tomography scans confirmed successful placement of the phantom implant electrode array into the basal turn of the cochlea. To our knowledge, this is the first study in the otolaryngology-head and neck surgery literature examining the use of master-slave-assisted cochleostomy with augmented reality for cochlear implants using the da Vinci Si system. The described system for cochleostomy has the potential to improve the

  16. Leaky mode suppression in planar optical waveguides written in Er:TeO{sub 2}–WO{sub 3} glass and CaF{sub 2} crystal via double energy implantation with MeV N{sup +} ions

    Energy Technology Data Exchange (ETDEWEB)

    Bányász, I., E-mail: banyasz@sunserv.kfki.hu [Department of Crystal Physics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O.B. 49, H-1525 Budapest (Hungary); Zolnai, Z.; Fried, M. [Research Institute for Technical Physics and Materials Science, Research Centre for Natural Sciences, Hungarian Academy of Sciences, P.O.B. 49, Budapest H-1525 (Hungary); Berneschi, S. [MDF-Lab, “Nello Carrara” Institute of Applied Physics, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); “Enrico Fermi” Center for Study and Research, Piazza del Viminale 2, 00184 Roma (Italy); Pelli, S.; Nunzi-Conti, G. [MDF-Lab, “Nello Carrara” Institute of Applied Physics, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy)

    2014-05-01

    Ion implantation proved to be an universal technique for producing waveguides in most optical materials. Tellurite glasses are good hosts of rare-earth elements for the development of fibre and integrated optical amplifiers and lasers covering all the main telecommunication bands. Er{sup 3+}-doped tellurite glasses are good candidates for the fabrication of broadband amplifiers in wavelength division multiplexing around 1.55 μm, as they exhibit large stimulated cross sections and broad emission bandwidth. Calcium fluoride is an excellent optical material, due to its perfect optical characteristics from UV wavelengths up to near IR. It has become a promising laser host material (doped with rare earth elements). Ion implantation was also applied to optical waveguide fabrication in CaF{sub 2} and other halide crystals. In the present work first single-energy implantations at 3.5 MeV at various fluences were applied. Waveguide operation up to 1.5 μm was observed in Er:Te glass, and up to 980 nm in CaF{sub 2}. Then double-energy implantations at a fixed upper energy of 3.5 MeV and lower energies between 2.5 and 3.2 MeV were performed to suppress leaky modes by increasing barrier width.

  17. Annealing of Al implanted 4H silicon carbide

    International Nuclear Information System (INIS)

    Hallen, A; Suchodolskis, A; Oesterman, J; Abtin, L; Linnarsson, M

    2006-01-01

    Al ions were implanted with multiple energies up to 250 keV at elevated temperatures in n-type 4H SiC epitaxial layers to reach a surface concentration of 1x10 20 cm -3 . These samples were then annealed at temperatures between 1500 and 1950 deg. C. A similar 4H SiC epitaxial sample was implanted by MeV Al ions to lower doses and annealed only at 200 and 400 deg. C. After annealing, cross-sections of the samples were characterized by scanning spreading resistance microscopy (SSRM). The results show that the resistivity of high-dose Al implanted samples has not reached a saturated value, even after annealing at the highest temperature. For the MeV Al implanted sample, the activation of Al has not yet started, but a substantial annealing of the implantation induced damage can be seen from the SSRM depth profiles

  18. Fragment ion distribution in charge-changing collisions of 2-MeV Si ions with C60

    Science.gov (United States)

    Itoh, A.; Tsuchida, H.; Miyabe, K.; Majima, T.; Nakai, Y.

    2001-09-01

    We have measured positive fragment ions produced in collisions of 2 MeV Siq+ (q=0, 1, 2, 4) projectiles with a C60 molecular target. The measurement was performed with a time-of-flight coincidence method between fragment ions and charge-selected outgoing projectiles. For all the charge-changing collisions investigated here, the mass distribution of small fragment ions C+n (n=1-12) can be approximated fairly well by a power-law form of n-λ as a function of the cluster size n. The power λ derived from each mass distribution is found to change strongly according to different charge-changing collisions. As a remarkable experimental finding, the values of λ(loss) in electron loss collisions are almost the same for the same final charge states k irrespective of the initial charge q, exhibiting a nearly perfect linear relationship with k. We also performed calculations of the projectile ionization on the basis of the semiclassical approximation and obtained inelastic energy deposition for individual collision processes. The estimated energy deposition is found to have a simple correlation with the experimentally determined values of λ(loss).

  19. In vitro and in vivo evaluation of zinc-modified ca-si-based ceramic coating for bone implants.

    Directory of Open Access Journals (Sweden)

    Jiangming Yu

    Full Text Available The host response to calcium silicate ceramic coatings is not always favorable because of their high dissolution rates, leading to high pH within the surrounding physiological environment. Recently, a zinc-incorporated calcium silicate-based ceramic Ca2ZnSi2O7 coating, developed on a Ti-6Al-4V substrate using plasma-spray technology, was found to exhibit improved chemical stability and biocompatibility. This study aimed to investigate and compare the in vitro response of osteoblastic MC3T3-E1 cells cultured on Ca2ZnSi2O7 coating, CaSiO3 coating, and uncoated Ti-6Al-4V titanium control at cellular and molecular level. Our results showed Ca2ZnSi2O7 coating enhanced MC3T3-E1 cell attachment, proliferation, and differentiation compared to CaSiO3 coating and control. In addition, Ca2ZnSi2O7 coating increased mRNA levels of osteoblast-related genes (alkaline phosphatase, procollagen α1(I, osteocalcin, insulin-like growth factor-I (IGF-I, and transforming growth factor-β1 (TGF-β1. The in vivo osteoconductive properties of Ca2ZnSi2O7 coating, compared to CaSiO3 coating and control, was investigated using a rabbit femur defect model. Histological and histomorphometrical analysis demonstrated new bone formation in direct contact with the Ca2ZnSi2O7 coating surface in absence of fibrous tissue and higher bone-implant contact rate (BIC in the Ca2ZnSi2O7 coating group, indicating better biocompatibility and faster osseointegration than CaSiO3 coated and control implants. These results indicate Ca2ZnSi2O7 coated implants have applications in bone tissue regeneration, since they are biocompatible and able to osseointegrate with host bone.

  20. Ion-implanted Si-nanostructures buried in a SiO{sub 2} substrate studied with soft-x-ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Williams, R.; Rubensson, J.E.; Eisebitt, S. [Forschungszentrum Juelich (Germany)] [and others

    1997-04-01

    In recent years silicon nanostructures have gained great interest because of their optical luminescence, which immediately suggests several applications, e.g., in optoelectronic devices. Nanostructures are also investigated because of the fundamental physics involved in the underlying luminescence mechanism, especially attention has been drawn to the influence of the reduced dimensions on the electronic structure. The forming of stable and well-defined nanostructured materials is one goal of cluster physics. For silicon nanostructures this goal has so far not been reached, but various indirect methods have been established, all having the problem of producing less well defined and/or unstable nanostructures. Ion implantation and subsequent annealing is a promising new technique to overcome some of these difficulties. In this experiment the authors investigate the electronic structure of ion-implanted silicon nanoparticles buried in a stabilizing SiO{sub 2} substrate. Soft X-ray emission (SXE) spectroscopy features the appropriate information depth to investigate such buried structures. SXE spectra to a good approximation map the local partial density of occupied states (LPDOS) in broad band materials like Si. The use of monochromatized synchrotron radiation (MSR) allows for selective excitation of silicon atoms in different chemical environments. Thus, the emission from Si atom sites in the buried structure can be separated from contributions from the SiO{sub 2} substrate. In this preliminary study strong size dependent effects are found, and the electronic structure of the ion-implanted nanoparticles is shown to be qualitatively different from porous silicon. The results can be interpreted in terms of quantum confinement and chemical shifts due to neighboring oxygen atoms at the interface to SiO{sub 2}.

  1. Hydrogen loss and its improved retention in hydrogen plasma treated a-SiNx:H films: ERDA study with 100 MeV Ag7+ ions

    Science.gov (United States)

    Bommali, R. K.; Ghosh, S.; Khan, S. A.; Srivastava, P.

    2018-05-01

    Hydrogen loss from a-SiNx:H films under irradiation with 100 MeV Ag7+ ions using elastic recoil detection analysis (ERDA) experiment is reported. The results are explained under the basic assumptions of the molecular recombination model. The ERDA hydrogen concentration profiles are composed of two distinct hydrogen desorption processes, limited by rapid molecular diffusion in the initial stages of irradiation, and as the fluence progresses a slow process limited by diffusion of atomic hydrogen takes over. Which of the aforesaid processes dominates, is determined by the continuously evolving Hydrogen concentration within the films. The first process dominates when the H content is high, and as the H concentration falls below a certain threshold (Hcritical) the irradiation generated H radicals have to diffuse through larger distances before recombining to form H2, thereby significantly bringing down the hydrogen evolution rate. The ERDA measurements were also carried out for films treated with low temperature (300 °C) hydrogen plasma annealing (HPA). The HPA treated films show a clear increase in Hcritical value, thus indicating an improved diffusion of atomic hydrogen, resulting from healing of weak bonds and passivation of dangling bonds. Further, upon HPA films show a significantly higher H concentration relative to the as-deposited films, at advanced fluences. These results indicate the potential of HPA towards improved H retention in a-SiNx:H films. The study distinguishes clearly the presence of two diffusion processes in a-SiNx:H whose diffusion rates differ by an order of magnitude, with atomic hydrogen not being able to diffuse further beyond ∼ 1 nm from the point of its creation.

  2. Depth profile of In and As in Si measured by RBS with He and C ions

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Q; Fang, Z [Newcastle Univ., NSW (Australia). Dept. of Physics; Ophel, T R [Australian National Univ., Canberra, ACT (Australia). Dept. of Nuclear Physics

    1994-12-31

    The depth profile of As and In implanted into Si have been measured by RBS (Rutherford Backscattering Spectrometry) with 2 MeV He ions and 6 MeV C ions. Advantages of enhanced depth and mass resolution with C ions have been demonstrated over the conventional He RBS. More reliable information for the depth profile of In and As in Si has been obtained. 12 refs., 3 figs.

  3. Depth profile of In and As in Si measured by RBS with He and C ions

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Q.; Fang, Z. [Newcastle Univ., NSW (Australia). Dept. of Physics; Ophel, T.R. [Australian National Univ., Canberra, ACT (Australia). Dept. of Nuclear Physics

    1993-12-31

    The depth profile of As and In implanted into Si have been measured by RBS (Rutherford Backscattering Spectrometry) with 2 MeV He ions and 6 MeV C ions. Advantages of enhanced depth and mass resolution with C ions have been demonstrated over the conventional He RBS. More reliable information for the depth profile of In and As in Si has been obtained. 12 refs., 3 figs.

  4. Reduction of transient diffusion from 1 endash 5 keV Si+ ion implantation due to surface annihilation of interstitials

    International Nuclear Information System (INIS)

    Agarwal, A.; Gossmann, H.-.; Eaglesham, D.J.; Pelaz, L.; Jacobson, D.C.; Haynes, T.E.; Erokhin, Y.E.

    1997-01-01

    The reduction of transient enhanced diffusion (TED) with reduced implantation energy has been investigated and quantified. A fixed dose of 1x10 14 cm -2 Si + was implanted at energies ranging from 0.5 to 20 keV into boron doping superlattices and enhanced diffusion of the buried boron marker layers was measured for anneals at 810, 950, and 1050 degree C. A linearly decreasing dependence of diffusivity enhancement on decreasing Si + ion range is observed at all temperatures, extrapolating to ∼1 for 0 keV. This is consistent with our expectation that at zero implantation energy there would be no excess interstitials from the implantation and hence no TED. Monte Carlo modeling and continuum simulations are used to fit the experimental data. The results are consistent with a surface recombination length for interstitials of <10 nm. The data presented here demonstrate that in the range of annealing temperatures of interest for p-n junction formation, TED is reduced at smaller ion implantation energies and that this is due to increased interstitial annihilation at the surface. copyright 1997 American Institute of Physics

  5. Influence of Si ion implantation on structure and morphology of g-C{sub 3}N{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Varalakshmi, B.; Sreenivasulu, K.V. [School of Engineering Sciences and Technology (SEST), University of Hyderabad, Hyderabad 500046 (India); Asokan, K. [Inter University Accelerator Centre (IUAC), Aruna Asaf Ali Marg, Near Vasant Kunj, New Delhi 110067 (India); Srikanth, V.V.S.S., E-mail: vvsssse@uohyd.ernet.in [School of Engineering Sciences and Technology (SEST), University of Hyderabad, Hyderabad 500046 (India)

    2016-07-15

    Effect of Si ion implantation on structural and morphological features of graphite-like carbon nitride (g-C{sub 3}N{sub 4}) was investigated. g-C{sub 3}N{sub 4} was prepared by using a simple atmospheric thermal decomposition process. The g-C{sub 3}N{sub 4} pellets were irradiated with a Si ion beam of energy 200 keV with different fluencies. Structural, morphological and elemental, and phase analysis of the implanted samples in comparison with the pristine samples was carried out by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) with energy dispersive spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) techniques, respectively. The observations revealed that Si ion implantation results in a negligible change in the crystallite size and alteration of the network-like to the sheet-like morphology of g-C{sub 3}N{sub 4} and Si ions in the g-C{sub 3}N{sub 4} network.

  6. SIMS analyses of ultra-low-energy B ion implants in Si: Evaluation of profile shape and dose accuracy

    International Nuclear Information System (INIS)

    Magee, C.W.; Hockett, R.S.; Bueyueklimanli, T.H.; Abdelrehim, I.; Marino, J.W.

    2007-01-01

    Numerous experimental studies for near-surface analyses of B in Si have shown that the B distribution within the top few nanometers is distorted by secondary ion mass spectrometry (SIMS) depth profiling with O 2 -flooding or normal incidence O 2 bombardment. Furthermore, the presence of surface oxide affects the X j determination as well as B profile shape when SIMS analyses are conducted while fully oxidizing the analytical area. Nuclear techniques such as elastic recoil detection (ERD), nuclear reaction analysis (NRA), and high-resolution Rutherford backscattering spectrometry (HR-RBS), are known to provide a profile shape near the surface that is free of artifacts. Comparisons with SIMS analyses have shown that SIMS analyses without fully oxidizing the analytical area agree well with these techniques at sufficiently high concentrations (where the nuclear techniques are applicable). The ability to measure both the B profile and an oxide marker with this non-oxidizing SIMS technique also allows accurate positioning of the B profile with respect to the SiO 2 /Si interface. This SIMS analysis protocol has been used to study the differences in near-surface dopant distribution for plasma-based implants. This study specifically focuses on measuring near-surface profile shapes as well as total implant doses for ultra-shallow B implants in Si especially those made with high peak B concentrations

  7. Study of the 28Si(n,α)25Mg induced by 14,55 MeV neutrons

    International Nuclear Information System (INIS)

    Devillers, D.

    1963-02-01

    The aim of this work is the study of the 28 Si(n,α) 25 Mg nuclear reaction. The silicon target is in fact a p-n junction detector that is placed in a neutron beam produced thanks to the D-T reaction by 150 kv electrostatic accelerator. The impulses due to the alpha particles generated by the neutrons inside the junction are analysed with adequate electronic equipment. Protons are generated in other nuclear reactions, they have the same energy as the alpha particles, most of them are not contained in the junction but all contribute to the experimental spectra. In order to make the discrimination between alpha and protons efficient, the thickness of the junction must be in the same magnitude as the alpha particle range in the junction. Edge effects are likely to disturb emission spectra. Corrections are necessary but they require a fine knowledge of the physics of junctions. In the first chapter we review the different reactions that are induced by neutrons in silicon. The second chapter deals with the experimental conditions concerning the studies of the junction detector and of the 28 Si(n,α) 25 Mg reaction itself. The determination of the cross-section requires to know the incident neutron flux accurately, we have applied the method of the associated particle and we have calibrated a scintillation counter operating with an anthracene crystal to measure the neutron flux. The third chapter gathers all the calculations concerning the edge effects in the junction detector. In the fourth chapter we present the experimental results with and without taking into account the edge effects. We have measured the values of the cross-sections corresponding to the first 6 excited states of 25 Mg

  8. Electrical properties of the regrown implantation-induced amorphous layer on (1 1-bar 0 0)- and (1 1 2-bar 0)-oriented 6H-SiC

    International Nuclear Information System (INIS)

    Nakamura, Tomonori; Tanabe, Hitoshi; Hitomi, Takeshi; Satoh, Masataka

    2003-01-01

    In the (1 1-bar 0 0) and (1 1 2-bar 0)-oriented 6H-SiC, the electrical properties and activation process of the implanted phosphorus in the layer regrown from the implantation-induced amorphous layer are investigated by means of Hall effect measurement and Rutherford backscattering spectrometry. The samples are implanted by 60 keV phosphorus ions at room temperature with doses of 3 x 10 15 and 1 x 10 15 cm -2 to form implantation-induced amorphous layer and the partially disordered implant-layer, respectively. The implanted phosphorus in the implantation-induced amorphous layer can be electrically activated by annealing at 1000 deg. C. The electrical activity for the case of the implantation-induced amorphous layer (ratio of sheet carrier concentration to ion dose) is 2-3 times larger than that for the case of the partially disordered implant-layer for the annealing temperature of 1500 deg. C

  9. Electroluminescence properties of Si MOS structures with incorporation of FeSi2 precipitates formed by iron implantation

    International Nuclear Information System (INIS)

    Chow, C.F.; Wong, S.P.; Gao, Y.; Ke, N.; Li, Q.; Cheung, W.Y.; Lourenco, M.A.; Homewood, K.P.

    2005-01-01

    Silicon MOS structures with FeSi 2 precipitates embedded in the MOS active region have been fabricated and the electroluminescence (EL) properties from these FeSi 2 -Si MOS structures were measured as a function of temperature from 80 K to 300 K. Clear EL signals were observed even at room temperature for samples prepared at appropriate processing conditions. The EL spectra consist of two peaks, one attributed to FeSi 2 and the other attributed to Si band edge emission. While the intensity of the FeSi 2 peak showed the usual thermal quenching behavior, the Si band edge emission showed the opposite trend with its intensity increased with increasing temperature. Details of the line shapes and their temperature dependence are analyzed and discussed

  10. Robustness up to 400°C of the passivation of c-Si by p-type a-Si:H thanks to ion implantation

    Science.gov (United States)

    Defresne, A.; Plantevin, O.; Roca i Cabarrocas, Pere

    2016-12-01

    Heterojunction solar cells based on crystalline silicon (c-Si) passivated by hydrogenated amorphous silicon (a-Si:H) thin films are one of the most promising architectures for high energy conversion efficiency. Indeed, a-Si:H thin films can passivate both p-type and n-type wafers and can be deposited at low temperature (layers, in particular p-type a-Si:H, show a dramatic degradation in passivation quality above 200°C. Yet, annealing at 300 - 400°C the TCO layer and metallic contacts is highly desirable to reduce the contact resistance as well as the TCO optical absorption. In this work, we show that as expected, ion implantation (5 - 30 keV) introduces defects at the c-Si/a-Si:H interface which strongly degrade the effective lifetime, down to a few micro-seconds. However, the passivation quality can be restored and lifetime values can be improved up to 2 ms over the initial value with annealing. We show here that effective lifetimes above 1 ms can be maintained up to 380°C, opening up the possibility for higher process temperatures in silicon heterojunction device fabrication.

  11. Structural and optical characterization of Mn doped ZnS nanocrystals elaborated by ion implantation in SiO2

    International Nuclear Information System (INIS)

    Bonafos, C.; Garrido, B.; Lopez, M.; Romano-Rodriguez, A.; Gonzalez-Varona, O.; Perez-Rodriguez, A.; Morante, J.R.; Rodriguez, R.

    1999-01-01

    Mn doped ZnS nanocrystals have been formed in SiO 2 layers by ion implantation and thermal annealing. The structural analysis of the processed samples has been performed mainly by Secondary Ion Mass Spectroscopy (SIMS) and Transmission Electron Microscopy (TEM). The data show the precipitation of ZnS nanocrystals self-organized into two layers parallel to the free surface. First results of the optical analysis of samples co-implanted with Mn show the presence of a yellow-green photoluminescence depending on the Mn concentration and the size of the nanocrystals, suggesting the doping with Mn of some precipitates

  12. 28Si(16O,16O) 28Si at elab = 50.53,55,66,72,81,142.5 and 215.2 MeV

    International Nuclear Information System (INIS)

    Kumar, A.; Kumar, S.; Kumar, S.

    1994-01-01

    Most of the HI elastic scattering studies suffer from the inevitable ambiguity of a potential extracted from a limited set of forward angle data at low energies and also confined to small region of the potential tail. The 16O+28Si system overcomes this ambiguity as a variety of experimental data are available at vast energies over full angular range. Here, real part of the nuclear potential is microscopically calculated for both oblate and prolate shapes of silicon nucleus and an average is taken. The imaginary part of the nuclear potential is assumed by adjusting a dimensionless strength parameter in the above real part. This approach reproduces fairly well the experimental DCS over full angular range, excitation function at cm = 90 degrees and 180 degrees and also backangle anomaly (ALAS)

  13. Influence of Si addition on the microstructure and mechanical properties of Ti-35Nb alloy for applications in orthopedic implants.

    Science.gov (United States)

    Tavares, A M G; Ramos, W S; de Blas, J C G; Lopes, E S N; Caram, R; Batista, W W; Souza, S A

    2015-11-01

    In the development of new materials for orthopedic implants, special attention has been given to Ti alloys that show biocompatible alloy elements and that are capable of reducing the elastic modulus. Accordingly, Ti-Nb-Si alloys show great potential for application. Thus, this is a study on the microstructures and properties of Ti-35Nb-xSi alloys (x=0, 0.15, 0.35 and 0.55) (wt%) which were thermally treated and cooled under the following conditions: furnace cooling (FC), air cooling (AC), and water quenching (WQ). The results showed that Si addition is effective to reduce the density of omega precipitates making beta more stable, and to produce grain refinement. Silicides, referred as (Ti,Nb)3Si, were formed for alloys containing 0.55% Si, and its formation presumably occurred during the heating at 1000°C. In all cooling conditions, the hardness values increased with the increasing of Si content, as a result from the strong Si solid solution strengthening effect, while the elastic modulus underwent a continuous reduction due to the reduction of omega precipitates in beta matrix. Lower elastic moduli were observed in water-quenched alloys, which concentration of 0.15% Si was more effective in their reduction, with value around 65 GPa. Regarding Ti-35Nb-xSi alloys (x=0, 0.15 and 0.35), the "double yield point" phenomenon, which is typical of alloys with shape memory effect, was observed. The increase in Si concentration also produced an increase from 382 MPa to 540 MPa in the alloys' mechanical strength. Ti-35Nb-0.55Si alloy, however, showed brittle mechanical behavior which was related to the presence of silicides at the grain boundary. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. N and Si Implantation Effect on Structural and Electrical Properties of Bridgman grown GaSe Single Crystal

    International Nuclear Information System (INIS)

    Karabulut, O.

    2004-01-01

    N and Si implantation to GaSe single crystals were carried out parallel to c-axis with ion beam of about 10 1 6 ions/cm 2 dose having energy values 30, 60 and 100 keV. Ion implantation modifications on Bridgman grown GaSe single crystals have been investigated by means of XRD, electrical conductivity, absorption and photoconductivity measurements. XRD measurements revealed that annealing results in a complete recovery of the crystalline nature that was moderately reduced upon implantation. It was observed that both N- and Siimplantation followed by annealing process decreased the resistivity values from 10 7 to 10 3 .-cm. The analysis of temperature dependent conductivity showed that at high temperature region above 200 K, the transport mechanism is dominated by thermal excitation in the doped and undoped GaSe samples. At lower temperatures, the conduction of carriers is dominated by variable range hopping mechanism in the implanted samples. Absorption and spectral photoconductivity measurements showed that the band edge is shifted in the implanted sample. All these modifications were attributed to the structural modifications and continuous shallow trap levels introduced upon implantation and annealing

  15. Photoluminescence and structural studies of Tb and Eu implanted at high temperatures into SiO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Bregolin, F.L. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, 91501-970, Porto Alegre-RS (Brazil); Sias, U.S., E-mail: uilson.sias@gmail.com [Instituto Federal Sul-rio-grandense, Campus Pelotas, Praca 20 de Setembro 455, 96015-360, Pelotas-RS (Brazil); Behar, M. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, 91501-970, Porto Alegre-RS (Brazil)

    2013-03-15

    The present work deals with the photoluminescence (PL) emitted from Eu and Tb ions implanted at room temperature (RT) up to 350 Degree-Sign C in a SiO{sub 2} matrix, followed by a further anneal process. The ions were implanted with energy of 100 keV and a fluence of 3 Multiplication-Sign 10{sup 15} ions/cm Superscript-Two . Further anneals were performed in atmospheres of N{sub 2} or O{sub 2} with temperatures ranging from 500 up to 800 Degree-Sign C. PL measurements were performed at RT and structural measurements were done via transmission electron microscopy (TEM). In addition, the Rutherford backscattering technique (RBS) was used to investigate the corresponding ion depth profiles. For Tb, the optimal implantation temperature was 200 Degree-Sign C, and the anneal one was of 500 Degree-Sign C. Under these conditions, the PL yield of the sharp band centered at 550 nm was significatively higher than the one obtained with RT implants. The PL spectra corresponding to the Eu ions show two bands, one narrow centered around 650 nm and a second broad one in the blue-green region. The implantation temperature plays a small influence on the PL shape and yield. However, the annealing atmosphere has a strong influence on it. Samples annealed in N{sub 2} present a broad PL band, ranging from 370 up to 840 nm. On the other hand, the O{sub 2} anneal conserves the original as-implanted spectrum, that is: a broad PL band in the blue-green region together with sharp PL band in the red one. For both ions, Tb and Eu, the TEM analyses indicate the formation of nanoclusters in the hot as-implanted samples. - Highlights: Black-Right-Pointing-Pointer Eu and Tb nanoparticles were obtained by hot ion implantation into SiO{sub 2} matrix. Black-Right-Pointing-Pointer TEM results indicate the formation of nanoclusters in the hot as-implanted samples. Black-Right-Pointing-Pointer Samples annealed in N{sub 2} presented a broad PL band (from 370 up to 840 nm). Black-Right-Pointing-Pointer O

  16. Hall effect mobility for SiC MOSFETs with increasing dose of nitrogen implantation into channel region

    Science.gov (United States)

    Noguchi, Munetaka; Iwamatsu, Toshiaki; Amishiro, Hiroyuki; Watanabe, Hiroshi; Kita, Koji; Yamakawa, Satoshi

    2018-04-01

    The Hall effect mobility (μHall) of the Si-face 4H-SiC metal–oxide–semiconductor field effect transistor (MOSFET) with a nitrogen (N)-implanted channel region was investigated by increasing the N dose. The μHall in the channel region was systematically examined regarding channel structures, that is, the surface and buried channels. It was experimentally demonstrated that increasing the N dose results in an improvement in μHall in the channel region due to the formation of the buried channel. However, further increase in N dose was found to decrease the μHall in the channel region, owing to the decrease in the electron mobility in the N-implanted bulk region.

  17. Extreme implanting in Si: A study of ion-induced damage at high temperature and high dose

    International Nuclear Information System (INIS)

    Holland, O.W.

    1994-01-01

    Ion-solid interactions near room temperature and below have been well studied in single-crystal Si. While this has led to a better understanding of the mechanisms responsible for nucleation and growth of lattice damage during irradiation, these studies have not, in general, been extended to high temperatures (e.g., >200 degrees C). This is the case despite the commercialization of ion beam technologies which utilize high-temperature processing, such as separation by implantation of oxygen (SIMOX). In this process, a silicon-on-insulator (SOI) material is produced by implanting a high dose of oxygen ions into a Si wafer to form a buried, stoichiometric oxide layer. Results will be presented of a study of damage accumulation during high-dose implantation of Si at elevated temperatures. In particular, O + -ions were used because of the potential impact of the results on the SIMOX technology. It will be shown that the nature of the damage accumulation at elevated temperatures is quite distinctive and portends the presence of a new mechanism, one which is only dominant under the extreme conditions encountered during ion beam synthesis (i.e., high temperature and high dose). This mechanism is discussed and shown to be quite general and not dependent on the chemical identity of the ions. Also, techniques for suppressing this mechanism by open-quotes defect engineeringclose quotes are discussed. Such techniques are technologically relevant because they offer the possibility of reducing the defect density of the SOI produced by SIMOX

  18. A new study of 25Mg(α, n)28Si angular distributions at Eα =3-5 MeV

    International Nuclear Information System (INIS)

    Caciolli, A.; Marchi, T.; Depalo, R.; Collazuol, G.; Montagnoli, G.; Appannababu, S.; Cinausero, M.; Gramegna, F.; Mastinu, P.; Rossi Alvarez, C.; Rigato, V.; Blasi, N.; Wieland, O.; Broggini, C.; Fabris, D.; Menegazzo, R.; Degerlier, M.; Leone, M.

    2014-01-01

    The observation of 26 Al gives us the proof of active nucleosynthesis in the Milky Way. However the identification of the main producers of 26 Al is still a matter of debate. Many sites have been proposed, but our poor knowledge of the nuclear processes involved introduces high uncertainties. In particular, the limited accuracy on the 25 Mg(α, n) 28 Si reaction cross section has been identified as the main source of nuclear uncertainty in the production of 26 Al in C/Ne explosive burning in massive stars, which has been suggested to be the main source of 26 Al in the Galaxy. We studied this reaction through neutron spectroscopy at the CN Van de Graaff accelerator of the Legnaro National Laboratories. Thanks to this technique we are able to discriminate the (α, n) events from possible contamination arising from parasitic reactions. In particular, we measured the neutron angular distributions at 5 different beam energies (between 3 and 5 MeV) in the 17.5 circle - 106 circle laboratory system angular range. The presented results disagree with the assumptions introduced in the analysis of a previous experiment. (orig.)

  19. Vacancy supersaturations produced by high-energy ion implantation

    International Nuclear Information System (INIS)

    Venezia, V.C.; Eaglesham, D.J.; Jacobson, D.C.; Gossmann, H.J.

    1998-01-01

    A new technique for detecting the vacancy clusters produced by high-energy ion implantation into silicon is proposed and tested. This technique takes advantage of the fact that metal impurities, such as Au, are gettered near one-half of the projected range (1/2 R p ) of MeV implants. The vacancy clustered region produced by a 2 MeV Si + implant into silicon has been labeled with Au diffused in from the front surface. The trapped Au was detected by Rutherford backscattering spectrometry (RBS) to profile the vacancy clusters. Cross section transmission electron microscopy (XTEM) analysis shows that the Au in the region of vacancy clusters is in the form of precipitates. By annealing MeV implanted samples prior to introduction of the Au, changes in the defect concentration within the vacancy clustered region were monitored as a function of annealing conditions

  20. Chemical effect of Si+ ions on the implantation-induced defects in ZnO studied by a slow positron beam

    Science.gov (United States)

    Jiang, M.; Wang, D. D.; Chen, Z. Q.; Kimura, S.; Yamashita, Y.; Mori, A.; Uedono, A.

    2013-01-01

    Undoped ZnO single crystals were implanted with 300 keV Si+ ions to a dose of 6 × 1016 cm-2. A combination of X-ray diffraction (XRD), positron annihilation, Raman scattering, high resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) was used to study the microstructure evolution after implantation and subsequent annealing. A very large increase of Doppler broadening S parameters in Si+-implanted region was detected by using a slow positron beam, indicating that vacancy clusters or microvoids are induced by implantation. The S parameters increase further after annealing up to 700 °C, suggesting agglomeration of these vacancies or microvoids to larger size. Most of these defects are removed after annealing up to 1100 °C. The other measurements such as XRD, Raman scattering, and PL all indicate severe damage and even disordered structure induced by Si+ implantation. The damage and disordered lattice shows recovery after annealing above 700 °C. Amorphous regions are observed by HRTEM measurement, directly testifies that amorphous phase is induced by Si+ implantation in ZnO. Analysis of the S - W correlation and the coincidence Doppler broadening spectra gives direct evidence of SiO2 precipitates in the sample annealed at 700 °C, which strongly supports the chemical effect of Si ions on the amorphization of ZnO lattice.

  1. Mn fraction substitutional site and defects induced magnetism in Mn-implanted 6H-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Bouziane, K., E-mail: Khalid.bouziane@uir.ac.ma [Pôle Energies Renouvelables et Etudes Pétrolières, Université Internationale de Rabat, 11000 – Salé el Jadida, Technopolis (Morocco); Al Azri, M.; Elzain, M. [Department of Physics, College of Science, Sultan Qaboos University, P.O. Box 36, Al-Khodh 123 (Oman); Chérif, S.M. [LSPM (CNRS-UPR 3407), Université Paris, 13-Nord, 99, Avenue Jean Baptiste Clément, 93430 Villetaneuse (France); Mamor, M. [Equipe MSISM, Faculté Poly-Disciplinaire, B.P. 4162 Safi, Université Cadi Ayyad, Marrakech (Morocco); Declémy, A. [Institut P’, CNRS – Université de Poitiers – ENSMA, UPR 3346, SP2MI – Téléport 2, 11 boulevard Marie et Pierre Curie, BP 30179, F-86962 Futuroscope Chasseneuil Cedex (France); Thomé, L. [CSNSM-Orsay, Bât. 108, Université d’Orsay, F-91405 Orsay (France)

    2015-05-25

    Highlights: • Shallow Mn-implanted 6H-SiC crystal. • Correlation between Mn-substitutional site concentration and magnetism. • Correlation between defects nature surrounding Mn site and magnetism. • Correlation of magnetism in Mn-doped SiC to Mn at Si sites and vacancy-related defect. - Abstract: n-type 6H-SiC (0 0 0 1) single crystal substrates were implanted with three fluences of manganese (Mn{sup +}) ions: 5 × 10{sup 15}, 1 × 10{sup 16} and 5 × 10{sup 16} cm{sup −2} with implantation energy of 80 keV at 365 °C to stimulate dynamic annealing. The samples were characterized using Rutherford backscattering channeling spectroscopy (RBS/C), high-resolution X-ray diffraction technique (HRXRD), and Superconducting Quantum Interference Device (SQUID) techniques. Two main defect regions have been identified using RBS/C spectra fitted with the McChasy code combined to SRIM simulations. Intermediate defects depth region is associated with vacancies (D{sub V}) and deeper defect (D{sub N}) essentially related to the Si and C interstitial defects. The defect concentration and the maximum perpendicular strain exhibit similar increasing trend with the Mn{sup +} fluence. Furthermore, the amount of Mn atoms at Si substitutional sites and the corresponding magnetic moment per Mn atom were found to increase with increasing Mn fluence from 0.7 μ{sub B} to 1.7 μ{sub B} and then collapsing to 0.2 μ{sub B}. Moreover, a strong correlation has been found between the magnetic moment and the combination of both large D{sub V}/D{sub N} ratio and high Mn at Si sites. These results are corroborated by our ab initio calculations considering the most stable configurations showing that besides the amount of Mn substituting Si sites, local vacancy-rich environment is playing a crucial role in enhancing the magnetism.

  2. Cathodoluminescence and ion beam analysis of ion-implanted combinatorial materials libraries on thermally grown SiO2

    International Nuclear Information System (INIS)

    Chen, C.-M.; Pan, H.C.; Zhu, D.Z.; Hu, J.; Li, M.Q.

    1999-01-01

    A method combining ion implantation and physical masking technique has been used to generate material libraries of various ion-implanted samples. Ion species of C, Ga, N, Pb, Sn, Y have been sequentially implanted to an SiO 2 film grown on a silicon wafer through combinatorial masks and consequently a library of 64 (2 6 ) samples is generated by 6 masking combinations. This approach offers rapid synthesis of samples with potential new compounds formed in the matrix, which may have specific luminescent properties. The depth-resolved cathodoluminescence (CL) measurements revealed some specific optical property in the samples correlated with implanted ion distributions. A marker-based technique is developed for the convenient location of sample site in the analysis of Rutherford backscattering spectrometry (RBS) and proton elastic scattering (PES), intended to characterize rapidly the ion implanted film libraries. These measurements demonstrate the power of nondestructively and rapidly characterizing composition and the inhomogeneity of the combinatorial film libraries, which may determine their physical properties

  3. Effect of ion implantation energy for the synthesis of Ge nanocrystals in SiN films with HfO2/SiO2 stack tunnel dielectrics for memory application

    Directory of Open Access Journals (Sweden)

    Gloux Florence

    2011-01-01

    Full Text Available Abstract Ge nanocrystals (Ge-NCs embedded in SiN dielectrics with HfO2/SiO2 stack tunnel dielectrics were synthesized by utilizing low-energy (≤5 keV ion implantation method followed by conventional thermal annealing at 800°C, the key variable being Ge+ ion implantation energy. Two different energies (3 and 5 keV have been chosen for the evolution of Ge-NCs, which have been found to possess significant changes in structural and chemical properties of the Ge+-implanted dielectric films, and well reflected in the charge storage properties of the Al/SiN/Ge-NC + SiN/HfO2/SiO2/Si metal-insulator-semiconductor (MIS memory structures. No Ge-NC was detected with a lower implantation energy of 3 keV at a dose of 1.5 × 1016 cm-2, whereas a well-defined 2D-array of nearly spherical and well-separated Ge-NCs within the SiN matrix was observed for the higher-energy-implanted (5 keV sample for the same implanted dose. The MIS memory structures implanted with 5 keV exhibits better charge storage and retention characteristics compared to the low-energy-implanted sample, indicating that the charge storage is predominantly in Ge-NCs in the memory capacitor. A significant memory window of 3.95 V has been observed under the low operating voltage of ± 6 V with good retention properties, indicating the feasibility of these stack structures for low operating voltage, non-volatile memory devices.

  4. Study of elastic pion scattering from /sup 9/Be, /sup 28/Si, /sup 58/Ni, and /sup 208/Pb at 162 MeV. [Total and differential cross sections, scattering yields, scattering amplitudes

    Energy Technology Data Exchange (ETDEWEB)

    Devereux, M.J.

    1979-05-01

    Elastic pion scattering from /sup 9/Be, /sup 28/Si, /sup 58/Ni, and /sup 208/Pb at 162 MeV is analyzed and compared with an optical model theory which incorporates a pion--nucleon range. Excellent fits to the data are obtained in all but one case. The fitted values of the pion--nucleon range, as well as other fitted values are listed. 108 references.

  5. Depth dependent modification of optical constants arising from H+ implantation in n-type 4H-SiC measured using coherent acoustic phonons

    Directory of Open Access Journals (Sweden)

    Andrey Baydin

    2016-06-01

    Full Text Available Silicon carbide (SiC is a promising material for new generation electronics including high power/high temperature devices and advanced optical applications such as room temperature spintronics and quantum computing. Both types of applications require the control of defects particularly those created by ion bombardment. In this work, modification of optical constants of 4H-SiC due to hydrogen implantation at 180 keV and at fluences ranging from 1014 to 1016 cm−2 is reported. The depth dependence of the modified optical constants was extracted from coherent acoustic phonon spectra. Implanted spectra show a strong dependence of the 4H-SiC complex refractive index depth profile on H+ fluence. These studies provide basic insight into the dependence of optical properties of 4H silicon carbide on defect densities created by ion implantation, which is of relevance to the fabrication of SiC-based photonic and optoelectronic devices.

  6. Study of the response of a silicon detector irradiated with 1 MeV neutrons; Etude de la reponse d`un detecteur Si irradie par des neutrons de 1 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Roy, P [Montreal Univ., PQ (Canada). Lab. de Physique Nucleaire

    1994-12-31

    The author studied the response of an n-type silicon detector irradiated with 1 MeV neutrons at fluences ranging from 0.26x10{sup 13} to 11.19x10{sup 13} neutrons/cm{sup 2}. The response of the irradiated detector to {sup 241}Am alpha particles was measured. 13 refs., 7 figs.

  7. Nuclear radiation detector based on ion implanted p-n junction in 4H-SiC

    International Nuclear Information System (INIS)

    Vervisch, V.; Issa, F.; Ottaviani, L.; Lazar, M.; Kuznetsov, A.; Szalkai, D.; Klix, A.; Lyoussi, A.; Vermeeren, L.; Hallen, A.

    2013-06-01

    In this paper, we propose a new device detector based on ion implanted p-n junction in 4H-SiC for nuclear instrumentation. We showed the interest to use 10 Boron as a Neutron Converter Layer in order to detect thermal neutrons. We present the main results obtained during irradiation tests performed in the Belgian Reactor 1. We show the capability of our detector by means of first results of the detector response at different reverse voltage biases and at different reactor power (authors)

  8. Co-Au core-shell nanocrystals formed by sequential ion implantation into SiO2

    International Nuclear Information System (INIS)

    Kluth, P.; Hoy, B.; Johannessen, B.; Dunn, S. G.; Foran, G. J.; Ridgway, M. C.

    2006-01-01

    Co-Au core-shell nanocrystals (NCs) were formed by sequential ion implantation of Au and Co into thin SiO 2 . The NCs were investigated by means of transmission electron microscopy and extended x-ray absorption fine structure spectroscopy. The latter reveals a bond length expansion in the Co core compared to monatomic Co NCs. Concomitantly, a significant contraction of the bond length and a significant reduction of the effective Au-Au coordination number were observed in the Au shells. Increased Debye-Waller factors indicate significant strain in the NCs. These experimental results verify recent theoretical predictions

  9. Analytical threshold voltage modeling of ion-implanted strained-Si double-material double-gate (DMDG) MOSFETs

    Science.gov (United States)

    Goel, Ekta; Singh, Balraj; Kumar, Sanjay; Singh, Kunal; Jit, Satyabrata

    2017-04-01

    Two dimensional threshold voltage model of ion-implanted strained-Si double-material double-gate MOSFETs has been done based on the solution of two dimensional Poisson's equation in the channel region using the parabolic approximation method. Novelty of the proposed device structure lies in the amalgamation of the advantages of both the strained-Si channel and double-material double-gate structure with a vertical Gaussian-like doping profile. The effects of different device parameters (such as device channel length, gate length ratios, germanium mole fraction) and doping parameters (such as projected range, straggle parameter) on threshold voltage of the proposed structure have been investigated. It is observed that the subthreshold performance of the device can be improved by simply controlling the doping parameters while maintaining other device parameters constant. The modeling results show a good agreement with the numerical simulation data obtained by using ATLAS™, a 2D device simulator from SILVACO.

  10. Enhanced Electrical Activation in In-Implanted Si0.35Ge0.65 by C Co-Doping

    International Nuclear Information System (INIS)

    Feng, Ruixing; Kremer, Felipe; Sprouster, David J.; Mirzaei, Sahar; Decoster, Stefan

    2016-01-01

    In this report, we have achieved a significant increase in the electrically active dopant fraction in Indium (In)-implanted Si 0.35 Ge 0.65 , by co-doping with the isovalent element Carbon (C). Electrical measurements have been correlated with X-ray absorption spectroscopy to determine the electrical properties and the In atom lattice location. With C+In co-doping, the solid solubility of In in Si 0.35 Ge 0.65 was at least tripled from between 0.02 and 0.06 at% to between 0.2 and 0.6 at% as a result of C–In pair formation, which suppressed In metal precipitation. A dramatic improvement of electrical properties was thus attained in the co-doped samples.

  11. Two concepts of introducing thin-film superconductivity in Ge and Si by use of Ga-ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Skrotzki, Richard [Dresden High Magnetic Field Laboratory (HLD) and Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Department of Chemistry and Food Chemistry, TU Dresden (Germany); Herrmannsdoerfer, Thomas; Fiedler, Jan; Heera, Viton; Voelskow, Matthias; Muecklich, Arndt; Schmidt, Bernd; Skorupa, Wolfgang; Helm, Manfred; Wosnitza, Joachim [Dresden High Magnetic Field Laboratory (HLD) and Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany)

    2012-07-01

    We report on two unconventional routes of embedding superconducting nanolayers in a semiconducting environment. Ion implantation and subsequent annealing have been used for preparation of superconducting thin-films of Ga-doped germanium (Ge:Ga) as well as 10 nm thin amorphous Ga-rich layers in silicon (Si:Ga). Structural investigations by means of XTEM, EDX, RBS/C, and SIMS have been performed in addition to low-temperature electrical transport and magnetization measurements. Regarding Ge:Ga, we unravel the evolution of T{sub c} with charge-carrier concentration while for Si:Ga recently implemented microstructuring renders critical-current densities or more than 50 kA/cm{sup 2}. Combined with a superconducting onset at around 10 K, this calls for on-chip application in novel heterostructured devices.

  12. Device-based local delivery of siRNA against mammalian target of rapamycin (mTOR) in a murine subcutaneous implant model to inhibit fibrous encapsulation.

    Science.gov (United States)

    Takahashi, Hironobu; Wang, Yuwei; Grainger, David W

    2010-11-01

    Fibrous encapsulation of surgically implanted devices is associated with elevated proliferation and activation of fibroblasts in tissues surrounding these implants, frequently causing foreign body complications. Here we test the hypothesis that inhibition of the expression of mammalian target of rapamycin (mTOR) in fibroblasts can mitigate the soft tissue implant foreign body response by suppressing fibrotic responses around implants. In this study, mTOR was knocked down using small interfering RNA (siRNA) conjugated with branched polyethylenimine (bPEI) in fibroblastic lineage cells in serum-based cell culture as shown by both gene and protein analysis. This mTOR knock-down led to an inhibition in fibroblast proliferation by 70% and simultaneous down-regulation in the expression of type I collagen in fibroblasts in vitro. These siRNA/bPEI complexes were released from poly(ethylene glycol) (PEG)-based hydrogel coatings surrounding model polymer implants in a subcutaneous rodent model in vivo. No significant reduction in fibrous capsule thickness and mTOR expression in the foreign body capsules were observed. The siRNA inefficacy in this in vivo implant model was attributed to siRNA dosing limitations in the gel delivery system, and lack of targeting ability of the siRNA complex specifically to fibroblasts. While in vitro data supported mTOR knock-down in fibroblast cultures, in vivo siRNA delivery must be further improved to produce clinically relevant effects on fibrotic encapsulation around implants. Copyright © 2010 Elsevier B.V. All rights reserved.

  13. High-current and low acceleration voltage arsenic ion implanted polysilicon-gate and source-drain electrode Si mos transistor

    International Nuclear Information System (INIS)

    Saito, Yasuyuki; Sugimura, Yoshiro; Sugihara, Michiyuki

    1993-01-01

    The fabrication process of high current arsenic (As) ion implanted polysilicon (Si) gate and source drain (SD) electrode Si n-channel metal oxide-semiconductor field effect transistor (MOSFET) was examined. Poly Si film n-type doping was performed by using high current (typical current: 2mA) and relatively low acceleration voltage (40keV) As ion implantation technique (Lintott series 3). It was observed that high dose As implanted poly Si films as is show refractoriness against radical fluorine excited by microwave. Using GCA MANN4800 (m/c ID No.2, resist: OFPR) mask pattern printing technique, the high current As ion implantation technique and radical fluorine gas phase etching (Chemical dry etching: CDE) technique, the n-channel Poly Si gate (ρs = ≅100Ω/□) enhancement MQSFETs(ρs source drain = ≅50Ω/□, SiO 2 gate=380 angstrom) with off-leak-less were obtained on 3 inch Czochralski grown 2Ωcm boron doped p type wafers (Osaka titanium). By the same process, a 8 bit single chip μ-processor with 26MHz full operation was performed

  14. Neutron scattering from 28Si and 32S from 8.0 to 18.9 MeV, dispersive optical model analyses, and ground-state correlations

    International Nuclear Information System (INIS)

    Al-Ohali, M.A.; Nagadi, M.M.; Naqvi, A.A.; Delaroche, J.P.; Howell, C.R.; Tornow, W.; Walter, R.L.; Weisel, G.J.; Howell, C.R.; Tornow, W.; Walter, R.L.; Weisel, G.J.; Weisel, G.J.

    2012-01-01

    Background: The nucleon-nucleus dispersive optical model (DOM) has been successful in providing good fits to scattering data and in making valuable predictions for bound-state properties in single-and double-closed shell nuclei. However, the generalizability of the DOM remains an ongoing issue. Purpose: We investigate the DOM in the continuum and bound-state regions of the open-shell, self-conjugate nuclei 28 Si and 32 S. We collect new differential cross section and analyzing power data for elastic scattering at incident neutron energies between 8.0 and 18.9 MeV. Methods: The measurements were conducted using a pulsed deuteron beam, the 2 He(d,n) 3 He source reaction, and time-of-flight techniques. All data were corrected for finite-geometry effects. Phenomenological DOM potentials were tailored to fit the differential and total cross section data, and then extrapolated to the bound-state regions. The DOM bound-state predictions were then compared to experimental data available for single-particle energies, occupation probabilities, root-mean-square radii, and spectroscopic factors. Results: The DOM bound-state predictions are in only fair agreement with experimental data and with USD shell-model predictions. Similar results are found after converting our neutron DOMs into proton DOMs. We investigate the separate effects of the dispersive surface and volume potential components on occupation probability and find that the volume component leads to a uniform depletion of the hole states, while the surface component acts mainly to deplete the valence orbitals. We compare these results to those of a variational multiparticle multi-hole configuration mixing (mp-mh CM) calculation using the Gogny D1S effective force. Conclusions: We find that the phenomenological DOM, which was originally designed for spherical nuclei, show certain deficiencies when applied to open-shell nuclei and suggest possible avenues of improvement. We also find that the predictions of occupation

  15. Single-Ion Implantation for the Development of Si-Based MOSFET Devices with Quantum Functionalities

    Directory of Open Access Journals (Sweden)

    Jeffrey C. McCallum

    2012-01-01

    Full Text Available Interest in single-ion implantation is driven in part by research into development of solid-state devices that exhibit quantum behaviour in their electronic or optical characteristics. Here, we provide an overview of international research work on single ion implantation and single ion detection for development of electronic devices for quantum computing. The scope of international research into single ion implantation is presented in the context of our own research in the Centre for Quantum Computation and Communication Technology in Australia. Various single ion detection schemes are presented, and limitations on dopant placement accuracy due to ion straggling are discussed together with pathways for scale-up to multiple quantum devices on the one chip. Possible future directions for ion implantation in quantum computing and communications are also discussed.

  16. Distribution of implanted hydrogen in amorphous silicon dioxide a-SiO2

    International Nuclear Information System (INIS)

    Mokrushin, A.D.; Agafonov, Yu.A.; Zinenko, V.I.; Pustovit, A.N.

    2004-01-01

    Hydrogen SIMS distributions are measured in quartz glasses implanted by different doses of H 2 + ions with energy 40 keV. There are two features in distributions: the availability of intensive peak close to the surface and near-constant dependence at large depth up to ions range. These peculiarities are perhaps attributable to the radiation induced diffusion of hydrogen atoms back to the surface via which ions are implanted [ru

  17. Study of low energy Si5- and Cs- implantation induced amorphization effects in Si(1 0 0)

    International Nuclear Information System (INIS)

    Lenka, H P; Joseph, B; Kuiri, P K; Sahu, G; Mahapatra, D P; Mishra, P; Ghose, D

    2008-01-01

    The damage growth and surface modifications in Si(1 0 0), induced by 25 keV Si 5 - cluster ions, as a function of fluence, φ, has been studied using atomic force microscopy (AFM) and channelling Rutherford backscattering spectrometry (RBS/C). RBS/C results indicate a nonlinear growth in damage from which it has been possible to get a threshold fluence, φ 0 , for amorphization as 2.5 x 10 13 ions cm -2 . For φ below φ 0 , a growth in damage as well as surface roughness has been observed. At a φ of 1 x 10 14 ions cm -2 , damage saturation coupled with a much reduced surface roughness has been found. In this case a power spectrum analysis of AFM data showed a significant drop in spectral density, as compared with the same obtained for a fluence, φ 0 . This drop, together with damage saturation, can be correlated with a transition to a stress relaxed amorphous phase. Irradiation with similar mass Cs - ions, at the same energy and fluence, has been found to result in a reduced accumulation of defects in the near surface region leading to reduced surface features.

  18. Characterization of vacancy-type defects induced by the implantation of Se and Si ions into GaAs by a slow positron beam

    International Nuclear Information System (INIS)

    Fujii, Satoshi; Shikata, Shinichi; Wei Long; Tanigawa, Shoichiro.

    1992-01-01

    Variable-energy (0-30keV) positron beam studies have been carried out on 200 keV Se-implanted and 70 keV Si-implanted GaAs specimens before and after annealing for electrical activation. From the measurements of Doppler broadened profiles as a function of incident positron energy, it was found that vacancy clusters with high concentration were introduced in the annealed specimen after Se implantation. From the parallel measurement of electrical characteristics, a higher activation efficiency was found for the higher concentration of vacancy clusters. That fact implies that electrons supplied by the activation of Se also convert the charge state of As vacancies from positive to negative. In contrast, no vacancy clusters were introduced in the Si-implanted GaAs. (author)

  19. Thermoluminescence of sol–gel derived Y{sub 2}O{sub 3}:Nd{sup 3+} nanophosphor exposed to 100 MeV Si{sup 8+} ions and gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Shivaramu, N.J. [Department of Physics, Jnanabharathi Campus, Bangalore University, Bangalore 560 056 (India); Lakshminarasappa, B.N., E-mail: bnlnarassappa@rediffmail.com [Department of Physics, Jnanabharathi Campus, Bangalore University, Bangalore 560 056 (India); Nagabhushana, K.R., E-mail: bhushankr@gmail.com [Department of Physics (S and H), PES Institute of Technology, 100 Feet Ring Road, BSK III stage, Bangalore 560085 (India); Singh, Fouran [Inter University Accelerator Centre, P.O. Box No. 10502, New Delhi 110 067 (India)

    2015-07-15

    Highlights: • Nanocrystalline Nd{sup 3+} doped Y{sub 2}O{sub 3} was synthesized by sol–gel technique. • Pellets of Y{sub 2}O{sub 3}:Nd{sup 3+} were irradiated with 100 MeV swift Si{sup 8+} ions and γ-rays. • The relative TL efficiency of Y{sub 2}O{sub 3}:Nd{sup 3+} of 100 MeV Si ion to γ-rays of {sup 60}Co and is found to be 0.059. • Gamma irradiated Y{sub 2}O{sub 3}:Nd{sup 3+} was observed, it is suitable for space dosimetry application. - Abstract: Nanocrystalline Nd{sup 3+} doped Y{sub 2}O{sub 3} was synthesized by sol–gel technique. Crystallite size calculated by Scherrer relation was found to be in the range 28–30 nm. Fourier transform infrared spectroscopy (FTIR) revealed Y−O, −OH stretching and C−O bending bonds. Pellets of Y{sub 2}O{sub 3}:Nd{sup 3+} were irradiated with 100 MeV swift Si{sup 8+} ions and γ-rays for the fluence/dose in the range 3 × 10{sup 11}–3 × 10{sup 13} ions cm{sup −2} and 1.0{sup -}14 kGy respectively. A prominent thermoluminescence (TL) glow with peak at 527 K and a weak one with peak at 600 K were observed in Si{sup 8+} ion irradiated samples while, a prominent TL glow with peak at 393 K besides a shoulder at 434 K and a weak one with peak at 581 K were observed in γ-irradiated phosphors. The relative TL efficiency of Y{sub 2}O{sub 3}:Nd{sup 3+} of 100 MeV Si ion beam to γ-rays of {sup 60}Co and is found to be 0.059. The TL kinetic parameters were calculated using Chen’s peak shape method and the results obtained are discussed. Y{sub 2}O{sub 3}:Nd{sup 3+} was observed for its use in space dosimetry application.

  20. Different strain relaxation mechanisms in strained Si/Si sub 1 sub - sub x Ge sub x /Si heterostructures by high dose B sup + and BF sub 2 sup + doping

    CERN Document Server

    Chen, C C; Zhang, S L; Zhu, D Z; Vantomme, A

    2002-01-01

    Strained Si/Si sub 0 sub . sub 8 Ge sub 0 sub . sub 2 /Si heterostructures are implanted at room temperature with 7.5 keV B sup + and 33 keV BF sub 2 sup + ions to a high dose of 2x10 sup 1 sup 5 ions/cm sup 2 , respectively. The samples are subsequently subjected to three-step anneals (spacer anneal, oxidation anneal and rapid thermal anneal), which are used to simulate a real fabrication process of SiGe-based MOSFET devices. The damage induced by implantation and its recovery are characterized by 2 MeV sup 4 He sup + RBS/channeling spectrometry. A damage layer on the surface is induced by B sup + implantation, but BF sup + sub 2 ion implantation amorphizes the surface of Si/Si sub 0 sub . sub 8 Ge sub 0 sub . sub 2 /Si heterostructure. Channeling angular scans along the axial direction demonstrate that the strain stored in the SiGe layer could be nearly completely retained for the B sup + implanted and subsequently annealed sample. However, the strain in the BF sub 2 sup + implanted/annealed SiGe layer has...

  1. Effects of dual-ion irradiation on the swelling of SiC/SiC composites

    International Nuclear Information System (INIS)

    Kishimoto, Hirotatsu; Kohyama, Akira; Ozawa, Kazumi; Kondo, Sosuke

    2005-01-01

    Silicon carbide (SiC) matrix composites reinforced by SiC fibers is a candidate structural material of fusion gas-cooled blanket system. From the viewpoint of material designs, it is important to investigate the swelling by irradiation, which results from the accumulation of displacement damages. In the fusion environment, (n, α) nuclear reactions are considered to produce helium gas in SiC. For the microstructural evolution, a dual-ion irradiation method is able to simulate the effects of helium. In the present research, 1.7 MeV tandem and 1 MeV single-end accelerators were used for Si self-ion irradiation and helium implantation, respectively. The average helium over displacement per atom (dpa) ratio in SiC was adjusted to 60 appm/dpa. The irradiation temperature ranged from room temperature to 1400degC. The irradiation-induced swelling was measured by the step height method. Helium that was implanted simultaneously with displacement damages in dual-ion irradiated SiC increased the swelling that was larger than that by single-ion irradiated SiC below 800degC. Since this increase was not observed above 1000degC, the interaction of helium and displacement damages was considered to change above 800degC. In this paper, the microstructural behavior and dimensional stability of SiC materials under the fusion relevant environment are discussed. (author)

  2. Mechanism of leakage of ion-implantation isolated AlGaN/GaN MIS-high electron mobility transistors on Si substrate

    Science.gov (United States)

    Zhang, Zhili; Song, Liang; Li, Weiyi; Fu, Kai; Yu, Guohao; Zhang, Xiaodong; Fan, Yaming; Deng, Xuguang; Li, Shuiming; Sun, Shichuang; Li, Xiajun; Yuan, Jie; Sun, Qian; Dong, Zhihua; Cai, Yong; Zhang, Baoshun

    2017-08-01

    In this paper, we systematically investigated the leakage mechanism of the ion-implantation isolated AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) on Si substrate. By means of combined DC tests at different temperatures and electric field dependence, we demonstrated the following original results: (1) It is proved that gate leakage is the main contribution to OFF-state leakage of ion-implantation isolated AlGaN/GaN MIS-HEMTs, and the gate leakage path is a series connection of the gate dielectric Si3N4 and Si3N4-GaN interface. (2) The dominant mechanisms of the leakage current through LPCVD-Si3N4 gate dielectric and Si3N4-GaN interface are identified to be Frenkel-Poole emission and two-dimensional variable range hopping (2D-VRH), respectively. (3) A certain temperature annealing could reduce the density of the interface state that produced by ion implantation, and consequently suppress the interface leakage transport, which results in a decrease in OFF-state leakage current of ion-implantation isolated AlGaN/GaN MIS-HEMTs.

  3. Nickel silicide formation in silicon implanted nickel

    Science.gov (United States)

    Rao, Z.; Williams, J. S.; Pogany, A. P.; Sood, D. K.; Collins, G. A.

    1995-04-01

    Nickel silicide formation during the annealing of very high dose (≥4.5×1017 ions/cm2) Si implanted Ni has been investigated, using ion beam analytical techniques, electron microscopy, and x-ray diffraction analysis. An initial amorphous Si-Ni alloy, formed as a result of high dose ion implantation, first crystallized to Ni2Si upon annealing in the temperature region of 200-300 °C. This was followed by the formation of Ni5Si2 in the temperature region of 300-400 °C and then by Ni3Si at 400-600 °C. The Ni3Si layer was found to have an epitaxial relationship with the substrate Ni, which was determined as Ni3Si∥Ni and Ni3Si∥Ni for Ni(100) samples. The minimum channeling yield in the 2 MeV He Rutherford backscattering and channeling spectra of this epitaxial layer improved with higher annealing temperatures up to 600 °C, and reached a best value measured at about 8%. However, the epitaxial Ni3Si dissolved after long time annealing at 600 °C or annealing at higher temperatures to liberate soluble Si into the Ni substrate. The epitaxy is attributed to the excellent lattice match between the Ni3Si and the Ni. The annealing behavior follows the predictions of the Ni-Si phase diagram for this nickel-rich binary system.

  4. Atomistic modeling of defect evolution in Si for amorphizing and subamorphizing implants

    International Nuclear Information System (INIS)

    Lopez, Pedro; Pelaz, Lourdes; Marques, Luis A.; Santos, Ivan; Aboy, Maria; Barbolla, Juan

    2004-01-01

    Solid phase epitaxial regrowth of pre-amorphizing implants has received significant attention as a method to achieve high dopant activation with minimal diffusion at low implant temperatures and suppress channelling. Therefore, a good understanding of the amorphization and regrowth mechanisms is required in process simulators. We present an atomistic amorphization and recrystallization model that uses the interstitial-vacancy (I-V) pair as a building block to describe the amorphous phase. I-V pairs are locally characterized by the number of neighbouring I-V pairs. This feature captures the damage generation and the dynamical annealing during ion implantation, and also explains the annealing behaviour of amorphous layers and amorphous pockets

  5. Formation of oxygen-related defects enhanced by fluorine in BF{sub 2}{sup +}-implanted Si studied by a monoenergetic positron beam

    Energy Technology Data Exchange (ETDEWEB)

    Uedono, Akira; Moriya, Tsuyoshi; Tanigawa, Shoichiro [Tsukuba Univ., Ibaraki (Japan). Inst. of Materials Science; Kawano, Takao; Nagai, Ryo; Umeda, Kazunori

    1995-12-01

    Defects in 25-keV BF{sub 2}{sup +}- or As{sup +}-implanted Si specimens were probed by a monoenergetic positron beam. For the As{sup +}-implanted specimen, the depth profile of defects was obtained from measurements of Doppler broadening profiles as a function of incident positron energy. The major species of the defects was identified as divacancies. For ion-implanted specimens after annealing treatment, oxygen-related defects were found to be formed. For the BF{sub 2}{sup +}-implanted specimen before annealing treatment, such defects were formed in the subsurface region, where oxygen atoms were implanted by recoil from oxide films. This was attributed to enhanced formation of oxygen-related defects by the presence of F atoms. (author)

  6. Sensitive detection of hydrogen in a-Si:H by coincidence measurement of elastically scattered 100 MeV /sup 3/He/sup 2 +/ ions and recoil protons

    Energy Technology Data Exchange (ETDEWEB)

    Fukada, Noboru; Imura, Takeshi; Hiraki, Akio [Osaka Univ., Suita (Japan). Faculty of Engineering; Itahashi, Takahisa; Fukuda, Tomokazu; Tanaka, Masayoshi

    1982-09-01

    We have drastically improved the sensitivity of the nuclear elastic scattering (NES) method for determining hydrogen concentrations in hydrogenated amorphous silicon (a-Si:H) films. A beam of 100 MeV /sup 3/He/sup 2 +/ ions was used in the experiment. By taking the coincidence of detection of the scattered /sup 3/He ion with that of the recoil proton, we could achieve a sensitivity of 0.1 atomic percent with a precision of about 1 percent for 1 ..mu..m films.

  7. Near surface silicide formation after off-normal Fe-implantation of Si(001) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Khanbabaee, B., E-mail: khanbabaee@physik.uni-siegen.de; Pietsch, U. [Solid State Physics, University of Siegen, D-57068 Siegen (Germany); Lützenkirchen-Hecht, D. [Fachbereich C - Physik, Bergische Universität Wuppertal, D-42097 Wuppertal (Germany); Hübner, R.; Grenzer, J.; Facsko, S. [Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden (Germany)

    2014-07-14

    We report on formation of non-crystalline Fe-silicides of various stoichiometries below the amorphized surface of crystalline Si(001) after irradiation with 5 keV Fe{sup +} ions under off-normal incidence. We examined samples prepared with ion fluences of 0.1 × 10{sup 17} and 5 × 10{sup 17} ions cm{sup −2} exhibiting a flat and patterned surface morphology, respectively. Whereas the iron silicides are found across the whole surface of the flat sample, they are concentrated at the top of ridges at the rippled surface. A depth resolved analysis of the chemical states of Si and Fe atoms in the near surface region was performed by combining X-ray photoelectron spectroscopy and X-ray absorption spectroscopy (XAS) using synchrotron radiation. The chemical shift and the line shape of the Si 2p core levels and valence bands were measured and associated with the formation of silicide bonds of different stoichiometric composition changing from an Fe-rich silicides (Fe{sub 3}Si) close to the surface into a Si-rich silicide (FeSi{sub 2}) towards the inner interface to the Si(001) substrate. This finding is supported by XAS analysis at the Fe K-edge which shows changes of the chemical environment and the near order atomic coordination of the Fe atoms in the region close to surface. Because a similar Fe depth profile has been found for samples co-sputtered with Fe during Kr{sup +} ion irradiation, our results suggest the importance of chemically bonded Fe in the surface region for the process of ripple formation.

  8. Hydrogen- and helium-implanted silicon: Low-temperature positron-lifetime studies

    DEFF Research Database (Denmark)

    Mäkinen, S.; Rajainmäki, H.; Linderoth, Søren

    1991-01-01

    High-purity single-crystal samples of float-zoned Si have been implanted with 6.95-MeV protons and with 25-MeV 3He2 ions at 15 K, and the positron-lifetime technique has been used to identify the defects created in the samples, and to study the effects of H and He on the annealing of point defects...... in Si. The results have been compared with those of proton-irradiated Si. A 100–300-K annealing stage was clearly observed in hydrogen (H+) -implanted Si, and this stage was almost identical to that in the p-irradiated Si. The final annealing state of the H+-implanted Si started at about 400 K......, and it is connected to annealing out of negatively charged divacancy-oxygen pairs. This stage was clearly longer than that for the p-irradiated Si, probably due to the breakup of Si-H bonds at about 550 K. The 100-K annealing stage was not seen with the He-implanted samples. This has been explained by assuming...

  9. Modelling the metal–semiconductor band structure in implanted ohmic contacts to GaN and SiC

    International Nuclear Information System (INIS)

    Pérez-Tomás, A; Fontserè, A; Placidi, M; Jennings, M R; Gammon, P M

    2013-01-01

    Here we present a method to model the metal–semiconductor (M–S) band structure to an implanted ohmic contact to a wide band gap semiconductor (WBG) such as GaN and SiC. The performance and understanding of the M–S contact to a WBG semiconductor is of great importance as it influences the overall performance of a semiconductor device. In this work we explore in a numerical fashion the ohmic contact properties to a WBG semiconductor taking into account the partial ionization of impurities and analysing its dependence on the temperature, the barrier height, the impurity level band energy and carrier concentration. The effect of the M–S Schottky barrier lowering and the Schottky barrier inhomogeneities are discussed. The model is applied to a fabricated ohmic contact to GaN where the M–S band structure can be completely determined. (paper)

  10. Influence of defects on the diffusion of As implanted in Si

    International Nuclear Information System (INIS)

    Brelot, A.

    1974-01-01

    The aim of this work was to find out whether the redistribution of arsenic atoms is affected by the manner of introduction (implantation or prediffusion) of this element. The redistribution equation can be resolved by taking a model which gives the value of the necessary parameters. The choice of this model is relatively arbitrary as knowledge stands at present. Ionic probe profiles reveal the presence of a profile end not hitherto observed, superimposed on the well-known profile tails. In addition the concentration of electrically active ions measured directly by successive peeling differs from that obtained by the Fair diffusion formula by more than 15%. It thus seems that implantation plays a part in the redistribution of arsenic [fr

  11. Non-linear optical properties of SiO2 with synthesized by implantation copper nanoparticles

    International Nuclear Information System (INIS)

    Stepanov, A.L.; Olivares, J.; Requejo-Isidro, J.; Del Coso, R.; De Nalda, R.; Solis, J.; Afonso, C.N.; Hole, D.; Townsend, P.D.; Naudon, A.

    2001-01-01

    In recent years there has been a growing interest in composite dielectrics containing metal nanoparticles for their potential application in wave-guide integrated all-optical non-linear switching devices. In present work, low energy high current ion implantation (50 keV) in silica at a well controlled substrate temperature (20 0 C) at a dose of 8·10 16 ion/cm 2 has been used to produce novel composites containing a large concentration of spherical Cu clusters with an average diameter of 4 nm and a very narrow size distribution. A very large value for the third order optical susceptibility, χ (3) = 10 -7 esu, has been measured in the vicinity of the surface plasmon resonance by degenerate four wave mixing at 585 nm. This value is among the largest values ever reported for Cu nano composites. Additionally, the response time of the non-linearity has been found to be shorter than 2 ps. The superior non-linear optical response of these implants is discussed in terms of the implantation conditions

  12. Optical and electrical properties of disordered layers in GaAs crystals produced by Si+ ion implantation

    International Nuclear Information System (INIS)

    Shigetomi, S.; Matsumori, T.

    1981-01-01

    The ion dose dependence and the annealing behavior of GaAs after implantation with 200 keV 2 x 10 12 -2 x 10 16 Si + ions/cm 2 as studied by using optical absorption, reflection, photoluminescence, sheet-resistivity, Hall effect and field effect methods. The experimental results of the optical absorption and reflection indicate that, when annealed at about 400 0 C, the disordered layers produced by high-dose implantation (2 x 10 15 -2 x 10 16 ions/cm 2 ), reorder epitaxially on the underlying crystal leaving relatively little residual disorder in the near-surface. However, from the experimental results of optical reflection, 800 0 C annealing is required for perfect recrystallization. The temperature dependence of the sheet-resistivity, with annealing temperature as a parameter, indicates that, next to the variable-range hopping and phonon-assisted hopping regions, a new region is observed. Holes, thermally-activated from localized states near the Fermi level Esub(F) to the mobility edge Esub(V) near the valence band, are responsible for electrical conduction in this region. (orig.)

  13. Counterdoped very shallow p+/n junctions obtained by B and Sb implantation and codiffusion in Si

    Science.gov (United States)

    Solmi, Sandro

    1998-02-01

    In this article we investigate the B and Sb codiffusion upon postimplantation annealing in order to fabricate very shallow p+/n junctions (⩽70 nm), suitable for a complementary metal-oxide-semiconductor technology with a channel length of 0.18 μm. The junctions are prepared by implanting Sb and subsequently BF2, at a higher dose, in an n-type Si substrate. The preamorphization with Sb avoids the B channeling and increases the n-type doping in the junction region, thus confining the depth of the p layer. Furthermore, both the transient enhanced diffusion, being the B implanted in a preamorphized layer, and the standard diffusion, due to the pairing between donors and acceptors, are strongly reduced. This procedure allows us to obtain very shallow junctions even after annealings with relatively high thermal budget, like 800 °C/8 h or 900 °C/1 h, or 950 °C/10 min or 1000 °C/60 s. We verified that dopant diffusion is strongly affected by a direct donor-acceptor interaction, and that good prediction of the experimental results can only be obtained using a simulation code which takes into account the formation of neutral, near immobile, Sb-B pairs.

  14. Maskless nano-implant of 20 keV Ga{sup +} in bulk Si(1 0 0) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Milazzo, R.G., E-mail: gabriella.milazzo@gmail.com [IMM-CNR, Strada VIII 5, Zona Industriale, I-95121 Catania (Italy); D’Arrigo, G.; Mio, A.M.; Rimini, E.; Spinella, C. [IMM-CNR, Strada VIII 5, Zona Industriale, I-95121 Catania (Italy); Peto, L.; Nadzeyka, A.; Bauerdick, S. [Raith GmbH, Konrad-Adenauer-Allee 8, 44263 Dortmund (Germany)

    2014-12-15

    Multidirectional SPEG (Solid Phase Epitaxial Growth) of silicon has been investigated in micro and nanoamorphous structures generated on a crystalline substrate by a nano-sized ion beam, Gaussian shaped and with a standard deviation of about 5 nm. The 20 keV Ga{sup +} ions were implanted at a fluence of 5 × 10{sup 14} ions cm{sup −2} in a bulk Si(1 0 0) single crystal. Two structures were used for the implants: circular regions of 100 nm and 1 μm diameters respectively and straight lines 10 nm in width and few microns in length along (1 0 0) or (1 1 0) directions. The lateral spread of ions has been taken into account in the damage estimation. Transmission Electron Microscopy indicates that the structures are made of an amorphous core surrounded by a defective and filamentary shell. The recovery of the damaged outer regions promptly occurs during the early stages of the thermal treatment at 500–600 °C for all the structures. By prolonging annealing time, re-crystallization of the amorphous cores is achieved too by the movement of the underneath crystal–amorphous interface. The re-growth is almost defects free when the contribution of the crystalline seed below the structures is present, defective and twin mediated if it misses as in the thinnest regions of the specimen.

  15. Search for aligned structure of /sup 12/C-. cap alpha. -/sup 12/C type at high excitation energy in /sup 28/Si. [46 MeV, J,. pi. , resonance, three-body problem

    Energy Technology Data Exchange (ETDEWEB)

    Burnereau, N

    1975-01-01

    The /sup 16/O+/sup 12/C..-->../sup 12/C+..cap alpha..+/sup 12/C reaction is studied mainly at 46MeV (at this energy a state of /sup 28/Si is presumably formed with a spin value of 14/sup +/; resonance of 19.7MeV c.m.). The motivation is to detect an ..cap alpha.. particle with a negligible energy in the c.m. system. This is the signature of the preformation of three aligned clusters in which the average location of the ..cap alpha.. particle is in between the two /sup 12/C's at the center of symmetry of the system. Such a detection is performed by detecting two /sup 12/C's in coincidence at specific angles. The data are understood by three-body calculations with a coupling of relative angular momenta governed by an unique J value. Experimentally, an ..cap alpha.. energy of 200keV is measured with good statistics, supporting the idea of aligned clusters as /sup 28/Si intrinsic shape, related to some highly excited states.

  16. Liquid phase epitaxy of binary III–V nanocrystals in thin Si layers triggered by ion implantation and flash lamp annealing

    Energy Technology Data Exchange (ETDEWEB)

    Wutzler, Rene, E-mail: r.wutzler@hzdr.de; Rebohle, Lars; Prucnal, Slawomir; Bregolin, Felipe L.; Hübner, Rene; Voelskow, Matthias; Helm, Manfred; Skorupa, Wolfgang [Helmholtz-Zentrum Dresden - Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstraße 400, 01328 Dresden (Germany)

    2015-05-07

    The integration of III–V compound semiconductors in Si is a crucial step towards faster and smaller devices in future technologies. In this work, we investigate the formation process of III–V compound semiconductor nanocrystals, namely, GaAs, GaSb, and InP, by ion implantation and sub-second flash lamp annealing in a SiO{sub 2}/Si/SiO{sub 2} layer stack on Si grown by plasma-enhanced chemical vapor deposition. Raman spectroscopy, Rutherford Backscattering spectrometry, and transmission electron microscopy were performed to identify the structural and optical properties of these structures. Raman spectra of the nanocomposites show typical phonon modes of the compound semiconductors. The formation process of the III–V compounds is found to be based on liquid phase epitaxy, and the model is extended to the case of an amorphous matrix without an epitaxial template from a Si substrate. It is shown that the particular segregation and diffusion coefficients of the implanted group-III and group-V ions in molten Si significantly determine the final appearance of the nanostructure and thus their suitability for potential applications.

  17. Microstructure and degradation performance of biodegradable Mg-Si-Sr implant alloys.

    Science.gov (United States)

    Gil-Santos, Andrea; Marco, Iñigo; Moelans, Nele; Hort, Norbert; Van der Biest, Omer

    2017-02-01

    In this work the microstructure and degradation behavior of several as-cast alloy compositions belonging to the Mg rich corner of the Mg-Si-Sr system are presented and related. The intermetallic phases are identified and analyzed describing the microstructure evolution during solidification. It is intended in this work to obtain insight in the behavior of the ternary alloys in in vitro tests and to analyze the degradation behavior of the alloys under physiologically relevant conditions. The as-cast specimens have been exposed to immersion tests, both mass loss (ML) and potentiodynamic polarization (PDP). The degradation rate (DR) have been assessed and correlated to microstructure features, impurity levels and alloy composition. The initial reactions resulted to be more severe while the degradation stabilizes with time. A higher DR is related with a high content of the Mg 17 Sr 2 phase and with the presence of coarse particles of the intermetallics Mg 2 Si, MgSiSr and MgSi 2 Sr. Specimens with a higher DR typically have higher levels of impurities and alloy contents. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Perspectives of the Si3N4-TiN ceramic composite as a biomaterial and manufacturing of complex-shaped implantable devices by electrical discharge machining (EDM).

    Science.gov (United States)

    Bucciotti, Francesco; Mazzocchi, Mauro; Bellosi, Alida

    2010-01-01

    In this work we investigated the suitability of electroconductive silicon nitride/titanium nitride composite for biomedical implantable devices with particular attention on the processing route that allows the net-shaping of complex components by electrical discharge machining (EDM). The composite, constituted mainly of a beta-Si3N4, dispersed TiN grains and a glassy grain boundary phase, exhibited a low density and high hardness, strength and toughness. Bulk, surface characteristics and properties of the Si3N4-TiN composite were analyzed. After the EDM process, the microstructure of the machined surface was examined. The obtained results showed that the Si3N4-TiN ceramic composite together with the EDM manufacturing process might potentially play a key role in implantable load-bearing prosthesis applications.

  19. Vacancy-related defect distributions in 11B-, 14N-, and 27Al-implanted 4H-SiC: Role of channeling

    International Nuclear Information System (INIS)

    Janson, M.S.; Slotte, J.; Kuznetsov, A.Yu.; Saarinen, K.; Hallen, A.

    2004-01-01

    The defect distributions in 11 B-, 14 N-, and 27 Al-implanted epitaxial 4H-SiC are studied using monoenergetic positron beams. At least three types of defects are needed to account for the Doppler broadening annihilation spectra and two of the defects are tentatively identified as V Si , and V Si V C . By comparing the defect profiles extracted from the annihilation spectra to the chemical profiles determined by secondary ion mass spectrometry, and to the primary defect profiles obtained from binary collision approximation simulations, it is concluded that the defects found at depths considerably deeper than the projected range of the implanted ions mainly originate from deeply channeled ions

  20. Promising Ta-Ti-Zr-Si metallic glass coating without cytotoxic elements for bio-implant applications

    Science.gov (United States)

    Lai, J. J.; Lin, Y. S.; Chang, C. H.; Wei, T. Y.; Huang, J. C.; Liao, Z. X.; Lin, C. H.; Chen, C. H.

    2018-01-01

    Tantalum (Ta) is considered as one of the most promising metal due to its high corrosion resistance, excellent biocompatibility and cell adhesion/in-growth capabilities. Although there are some researches exploring the biomedical aspects of Ta and Ta based alloys, systematic characterizations of newly developed Ta-based metallic glasses in bio-implant applications is still lacking. This study employs sputtering approach to produced thin-film Ti-based metallic glasses due to the high melting temperature of Ta (3020 °C). Two fully amorphous Ta-based metallic glasses composed of Ta57Ti17Zr15Si11 and Ta75Ti10Zr8Si7 are produced and experimentally characterized in terms of their mechanical properties, bio-corrosion properties, surface hydrophilic characteristics, and in-vitro cell viability and cells attachment tests. Compare to conventional pure Ti and Ta metals, the developed Ta-based metallic glasses exhibit higher hardness and lower modulus which are better match to the mechanical properties of bone. MTS assay results show that Ta-based metallic glasses show comparable cell viability and cell attachment rate compared to that of pure Ti and Ta surface in a 72 h in-vitro test.

  1. Effect of the energy of recoil atoms on conductivity compensation in moderately doped n-Si and n-SiC under irradiation with MeV electrons and protons

    Energy Technology Data Exchange (ETDEWEB)

    Kozlovski, V.V. [St. Petersburg State Polytechnic University, St. Petersburg 195251 (Russian Federation); Lebedev, A.A., E-mail: shura.lebe@mail.ioffe.ru [Ioffe Physical Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation); National Research University of Information Technologies, Mechanics, and Optics, St. Petersburg 197101 (Russian Federation); Emtsev, V.V.; Oganesyan, G.A. [Ioffe Physical Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation)

    2016-10-01

    Processes of radiation defect formation and conductivity compensation in silicon and silicon carbide irradiated with 0.9 MeV electrons are considered in comparison with the electron irradiation at higher energies. The experimental values of the carrier removal rate at the electron energy of 0.9 MeV are nearly an order of magnitude smaller than the similar values of the parameter for higher energy electrons (6–9 MeV). At the same time, the formation cross-section of primary radiation defects (Frenkel pairs, FPs) is nearly energy-independent in this range. It is assumed that these differences are due to the influence exerted by the energy of primary knocked-on atoms (PKAs). As the PKA energy increases, the average distance between the genetically related FPs grows and, as a consequence, the fraction of FPs unrecombined under irradiation becomes larger. The FP recombination radius is estimated (∼1.1 nm), which makes it possible to ascertain the charge state of the recombining components. Second, the increase in the PKA energy enables formation of new, more complex secondary radiation defects. At electron energies exceeding 15 MeV, the average PKA energies are closer to the values obtained under irradiation with 1 MeV protons, compared with an electron irradiation at the same energy. As for the radiation-induced defect formation, the irradiation of silicon with MeV protons can be, in principle, regarded as a superposition of the irradiation with 1 MeV electrons and that with silicon ions having energy of ∼1 keV, with the “source” of silicon ions generating these ions uniformly across the sample thickness.

  2. The structure and elemental composition of the SiO2 layers with zinc-based nano clusters created by high-dose implantation and annealing

    International Nuclear Information System (INIS)

    Mokhovikov, M.A.; Komarov, F.F.; Vlasukova, L.A.; Mil'chanin, O.V.; Wendler, E.; Wesch, W.; Zhukovski, P.; Vengerek, P.

    2015-01-01

    We present the results of the structure and elemental composition of the SiO 2 layers after high-dose zinc implantation (10 16 - 10 17 sm -2 ) at room temperature and at 500°C, as well as after 700°C annealing. In the case of 'hot' implantation the formation of nano sized (to 5 nm) clusters containing atoms of zinc is registered in as-implanted samples. TEM-analysis proves crystalline structure of these precipitates. Subsequent annealing results in a redistribution of zinc within the implanted layer and in the formation of large crystallites (10 -12 nm for a dose of 5*10 16 cm -2 and 12-18 nm for a dose of 10 17 cm -2 ) in the area of high impurity concentration. (authors)

  3. Origin of the lattice sites occupied by implanted Co in Si

    CERN Document Server

    Silva, Daniel; Wahl, Ulrich; Martins Correia, Joao; Da Costa Pereira, Lino Miguel; Amorim, Lígia; Castro Ribeiro Da Silva, Manuel; Esteves De Araujo, Araujo Joao Pedro

    2014-01-01

    We have investigated the lattice location of implanted 61Co in silicon. By means of emission channeling, three different lattice sites have been identified: ideal substitutional sites, displaced bond-centered sites and displaced tetrahedral interstitial sites. To assess the origin of the observed lattice sites we have compared our results to emission channeling studies on 59Fe and 65Ni and to Mössbauer spectroscopy experiments on 57Co, present in literature. The possible interpretation of several 57Co Mössbauer lines is discussed in the light of our new results on the 61Co lattice location. The conclusions are relevant for the microscopic understanding of some gettering techniques.

  4. Accumulation and release of implanted hydrogen from blisters in Si during the thermal treatment

    International Nuclear Information System (INIS)

    Aleksandrov, P.A.; Baranova, E.K.; Baranova, I.V.; Budaragin, V.V.; Litvinov, V.L.

    2004-01-01

    The processes of accumulation of ion implanted hydrogen in blisters in silicon and its release during the thermal treatment at 350-1020 deg C have been studied by optical techniques. It is established that accumulation of gaseous hydrogen inside blisters takes place at temperatures lower than ∼ 450-500 deg C and is accompanied by the growth of blisters thickness and deformation of their caps. At higher temperatures hydrogen leaves cavities and dissolves in silicon. Due to internal pressure dropping the elasticity deformed top layer partially relaxes, and the blister thickness decreases. Etching of the surface layer reveals the agglomerations of small voids ( [ru

  5. Effects of 6 MeV electron irradiation on the electrical properties and device parameters of Al/Al{sub 2}O{sub 3}/TiO{sub 2}/n-Si MOS capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Laha, P.; Banerjee, I.; Barhai, P.K. [Department of Applied Physics, Birla Institute of Technology, Mesra, Ranchi 835215 (India); Das, A.K. [Laser and Plasma Technology Division, Bhabha Atomic Research Center, Mumbai 400085 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Ganeshkhind, Pune 411007 (India); Mahapatra, S.K., E-mail: skm@physics.ucla.edu [Department of Applied Physics, Birla Institute of Technology, Mesra, Ranchi 835215 (India)

    2012-07-15

    Highlights: Black-Right-Pointing-Pointer The electron irradiation effects make variation in the device parameters. Black-Right-Pointing-Pointer The device parameters changes due to percentage of defects and charge trapping. Black-Right-Pointing-Pointer Leakage current of Al/Al{sub 2}O{sub 3}/TiO{sub 2}/n-Si changes due to interface dangling bonds. Black-Right-Pointing-Pointer The leakage current mechanism of MOS structures is due to Poole-Frenkel effect. - Abstract: The effects of 6 MeV electron irradiation on the electrical properties and device parameter characteristics of Al/Al{sub 2}O{sub 3}/TiO{sub 2}/n-Si metal-oxide-semiconductor capacitors have been studied. Twelve Al/Al{sub 2}O{sub 3}/TiO{sub 2}/n-Si MOS capacitors were fabricated using r.f. magnetron sputtering and divided into four groups. The first group was not irradiated and treated as virgin. The rest were irradiated with 6 MeV electrons at doses 10, 20, and 30 kGy, maintaining the dose rate at {approx}1 kGy/min. Variations in crystallinity of the virgin and irradiated capacitors were studied using grazing incident X-ray diffraction. The thickness and in-depth elemental distributions of individual layers were determined using secondary ion mass apectrometry. Capacitance-voltage, conductance-voltage and leakage current-voltage characteristics of the virgin and irradiated samples were studied. The device parameters (flat band voltage, surface charge density and interface trap density of the virgin and irradiated structures) were determined. The electrical properties of the capacitors were investigated and the Poole-Frenkel coefficient of the capacitors was determined from leakage current measurements. The leakage current mechanism has been explained.

  6. Effects of 6 MeV electron irradiation on the electrical properties and device parameters of Al/Al2O3/TiO2/n-Si MOS capacitors

    International Nuclear Information System (INIS)

    Laha, P.; Banerjee, I.; Barhai, P.K.; Das, A.K.; Bhoraskar, V.N.; Mahapatra, S.K.

    2012-01-01

    Highlights: ► The electron irradiation effects make variation in the device parameters. ► The device parameters changes due to percentage of defects and charge trapping. ► Leakage current of Al/Al 2 O 3 /TiO 2 /n-Si changes due to interface dangling bonds. ► The leakage current mechanism of MOS structures is due to Poole–Frenkel effect. - Abstract: The effects of 6 MeV electron irradiation on the electrical properties and device parameter characteristics of Al/Al 2 O 3 /TiO 2 /n-Si metal–oxide–semiconductor capacitors have been studied. Twelve Al/Al 2 O 3 /TiO 2 /n-Si MOS capacitors were fabricated using r.f. magnetron sputtering and divided into four groups. The first group was not irradiated and treated as virgin. The rest were irradiated with 6 MeV electrons at doses 10, 20, and 30 kGy, maintaining the dose rate at ∼1 kGy/min. Variations in crystallinity of the virgin and irradiated capacitors were studied using grazing incident X-ray diffraction. The thickness and in-depth elemental distributions of individual layers were determined using secondary ion mass apectrometry. Capacitance–voltage, conductance–voltage and leakage current–voltage characteristics of the virgin and irradiated samples were studied. The device parameters (flat band voltage, surface charge density and interface trap density of the virgin and irradiated structures) were determined. The electrical properties of the capacitors were investigated and the Poole–Frenkel coefficient of the capacitors was determined from leakage current measurements. The leakage current mechanism has been explained.

  7. High energy P implants in silicon

    International Nuclear Information System (INIS)

    Raineri, V.; Cacciato, A.; Benyaich, F.; Priolo, F.; Rimini, E.; Galvagno, G.; Capizzi, S.

    1992-01-01

    Phosphorus ions in the energy range 0.25-1 MeV and in the dose range 2x10 13 -1x10 15 P/cm 2 were implanted into (100) Si single crystal at different tilt angles. In particular channeling and random conditions were investigated. For comparison some implants were performed on samples with a 2 μm thick surface amorphous layer. Chemical concentration P profiles were obtained by secondary ion mass spectrometry. Carrier concentration and mobility profile measurements were carried out by sheet resistance and Hall measurements on implanted van der Pauw patterns. Carrier concentration profiles were also obtained by spreading resistance (SR) measurements. The damage in the as-implanted samples was determined by backscattering and channeling spectrometry (RBS) as a function of the dose and implantation energy. Comparison of random implants in crystal with implants in amorphous layers shows that in the first case it is impossible to completely avoid the channeling tail. In the implants performed under channeling conditions at low doses the P profiles are flat over more than 2 μm thick layers. Furthermore, by increasing the implanted dose, the shape of the profiles dramatically changes due to the dechanneling caused by the crystal disorder. The data are discussed and compared with Monte Carlo simulations using the MARLOWE code. A simple description of the electronic energy loss provides an excellent agreement between the calculated and experimental profiles. (orig.)

  8. Lattice damage in ion-implanted silicon-germanium alloys

    International Nuclear Information System (INIS)

    Haynes, T.E.; Holland, O.W.

    1992-08-01

    The damage produced in Si 1-x Ge x alloys (0≤x≤1) by implantation of 70--100 keV 30 Si + has been measured as a function of temperature and fluence by ion channeling. For all compositions, the damage efficiency decreased sharply as the implant temperature was increased between room temperature and 150 degrees C. Furthermore, the damage efficiency in alloys of intermediate compositions (0.34≤x≤0.5) exceeds that in Ge, especially at elevated temperatures, despite the larger cascade energy density in Ge. It is shown that this behavior can be described based on a model in which the point-defect mobility is the dominant factor controlling damage retention, rather than the cascade energy density. This approach provides a framework for understanding other temperature-dependent phenomena related to damage growth in Si-Ge alloys including dose-rate effects and damage saturation in MeV implantation

  9. Change in equilibrium position of misfit dislocations at the GaN/sapphire interface by Si-ion implantation into sapphire—I. Microstructural characterization

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung Bo, E-mail: bolee@snu.ac.kr; Han, Heung Nam, E-mail: hnhan@snu.ac.kr; Lee, Dong Nyung [Department of Materials Science and Engineering and Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul 151-744 (Korea, Republic of); Ju, Jin-Woo [Korea Photonics Technology Institute, Gwangju 500-779 (Korea, Republic of); Kim, Young-Min; Yoo, Seung Jo; Kim, Jin-Gyu [Korea Basic Science Institute, Daejeon 305-806 (Korea, Republic of)

    2015-07-15

    Much research has been done to reduce dislocation densities for the growth of GaN on sapphire, but has paid little attention to the elastic behavior at the GaN/sapphire interface. In this study, we have examined effects of the addition of Si to a sapphire substrate on its elastic property and on the growth of GaN deposit. Si atoms are added to a c-plane sapphire substrate by ion implantation. The ion implantation results in scratches on the surface, and concomitantly, inhomogeneous distribution of Si. The scratch regions contain a higher concentration of Si than other regions of the sapphire substrate surface, high-temperature GaN being poorly grown there. However, high-temperature GaN is normally grown in the other regions. The GaN overlayer in the normally-grown regions is observed to have a lower TD density than the deposit on the bare sapphire substrate (with no Si accommodated). As compared with the film on an untreated, bare sapphire, the cathodoluminescence defect density decreases by 60 % for the GaN layer normally deposited on the Si-ion implanted sapphire. As confirmed by a strain mapping technique by transmission electron microscopy (geometric phase analysis), the addition of Si in the normally deposited regions forms a surface layer in the sapphire elastically more compliant than the GaN overlayer. The results suggest that the layer can largely absorb the misfit strain at the interface, which produces the overlayer with a lower defect density. Our results highlight a direct correlation between threading-dislocation density in GaN deposits and the elastic behavior at the GaN/sapphire interface, opening up a new pathway to reduce threading-dislocation density in GaN deposits.

  10. Structural properties of the formation of zinc-containing nanoparticles obtained by ion implantation in Si (001 and subsequent thermal annealing

    Directory of Open Access Journals (Sweden)

    Ksenia B. Eidelman

    2017-09-01

    We show that a damaged layer with a large concentration of radiation induced defects forms near the surface as a result of the implantation of Zn+ ions with an energy of 50 keV. In the as-implanted state, nanoparticles of metallic Zn with a size of about 25 nm form at a depth of 40 nm inside the damaged silicon layer. Subsequent annealing at 800 °C in a dry oxygen atmosphere leads to structural changes in the defect layer and the formation of Zn2SiO4 nanoparticles at a depth of 25 nm with an average size of 3 nm, as well as oxidation of the existing Zn particles to the Zn2SiO4 phase. The oxidation of the metallic Zn nanoparticles starts from the surface of the particles and leads to the formation of particles with a “core-shell” structure. Analysis of the phase composition of the silicon layer after two-stage implantation with O+ and Zn+ ions showed that Zn and Zn2SiO4 particles form in the as-implanted state. Subsequent annealing at 800 °C in a dry oxygen atmosphere leads to an increase in the particle size but does not change the phase composition of the near-surface layer. ZnO nanoparticles were not observed under these experimental conditions of ion beam synthesis.

  11. Elimination of carbon vacancies in 4H-SiC epi-layers by near-surface ion implantation: Influence of the ion species

    Science.gov (United States)

    Ayedh, H. M.; Hallén, A.; Svensson, B. G.

    2015-11-01

    The carbon vacancy (VC) is a prevailing point defect in high-purity 4H-SiC epitaxial layers, and it plays a decisive role in controlling the charge carrier lifetime. One concept of reducing the VC-concentration is based on carbon self-ion implantation in a near surface layer followed by thermal annealing. This leads to injection of carbon interstitials (Ci's) and annihilation of VC's in the epi-layer "bulk". Here, we show that the excess of C atoms introduced by the self-ion implantation plays a negligible role in the VC annihilation. Actually, employing normalized implantation conditions with respect to displaced C atoms, other heavier ions like Al and Si are found to be more efficient in annihilating VC's. Concentrations of VC below ˜2 × 1011 cm-3 can be reached already after annealing at 1400 °C, as monitored by deep-level transient spectroscopy. This corresponds to a reduction in the VC-concentration by about a factor of 40 relative to the as-grown state of the epi-layers studied. The negligible role of the implanted species itself can be understood from simulation results showing that the concentration of displaced C atoms exceeds the concentration of implanted species by two to three orders of magnitude. The higher efficiency for Al and Si ions is attributed to the generation of collision cascades with a sufficiently high energy density to promote Ci-clustering and reduce dynamic defect annealing. These Ci-related clusters will subsequently dissolve during the post-implant annealing giving rise to enhanced Ci injection. However, at annealing temperatures above 1500 °C, thermodynamic equilibrium conditions start to apply for the VC-concentration, which limit the net effect of the Ci injection, and a competition between the two processes occurs.

  12. Room-temperature vacancy migration in crystalline Si from an ion-implanted surface layer

    DEFF Research Database (Denmark)

    Larsen, Arne Nylandsted; Christensen, Carsten; Petersen, Jon Wulff

    1999-01-01

    Migration of vacancies in crystalline, n-type silicon at room temperature from Ge+-implanted (150 keV, 5×109–1×1011 cm–2) surface layers was studied by tracing the presence of P–V pairs (E centers) in the underlying layer using deep level transient spectroscopy (DLTS). Under the conditions we have......–Et[approximate]0.15 eV that has donor character. It is argued that the center associated with this line is most probably the P2–V complex; it anneals at about 550 K. A lower limit of the RT-diffusion coefficient of the doubly charged, negative vacancy is estimated to be 4×10–11 cm2/s. ©1999 American Institute...

  13. Structural and optical characterization of Mn doped ZnS nanocrystals elaborated by ion implantation in SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Bonafos, C. E-mail: bonafos@el.ub.es; Garrido, B.; Lopez, M.; Romano-Rodriguez, A.; Gonzalez-Varona, O.; Perez-Rodriguez, A.; Morante, J.R.; Rodriguez, R

    1999-01-01

    Mn doped ZnS nanocrystals have been formed in SiO{sub 2} layers by ion implantation and thermal annealing. The structural analysis of the processed samples has been performed mainly by Secondary Ion Mass Spectroscopy (SIMS) and Transmission Electron Microscopy (TEM). The data show the precipitation of ZnS nanocrystals self-organized into two layers parallel to the free surface. First results of the optical analysis of samples co-implanted with Mn show the presence of a yellow-green photoluminescence depending on the Mn concentration and the size of the nanocrystals, suggesting the doping with Mn of some precipitates.

  14. Cytokine induction of sol–gel-derived TiO2 and SiO2 coatings on metallic substrates after implantation to rat femur

    Science.gov (United States)

    Urbanski, Wiktor; Marycz, Krzysztof; Krzak, Justyna; Pezowicz, Celina; Dragan, Szymon Feliks

    2017-01-01

    Material surface is a key determinant of host response on implanted biomaterial. Therefore, modification of the implant surface may optimize implant–tissue reactions. Inflammatory reaction is inevitable after biomaterial implantation, but prolonged inflammation may lead to adverse reactions and subsequent implant failure. Proinflammatory activities of cytokines like interleukin (IL)-1, IL-6, and tumor necrosis factor-alpha (TNF-α) are attractive indicators of these processes and ultimately characterize biocompatibility. The objective of the study was to evaluate local cytokine production after implantation of stainless steel 316L (SS) and titanium alloy (Ti6Al4V) biomaterials coated with titanium dioxide (TiO2) and silica (SiO2) coatings prepared by sol–gel method. Biomaterials were implanted into rat femur and after 12 weeks, bones were harvested. Bone–implant tissue interface was evaluated; immunohistochemical staining was performed to identify IL-6, TNF-α, and Caspase-1. Histomorphometry (AxioVision Rel. 4.6.3 software) of tissue samples was performed in order to quantify the cytokine levels. Both the oxide coatings on SS and Ti6Al4V significantly reduced cytokine production. However, the lowest cytokine levels were observed in TiO2 groups. Cytokine content in uncoated groups was lower in Ti6Al4V than in SS, although coating of either metal reduced cytokine production to similar levels. Sol–gel TiO2 or SiO2 coatings reduced significantly the production of proinflammatory cytokines by local tissues, irrespective of the material used as a substrate, that is, either Ti6Al4V or SS. This suggests lower inflammatory response, which directly points out improvement of materials’ biocompatibility. PMID:28280331

  15. Spectroscopy of the {sup 29}Si({ital p},{gamma}) reaction for {ital E}{sub {ital p}}=1.75{endash}2.51 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, P.M.; Bilpuch, E.G.; Bybee, C.R.; Mitchell, G.E.; Moore, E.F.; Shriner, J.D.; Shriner, J.F. Jr.; Vavrina, G.A.; Westerfeldt, C.R. [Duke University, Durham, North Carolina 27708 (United States)]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 North Carolina State University, Raleigh, North Carolina 27695 (United States)]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 Tennessee Technological University, Cookeville, Tennessee 38505 (United States)

    1996-12-01

    The {sup 29}Si({ital p},{gamma}) reaction has been studied for 30 resonances in the range {ital E}{sub {ital p}}=1.75{endash}2.51 MeV. Branching ratios have been measured for 28 of these resonances. The separation energy {ital S}{sub {ital p}} for {sup 30}P has been determined to be 5594.5{plus_minus}0.5 keV. Improved spin, parity, and isospin assignments have been made to a number of the resonant states. A new level has been identified in {sup 30}P at {ital E}{sub {ital x}}=6006 keV, and its {gamma}-ray branching ratios have been measured. {copyright} {ital 1996 The American Physical Society.}

  16. Kinetic aspects of the growth of platelets and voids in H implanted Si

    International Nuclear Information System (INIS)

    Grisolia, J.; Cristiano, F.; Ben Assayag, G.; Claverie, A.

    2001-01-01

    We have undertaken a systematic and quantitative study of the extended defects formed after high-dose proton implantation in silicon. This study is based on the transmission electron microscopy (TEM) and secondary ion mass spectroscopy (SIMS) experiments to 'follow' the thermal evolution of platelets and voids for a large variety of annealing conditions up to 900 deg. C. Up to about 500 deg. C, only platelets are observed and, as the anneal proceeds, they grow in size and reduce their density through the conservative exchange of hydrogen (H) atoms. On the contrary, above 500 deg. C, H starts to diffuse out of the defect-rich region and this out-diffusion can be completed after 700 deg. C anneals. Concurrently, platelets tend to disappear and voids appear. Above 700 deg. C anneals, hydrogen cannot be detected anymore in the layers and only voids remain. Upon time, they also grow in size and reduce their density. This is again attributed to the Ostwald ripening of voids which involves now vacancy diffusion from small voids to large ones. In summary, we have shown that platelets and voids both undergo quasi-conservative ripening upon annealing; at low-temperature (LT) platelets exchange the H atoms they are composed of while at high-temperature voids exchange vacancies

  17. In vivo study of nanostructured diopside (CaMgSi{sub 2}O{sub 6}) coating on magnesium alloy as biodegradable orthopedic implants

    Energy Technology Data Exchange (ETDEWEB)

    Razavi, Mehdi, E-mail: mrzavi2659@gmail.com [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); School of Materials Science and Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); School of Electrical and Computer Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); Fathi, Mohammadhossein [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Dental Materials Research Center, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of); Savabi, Omid [Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Razavi, Seyed Mohammad [School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Heidari, Fariba; Manshaei, Maziar [Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Vashaee, Daryoosh [School of Electrical and Computer Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); Tayebi, Lobat, E-mail: lobat.tayebi@okstate.edu [School of Materials Science and Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078 (United States)

    2014-09-15

    Highlights: • In vitro biocompatibility of biodegradable Mg alloy was improved by diopside coating. • In vivo biocompatibility of biodegradable Mg alloy was improved by diopside coating. • Degradation behavior of biodegradable Mg alloy was improved by diopside coating. - Abstract: In order to improve the corrosion resistance and bioactivity of a biodegradable magnesium alloy, we have recently prepared a nanostructured diopside (CaMgSi{sub 2}O{sub 6}) coating on AZ91 magnesium alloy through a combined micro-arc oxidation (MAO) and electrophoretic deposition (EPD) method (reported elsewhere). In this work, we performed a detailed biocompatibility analysis of the implants made by this material and compared their performance with those of the uncoated and micro arc oxidized magnesium implants. The biocompatibility evaluation of samples was performed by culturing L-929 cells and in vivo animal study, including implantation of samples in greater trochanter of rabbits, radiography and histological examinations. The results from both the in vitro and in vivo studies indicated that the diopside/MAO coated magnesium implant significantly enhanced cell viability, biodegradation resistance and new bone formation compared with both the uncoated and the micro-arc oxidized magnesium implants. Our data provides an example of how the proper surface treatment of magnesium implants can overcome their drawbacks in terms of high degradation rate and gas bubble formation under physiological conditions.

  18. In vivo study of nanostructured diopside (CaMgSi2O6) coating on magnesium alloy as biodegradable orthopedic implants

    International Nuclear Information System (INIS)

    Razavi, Mehdi; Fathi, Mohammadhossein; Savabi, Omid; Razavi, Seyed Mohammad; Heidari, Fariba; Manshaei, Maziar; Vashaee, Daryoosh; Tayebi, Lobat

    2014-01-01

    Highlights: • In vitro biocompatibility of biodegradable Mg alloy was improved by diopside coating. • In vivo biocompatibility of biodegradable Mg alloy was improved by diopside coating. • Degradation behavior of biodegradable Mg alloy was improved by diopside coating. - Abstract: In order to improve the corrosion resistance and bioactivity of a biodegradable magnesium alloy, we have recently prepared a nanostructured diopside (CaMgSi 2 O 6 ) coating on AZ91 magnesium alloy through a combined micro-arc oxidation (MAO) and electrophoretic deposition (EPD) method (reported elsewhere). In this work, we performed a detailed biocompatibility analysis of the implants made by this material and compared their performance with those of the uncoated and micro arc oxidized magnesium implants. The biocompatibility evaluation of samples was performed by culturing L-929 cells and in vivo animal study, including implantation of samples in greater trochanter of rabbits, radiography and histological examinations. The results from both the in vitro and in vivo studies indicated that the diopside/MAO coated magnesium implant significantly enhanced cell viability, biodegradation resistance and new bone formation compared with both the uncoated and the micro-arc oxidized magnesium implants. Our data provides an example of how the proper surface treatment of magnesium implants can overcome their drawbacks in terms of high degradation rate and gas bubble formation under physiological conditions

  19. Surface temperature measurements for ion-bombarded Si and GaAs at 1.0 to 2.0 MeV

    International Nuclear Information System (INIS)

    Lowe, L.F.; Kennedy, J.K.; Davies, D.E.; Deane, M.L.; Eyges, L.J.

    1975-01-01

    Surface temperatures of ion-bombarded silicon and gallium arsenide have been measured using an infrared detector. Ion beams of N + , N + 2 , O + , O + 2 , C + , CO + , and H + were used at energies from 1--2.0 MeV and at current densities up to 12 μAcenter-dotcm/sup -2/. No temperature dependence was found on ion species, energy, or current. The change in temperature depended only on beam power, target material, and sample mounting technique. With proper mounting temperature increases of 20 degreeC for silicon and 65 degreeC for gallium arsenide were observed for a beam power density of 1.0 Wcenter-dotcm/sup -2/

  20. Moessbauer and channeling experiments on TeSi and SmSi

    International Nuclear Information System (INIS)

    Kemerink, G.J.; Boerma, D.O.; Waard, H. de; Wit, J.C. de; Drentje, S.A.

    1980-01-01

    Considerable effort is made to obtain an insight in the structural and electronic properties of ion implanted elemental semiconductors. This research is strongly stimulated by the many applications of semi-conductor devices. We report here on Moessbauer studies of 129 TeSi and 153 SmSi, using the 27.8 keV transition in 129 I and the 103.2 keV transition in 153 Eu, respectively, and on channeling experiments on 128 TeSi and 152 SmSi with a 2 MeV α-beam from the Groningen Van de Graaff generator. In the Moessbauer experiments we used Cu 129 I and EuF 3 .1/2H 2 O as absorber materials. Source and absorber were held at 4.2 K. The implantations were generally done at room temperature with an implantation energy of 100-115 keV. For the Moessbauer and channeling measurements we applied similar Si single crystals and the same implantation and annealing conditions. Crystals with low doses could only be investigated with the Moessbauer effect

  1. Coating of biodegradable magnesium alloy bone implants using nanostructured diopside (CaMgSi{sub 2}O{sub 6})

    Energy Technology Data Exchange (ETDEWEB)

    Razavi, Mehdi, E-mail: mehdi.razavi@okstate.edu [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Department of Anatomical Sciences and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); School of Materials Science and Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); School of Electrical and Computer Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); Fathi, Mohammadhossein [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Dental Materials Research Center, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of); Savabi, Omid [Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Beni, Batoul Hashemi [Department of Anatomical Sciences and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Razavi, Seyed Mohammad [School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Vashaee, Daryoosh [School of Electrical and Computer Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); and others

    2014-01-01

    Magnesium alloys with their biodegradable characteristic can be a very good candidate to be used in orthopedic implants. However, magnesium alloys may corrode and degrade too fast for applications in the bone healing procedure. In order to enhance the corrosion resistance and the in vitro bioactivity of a magnesium alloy, a nanostructured diopside (CaMgSi{sub 2}O{sub 6}) film was coated on AZ91 magnesium alloy through combined micro-arc oxidation (MAO) and electrophoretic deposition (EPD) methods. The crystalline structures, morphologies and compositions of the coated and uncoated substrates were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy. Polarization, electrochemical impedance spectroscopy, and immersion test in simulated body fluid (SBF) were employed to evaluate the corrosion resistance and the in vitro bioactivity of the samples. The results of our investigation showed that the nanostructured diopside coating deposited on the MAO layer increases the corrosion resistance and improves the in vitro bioactivity of the biodegradable magnesium alloy.

  2. Coating of biodegradable magnesium alloy bone implants using nanostructured diopside (CaMgSi2O6)

    Science.gov (United States)

    Razavi, Mehdi; Fathi, Mohammadhossein; Savabi, Omid; Beni, Batoul Hashemi; Razavi, Seyed Mohammad; Vashaee, Daryoosh; Tayebi, Lobat

    2014-01-01

    Magnesium alloys with their biodegradable characteristic can be a very good candidate to be used in orthopedic implants. However, magnesium alloys may corrode and degrade too fast for applications in the bone healing procedure. In order to enhance the corrosion resistance and the in vitro bioactivity of a magnesium alloy, a nanostructured diopside (CaMgSi2O6) film was coated on AZ91 magnesium alloy through combined micro-arc oxidation (MAO) and electrophoretic deposition (EPD) methods. The crystalline structures, morphologies and compositions of the coated and uncoated substrates were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy. Polarization, electrochemical impedance spectroscopy, and immersion test in simulated body fluid (SBF) were employed to evaluate the corrosion resistance and the in vitro bioactivity of the samples. The results of our investigation showed that the nanostructured diopside coating deposited on the MAO layer increases the corrosion resistance and improves the in vitro bioactivity of the biodegradable magnesium alloy.

  3. Coating of biodegradable magnesium alloy bone implants using nanostructured diopside (CaMgSi2O6)

    International Nuclear Information System (INIS)

    Razavi, Mehdi; Fathi, Mohammadhossein; Savabi, Omid; Beni, Batoul Hashemi; Razavi, Seyed Mohammad; Vashaee, Daryoosh

    2014-01-01

    Magnesium alloys with their biodegradable characteristic can be a very good candidate to be used in orthopedic implants. However, magnesium alloys may corrode and degrade too fast for applications in the bone healing procedure. In order to enhance the corrosion resistance and the in vitro bioactivity of a magnesium alloy, a nanostructured diopside (CaMgSi 2 O 6 ) film was coated on AZ91 magnesium alloy through combined micro-arc oxidation (MAO) and electrophoretic deposition (EPD) methods. The crystalline structures, morphologies and compositions of the coated and uncoated substrates were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy. Polarization, electrochemical impedance spectroscopy, and immersion test in simulated body fluid (SBF) were employed to evaluate the corrosion resistance and the in vitro bioactivity of the samples. The results of our investigation showed that the nanostructured diopside coating deposited on the MAO layer increases the corrosion resistance and improves the in vitro bioactivity of the biodegradable magnesium alloy.

  4. Structural, surface potential and optical studies of AlGaN based double heterostructures irradiated by 120 MeV Si{sup 9+} swift heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Arivazhagan, P., E-mail: arivazhaganau2008@gmail.com [Crystal Growth Centre, Anna University, Chennai, 600 025 (India); Ramesh, R.; Balaji, M. [Crystal Growth Centre, Anna University, Chennai, 600 025 (India); Asokan, K. [Inter-University Accelerator Centre (IUAC), New Delhi (India); Baskar, K. [Crystal Growth Centre, Anna University, Chennai, 600 025 (India)

    2016-09-15

    The Al{sub 0.33}Ga{sub 0.77}N/Al{sub 0.14}Ga{sub 0.86}N based double heterostructure was irradiated using Si{sup 9+} ion at room temperature (RT) and liquid nitrogen temperature (LNT) with four dissimilar ion fluence. The effect of Si{sup 9+} ion irradiation in dislocation densities and in-plane strain of GaN layer were discussed. The in-plane strain values of Al{sub x}Ga{sub 1-x}N layers were calculated from asymmetric reciprocal space mapping (RSM). The surface modification and the variation in phase shift on Al{sub 0.33}Ga{sub 0.77}N surfaces due to the irradiation were measured by Electrostatic Force Microscopy (EFM). The capacitance of the tip-sample system was determined from EFM. The band edge emissions of heterostructures were measured by the room temperature phototluminescence (PL) and the shift in the Al{sub 0.14}Ga{sub 0.86}N active layer emission peaks towards the low energy side at low fluence ion irradiation has been noted. - Highlights: • Effects of Si{sup 9+} ion irradiation on AlGaN double heterostructures were investigated. • Dislocation densities of GaN reduced at liquid nitrogen temperature irradiation. • Variation in phase shift on Al{sub 0.33}Ga{sub 0.77}N surfaces was measured by EFM. • Capacitance per unit area values of AFM tip-sample surface system were calculated. • Si{sup 9+} irradiations play an important role to tune the energy gap in Al{sub 0.14}Ga{sub 0.86}N.

  5. Analysis of As implantation profiles in silica by nuclear microanalysis and secondary ion emission

    International Nuclear Information System (INIS)

    Dieumegard, D.; Croset, M.; Cohen, C.; Lhoir, A.; Rigo, S.; Chaumont, J.

    1974-01-01

    Results obtained from analysis using, either the method of elastic backscattering of light or semi-heavy ions ( 4 He + , 14 N + ) about one MeV energy, or the secondary ion emission method are compared. The choice of As implanted Si is explained by the following reasons: As is an element relatively heavy in comparison with Si, that allows an analysis to be effected on a few thousands Angstroems depth in silica using elastic backscattering; the silica chosen as substrate being an amorphous material allows channeling phenomena to the avoided during implantation and analysis [fr

  6. Enhancing Hydrogen Diffusion in Silica Matrix by Using Metal Ion Implantation to Improve the Emission Properties of Silicon Nanocrystals

    Directory of Open Access Journals (Sweden)

    J. Bornacelli

    2014-01-01

    Full Text Available Efficient silicon-based light emitters continue to be a challenge. A great effort has been made in photonics to modify silicon in order to enhance its light emission properties. In this aspect silicon nanocrystals (Si-NCs have become the main building block of silicon photonic (modulators, waveguide, source, and detectors. In this work, we present an approach based on implantation of Ag (or Au ions and a proper thermal annealing in order to improve the photoluminescence (PL emission of Si-NCs embedded in SiO2. The Si-NCs are obtained by ion implantation at MeV energy and nucleated at high depth into the silica matrix (1-2 μm under surface. Once Si-NCs are formed inside the SiO2 we implant metal ions at energies that do not damage the Si-NCs. We have observed by, PL and time-resolved PL, that ion metal implantation and a subsequent thermal annealing in a hydrogen-containing atmosphere could significantly increase the emission properties of Si-NCs. Elastic Recoil Detection measurements show that the samples with an enhanced luminescence emission present a higher hydrogen concentration. This suggests that ion metal implantation enhances the hydrogen diffusion into silica matrix allowing a better passivation of surface defects on Si NCs.

  7. Moessbauer-spectroscopic study of structure and magnetism of the exchange-coupled layer systems Fe/FeSn{sub 2}, and Fe/FeSi/Si and the ion-implanted diluted magnetic semiconductor SiC(Fe); Moessbauerspektroskopische Untersuchung von Struktur und Magnetismus der austauschgekoppelten Schichtsysteme Fe/FeSn{sub 2} und Fe/FeSi/Si und des ionenimplantierten verduennten magnetischen Halbleiters SiC(Fe)

    Energy Technology Data Exchange (ETDEWEB)

    Stromberg, Frank

    2009-07-07

    In line with this work the structural and magnetic properties of the exchange coupled layered systems Fe/FeSn{sub 2} and Fe/FeSi/Si and of the Fe ion implanted diluted magnetic semiconductor (DMS) SiC(Fe) were investigated. The main measuring method was the isotope selective {sup 57}Fe conversion electron Moessbauer spectroscopy (CEMS), mostly in connection with the {sup 57}Fe tracer layer technique, in a temperature range from 4.2 K to 340 K. Further measurement techniques were X-ray diffraction (XRD), electron diffraction (LEED, RHEED), SQUID magnetometry and FMR (Ferromagnetic Resonance). In the first part of this work the properties of thin AF FeSn{sub 2}(001) films and of the exchange-bias system Fe/FeSn{sub 2}(001) on InSb(001) were investigated. With the application of {sup 57}Fe-tracer layers and CEMS both the Fe-spin structure and the temperature dependence of the magnetic hyperfine field (B{sub hf}) of FeSn{sub 2} could be examined. The evaporation of Fe films on the FeSn{sub 2} films produced in the latter ones a high perpendicular spin component at the Fe/FeSn{sub 2} interface. In some distance from the interface the Fe spins rotate back into the sample plane. Furthermore {sup 57}Fe-CEMS provided a correlation between the absolute value of the exchange field vertical stroke He vertical stroke and the amount of magnetic defects within the FeSn{sub 2}. Temperature dependent CEMS-measurements yielded informations about the spin dynamics within the AF. The transition temperatures T{sub B}{sup *}, which were interpreted as superparamagnetic blocking temperatures, obtain higher values compared to the temperatures T{sub B} of the exchange-bias effect, obtained with magnetometry measurements. The second part of this work deals with the indirect exchange coupling within Fe/FeSi/Si/FeSi/Fe multilayers and FeSi diffusion barriers. The goal was to achieve Fe free Si interlayers. The CEMS results show that starting from a thickness of t{sub FeSi}=10-12 A of the

  8. Effects of 5.4 MeV alpha-particle irradiation on the electrical properties of nickel Schottky diodes on 4H–SiC

    Energy Technology Data Exchange (ETDEWEB)

    Omotoso, E. [Department of Physics, University of Pretoria, Private Bag X20, Hatfield 0028 (South Africa); Department of Physics, Obafemi Awolowo University, Ile-Ife 220005 (Nigeria); Meyer, W.E.; Auret, F.D.; Paradzah, A.T.; Diale, M.; Coelho, S.M.M.; Janse van Rensburg, P.J.; Ngoepe, P.N.M. [Department of Physics, University of Pretoria, Private Bag X20, Hatfield 0028 (South Africa)

    2015-12-15

    Current–voltage, capacitance–voltage and conventional deep level transient spectroscopy at temperature ranges from 40 to 300 K have been employed to study the influence of alpha-particle irradiation from an {sup 241}Am source on Ni/4H–SiC Schottky contacts. The nickel Schottky barrier diodes were resistively evaporated on n-type 4H–SiC samples of doping density of 7.1 × 10{sup 15} cm{sup −3}. It was observed that radiation damage caused an increase in ideality factors of the samples from 1.04 to 1.07, an increase in Schottky barrier height from 1.25 to 1.31 eV, an increase in series resistance from 48 to 270 Ω but a decrease in saturation current density from 55 to 9 × 10{sup −12} A m{sup −2} from I–V plots at 300 K. The free carrier concentration of the sample decreased slightly after irradiation. Conventional DLTS showed peaks due to four deep levels for as-grown and five deep levels after irradiation. The Richardson constant, as determined from a modified Richardson plot assuming a Gaussian distribution of barrier heights for the as-grown and irradiated samples were 133 and 151 A cm{sup −2} K{sup −2}, respectively. These values are similar to literature values.

  9. Cytokine induction of sol–gel-derived TiO2 and SiO2 coatings on metallic substrates after implantation to rat femur

    Directory of Open Access Journals (Sweden)

    Urbanski W

    2017-02-01

    Full Text Available Wiktor Urbanski,1 Krzysztof Marycz,2 Justyna Krzak,3 Celina Pezowicz,4 Szymon Feliks Dragan1 1Department of Orthopaedic Surgery and Traumatology, Wroclaw University Hospital, 2Electron Microscope Laboratory, Wroclaw University of Environmental and Life Sciences, 3Institute of Materials Science and Applied Mechanics, 4Division of Biomedical Engineering and Experimental Mechanics, Wroclaw University of Technology, Wroclaw, Poland Abstract: Material surface is a key determinant of host response on implanted biomaterial. Therefore, modification of the implant surface may optimize implant–tissue reactions. Inflammatory reaction is inevitable after biomaterial implantation, but prolonged inflammation may lead to adverse reactions and subsequent implant failure. Proinflammatory activities of cytokines like interleukin (IL-1, IL-6, and tumor necrosis factor-alpha (TNF-α are attractive indicators of these processes and ultimately characterize biocompatibility. The objective of the study was to evaluate local cytokine production after implantation of stainless steel 316L (SS and titanium alloy (Ti6Al4V biomaterials coated with titanium dioxide (TiO2 and silica (SiO2 coatings prepared by sol–gel method. Biomaterials were implanted into rat femur and after 12 weeks, bones were harvested. Bone–implant tissue interface was evaluated; immunohistochemical staining was performed to identify IL-6, TNF-α, and Caspase-1. Histomorphometry (AxioVision Rel. 4.6.3 software of tissue samples was performed in order to quantify the cytokine levels. Both the oxide coatings on SS and Ti6Al4V significantly reduced cytokine production. However, the lowest cytokine levels were observed in TiO2 groups. Cytokine content in uncoated groups was lower in Ti6Al4V than in SS, although coating of either metal reduced cytokine production to similar levels. Sol–gel TiO2 or SiO2 coatings reduced significantly the production of proinflammatory cytokines by local tissues

  10. Microbeam line of MeV heavy ions for materials modification and in-situ analysis

    International Nuclear Information System (INIS)

    Horino, Yuji; Chayahara, Akiyoshi; Kiuchi, Masato; Fujii, Kanenaga; Satoh, Mamoru; Takai, Mikio.

    1990-01-01

    A microbeam line for MeV heavy ions of almost any element has been developed for microion-beam processing such as maskless MeV ion implantation and its in-situ analysis. Beam spot sizes of 4.0 μm x 4.0 μm for 3 MeV C 2+ and 9.6 μm x 4.8 μm for 1.8 MeV Au 2+ beams were obtained. Maskless MeV gold ion implantation to a silicon substrate and in-situ microanalysis before and after ion implantation were demonstrated. (author)

  11. Elimination of carbon vacancies in 4H-SiC epi-layers by near-surface ion implantation: Influence of the ion species

    Energy Technology Data Exchange (ETDEWEB)

    Ayedh, H. M.; Svensson, B. G. [University of Oslo, Department of Physics/Center for Materials Science and Nanotechnology, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Hallén, A. [School of Information and Communication Technology (ICT), Royal Institute of Technology, SE-164 40 Kista-Stockholm (Sweden)

    2015-11-07

    The carbon vacancy (V{sub C}) is a prevailing point defect in high-purity 4H-SiC epitaxial layers, and it plays a decisive role in controlling the charge carrier lifetime. One concept of reducing the V{sub C}-concentration is based on carbon self-ion implantation in a near surface layer followed by thermal annealing. This leads to injection of carbon interstitials (C{sub i}'s) and annihilation of V{sub C}'s in the epi-layer “bulk”. Here, we show that the excess of C atoms introduced by the self-ion implantation plays a negligible role in the V{sub C} annihilation. Actually, employing normalized implantation conditions with respect to displaced C atoms, other heavier ions like Al and Si are found to be more efficient in annihilating V{sub C}'s. Concentrations of V{sub C} below ∼2 × 10{sup 11} cm{sup −3} can be reached already after annealing at 1400 °C, as monitored by deep-level transient spectroscopy. This corresponds to a reduction in the V{sub C}-concentration by about a factor of 40 relative to the as-grown state of the epi-layers studied. The negligible role of the implanted species itself can be understood from simulation results showing that the concentration of displaced C atoms exceeds the concentration of implanted species by two to three orders of magnitude. The higher efficiency for Al and Si ions is attributed to the generation of collision cascades with a sufficiently high energy density to promote C{sub i}-clustering and reduce dynamic defect annealing. These C{sub i}-related clusters will subsequently dissolve during the post-implant annealing giving rise to enhanced C{sub i} injection. However, at annealing temperatures above 1500 °C, thermodynamic equilibrium conditions start to apply for the V{sub C}-concentration, which limit the net effect of the C{sub i} injection, and a competition between the two processes occurs.

  12. Comparative study of as-implanted and pre-damaged ion-beam-synthesized ZnS nanocrystallites in SiO sub 2

    CERN Document Server

    Gao, K Y; Grosshans, I; Hipp, W; Stritzker, B

    2002-01-01

    The semiconducting ZnS nanocrystallites were synthesized by sequential high dose ion implantation of Zn and S in thermally grown SiO sub 2 on Si(1 0 0) and subsequent rapid thermal annealing (RTA). Some samples were pre-implanted with Ar ions in order to investigate the influence of radiation induced damage on the formation of ZnS nanocrystallites. The crystal structure of the ZnS crystallites, their size distribution and the concentration depth profile were analyzed by X-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS) and cross-sectional transmission-electron-microscopy (XTEM). The XRD results indicate, that the phase transition from cubic zinc blende to hexagonal wurtzite structure of ZnS nanocrystallites begins at temperatures below 1000 degree sign C. The RBS results show a clear redistribution of Zn and S after RTA annealing. The concentration of Zn is seriously reduced due to strong diffusion towards deeper regions and the surface, while Ar pre-implantation partially suppressed the c...

  13. Preparation and characterization of TiO2 and Si-doped octacalcium phosphate composite coatings on zirconia ceramics (Y-TZP) for dental implant applications

    Science.gov (United States)

    Bao, Lei; Liu, Jingxiao; Shi, Fei; Jiang, Yanyan; Liu, Guishan

    2014-01-01

    In order to prevent the low temperature degradation and improve the bioactivity of zirconia ceramic implants, TiO2 and Si-doped octacalcium phosphate composite coating was prepared on zirconia substrate. The preventive effect on low temperature degradation and surface morphology of the TiO2 layer were studied. Meanwhile, the structure and property changes of the bioactive coating after doping Si were discussed. The results indicate that the dense TiO2 layer, in spite of some microcracks, inhibited the direct contact of the water vapor with the sample's surface and thus prevented the low temperature degradation of zirconia substrates. The acceleration aging test shows that the ratio of the monoclinic phase transition decreased from 10% for the original zirconia substrate to 4% for the TiO2-coated substrate. As to the Si-doped octacalcium phosphate coating prepared by biomimetic method, the main phase composition of the coating was octacalcium phosphate. The morphology of the coating was lamellar-like, and the surface was uniform and continuous with no cracks being observed. It is suggested that Si was added into the coating both through substituting for PO43- and doping as NaSiO3.

  14. New, fast corroding high ductility Mg–Bi–Ca and Mg–Bi–Si alloys, with no clinically observable gas formation in bone implants

    International Nuclear Information System (INIS)

    Remennik, S.; Bartsch, I.; Willbold, E.; Witte, F.; Shechtman, D.

    2011-01-01

    Highlights: ► Biodegradable, biocompatible and highly ductile Mg alloys based on the Mg–Bi system have been produced by rapid solidification and extrusion processes. ► The implants corroded fast within the first 4 weeks after implantation in rabbit bone, but no gas formation has been clinically observed. ► The corrosion rate could be significantly reduced in vitro and in vivo by using high purity magnesium for the alloy production. - Abstract: Current approaches to initial corrosion rate reduction of biodegradable magnesium alloys include alloying with rare earth elements, mechanical processing, coatings and the use of metallic glasses. The latter has limited ductility needed for implant adaptively to various surgery procedures. Furthermore, slow corroding magnesium alloys, coatings or metallic glasses have not proved to be fully dissolvable in vivo. With this in mind, we have developed a new class of biocompatible, biodegradable ductile magnesium alloys with 40% elongation at room temperature. The alloys are based on the Mg–Bi system and undergo a series of production routes, which include rapid solidification (RS) and various extrusion processes. The Mg–Bi–Si (B-BS) system exhibited a high corrosion rates in vitro and was excluded from in vivo screening. In preliminary experiments of Mg–Bi–Ca (B-BX) in rabbit femur bones, the alloy corroded rapidly without any clinically visible gas formation. Only 30% of the B-BX implant remained uncorroded after 4 weeks of implantation. After using low iron Mg for implant preparation the corrosion rate of HP-B-BX was reduced in bone leaving 70% of the implant uncorroded after 4 weeks, while the corrosion in intramuscular and subcutaneous sites were still high leaving only 40% and 10% uncorroded after 4 weeks. The foreign body reaction was very mild and enhanced bone formation could be observed in the vicinity of the corroding implant. Thus, these new magnesium alloys are potentially promising biomaterials

  15. Effect of 120 MeV 28Si9+ ion irradiation on structural and magnetic properties of NiFe2O4 and Ni0.5Zn0.5Fe2O4

    Science.gov (United States)

    Sharma, R.; Raghuvanshi, S.; Satalkar, M.; Kane, S. N.; Tatarchuk, T. R.; Mazaleyrat, F.

    2018-05-01

    NiFe2O4, Ni0.5Zn0.5Fe2O4 samples were synthesized using sol-gel auto combustion method, and irradiated by using 120 MeV 28Si9+ ion with ion fluence of 1×1012 ions/cm2. Characterization of pristine, irradiated samples were done using X-Ray Diffraction (XRD), Field Emission Scanning Microscopy (FE-SEM), Energy Dispersive X-ray Analysis (EDAX) and Vibrating Sample Magnetometer (VSM). XRD validates the single phase nature of pristine, irradiated Ni- Zn nano ferrite except for Ni ferrite (pristine, irradiated) where secondary phases of α-Fe2O3 and Ni is observed. FE- SEM images of pristine Ni, Ni-Zn ferrite show inhomogeneous nano-range particle size distribution. Presence of diamagnetic ion (Zn2+) in NiFe2O4 increases oxygen positional parameter (u 4¯3m ), experimental, theoretical saturation magnetization (Msexp., Msth.), while decreases the grain size (Ds) and coercivity (Hc). With irradiation Msexp., Msth. increases but not much change are observed in Hc. New antistructure modeling for the pristine, irradiated Ni and Ni-Zn ferrite samples was used for describing the surface active centers.

  16. 2-D analytical modeling of subthreshold current and subthreshold swing for ion-implanted strained-Si double-material double-gate (DMDG) MOSFETs

    Science.gov (United States)

    Goel, Ekta; Singh, Kunal; Singh, Balraj; Kumar, Sanjay; Jit, Satyabrata

    2017-09-01

    In this paper, the subthreshold behavior of ion-implanted strained-Si double-material double-gate (DMDG) MOSFETs has been analyzed by means of subthreshold current and subthreshold swing. The surface potential based formulation of subthreshold current and subthreshold swing is done by solving the 2-D Poisson's equations in the channel region using parabolic approximation method. The dependence of subthreshold characteristics on various device parameters such as gate length ratio, Ge mole fraction, peak doping concentration, projected range, straggle parameter etc. has been studied. The modeling results are found to be well matched with the simulation data obtained by a 2-D device simulator, ATLAS™, from SILVACO.

  17. Silicon exfoliation by hydrogen implantation: Actual nature of precursor defects

    Energy Technology Data Exchange (ETDEWEB)

    Kuisseu, Pauline Sylvia Pokam, E-mail: pauline-sylvia.pokam-kuisseu@cnrs-orleans.fr [CEMHTI-CNRS, 3A, rue de la férollerie, 45071 Orléans (France); Pingault, Timothée; Ntsoenzok, Esidor [CEMHTI-CNRS, 3A, rue de la férollerie, 45071 Orléans (France); Regula, Gabrielle [IM2NP-CNRS-Université d’Aix-Marseille, Avenue Escadrille Normandie Niemen, 13397 Marseille (France); Mazen, Frédéric [CEA-Leti, MINATEC campus, 17, rue des Martyrs, 38054 Grenoble Cedex 9 (France); Sauldubois, Audrey [Université d’Orléans, rue de Chartres – Collegium ST, 45067 Orléans (France); Andreazza, Caroline [ICMN-CNRS-Université d’Orléans, 1b rue de la férollerie, 45071 Orléans (France)

    2017-06-15

    MeV energy hydrogen implantation in silicon followed by a thermal annealing is a very smart way to produce high crystalline quality silicon substrates, much thinner than what can be obtained by diamond disk or wire sawing. Using this kerf-less approach, ultra-thin substrates with thicknesses between 15 µm and 100 µm, compatible with microelectronic and photovoltaic applications are reported. But, despite the benefits of this approach, there is still a lack of fundamental studies at this implantation energy range. However, if very few papers have addressed the MeV energy range, a lot of works have been carried out in the keV implantation energy range, which is the one used in the smart-cut® technology. In order to check if the nature and the growth mechanism of extended defects reported in the widely studied keV implantation energy range could be extrapolated in the MeV range, the thermal evolution of extended defects formed after MeV hydrogen implantation in (100) Si was investigated in this study. Samples were implanted at 1 MeV with different fluences ranging from 6 × 10{sup 16} H/cm{sup 2} to 2 × 10{sup 17} H/cm{sup 2} and annealed at temperatures up to 873 K. By cross-section transmission electron microscopy, we found that the nature of extended defects in the MeV range is quite different of what is observed in the keV range. In fact, in our implantation conditions, the generated extended defects are some kinds of planar clusters of gas-filled lenses, instead of platelets as commonly reported in the keV energy range. This result underlines that hydrogen behaves differently when it is introduced in silicon at high or low implantation energy. The activation energy of the growth of these extended defects is independent of the chosen fluence and is between (0.5–0.6) eV, which is very close to the activation energy reported for atomic hydrogen diffusion in a perfect silicon crystal.

  18. Ion-implantation and analysis for doped silicon slot waveguides

    Directory of Open Access Journals (Sweden)

    McCallum J. C.

    2012-10-01

    Full Text Available We have utilised ion implantation to fabricate silicon nanocrystal sensitised erbium-doped slot waveguide structures in a Si/SiO2/Si layered configuration and photoluminescence (PL and Rutherford backscattering spectrometry (RBS to analyse these structures. Slot waveguide structures in which light is confined to a nanometre-scale low-index region between two high-index regions potentially offer significant advantages for realisation of electrically-pumped Si devices with optical gain and possibly quantum optical devices. We are currently investigating an alternative pathway in which high quality thermal oxides are grown on silicon and ion implantation is used to introduce the Er and Si-ncs into the SiO2 layer. This approach provides considerable control over the Er and Si-nc concentrations and depth profiles which is important for exploring the available parameter space and developing optimised structures. RBS is well-suited to compositional analysis of these layered structures. To improve the depth sensitivity we have used a 1 MeV α beam and results indicate that a layered silicon-Er:SiO2/silicon structure has been fabricated as desired. In this paper structural results will be compared to Er photoluminescence profiles for samples processed under a range of conditions.

  19. Influence of irradiation spectrum and implanted ions on the amorphization of ceramics

    International Nuclear Information System (INIS)

    Zinkle, S.J.; Snead, L.L.

    1995-01-01

    Polycrystalline Al2O3, magnesium aluminate spinel (MgAl2O4), MgO, Si3N4, and SiC were irradiated with various ions at 200-450 K, and microstructures were examined following irradiation using cross-section TEM. Amorphization was not observed in any of the irradiated oxide ceramics, despsite damage energy densities up to ∼7 keV/atom (70 displacements per atom). On the other hand, SiC readily amorphized after damage levels of ∼0.4 dpa at room temperature (RT). Si3N4 exhibited intermediate behavior; irradiation with Fe 2+ ions at RT produced amorphization in the implanted ion region after damage levels of ∼1 dpa. However, irradiated regions outside the implanted ion region did not amorphize even after damage levels > 5 dpa. The amorphous layer in the Fe-implanted region of Si3N4 did not appear if the specimen was simultaneoulsy irradiated with 1-MeV He + ions at RT. By comparison with published results, it is concluded that the implantation of certain chemical species has a pronounced effect on the amorphization threshold dose of all five materials. Intense ionizing radiation inhibits amorphization in Si3N4, but does not appear to significantly influence the amorphization of SiC

  20. The effect of Ni pre-implantation on surface morphology and optical absorption properties of Ag nanoparticles embedded in SiO2

    International Nuclear Information System (INIS)

    Shen, Yanyan; Qi, Ting; Qiao, Yu; Yu, Shengwang; Hei, Hongjun; He, Zhiyong

    2016-01-01

    Graphical abstract: - Highlights: • Ag concentration increased significantly due to the Ni pre-implantation. • Deposition and accumulation process of Ag atoms depends on Ni fluences. • The incorporation of Ni elements in Ag NPs can damp SPR absorption intensity. • AgNi alloy NPs embedded in SiO 2 have been created by sequentially implantation. • Unique SPR absorption with dual peaks centered at 406 nm and 563 nm was observed. - Abstract: The effect of Ni ion fluence on Ag nucleation and particle growth was investigated by sequentially implantation of 60 keV Ni ions at fluences of 1 × 10 16 , 5 × 10 16 , 1 × 10 17 ions/cm 2 and 70 keV Ag ions at a fluence of 5 × 10 16 ions/cm 2 . Due to the modification of the deposition and accumulation process of Ag implants caused by Ni pre-implantation, the surface morphology, structures, and optical absorption properties of the Ag nanoparticles (NPs) depends strongly on the Ni fluences. UV–vis absorption spectroscopy study showed that the introducing of Ni atoms lead to intensity decrease in the Ag SPR band. Remarkable local concentration increase of Ag profiles appeared for the sample pre-implanted by Ni ions of 5.0 × 10 16 ions/cm 2 . In particular, the AgNi alloy NPs with dual absorption peaks centered at 406 nm and 563 nm have been formed after 600 °C annealing in Ar atmosphere. However, at a low fluence of 1.0 × 10 16 ions/cm 2 , only small increase of the local Ag concentration than the Ag ions singly implanted sample can be observed. At a high fluence of 1.0 × 10 17 ions/cm 2 , lots Ag atoms are trapped close to the surface, which result in heavy sputtering loss of Ag atoms and the sublimation of Ag atoms after 600 °C annealing.

  1. The interaction between Xe and F in Si (1 0 0) pre-amorphised with 20 keV Xe and implanted with low energy BF{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Werner, M. [Joule Physics Laboratory, Institute of Materials Research, University of Salford, Salford M54WT (United Kingdom)]. E-mail: m.werner@pgr.salford.ac.uk; Berg, J.A. van den [Joule Physics Laboratory, Institute of Materials Research, University of Salford, Salford M54WT (United Kingdom); Armour, D.G. [Joule Physics Laboratory, Institute of Materials Research, University of Salford, Salford M54WT (United Kingdom); Carter, G. [Joule Physics Laboratory, Institute of Materials Research, University of Salford, Salford M54WT (United Kingdom); Feudel, T. [AMD Saxony LLC and Co. KG, Wilschdorfer Landstrasse, 101 D-01109 Dresden (Italy); Herden, M. [AMD Saxony LLC and Co. KG, Wilschdorfer Landstrasse, 101 D-01109 Dresden (Italy); Bersani, M. [ITC IRST, 38050 Povo, Trento (Italy); Giubertoni, D. [ITC IRST, 38050 Povo, Trento (Italy); Bailey, P. [CCLRC Daresbury Laboratory, Daresbury WA44A (United Kingdom); Noakes, T.C.Q. [CCLRC Daresbury Laboratory, Daresbury WA44A (United Kingdom)

    2004-12-15

    The pre-amorphisation of Si by Xe{sup +} ions, before source/drain and extension implants, is an attractive alternative to Ge{sup +} or Si{sup +}, as it produces sharper amorphous/crystalline interfaces. Si (1 0 0) samples pre-amorphised with 20 keV Xe{sup +} to a nominal dose of 2E14 cm{sup -2} were implanted with 1 and 3 keV BF{sub 2} {sup +} to doses of 7E14 cm{sup -2}. Samples were annealed at temperatures ranging from 600 to 1130 deg. C and investigated by medium energy ion scattering (MEIS) and secondary ion mass spectrometry (SIMS). Following annealing, it was observed that implanted Xe has interacted with F originating from the BF{sub 2} {sup +} implant. MEIS studies showed that for all annealing conditions, approximately half of the Xe accumulated at depths of 7 nm for the 1 keV and at 13 nm for the 3 keV BF{sub 2} {sup +} implant. This equates to the end of range of B and F within the amorphous Si. SIMS showed that in the pre-amorphised samples, approximately 10% of the F migrates into the bulk and is trapped at the same depth in a {approx}1:1 ratio to Xe. A small fraction of the implanted B is also trapped. The effect is interpreted in terms of the formation of a defect structure within the amorphised Si, leading to F stabilised Xe bubble or XeF compound formation.

  2. P- and N-type implantation doping of GaN with Ca and O

    International Nuclear Information System (INIS)

    Zolper, J.C.; Wilson, R.G.; Pearton, S.J.

    1996-01-01

    III-N photonic devices have made great advances in recent years following the demonstration of doping of GaN p-type with Mg and n-type with Si. However, the deep ionization energy level of Mg in GaN (∼ 160 meV) limits the ionized of acceptors at room temperature to less than 1.0% of the substitutional Mg. With this in mind, the authors used ion implantation to characterize the ionization level of Ca in GaN since Ca had been suggested by Strite to be a shallow acceptor in GaN. Ca-implanted GaN converted from n-to-p type after a 1,100 C activation anneal. Variable temperature Hall measurements give an ionization level at 169 meV. Although this level is equivalent to that of Mg, Ca-implantation may have advantages (shallower projected range and less straggle for a given energy) than Mg for electronic devices. In particular, the authors report the first GaN device using ion implantation doping. This is a GaN junction field effect transistor (JFET) which employed Ca-implantation. A 1.7 microm JFET had a transconductance of 7 mS/mm, a saturation current at 0 V gate bias of 33 mA/mm, a f t of 2.7 GHz, and a f max of 9.4 GHz. O-implantation was also studied and shown to create a shallow donor level (∼ 25 meV) that is similar to Si. SIMS profiles of as-implanted and annealed samples showed no measurable redistribution of either Ca or O in GaN at 1,125 C

  3. Vacancy effects on the formation of helium and krypton cavities in 3-C-SiC irradiated and annealed at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Zang, Hang; Liu, Wenbo; Li, Tao; He, Chaohui; Yun, Di; Jiang, Weilin; Devaraj, Arun; Edwards, Danny J.; Henager, Charles H.; Kurtz, Richard J.; Wang, Zhiguang

    2017-02-27

    Polycrystalline 3C-SiC was sequentially irradiated at 400 and 750°C with 120 keV He2+ and 4 MeV Kr15+ ions to 1017 and 41016 cm-2, respectively. The Kr15+ ions penetrated the entire depth of the He2+ ion implantation region. Three areas of He2+, Kr15+ and He2+ + Kr15+ ion implanted 3C-SiC were created through masked overlapping irradiations. The sample was subsequently annealed at 1600°C in vacuum and characterized using cross-sectional transmission electron microscopy and energy-dispersive x-ray spectroscopy. Compared to the He2+ ion only implanted 3C-SiC, helium cavities in the He2+ and Kr15+ co-implanted 3C-SiC had a smaller size but higher density. At 25 dpa, presence of He in the co-implanted 3C-SiC significantly promoted cavity growth; much smaller voids were formed in the Kr15+ ion only irradiated 3C-SiC at the same dose. In addition, local Kr migration and trapping at cavities occurred, but long-range Kr diffusion in 3C-SiC was not observed up to 1600°C.

  4. Laser ion implantation of Ge in SiO2 using a post-ion acceleration system

    Czech Academy of Sciences Publication Activity Database

    Cutroneo, Mariapompea; Macková, Anna; Torrisi, L.; Lavrentiev, Vasyl

    2017-01-01

    Roč. 35, č. 1 (2017), s. 72-80 ISSN 0263-0346 R&D Projects: GA MŠk LM2015056; GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:61389005 Keywords : laser ion implantation * post-acceleration Subject RIV: BH - Optics, Masers, Laser s OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 1.420, year: 2016

  5. Arsenic implantation into polycrystalline silicon and diffusion to silicon substrate

    International Nuclear Information System (INIS)

    Tsukamoto, K.; Akasaka, Y.; Horie, K.

    1977-01-01

    Arsenic implantation into polycrystalline silicon and drive-in diffusion to silicon substrate have been investigated by MeV He + backscattering analysis and also by electrical measurements. The range distributions of arsenic implanted into polycrystalline silicon are well fitted to Gaussian distributions over the energy range 60--350 keV. The measured values of R/sub P/ and ΔR/sub P/ are about 10 and 20% larger than the theoretical predictions, respectively. The effective diffusion coefficient of arsenic implanted into polycrystalline silicon is expressed as D=0.63 exp[(-3.22 eV/kT)] and is independent of the arsenic concentration. The drive-in diffusion of arsenic from the implanted polycrystalline silicon layer into the silicon substrate is significantly affected by the diffusion atmosphere. In the N 2 atmosphere, a considerable amount of arsenic atoms diffuses outward to the ambient. The outdiffusion can be suppressed by encapsulation with Si 3 N 4 . In the oxidizing atmosphere, arsenic atoms are driven inward by growing SiO 2 due to the segregation between SiO 2 and polycrystalline silicon, and consequently the drive-in diffusion of arsenic is enhanced. At the interface between the polycrystalline silicon layer and the silicon substrate, arsenic atoms are likely to segregate at the polycrystalline silicon side

  6. Synthesis and Cell Seeding Assessment of Novel Biphasic Nano Powder in the CaO–MgO–SiO2 System for Bone Implant Application

    Directory of Open Access Journals (Sweden)

    Kazem Marzban

    2017-02-01

    Full Text Available Objective(s: CaO–MgO–SiO2 system bioceramics possess good characteristics for hard tissue engineering applications. The aim of the study was to synthesize the nano powder by using a sol-gel method and evaluate of bioactivity in the cells culture. Methods: To characterize of powder X-ray diffraction (XRD, transmission electron microscopy (TEM and to evaluate the bioactivity sample cell seeding and methylthiazol tetrazolium (MTT assay were performed. Results: X-ray diffraction (XRD analysis showed that the biphasic powder was obtained at 1300°C for 2 h by using a sol-gel method. Transmission electron microscopy (TEM image showed that powder particle size was about 45 nm. Besides, cell culture results indicated that the percentage of viability values was increased by the extension of period. Conclusions: found that the sample is cytocompatible and has cell proliferation potential in culture medium. The present study demonstrates that, the biphasic CaO–MgO–SiO2 system can be used to achieve novel bioactive materials for bone implant application.

  7. Electrical and structural properties of surfaces and interfaces in Ti/Al/Ni Ohmic contacts to p-type implanted 4H-SiC

    Science.gov (United States)

    Vivona, M.; Greco, G.; Bongiorno, C.; Lo Nigro, R.; Scalese, S.; Roccaforte, F.

    2017-10-01

    In this work, the electrical and structural properties of Ti/Al/Ni Ohmic contacts to p-type implanted silicon carbide (4H-SiC) were studied employing different techniques. With increasing the annealing temperature, an improvement of the electrical properties of the contacts is highlighted, until an Ohmic behavior is obtained at 950 °C, with a specific contact resistance ρc = 2.3 × 10-4 Ω cm2. A considerable intermixing of the metal layers occurred upon annealing, as a consequence of the formation of different phases, both in the uppermost part of the stack (mainly Al3Ni2) and at the interface with SiC, where the formation of preferentially aligned TiC is observed. The formation of an Ohmic contact was associated with the occurrence of the reaction and the disorder at the interface, where the current transport is dominated by the thermionic field emission mechanism with a barrier height of 0.56 eV.

  8. High energy ion implantation

    International Nuclear Information System (INIS)

    Ziegler, J.F.

    1985-01-01

    High energy ion implantation offers the oppertunity for unique structures in semiconductor processing. The unusual physical properties of such implantations are discussed as well as the special problems in masking and damage annealing. A review is made of proposed circuit structures which involve deep implantation. Examples are: deep buried bipolar collectors fabricated without epitaxy, barrier layers to reduce FET memory sensitivity to soft-fails, CMOS isolation well structures, MeV implantation for customization and correction of completed circuits, and graded reach-throughs to deep active device components. (orig.)

  9. Synthesis, mechanical properties and corrosion behavior of powder metallurgy processed Fe/Mg2Si composites for biodegradable implant applications.

    Science.gov (United States)

    Sikora-Jasinska, M; Paternoster, C; Mostaed, E; Tolouei, R; Casati, R; Vedani, M; Mantovani, D

    2017-12-01

    Recently, Fe and Fe-based alloys have shown their potential as degradable materials for biomedical applications. Nevertheless, the slow corrosion rate limits their performance in certain situations. The shift to iron matrix composites represents a possible approach, not only to improve the mechanical properties, but also to accelerate and tune the corrosion rate in a physiological environment. In this work, Fe-based composites reinforced by Mg 2 Si particles were proposed. The initial powders were prepared by different combinations of mixing and milling processes, and finally consolidated by hot rolling. The influence of the microstructure on mechanical properties and corrosion behavior of Fe/Mg 2 Si was investigated. Scanning electron microscopy and X-ray diffraction were used for the assessment of the composite structure. Tensile and hardness tests were performed to characterize the mechanical properties. Potentiodynamic and static corrosion tests were carried out to investigate the corrosion behavior in a pseudo-physiological environment. Samples with smaller Mg 2 Si particles showed a more homogenous distribution of the reinforcement. Yield and ultimate tensile strength increased when compared to those of pure Fe (from 400MPa and 416MPa to 523MPa and 630MPa, respectively). Electrochemical measurements and immersion tests indicated that the addition of Mg 2 Si could increase the corrosion rate of Fe even twice (from 0.14 to 0.28mm·year -1 ). It was found that the preparation method of the initial composite powders played a major role in the corrosion process as well as in the corrosion mechanism of the final composite. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Slowing down of 2–11 MeV {sup 12}C, {sup 16}O, {sup 28}Si and {sup 63}Cu heavy ions through Si{sub 3}N{sub 4} thin foil by using Time-of-Flight spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Guesmia, A., E-mail: guesmia@tlabs.ac.za [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Departement de physique, Faculté des Sciences Université Saad Dahleb, B. P. 270, Route de Soumaa, Blida (Algeria); Departement de physique, Faculté des Sciences Université M’hamedBougara, Boumerdes (Algeria); Msimanga, M. [Physics Department, Tshwane University of Technology, P Bag X 680, Pretoria 0001 (South Africa); Pineda-Vargas, C.A. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Faculty of Health and Wellness Sciences, CPUT, P.O. Box 1906, Bellville 7535 (South Africa); Ammi, H.; Dib, A.; Ster, M. [Centre de Recherche Nucleaire d’Alger, 2 Bd. Frantz Fanon, B. P. 399, Alger-Gare, Algiers (Algeria)

    2016-03-15

    The stopping force and the energy-loss straggling of {sup 63}Cu, {sup 28}Si, {sup 16}O and {sup 12}C partially stripped heavy ions crossing silicon nitride foil has been determined over a continuous range of energies 2–11 MeV, by using a method based on the Heavy Ion-Elastic Recoil Detection Analysis (HI-ERDA) technique using a Time of Flight (ToF) spectrometer. The obtained energy loss straggling values corrected for non-statistical straggling and the thickness variation using the Besenbacher’s method have been analyzed and compared with the corresponding computed values. For computed electronic straggling we have used alternatively the widely used formulations such as, the universal Bohr straggling deduced from the Bohr stopping model, and the Lindhard–Scharff formula including the Bunching effect given by Hvelplund–Firsov formula according to the Besenbacher approach. The aim of such comparison is to check the reliability and accuracy of the existing energy loss straggling formulations, in the light of the present experimental results. The experimental results of energy loss straggling of all ions are found to be greater than those predicted by the Bohr stopping model or Lindhard–Scharff prediction model. The introduction of the bunching effect improves the comparison and gives an estimation of other effects such as charge exchange.

  11. Deep ultra violet and visible Raman spectroscopy studies of ion implanted 6H-SiC: Recrytallisation behaviour and thermal decomposition/thermal etching of the near surface region

    Energy Technology Data Exchange (ETDEWEB)

    Kuhudzai, R.J., E-mail: rj.kuhudzai@tuks.co.za [Physics Department, University of Pretoria, Pretoria (South Africa); Malherbe, J.B.; Berg, N.G. van der; Hlatshwayo, T.T.; Odutemowo, O.; Prinsloo, L.C. [Physics Department, University of Pretoria, Pretoria (South Africa); Buys, A.V. [Laboratory for Microscopy and Microanalysis, University of Pretoria (South Africa); Erasmus, R. [School of Physics, University of the Witwatersrand, Johannesburg (South Africa); Wendler, E. [Institut Für Festköperphysik, Friedrich-Schiller-Universität Jena, Jena (Germany)

    2015-12-15

    The recystallisation behaviour and thermal decomposition of the near surface amorphised region of 6H-SiC have been investigated by Raman spectroscopy. 360 keV ions of iodine and silver were implanted at room temperature into wafers of 6H-SiC resulting in the amorphisation of the near surface region. Vacuum annealing of the samples was performed at 1200 °C for 5 h and then sequentially from 1200 to 1600 °C in steps of 100 °C for 30 h at each annealing temperature. Raman spectroscopy was performed using two laser wavelength excitation regimes, the 514 nm laser (visible region) and the 244 nm laser (deep ultraviolet region, DUV). Measurements in the visible region for samples annealed at 1200 °C for 5 h showed that the characteristic 6H-SiC peaks, namely, the Transverse Optical (TO) and Longitudinal Optical (LO) are similar to the virgin samples, albeit with lower intensity due to some retained defects upon recystallisation of the SiC surface region. The similarities between the virgin spectra and the annealed sample were due to the deep penetration of the 514 nm laser into 6H-SiC resulting in the signal from the bulk undamaged 6H-SiC contributing to the overall spectra. However, DUV laser excitation, which only probes the near surface region, shows that after annealing the peaks are broader and asymmetrical compared to the virgin samples. DUV Raman spectra of samples annealed at 1600 °C indicate that SiC has completely decomposed and the top surface layer is now covered by a carbon layer. However the deeper penetrating laser in the visible region showed that the extent of decomposition at 1600 °C was greater for the silver implanted samples than for the iodine implanted samples.

  12. Doping of GaN by ion implantation: Does It Work?

    International Nuclear Information System (INIS)

    Suvkhanov, A.; Wu, W.; Price, K.; Parikh, N.; Irene, E.; Hunn, J.; Thomson, D.; Davis, R.F.; Krasnobaev, L.

    1998-04-01

    Epitaxially grown GaN by metal organic chemical vapor deposition (MOCVD) on SiC were implanted with 100 keV Si + (for n-type) and 80 keV Mg + (for p-type) with various fluences from 1 x 10 12 to 7 x 10 15 ions/cm 2 at liquid nitrogen temperature (LT), room temperature (RT), and 700 C (HT). High temperature (1,200 C and 1,500 C) annealing was carried out after capping the GaN with epitaxial AlN by MOCVD to study damage recovery. Samples were capped by a layer of AlN in order to protect the GaN surface during annealing. Effects of implant temperature, damage and dopant activation are critically studied to evaluate a role of ion implantation in doping of GaN. The damage was studied by Rutherford Backscattering/Channeling, spectroscopic ellipsometry and photoluminescence. Results show dependence of radiation damage level on temperature of the substrate during implantation: implantations at elevated temperatures up to 550 C decrease the lattice disorder; hot implants above 550 C can not be useful in doping of GaN due to nitrogen loss from the surface. SE measurements have indicated very high sensitivity to the implantation damage. PL measurements at LT of 80 keV Mg + (5 x 10 14 cm 2 ) implanted and annealed GaN showed two peaks: one ∼ 100 meV and another ∼ 140 meV away from the band edge

  13. Damage accumulation and annealing in 6H-SiC irradiated with Si+

    International Nuclear Information System (INIS)

    Jiang, W.; Weber, W.J.; Thevuthasan, S.; McCready, D.E.

    1998-01-01

    Damage accumulation and annealing in 6H-silicon carbide (α-SiC) single crystals have been studied in situ using 2.0 MeV He + RBS in a left angle 0001 right angle -axial channeling geometry (RBS/C). The damage was induced by 550 keV Si + ion implantation (30 off normal) at a temperature of -110 C, and the damage recovery was investigated by subsequent isochronal annealing (20 min) over the temperature range from -110 C to 900 C. At ion fluences below 7.5 x 10 13 Si + /cm 2 (0.04 dpa in the damage peak), only point defects appear to be created. Furthermore, the defects on the Si sublattice can be completely recovered by thermal annealing at room temperature (RT), and recovery of defects on the C sublattice is suggested. At higher fluences, amorphization occurs; however, partial damage recovery at RT is still observed, even at a fluence of 6.6 x 10 14 Si + /cm 2 (0.35 dpa in the damage peak) where a buried amorphous layer is produced. At an ion fluence of 6.0 x 10 15 Si + /cm 2 (-90 C), an amorphous layer is created from the surface to a depth of 0.6 μm. Because of recovery processes at the buried crystalline-amorphous interface, the apparent thickness of this amorphous layer decreases slightly (<10%) with increasing temperature over the range from -90 C to 600 C. (orig.)

  14. Damage and in-situ annealing during ion implantation

    International Nuclear Information System (INIS)

    Sadana, D.K.; Washburn, J.; Byrne, P.F.; Cheung, N.W.

    1982-11-01

    Formation of amorphous (α) layers in Si during ion implantation in the energy range 100 keV-11 MeV and temperature range liquid nitrogen (LN)-100 0 C has been investigated. Cross-sectional transmission electron microscopy (XTEM) shows that buried amorphous layers can be created for both room temperature (RT) and LN temperature implants, with a wider 100 percent amorphous region for the LN cooled case. The relative narrowing of the α layer during RT implantation is attributed to in-situ annealing. Implantation to the same fluence at temperatures above 100 0 C does not produce α layers. To further investigate in situ annealing effects, specimens already containing buried α layers were further irradiated with ion beams in the temperature range RT-400 0 C. It was found that isolated small α zones (less than or equal to 50 diameter) embedded in the crystalline matrix near the two α/c interfaces dissolved into the crystal but the thickness of the 100 percent α layer was not appreciably affected by further implantation at 200 0 C. A model for in situ annealing during implantation is presented

  15. Enhancement mode operation in AlInN/GaN (MIS)HEMTs on Si substrates using a fluorine implant

    International Nuclear Information System (INIS)

    Zaidi, Z H; Lee, K B; Qian, H; Jiang, S; Houston, P A; Guiney, I; Wallis, D J; Humphreys, C J

    2015-01-01

    We have demonstrated enhancement mode operation of AlInN/GaN (MIS)HEMTs on Si substrates using the fluorine treatment technique. The plasma RF power and treatment time was optimized to prevent the penetration of the fluorine into the channel region to maintain high channel conductivity and transconductance. An analysis of the threshold voltage was carried out which defined the requirement for the fluorine sheet concentration to exceed the charge at the dielectric/AlInN interface to achieve an increase in the positive threshold voltage after deposition of the dielectric. This illustrates the importance of control of both the plasma conditions and the interfacial charge for a reproducible threshold voltage. A positive threshold voltage of +3 V was achieved with a maximum drain current of 367 mA mm −1 at a forward gate bias of 10 V. (paper)

  16. Measurement and modelling of the radiation damage of silicon by MeV Ag ions

    International Nuclear Information System (INIS)

    Lindner, J.K.N.; Eder, J.; Stritzker, B.

    1999-01-01

    Depth profiles of the radiation damage produced by 4 MeV Ag ions in Si(111) at temperatures of 210--450 K are studied by optical reflectivity depth profiling and TEM for doses between 10 12 and 10 15 Ag/cm 2 . For high implantation temperatures, the depth of maximum damage is shown to be dose dependent. Point defect diffusion is shown to result in long tails of defect depth profiles. High-temperature amorphization is observed to proceed via the formation and bridge-like coalescence of isolated amorphous volumina. The damage at the depth of the maximum in the nuclear stopping power is described as a function of dose and temperature by the Hecking model. The model parameters and a comparison with those obtained for lighter ions reflect the particular properties of heavy ion collision cascades

  17. Porous SiO_2 nanofiber grafted novel bioactive glass–ceramic coating: A structural scaffold for uniform apatite precipitation and oriented cell proliferation on inert implant

    International Nuclear Information System (INIS)

    Das, Indranee; De, Goutam; Hupa, Leena; Vallittu, Pekka K.

    2016-01-01

    A composite bioactive glass–ceramic coating grafted with porous silica nanofibers was fabricated on inert glass to provide a structural scaffold favoring uniform apatite precipitation and oriented cell proliferation. The coating surfaces were investigated thoroughly before and after immersion in simulated body fluid. In addition, the proliferation behavior of fibroblast cells on the surface was observed for several culture times. The nanofibrous exterior of this composite bioactive coating facilitated homogeneous growth of flake-like carbonated hydroxyapatite layer within a short period of immersion. Moreover, the embedded porous silica nanofibers enhanced hydrophilicity which is required for proper cell adhesion on the surface. The cells proliferated well following a particular orientation on the entire coating by the assistance of nanofibrous scaffold-like structural matrix. This newly engineered composite coating was effective in creating a biological structural matrix favorable for homogeneous precipitation of calcium phosphate, and organized cell growth on the inert glass surface. - Highlights: • Fabricated porous SiO_2 nanofibers grafted composite bioactive glass–ceramic coating on inert glass. • The newly engineered coating facilitates uniformly dense apatite precipitation. • Embedded porous silica nanofibers enhance hydrophilicity of the coated surface. • Cells proliferate well on the entire coating following a particular orientation by the assistance of nanofibers. • The coatings have potential to be used as biological scaffold on the surface of implants.

  18. Porous SiO{sub 2} nanofiber grafted novel bioactive glass–ceramic coating: A structural scaffold for uniform apatite precipitation and oriented cell proliferation on inert implant

    Energy Technology Data Exchange (ETDEWEB)

    Das, Indranee [Nano-Structured Materials Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata 700032 (India); De, Goutam, E-mail: gde@cgcri.res.in [Nano-Structured Materials Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata 700032 (India); Hupa, Leena [Johan Gadolin Process Chemistry Centre, Åbo Akademi University, FI-20500 Åbo (Finland); Vallittu, Pekka K. [Turku Clinical Biomaterials Centre—TCBC, University of Turku, FI-20520 Turku (Finland); Institute of Dentistry, University of Turku, Department of Biomaterials Science and City of Turku, Welfare Division, Turku (Finland)

    2016-05-01

    A composite bioactive glass–ceramic coating grafted with porous silica nanofibers was fabricated on inert glass to provide a structural scaffold favoring uniform apatite precipitation and oriented cell proliferation. The coating surfaces were investigated thoroughly before and after immersion in simulated body fluid. In addition, the proliferation behavior of fibroblast cells on the surface was observed for several culture times. The nanofibrous exterior of this composite bioactive coating facilitated homogeneous growth of flake-like carbonated hydroxyapatite layer within a short period of immersion. Moreover, the embedded porous silica nanofibers enhanced hydrophilicity which is required for proper cell adhesion on the surface. The cells proliferated well following a particular orientation on the entire coating by the assistance of nanofibrous scaffold-like structural matrix. This newly engineered composite coating was effective in creating a biological structural matrix favorable for homogeneous precipitation of calcium phosphate, and organized cell growth on the inert glass surface. - Highlights: • Fabricated porous SiO{sub 2} nanofibers grafted composite bioactive glass–ceramic coating on inert glass. • The newly engineered coating facilitates uniformly dense apatite precipitation. • Embedded porous silica nanofibers enhance hydrophilicity of the coated surface. • Cells proliferate well on the entire coating following a particular orientation by the assistance of nanofibers. • The coatings have potential to be used as biological scaffold on the surface of implants.

  19. Surface damage studies of ETFE polymer bombarded with low energy Si ions (≤100 keV)

    International Nuclear Information System (INIS)

    Minamisawa, Renato Amaral; Almeida, Adelaide De; Budak, Satilmis; Abidzina, Volha; Ila, Daryush

    2007-01-01

    Surface studies of ethylenetetrafluoroethylene (ETFE), bombarded with Si in a high-energy tandem Pelletron accelerator, have recently been reported. Si ion bombardment with a few MeV to a few hundred keV energies was shown to be sufficient to produce damage on ETFE film. We report here the use of a low energy implanter with Si ion energies lower than 100 keV, to induce changes on ETFE films. In order to determine the radiation damage, ETFE bombarded films were simulated with SRIM software and analyzed with optical absorption photometry (OAP), Raman and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy to show quantitatively the physical and chemical property changes. Carbonization occurs following higher dose implantation, and hydroperoxides were formed following dehydroflorination of the polymer

  20. Study of crystal damage by ion implantation using micro RBS/channeling

    International Nuclear Information System (INIS)

    Grambole, D.; Herrmann, F.; Heera, V.; Meijer, J.

    2007-01-01

    The combination of microbeam implantation and in-situ micro RBS/channeling analysis in the Rossendorf nuclear microprobe facility enables crystal damage studies with high current densities not achievable in standard ion implantation experiments. Si(1 0 0) samples were implanted with 600 keV Si + ions and a fluence of 1 x 10 16 cm -2 . Using a beam spot of 200 μm x 200 μm current densities from 4 to 120 μA/cm 2 were obtained. The substrate temperature was varied between RT and 265 deg. C. The implanted regions were subsequently analysed by micro RBS/channeling with a 3 MeV He + beam having a spot size of 50 μm x 50 μm. Crystal damage up to amorphisation was observed in dependence on the substrate temperature. Above a critical temperature T C no amorphisation occurs. T C was determined for each series of samples implanted with the same ion current density j. It was found that the empirical Arrhenius relation j ∼ exp(-E a /kT C ), known from standard implantation experiments, is also valid at high current densities. The observed Arrhenius law can be derived from a model of epitaxial crystallisation stimulated by defect diffusion

  1. Device-based local delivery of siRNA against mammalian target of rapamycin (mTOR) in a murine subcutaneous implant model to inhibit fibrous encapsulation

    OpenAIRE

    Takahashi, Hironobu; Wang, Yuwei; Grainger, David W.

    2010-01-01

    Fibrous encapsulation of surgically implant devices is associated with elevated proliferation and activation of fibroblasts in tissues surrounding these implants, frequently causing foreign body complications. Here we test the hypothesis that inhibition of the expression of mammalian target of rapamycin (mTOR) in fibroblasts can mitigate the soft tissue implant foreign body response by suppressing fibrotic responses around implants. In this study, mTOR was knocked down using small interfering...

  2. Vacancy effects on the formation of He and Kr cavities in 3C-SiC irradiated and annealed at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Zang, Hang; Jiang, Weilin; Liu, Wenbo; Devaraj, Arun; Edwards, Danny J.; Henager, Charles H.; Kurtz, Richard J.; Li, Tao; He, Chaohui; Yun, Di; Wang, Zhiguang

    2016-12-01

    Polycrystalline 3C-SiC was sequentially irradiated at 400 and 750°C with 120 keV He2+ and 4 MeV Kr15+ ions to E21 and 4E20 ions/m2 with profiles of the implanted species peaked at 450 and 1500 nm, respectively. The masked overlapping irradiation created three study areas of He2+, Kr15+ and He2+ + Kr15+ implanted SiC. The doses at the depth of the peak He concentration in He2+ and He2+ + Kr15+ implanted SiC correspond to 4 and 25 dpa. The sample was subsequently annealed at 1600°C for 3 h in vacuum and characterized using cross-sectional transmission electron microscopy and energy-dispersive x-ray spectroscopy. Compared to the He2+ implanted SiC, He cavities show a smaller size and higher density in the co-implanted SiC. At 25 dpa, He presence in the co-implanted 3C-SiC significantly promotes He cavity growth, as contrasted to the smaller voids formed without He in the Kr15+ irradiated SiC at the same dose. In addition, local Kr migration and trapping at cavities occur, but long-range Kr diffusion in SiC is not observed up to 1600°C.

  3. SIMS analysis of isotopic impurities in ion implants

    International Nuclear Information System (INIS)

    Sykes, D.E.; Blunt, R.T.

    1986-01-01

    The n-type dopant species Si and Se used for ion implantation in GaAs are multi-isotopic with the most abundant isotope not chosen because of potential interferences with residual gases. SIMS analysis of a range of 29 Si implants produced by several designs of ion implanter all showed significant 28 Si impurity with a different depth distribution from that of the deliberately implanted 29 Si isotope. This effect was observed to varying degrees with all fifteen implanters examined and in every 29 Si implant analysed to date 29 Si + , 29 Si ++ and 30 Si implants all show the same effect. In the case of Se implantation, poor mass resolution results in the implantation of all isotopes with the same implant distribution (i.e. energy), whilst implants carried out with good mass resolution show the implantation of all isotopes with the characteristic lower depth distribution of the impurity isotopes as found in the Si implants. This effect has also been observed in p-type implants into GaAs (Mg) and for Ga implanted in Si. A tentative explanation of the effect is proposed. (author)

  4. The Effect of Annealing at 15000C on Migration and Release of Ion Implanted Silver in CVD Silicon Carbide

    International Nuclear Information System (INIS)

    HJ MacLean; RG Ballinger; LE Kolaya; SA Simonson; N Lewis; M Hanson

    2004-01-01

    The transport of silver in CVD β-SiC has been studied using ion implantation. Silver ions were implanted in β-SiC using the ATLAS accelerator facility at the Argonne National Laboratory. Ion beams with energies of 93 and 161 MeV were used to achieve deposition with peak concentrations at depths of approximately 9 and 13 (micro)m, respectively. As-implanted samples were then annealed at 1500 C for 210 or 480 hours. XPS, SEM, TEM, STEM, and optical methods were used to analyze the material before and after annealing. Silver concentration profiles were determined using XPS before and after annealing. STEM and SEM equipped with quantitative chemical analysis capability were used to more fully characterize the location and morphology of the silver before and after annealing. The results show that, within the uncertainty of measurement techniques, there is no silver migration, via either inter- or intragrannular paths, for the times and temperature studied. Additionally, the silver was observed to phase separate within the SiC after annealing. The irradiation damage from the implantation process resulted in a three-layer morphology in the as-implanted condition: (1) a layer of unaltered SiC, followed by (2) a layer of crystallized SiC, followed by (3) an amorphized layer which contained essentially all of the implanted silver. After annealing the layer structure changed. Layer 1 was unaltered. The grains in layer 2 recrystallized to form an epitaxial (columnar) layer. Layer 3 recrystallized to form a fine grain equiaxed layer. The results of this work do not support the long held assumption that silver release from CVD SiC, used for gas-reactor coated particle fuel, is dominated by grain boundary diffusion

  5. Quantum effects in ion implanted devices

    International Nuclear Information System (INIS)

    Jamieson, D.N.; Chan, V.; Hudson, F.E.; Andresen, S.E.; Yang, C.; Hopf, T.; Hearne, S.M.; Pakes, C.I.; Prawer, S.; Gauja, E.; Yang, C.; Dzurak, A.S.; Yang, C.; Clark, R.G.; Yang, C.

    2005-01-01

    Fabrication of nanoscale devices that exploit the rules of quantum mechanics to process information presents formidable technical challenges because it will be necessary to control quantum states at the level of individual atoms, electrons or photons. We have developed a pathway to the construction of quantum devices using ion implantation and demonstrate, using charge transport analysis, that the devices exhibit single electron effects. We construct devices that employ two P donors in Si by employing the technique of ion beam induced charge (IBIC) in which single 14 keV P ions can be implanted into ultra-pure silicon by monitoring on-substrate detector electrodes. We have used IBIC with a MeV nuclear microprobe to map and measure the charge collection efficiency in the development of the electrode structure and show that 100% charge collection efficiency can be achieved leading to the fabrication of prototype devices that display quantum effects in the transport of single charge quanta between the islands of implanted donors. (author). 9 refs., 4 figs., 1 tab

  6. Study of radiation damage restoration and antimony ions redistribution in Si(1 0 0) and Si(1 1 1) crystals

    CERN Document Server

    Labbani, R; Chafi, Z

    2002-01-01

    In this work, we study the radiation damage restoration and antimony ions redistribution into and oriented silicon substrates. The samples are implanted with antimony to a dose of 5x10 sup 1 sup 4 Sb sup + cm sup - sup 2 at 60 keV energy, then annealed under oxygen atmosphere at 900 deg. C, 30 min. The thin layer of SiO sub 2 (which is formed on Si surface by dry oxidation and expected to prevent any loss of Sb sup + dopant during Si recovery) is removed by a 10% HF solution. The specimens are analyzed by H sup + Rutherford Backscattering Spectrometry operating at 0.3 MeV energy in both random and channelling modes. The values of the projected range, R sub p , the standard deviation, DELTA R sub p , and the dose of antimony ions, which are estimated with a simple program, are in agreement with tabulated ones. It is also shown that the surface damage restoration is better for Si(1 0 0) samples than for Si(1 1 1) ones, in other words, the radiation damage is more significant in Si(1 1 1) substrates. Moreover,...

  7. Damage growth in Si during self-ion irradiation: A study of ion effects over an extended energy range

    International Nuclear Information System (INIS)

    Holland, O.W.; El-Ghor, M.K.; White, C.W.

    1989-01-01

    Damage nucleation/growth in single-crystal Si during ion irradiation is discussed. For MeV ions, the rate of growth as well as the damage morphology are shown to vary widely along the track of the ion. This is attributed to a change in the dominant, defect-related reactions as the ion penetrates the crystal. The nature of these reactions were elucidated by studying the interaction of MeV ions with different types of defects. The defects were introduced into the Si crystal prior to high-energy irradiation by self-ion implantation at a medium energy (100 keV). Varied damage morphologies were produced by implanting different ion fluences. Electron microscopy and ion-channeling measurements, in conjunction with annealing studies, were used to characterize the damage. Subtle changes in the predamage morphology are shown to result in markedly different responses to the high-energy irradiation, ranging from complete annealing of the damage to rapid growth. These divergent responses occur over a narrow range of dose (2--3 times 10 14 cm -2 ) of the medium-energy ions; this range also marks a transition in the growth behavior of the damage during the predamage implantation. A model is proposed which accounts for these observations and provides insight into ion-induced growth of amorphous layers in Si and the role of the amorphous/crystalline interface in this process. 15 refs, 9 figs

  8. High resolution investigation of the 30Si(þ, þ)30Si reaction

    NARCIS (Netherlands)

    Walinga, J.; Rinsvelt, H.A. van; Endt, P.M.

    The differential cross section for elastic scattering of protons on 30Si was measured with surface barrier counters at four angles. Thirty-six 30Si(þ, γ)31P resonances are known in the Ep=1–2MeV region. Fifteen of these were also observed in the 30Si(þ, þ)30Si reaction, with natural widths varying

  9. The compaction of fused silica resulting from ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, C.M.; Ridgway, M.C. [Australian National Univ., Canberra, ACT (Australia); Leech, P.L. [Telstra Research Laboratories, Clayton, Victoria (Australia)

    1996-12-31

    Ion implantation of fused silica results in compaction and consequently an increase in refractive index. This method of modifying the near-surface region has been shown as a potential means for fabricating single mode channel waveguides. This study has measured the compaction of the implanted regions for Si implantations as a function of dose (2x10{sup 12} - 6x10{sup l6} ions/cm{sup 2}), energy (1-9 MeV) and post-implantation annealing temperature (200-900 degree C). For a given energy, a dose-dependence of the step height (depth of compacted region) is observed for doses less than {approx}10{sup 15} ions/cm{sup 2}. At higher doses the step height saturates. For a given dose, a linear trend is evident for the step height as a function of energy suggesting that the major mechanism for this compaction is electronic stopping. As the annealing temperature increases, the step height gradually decreases from {approx}0.1-0.2 {mu} to -10-20% of the original value. From the annealing data, it is possible to extract an activation energy of 0.08 eV associated with the thermal removal of the compacted region. 4 refs., 4 figs.

  10. The compaction of fused silica resulting from ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, C M; Ridgway, M C [Australian National Univ., Canberra, ACT (Australia); Leech, P L [Telstra Research Laboratories, Clayton, Victoria (Australia)

    1997-12-31

    Ion implantation of fused silica results in compaction and consequently an increase in refractive index. This method of modifying the near-surface region has been shown as a potential means for fabricating single mode channel waveguides. This study has measured the compaction of the implanted regions for Si implantations as a function of dose (2x10{sup 12} - 6x10{sup l6} ions/cm{sup 2}), energy (1-9 MeV) and post-implantation annealing temperature (200-900 degree C). For a given energy, a dose-dependence of the step height (depth of compacted region) is observed for doses less than {approx}10{sup 15} ions/cm{sup 2}. At higher doses the step height saturates. For a given dose, a linear trend is evident for the step height as a function of energy suggesting that the major mechanism for this compaction is electronic stopping. As the annealing temperature increases, the step height gradually decreases from {approx}0.1-0.2 {mu} to -10-20% of the original value. From the annealing data, it is possible to extract an activation energy of 0.08 eV associated with the thermal removal of the compacted region. 4 refs., 4 figs.

  11. Effects of implantation temperature and thermal annealing on the Ga{sup +} ion beam induced optical contrast formation in a-SiC:H

    Energy Technology Data Exchange (ETDEWEB)

    Tsvetkova, T., E-mail: tania_tsvetkova@yahoo.co.uk [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); University of Exeter, College of Engineering, Mathematics and Physical Sciences, Harrison Building, North Park Rd, Exeter EX4 4QF (United Kingdom); Wright, C.D. [University of Exeter, College of Engineering, Mathematics and Physical Sciences, Harrison Building, North Park Rd, Exeter EX4 4QF (United Kingdom); Kitova, S. [Institute of Optical Materials and Technologies, Bulgarian Academy of Sciences, 109 Acad. G. Bontchev St., 1113 Sofia (Bulgaria); Bischoff, L. [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 51 01 19, 01314 Dresden (Germany); Zuk, J. [Institute of Physics, Maria Curie-Sklodovska University, Pl. M.Curie-Sklodovskiej 1, 20-031 Lublin (Poland)

    2013-07-15

    The effects of implantation temperature and post-implantation thermal annealing on the Ga{sup +} ion beam induced optical contrast formation in hydrogenated silicon–carbon alloy films have been studied. As a result of the implantation a well-expressed “darkening” effect (i.e. absorption edge shift to the longer-wavelength/lower-photon-energy region) has been registered. It is accompanied by a remarkable increase of the absorption coefficient up to 2 orders of magnitude in the measured photon energy range (1.5–3.1 eV). The optical contrast thus obtained (between implanted and unimplanted regions of the film material) has been made use of in the form of optical pattern formation by computer-operated Ga{sup +}-focused ion beam. Possible applications of this effect in the area of submicron lithography and high-density optical data storage have been suggested with regard to the most widely spread focused micro-beam systems based on Ga{sup +} liquid metal ion sources. The fact that Ga has a very low melting point (T{sub m} = 29.8 °C) and an unusual feature of volume contraction on melting are factors which favour Ga incorporation upon ion-implantation as dispersed clusters, or small nanoparticles. It has been previously noted that Ga precipitation into nanoparticles can vary dramatically (in terms of particle size) with Ga concentration and small changes in surface implant temperature, thus affecting the optical properties of the target. The precise role of implantation temperature effects, i.e. the target temperature during Ga{sup +} ion irradiation, on the optical contrast obtainable, has been therefore a key part of this study. Appropriate post-implantation annealing treatments were also studied, since these are expected to offer further benefits in reducing the required ion dose and enhancing contrast, thus increasing the cost-effectiveness of the bit-writing method.

  12. 0,01-5 MeV heavy ion accelerators

    International Nuclear Information System (INIS)

    Golubev, V.P.; Ivanov, A.S.; Nikiforov, S.A.; Svin'in, M.P.; Tarvid, G.V.; Troshikhin, A.G.; Fedotov, M.T.

    1983-01-01

    The results of development of an accelerating complex on the base of the UP-2-1 heavy ion charge exchange accelerator and IMPLANT-500 high-voltage heavy ion accelerator are given. The accelerating complex provides overlapping of the 0.01 MeV to 5 MeV energy range at accelerated beam currents of 10 -3 -10 -6 A order. The structural features of accelerators and their basic units and systems are considered. The UP-2-1 accelerator is designed for researches in the field of experimental physics and applied problem solutions. The IMPLANT-500 accelerator is designed for commercial ion-beam facilities with closed loop of silicon plate treatment

  13. Cross Section Measurements of the {sup 58}Ni (n, p) {sup 58}Co and {sup 29}Si (n, alpha) Reactions in the Energy Range 2.2 to 3.8 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Konijn, J; Lauber, A

    1963-08-15

    The Si(n, a) Mg and Ni(n, p) Co reaction cross-sections have been measured using a surface barrier solid state detector to record the charged particles. Absolute measurements of the neutron flux were made, recording the proton recoils from a thin polyethylene radiator with the solid state detector. Both reaction cross-sections show strong fluctuations as a function of energy, which may be due to the statistical fluctuation of the level densities. Estimations of the level densities of the intermediate nuclei from the relative fluctuations of the cross section curves are in good agreement with those expected on theoretical grounds. The agreement with earlier measurements of the nickel reaction is good, while absolute values for the cross-sections on the silicon reaction have not been reported before in this energy region.

  14. Quantum effects in ion implanted devices

    International Nuclear Information System (INIS)

    Jamieson, D.N.; Chan, V.; Hudson, F.E.; Andresen, S.E.; Yang, C.; Hopf, T.; Hearne, S.M.; Pakes, C.I.; Prawer, S.; Gauja, E.; Dzurak, A.S.; Clark, R.G.

    2006-01-01

    Fabrication of nanoscale devices that exploit the rules of quantum mechanics to process information presents formidable technical challenges because of the need to control quantum states at the level of individual atoms, electrons or photons. We have used ion implantation to fabricate devices on the scale of 10 nm that have allowed the development and test of nanocircuitry for the control of charge transport at the level of single electrons. This fabrication method is compatible with the construction of devices that employ counted P dopants in Si by employing the technique of ion beam induced charge (IBIC) in which single 14 keV P ions can be implanted into ultra-pure silicon substrates by monitoring on-substrate detector electrodes. We have used IBIC with a MeV nuclear microprobe to map and measure the charge collection efficiency in the development of the electrode structure and show that 100% charge collection efficiency can be achieved. Prototype devices fabricated by this method have been used to investigate quantum effects in the control and transport of single electrons with potential applications to solid state quantum information processing devices

  15. Effect of low-oxygen-concentration layer on iron gettering capability of carbon-cluster ion-implanted Si wafer for CMOS image sensors

    Science.gov (United States)

    Onaka-Masada, Ayumi; Nakai, Toshiro; Okuyama, Ryosuke; Okuda, Hidehiko; Kadono, Takeshi; Hirose, Ryo; Koga, Yoshihiro; Kurita, Kazunari; Sueoka, Koji

    2018-02-01

    The effect of oxygen (O) concentration on the Fe gettering capability in a carbon-cluster (C3H5) ion-implanted region was investigated by comparing a Czochralski (CZ)-grown silicon substrate and an epitaxial growth layer. A high Fe gettering efficiency in a carbon-cluster ion-implanted epitaxial growth layer, which has a low oxygen region, was observed by deep-level transient spectroscopy (DLTS) and secondary ion mass spectroscopy (SIMS). It was demonstrated that the amount of gettered Fe in the epitaxial growth layer is approximately two times higher than that in the CZ-grown silicon substrate. Furthermore, by measuring the cathodeluminescence, the number of intrinsic point defects induced by carbon-cluster ion implantation was found to differ between the CZ-grown silicon substrate and the epitaxial growth layer. It is suggested that Fe gettering by carbon-cluster ion implantation comes through point defect clusters, and that O in the carbon-cluster ion-implanted region affects the formation of gettering sinks for Fe.

  16. Characterization of diamond amorphized by ion implantation

    International Nuclear Information System (INIS)

    Allen, W.R.; Lee, E.H.

    1992-01-01

    Single crystal diamond has been implanted at 1 MeV with 2 x 10 20 Ar/m 2 . Rutherford backscattering spectrometry in a channeled geometry revealed a broad amorphized region underlying a thin, partially crystalline layer. Raman spectroscopy disclosed modifications in the bonding characteristic of the appearance of non-diamond carbon. The complementary nature of the two analysis techniques is demonstrated. The Knoop hardness of the implanted diamond was reduced by implantation

  17. Loss of mechanical properties in vivo and bone-implant interface strength of AZ31B magnesium alloy screws with Si-containing coating.

    Science.gov (United States)

    Tan, Lili; Wang, Qiang; Lin, Xiao; Wan, Peng; Zhang, Guangdao; Zhang, Qiang; Yang, Ke

    2014-05-01

    In this study the loss of mechanical properties and the interface strength of coated AZ31B magnesium alloy (a magnesium-aluminum alloy) screws with surrounding host tissues were investigated and compared with non-coated AZ31B, degradable polymer and biostable titanium alloy screws in a rabbit animal model after 1, 4, 12 and 21weeks of implantation. The interface strength was evaluated in terms of the extraction torque required to back out the screws. The loss of mechanical properties over time was indicated by one-point bending load loss of the screws after these were extracted at different times. AZ31B samples with a silicon-containing coating had a decreased degradation rate and improved biological properties. The extraction torque of Ti6Al4V, poly-l-lactide (PLLA) and coated AZ31B increased significantly from 1week to 4weeks post-implantation, indicating a rapid osteosynthesis process over 3weeks. The extraction torque of coated AZ31B increased with implantation time, and was higher than that of PLLA after 4weeks of implantation, equalling that of Ti6Al4V at 12weeks and was higher at 21weeks. The bending loads of non-coated AZ31B and PLLA screws degraded sharply after implantation, and that of coated AZ31B degraded more slowly. The biodegradation mechanism, the coating to control the degradation rate and the bioactivity of magnesium alloys influencing the mechanical properties loss over time and bone-implant interface strength are discussed in this study and it is concluded that a suitable degradation rate will result in an improvement in the mechanical performance of magnesium alloys, making them more suitable for clinical application. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  18. Characterisation of point defects in SiC by microscopic optical spectroscopy

    International Nuclear Information System (INIS)

    Evans, G.A.

    2001-09-01

    Defects have a dramatic effect on the properties of semiconductors. In SiC, intrinsic defects can be introduced during growth or device-processing steps such as implantation. In this work electron irradiation has been used for the controlled generation of defects in SiC. The irradiated material has been annealed and subsequent low temperature photoluminescence (LTPL) measurements have been performed. A key element in this work has been the ability to perform both the irradiation and characterisation on a microscopic scale. These results have allowed a variety of new optical centres to be discovered, and have also significantly enhanced the pool of knowledge about other defect centres. Utilising low voltage irradiations has enabled the electron irradiation voltage displacement thresholds for Carbon and Silicon displacements to be investigated. In 4H-SiC the electron irradiation voltage displacement thresholds were found to be 88kV for C displacement and 225kV for Si displacement. A large number of previously unreported luminescence features have been measured in 4H, 6H and 15R-SiC material. The criteria used for comparison are the voltage threshold, annealing characteristics, spatial distribution with respect to the irradiated region, and the characteristics of associated local modes and vibronic structures. Compelling evidence has been found to support the assignment of centres in 4H and 6H-SiC to a C-C dumbbell split interstitial defect. Two high energy local modes at 133meV and 180meV are associated with these centres. In 13 C enriched 6H-SiC material the 180meV local mode splits into three components whilst the 133meV local mode splits into two components. This splitting is interpreted as being caused by isotopic substitutions between the components of the C-C dumbbell. The high energy local mode corresponds to the bonding between the two constituent atoms of the dumbbell whilst the low energy local mode is associated with the bonding between either a C 13 or 12

  19. Ion-beam synthesis and photoluminescence of SiC nanocrystals assisted by MeV-heavy-ion-beam annealing

    International Nuclear Information System (INIS)

    Khamsuwan, J.; Intarasiri, S.; Kirkby, K.; Chu, P.K.; Singkarat, S.; Yu, L.D.

    2012-01-01

    This work explored a novel way to synthesize silicon carbide (SiC) nanocrystals for photoluminescence. Carbon ions at 90 keV were implanted in single crystalline silicon wafers at elevated temperature, followed by irradiation using xenon ion beams at an energy of 4 MeV with two low fluences of 5 × 10 13 and 1 × 10 14 ions/cm 2 at elevated temperatures for annealing. X-ray diffraction, Raman scattering, infrared spectroscopy and transmission electron microscopy were used to characterize the formation of nanocrystalline SiC. Photoluminescence was measured from the samples. The results demonstrated that MeV-heavy-ion-beam annealing could indeed induce crystallization of SiC nanocrystals and enhance emission of photoluminescence with violet bands dominance due to the quantum confinement effect.

  20. Vacancy effects on the formation of He and Kr cavities in 3C-SiC irradiated and annealed at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Zang, Hang, E-mail: zanghang@xjtu.edu.cn [Department of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Jiang, Weilin, E-mail: weilin.jiang@pnnl.gov [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Liu, Wenbo [Department of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Devaraj, Arun; Edwards, Danny J.; Henager, Charles H.; Kurtz, Richard J. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Li, Tao; He, Chaohui; Yun, Di [Department of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Wang, Zhiguang [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2016-12-15

    Highlights: • He and Kr cavities are formed in ion-implanted and 1600 °C annealed 3C-SiC. • A higher vacancy concentration leads to formation of cavities with a smaller size and higher density. • Presence of He in irradiated 3C-SiC can significantly promote cavity growth. • Small voids are formed in Kr ion penetrated 3C-SiC during thermal annealing at 1600 °C. • Local Kr migration and trapping at cavities in SiC are observed, but long-range Kr diffusion does not occur at 1600 °C. - Abstract: Polycrystalline 3C-SiC was sequentially irradiated at 400 and 750 °C with 120 keV He{sup 2+} and 4 MeV Kr{sup 15+} ions to 10{sup 17} and 4 × 10{sup 16} cm{sup −2}, respectively. The Kr{sup 15+} ions penetrated the entire depth region of the He{sup 2+} ion implantation. Three areas of He{sup 2+}, Kr{sup 15+} and He{sup 2+} + Kr{sup 15+} ion implanted SiC were created through masked overlapping irradiation. The sample was subsequently annealed at 1600 °C in vacuum and characterized using cross-sectional transmission electron microscopy and energy-dispersive X-ray spectroscopy. Compared to the He{sup 2+} ion only implanted SiC, He cavities show a smaller size and higher density in the co-implanted SiC. At 25 dpa, presence of He in the co-implanted 3C-SiC significantly promotes cavity growth; much smaller voids are formed in the Kr{sup 15+} ion only irradiated SiC at the same dose. In addition, local Kr migration and trapping at cavities occurs, but long-range Kr diffusion in SiC is not observed up to 1600 °C.

  1. Ion implantation

    International Nuclear Information System (INIS)

    Dearnaley, Geoffrey

    1975-01-01

    First, ion implantation in semiconductors is discussed: ion penetration, annealing of damage, gettering, ion implanted semiconductor devices, equipement requirements for ion implantation. The importance of channeling for ion implantation is studied. Then, some applications of ion implantation in metals are presented: study of the corrosion of metals and alloys; influence or ion implantation on the surface-friction and wear properties of metals; hyperfine interactions in implanted metals

  2. cap alpha. -transfer reactions /sup 27/Al(/sup 6/Li, d)/sup 31/P, /sup 29/Si(/sup 6/Li, d)/sup 33/S and /sup 31/P(/sup 6/Li, d)/sup 35/Cl at 36 MeV. [Angular distributions, EFR DWBA, spectroscopic strengths

    Energy Technology Data Exchange (ETDEWEB)

    Eswaran, M A; Gove, H E; Cook, R; Sikora, B [Rochester Univ., NY (USA). Nuclear Structure Research Lab.

    1979-08-13

    The ..cap alpha..-transfer reactions /sup 27/Al(/sup 6/Li,d)/sup 31/P,/sup 29/Si(/sup 6/Li,d) /sup 33/S and /sup 31/P(Li,d)/sup 35/Cl have been studied at a /sup 6/Li energy of 36 MeV. Absolute cross sections and angular distributions have been measured and an exact finite-range distorted-wave Born approximation analysis assuming a direct cluster transfer has been used to extract from the data ..cap alpha..-particle spectroscopic strengths for levels populated in /sup 31/P, /sup 33/S and /sup 35/Cl in three reactions respectively. The results show that in the case of most of the low-lying excited states of /sup 31/P a single value of L of the transferred ..cap alpha..-particle contributes, though a multiplicity of L-values are allowed by angular momentum selection rules. It is also found that the ..cap alpha..-particle spectroscopic strength of the ground state of /sup 31/P is a factor of 2 more than the strengths of the ground states of /sup 33/S and /sup 35/Cl. The ..cap alpha..-spectroscopic strengths of ground states of these, as well as other odd-A s-d shell nuclei, are compared with the presently available shell model calculations.

  3. Sacroiliac joint stability: Finite element analysis of implant number, orientation, and superior implant length.

    Science.gov (United States)

    Lindsey, Derek P; Kiapour, Ali; Yerby, Scott A; Goel, Vijay K

    2018-03-18

    To analyze how various implants placement variables affect sacroiliac (SI) joint range of motion. An experimentally validated finite element model of the lumbar spine and pelvis was used to simulate a fusion of the SI joint using various placement configurations of triangular implants (iFuse Implant System ® ). Placement configurations were varied by changing implant orientation, superior implant length, and number of implants. The range of motion of the SI joint was calculated using a constant moment of 10 N-m with a follower load of 400 N. The changes in motion were compared between the treatment groups to assess how the different variables affected the overall motion of the SI joint. Transarticular placement of 3 implants with superior implants that end in the middle of the sacrum resulted in the greatest reduction in range of motion (flexion/extension = 73%, lateral bending = 42%, axial rotation = 72%). The range of motions of the SI joints were reduced with use of transarticular orientation (9%-18%) when compared with an inline orientation. The use of a superior implant that ended mid-sacrum resulted in median reductions of (8%-14%) when compared with a superior implant that ended in the middle of the ala. Reducing the number of implants, resulted in increased SI joint range of motions for the 1 and 2 implant models of 29%-133% and 2%-39%, respectively, when compared with the 3 implant model. Using a validated finite element model we demonstrated that placement of 3 implants across the SI joint using a transarticular orientation with superior implant reaching the sacral midline resulted in the most stable construct. Additional clinical studies may be required to confirm these results.

  4. Sub-barrier fusion of Si+Si systems

    Science.gov (United States)

    Colucci, G.; Montagnoli, G.; Stefanini, A. M.; Bourgin, D.; Čolović, P.; Corradi, L.; Courtin, S.; Faggian, M.; Fioretto, E.; Galtarossa, F.; Goasduff, A.; Haas, F.; Mazzocco, M.; Scarlassara, F.; Stefanini, C.; Strano, E.; Urbani, M.; Szilner, S.; Zhang, G. L.

    2017-11-01

    The near- and sub-barrier fusion excitation function has been measured for the system 30Si+30Si at the Laboratori Nazionali di Legnaro of INFN, using the 30Si beam of the XTU Tandem accelerator in the energy range 47 - 90 MeV. A set-up based on a beam electrostatic deflector was used for detecting fusion evaporation residues. The measured cross sections have been compared to previous data on 28Si+28Si and Coupled Channels (CC) calculations have been performed using M3Y+repulsion and Woods-Saxon potentials, where the lowlying 2+ and 3- excitations have been included. A weak imaginary potential was found to be necessary to reproduce the low energy 28Si+28Si data. This probably simulates the effect of the oblate deformation of this nucleus. On the contrary, 30Si is a spherical nucleus, 30Si+30Si is nicely fit by CC calculations and no imaginary potential is needed. For this system, no maximum shows up for the astrophysical S-factor so that we have no evidence for hindrance, as confirmed by the comparison with CC calculations. The logarithmic derivative of the two symmetric systems highlights their different low energy trend. A difference can also be noted in the two barrier distributions, where the high-energy peak present in 28Si+28Si is not observed for 30Si+30Si, probably due to the weaker couplings in last case.

  5. Sub-barrier fusion of Si+Si systems

    Directory of Open Access Journals (Sweden)

    Colucci G.

    2017-01-01

    Full Text Available The near- and sub-barrier fusion excitation function has been measured for the system 30Si+30Si at the Laboratori Nazionali di Legnaro of INFN, using the 30Si beam of the XTU Tandem accelerator in the energy range 47 - 90 MeV. A set-up based on a beam electrostatic deflector was used for detecting fusion evaporation residues. The measured cross sections have been compared to previous data on 28Si+28Si and Coupled Channels (CC calculations have been performed using M3Y+repulsion and Woods-Saxon potentials, where the lowlying 2+ and 3− excitations have been included. A weak imaginary potential was found to be necessary to reproduce the low energy 28Si+28Si data. This probably simulates the effect of the oblate deformation of this nucleus. On the contrary, 30Si is a spherical nucleus, 30Si+30Si is nicely fit by CC calculations and no imaginary potential is needed. For this system, no maximum shows up for the astrophysical S-factor so that we have no evidence for hindrance, as confirmed by the comparison with CC calculations. The logarithmic derivative of the two symmetric systems highlights their different low energy trend. A difference can also be noted in the two barrier distributions, where the high-energy peak present in 28Si+28Si is not observed for 30Si+30Si, probably due to the weaker couplings in last case.

  6. Comparison between radical- and energetic ion-induced growth of SiCxNy films in plasma immersion ion implantation and deposition

    International Nuclear Information System (INIS)

    Afanasyev-Charkin, I.V.; Nastasi, M.

    2004-01-01

    Ternary SiC x N y compounds are materials with some remarkable properties such as high oxidation resistance and high hardness. In this work we compare the properties of SiC x N y films obtained using radio-frequency (rf) and pulsed glow discharge (PGD) plasmas with combinations of SiH 4 , C 2 H 2 , N 2 , and Ar source gases. The pulsed voltage used for the rf deposition was 200 V and for the PGD deposition it was 4 kV. During the rf growth, the growth takes place mostly by attaching neutral radicals to form chemical bonds. In the PGD method, the deposition takes place by subplantation and surface activation by energetic ions. We show that in the case of low-energy RF deposition, a high relative number of C-N bonds with sp 3 hybridization is formed and very few Si-C bonds can be observed. Apparently the growth of carbon nitride and silicon nitride networks takes place independently. This indicates that SiH 3 radicals attach to the dangling bonds of silicon and nitrogen, whereas C 2 H radicals attach to the dangling bonds of carbon and nitrogen. During pulsed glow discharge deposition, bonds between all three components are formed apparently by means of subplantation and damage-induced disorder. The hardness of the PGD films exceed that of the RF films, showing that to form a dense SiC x N y film one has to either supply energy during the growth of the films by heating the substrate, as in the case of chemical vapor deposition or by using energetic ions

  7. Sol-gel synthesis and characterization of SiO{sub 2}/PEG hybrid materials containing quercetin as implants with antioxidant properties

    Energy Technology Data Exchange (ETDEWEB)

    Catauro, Michelina; Bollino, Flavia [Department of Industrial and Information Engineering, Second University of Naples, Via Roma 21, 81031 Aversa (Italy); Gloria, Antonio [Institute of Polymers, Composites and Biomaterials - National Research Council of Italy, V.le J. F. Kennedy 54 - Mostra d’Oltremare Pad. 20, 80125 Naples (Italy)

    2016-05-18

    In the present work, Silica/Polyethylene glycol (PEG) hybrid nanocomposites containing an antioxidant agent, the quercetin, were synthesized via sol-gel to be used as implants with antioxidant properties. Fourier transform infrared (FT-IR) analysis proved that a modification of both polymer and quercetin occurs due to synthesis process. Scanning electron microscope (SEM) showed that the proposed materials were hybrid nanocomposites. The bioactivity was ascertained by soaking the samples in a simulated body fluid (SBF).

  8. Multi-dimensional microanalysis of masklessly implanted atoms using focused heavy ion beam

    International Nuclear Information System (INIS)

    Mokuno, Yoshiaki; Iiorino, Yuji; Chayahara, Akiyoshi; Kiuchi, Masato; Fujii, Kanenaga; Satou, Mamoru

    1992-01-01

    Multi-dimensional structure fabricated by maskless MeV gold implantation in silicon wafer was analyzed by 3 MeV carbon ion microprobe using a microbeam line developed at GIRIO. The minimum line width of the implanted region was estimated to be about 5 μm. The advantages of heavy ions for microanalysis were demonstrated. (author)

  9. Formation mechanism of SiC in C-Si system by ion irradiation

    International Nuclear Information System (INIS)

    Hishita, Shunichi; Aizawa, Takashi; Suehara, Shigeru; Haneda, Hajime

    2003-01-01

    The irradiation effects of 2 MeV He + , Ne + , and Ar + ions on the film structure of the C-Si system were investigated with RHEED and XPS. The ion dose dependence of the SiC formation was kinetically analyzed. The SiC formation at moderate temperature was achieved by 2 MeV ion irradiation when the thickness of the initial carbon films was appropriate. The evolution process of the SiC film thickness consisted of the 3 stages. The first stage was the steep increase of the SiC, and was governed by the inelastic collision. The second was the gentle increase of the SiC, and was governed by the diffusion. The last was the decrease of the SiC, and was caused by the sputtering. The formation mechanism of the SiC was discussed. (author)

  10. Activation of ion implanted Si for backside processing by Ultra-fast Laser Thermal Annealing: Energy homogeneity and micro-scale sheet resistance

    DEFF Research Database (Denmark)

    Huet, K.; Lin, Rong; Boniface, C

    2009-01-01

    In this paper ion activation of implanted silicon using ultra-fast laser thermal annealing (LTA) process was discussed. The results stated that there was high dopant activation using LTA process for over 70%, excellent within shot activation uniformity, and there was a possibility for overlap...... parameter optimization. It was observed that, for activation LTA process, shallow box-shaped profiles- high diffusivity of B in liquids and high-temperatures was observed only near the surface in a submicrosecond timescale. Possible solutions were suggested as to low-cost and high-end for overlap...

  11. High energy ion implantation for IC processing

    International Nuclear Information System (INIS)

    Oosterhoff, S.

    1986-01-01

    In this thesis the results of fundamental research on high energy ion implantation in silicon are presented and discussed. The implantations have been carried out with the 500 kV HVEE ion implantation machine, that was acquired in 1981 by the IC technology and Electronics group at Twente University of Technology. The damage and anneal behaviour of 1 MeV boron implantations to a dose of 10 13 /cm 2 have been investigated as a function of anneal temperature by sheet resistance, Hall and noise measurements. (Auth.)

  12. β-delayed charged particle decays of neutron-deficient nuclei 20Mg and 23Si and 22Si

    International Nuclear Information System (INIS)

    Babo, Mathieu

    2016-01-01

    The neutron-deficient nuclei 20 Mg, 23 Si and 22 Si were produced by fragmentation at NSCL, at MSU (USA), and implanted into an array of 3 double sided stripped Si detectors, surrounded by 16 high-purity Ge detectors. This novel arrangement allowed the detection of the charged particles emitted by the unbound excited states in coincidence with the γ rays emitted by the de-excitation of the daughter. The βp decay of 20 Mg is very well-known and therefore was used to test and optimize the analysis program. The β-delayed proton transitions to the first 3 excited states in 19 Ne were identified and compared to previous measurements. The half-life, the branching ratio of the transitions and the excitation energies, including the IAS, were measured and are in good agreement with the adopted values. The study of the β+ decay of 23 Si allowed the identification of 14 excited states in 23 Al. The emission of 2 protons from the IAS was unambiguously identified. The measurement of the IAS energy allowed a better determination of the mass excess of 23 Si, giving 23.27 (7) MeV. A possible β3p decay channel was also tentatively identified. Most of the theoretical predictions are in favor of a 2-proton radioactive 22 Si. The β2p decays to the first excited state and the ground state of 20 Na were identified. The branching ratio of the decay to the IAS is 2.05 (44) %, and the IAS excitation energy was measured to be 9040 (54) keV. The additional measurement of the half-life gives T 1/2 = 30.38 (45) ms, and allowed the determination of the partial half-life. In this study, we propose a parameterization of the statistical rate function f for the superallowed Fermi β decays. This allow the first indirect mass measurement of 22 Si ground state, 31.49 (14) MeV. The two-proton threshold is then S2p = 645 (100) keV and does not allow 2p radioactivity. (author) [fr

  13. Transverse microanalysis of high energy Ion implants

    Energy Technology Data Exchange (ETDEWEB)

    Dooley, S P; Jamieson, D N; Nugent, K W; Prawer, S [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1997-12-31

    High energy ion implants in semiconductor materials have been analyzed by Channeling Contrast Microscopy (CCM) perpendicular to the implant direction, allowing imaging of the entire ion track. The damage produced by Channeled and Random 1.4 MeV H{sup +} implants into the edge of a <100> type IIa diamond wafer were analyzed by channeling into the face of the crystal. The results showed negligible damage in the surface region of the implants, and swelling induced misalignment at the end of range of the implants. Channeled 1.4 MeV H{sup +} implants in diamond had a range only 9% deeper than Random implants, which could be accounted for by dechanneling of the beam. The channeling of H{sup +}{sub 2} ions has been previously found to be identical to that of protons of half energy, however the current experiment has shown a 1% increase in {chi}{sub min} for H{sup +}{sub 2} in diamond compared to H{sup +} at 1,2 MeV per proton. This is due to repulsion between protons within the same channel. 5 refs., 2 figs.

  14. Transverse microanalysis of high energy Ion implants

    Energy Technology Data Exchange (ETDEWEB)

    Dooley, S.P.; Jamieson, D.N.; Nugent, K.W.; Prawer, S. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    High energy ion implants in semiconductor materials have been analyzed by Channeling Contrast Microscopy (CCM) perpendicular to the implant direction, allowing imaging of the entire ion track. The damage produced by Channeled and Random 1.4 MeV H{sup +} implants into the edge of a <100> type IIa diamond wafer were analyzed by channeling into the face of the crystal. The results showed negligible damage in the surface region of the implants, and swelling induced misalignment at the end of range of the implants. Channeled 1.4 MeV H{sup +} implants in diamond had a range only 9% deeper than Random implants, which could be accounted for by dechanneling of the beam. The channeling of H{sup +}{sub 2} ions has been previously found to be identical to that of protons of half energy, however the current experiment has shown a 1% increase in {chi}{sub min} for H{sup +}{sub 2} in diamond compared to H{sup +} at 1,2 MeV per proton. This is due to repulsion between protons within the same channel. 5 refs., 2 figs.

  15. Tailoring of SiC nanoprecipitates formed in Si

    Energy Technology Data Exchange (ETDEWEB)

    Velisa, G., E-mail: gihan.velisa@cea.fr [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France); Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O. Box MG-6, 077125 Magurele (Romania); Trocellier, P. [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France); Thomé, L. [Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse, UMR8609, Bât. 108, 91405 Orsay (France); Vaubaillon, S. [CEA, INSTN, UEPTN, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France); Miro, S.; Serruys, Y.; Bordas, É. [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France); Meslin, E. [CEA, DEN, Service de Recherches de Métallurgie Physique, F-91191 Gif-sur-Yvette (France); Mylonas, S. [Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse, UMR8609, Bât. 108, 91405 Orsay (France); Coulon, P.E. [Ecole Polytechnique, Laboratoire des Solides Irradiés, CEA/DSM/IRAMIS-CNRS, 91128 Palaiseau Cedex (France); Leprêtre, F.; Pilz, A.; Beck, L. [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France)

    2013-07-15

    The SiC synthesis through single-beam of C{sup +}, and simultaneous-dual-beam of C{sup +} and Si{sup +} ion implantations into a Si substrate heated at 550 °C has been studied by means of three complementary analytical techniques: nuclear reaction analysis (NRA), Raman, and transmission electron microscopy (TEM). It is shown that a broad distribution of SiC nanoprecipitates is directly formed after simultaneous-dual-beam (520-keV C{sup +} and 890-keV Si{sup +}) and single-beam (520-keV C{sup +}) ion implantations. Their shape appear as spherical (average size ∼4–5 nm) and they are in epitaxial relationship with the silicon matrix.

  16. The structure modification of Si-SiO2 irradiated by Fe+ ion

    International Nuclear Information System (INIS)

    Jin Tao; Ma Zhongquan; Guo Qi

    1992-01-01

    The effect of the iron ion implantation on the oxide surface and SiO 2 -Si interface of MOS structure was studied by X-ray photo-electron spectroscopy (XPS), and the chemical states of compounds formed were examined. The results obtained show that in the surface layers of SiO 2 the pure Si micro-regions are formed under the implantation and the interface layers of SiO 2 the pure Si micro-regions are formed under the implantation and the interface thickness is almost doubled that leads to failure of MOS capacitors. The physical and chemical mechanisms of MOS structure change by Fe + ion implantation are also discussed and analyzed

  17. Rapid thermal and swift heavy ion induced annealing of Co ion implanted GaN films

    International Nuclear Information System (INIS)

    Baranwal, V.; Pandey, A. C.; Gerlach, J. W.; Rauschenbach, B.; Karl, H.; Kanjilal, D.; Avasthi, D. K.

    2008-01-01

    Thin epitaxial GaN films grown on 6H-SiC(0001) substrates were implanted with 180 keV Co ions at three different fluences. As-implanted samples were characterized with secondary ion mass spectrometry and Rutherford backscattering spectrometry to obtain the Co depth profiles and the maximum Co concentrations. As-implanted samples were annealed applying two different techniques: rapid thermal annealing and annealing by swift heavy ion irradiation. Rapid thermal annealing was done at two temperatures: 1150 deg. C for 20 s and 700 deg. C for 5 min. 200 MeV Ag ions at two fluences were used for annealing by irradiation. Crystalline structure of the pristine, as-implanted, and annealed samples was investigated using x-ray diffraction, and the results were compared. Improvement of the crystalline quality was observed for rapid thermal annealed samples at the higher annealing temperature as confirmed with rocking curve measurements. The results indicate the presence of Co clusters in these annealed samples. Swift heavy ion irradiation with the parameters chosen for this study did not lead to a significant annealing

  18. Paraffin/expanded graphite phase change composites with enhanced thermal conductivity prepared by implanted β-SiC nanowires with chemical vapor deposition method

    Science.gov (United States)

    Yin, Zhaoyu; Zhang, Xiaoguang; Huang, Zhaohui; Liu, Silin; Zhang, Weiyi; Liu, Yan'gai; Wu, Xiaowen; Fang, Minghao; Min, Xin

    2018-02-01

    Expanded graphite/β-SiC nanowires composites (ESNC) were prepared through chemical vapor deposition, and paraffin/expanded graphite/β-SiC nanowires composites (PESNC) were made through vacuum impregnation to overcome liquid leakage during phase transition and enhance the thermal conductivity of paraffin. Fourier transform infrared spectroscopy showed no chemical interactions between the paraffin and ESNC. Differential scanning calorimetry estimated the temperature and latent heat of PESNC during melting to 45.73 °C and 124.31 J g-1, respectively. The respective values of these quantities during freezing were recorded as 48.93 °C and 124.14 J g-1. The thermal conductivity of PESNC was estimated to 0.75 W mK-1, which was 3.26-folds that of pure paraffin (0.23 W mK-1). PESNC perfectly maintained its phase transition after 200 melting-freezing cycles. The resulting ideal thermal conductivity, good chemical stability, thermal properties and thermal reliability of PESNC are promising for use in energy efficient buildings and solar energy systems.

  19. Effect of Si, Mn, Sn on Tensile and Corrosion Properties of Mg-4Zn-0.5Ca Alloys for Biodegradable Implant Materials

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Dae Hyun; Nam, Ji Hoon; Lee, Byeong Woo; Park, Ji Yong; Shin, Hyun Jung; Park, Ik Min [Pusan National University, Busan (Korea, Republic of)

    2015-03-15

    Effect of elements Si, Mn, Sn on tensile and corrosion properties of Mg-4Zn-0.5Ca alloys were investigated. The results of tensile properties show that the yield strength, ultimate tensile strength and elongation of Mg-4Zn-0.5Ca alloy increased significantly with the addition of 0.6 wt% Mn. This is considered the grain refinement effect due to addition of Mn. However addition of 0.6 wt% Si decreased yield strength, ultimate tensile strength and elongation. The bio-corrosion behavior of Mg-4Zn-0.5Ca-X alloys were investigated using immersion tests and potentiodynamic polarization test in Hank's solution. Immersion test showed that corrosion rate of Mg-4Zn-0.5Ca-0.6Mn alloy was the lowest rate and addition of 1.0 wt% Sn accelerated corrosion rate due to micro-galvanic effect in α-Mg/CaMgSn phases interface. And corrosion potential (E{sub c}orr) of Mg-4Zn-0.5Ca-0.6Mn alloy was the most noble among Mg-4Zn-0.5Ca-X alloys.

  20. Effect of hydrostatic pressure on photoluminescence spectra from structures with Si nanocrystals fabricated in SiO2 matrix

    International Nuclear Information System (INIS)

    Zhuravlev, K.S.; Tyschenko, I.E.; Vandyshev, E.N.; Bulytova, N.V.; Misiuk, A.; Rebohle, L.; Skorupa, W.

    2002-01-01

    The effect of hydrostatic pressure applied at high temperature on photoluminescence of Si-implanted SiO 2 films was studied. A 'blue'-shift of PL spectrum from the SiO 2 films implanted with Si + ions to total dose of 1.2x10 17 cm -2 with increase in hydrostatic pressure was observed. For the films implanted with Si + ions to a total dose of 4.8x10 16 cm -2 high temperature annealing under high hydrostatic pressure (12 kbar) causes a 'red'-shift of photoluminescence spectrum. The 'red' photoluminescence bands are attributed to Si nanocrystals while the 'blue' ones are related to Si nanocrystals of reduced size or chains of silicon atoms or Si-Si defects. A decrease in size of Si nanocluster occurs in result of the pressure-induced decrease in the diffusion of silicon atoms. (author)

  1. Structural Changes in Polymer Films by Fast Ion Implantation

    Science.gov (United States)

    Parada, M. A.; Minamisawa, R. A.; Muntele, C.; Muntele, I.; De Almeida, A.; Ila, D.

    2006-11-01

    In applications from food wrapping to solar sails, polymers films can be subjected to intense charged panicle bombardment and implantation. ETFE (ethylenetetrafluoroethylene) with high impact resistance is used for pumps, valves, tie wraps, and electrical components. PFA (tetrafluoroethylene-per-fluoromethoxyethylene) and FEP (tetrafluoroethylene-hexa-fluoropropylene) are sufficiently biocompatible to be used as transcutaneous implants since they resist damage from the ionizing space radiation, they can be used in aerospace engineering applications. PVDC (polyvinyllidene-chloride) is used for food packaging, and combined with others plastics, improves the oxygen barrier responsible for the food preservation. Fluoropolymers are also known for their radiation dosimetry applications, dependent on the type and energy of the radiation, as well as of the beam intensity. In this work ETFE, PFA, FEP and PVDC were irradiated with ions of keV and MeV energies at several fluences and were analyzed through techniques as RGA, OAP, FTIR, ATR and Raman spectrophotometry. CF3 is the main specie emitted from PFA and FEP when irradiated with MeV protons. H and HF are released from ETFE due to the broken C-F and C-H bonds when the polymer is irradiated with keV Nitrogen ions and protons. At high fluence, especially for keV Si and N, damage due to carbonization is observed with the formation of hydroperoxide and polymer dehydroflorination. The main broken bonds in PVDC are C-O and C-Cl, with the release of Cl and the formation of double carbon bonds. The ion fluence that causes damage, which could compromise fluoropolymer film applications, has been determined.

  2. Deep levels in as-grown and Si-implanted In(0.2)Ga(0.8)As-GaAs strained-layer superlattice optical guiding structures

    Science.gov (United States)

    Dhar, S.; Das, U.; Bhattacharya, P. K.

    1986-01-01

    Trap levels in about 2-micron In(0.2)Ga(0.8)As(94 A)/GaAs(25 A) strained-layer superlattices, suitable for optical waveguides, have been identified and characterized by deep-level transient spectroscopy and optical deep-level transient spectroscopy measurements. Several dominant electron and hole traps with concentrations of approximately 10 to the 14th/cu cm, and thermal ionization energies Delta-E(T) varying from 0.20 to 0.75 eV have been detected. Except for a 0.20-eV electron trap, which might be present in the In(0.2)Ga(0.8)As well regions, all the other traps have characteristics similar to those identified in molecular-beam epitaxial GaAs. Of these, a 0.42-eV hole trap is believed to originate from Cu impurities, and the others are probably related to native defects. Upon Si implantation and halogen lamp annealing, new deep centers are created. These are electron traps with Delta-E(T) = 0.81 eV and hole traps with Delta-E(T) = 0.46 eV. Traps occurring at room temperature may present limitations for optical devices.

  3. Cochlear Implants

    Science.gov (United States)

    ... implant, including: • How long a person has been deaf, •The number of surviving auditory nerve fibers, and • ... Implant, Severe Sensoryneurial Hearing Loss Get Involved Professional Development Practice Management ENT Careers Marketplace Privacy Policy Terms ...

  4. 4H-SiC vertical double implanted metal–oxide–semiconductor drift region—energy aspects of its formation and analysis

    International Nuclear Information System (INIS)

    Alkhem, Abdel; Šašić, Rajko M; Ostojić, Stanko M; Lukić, Petar M

    2014-01-01

    A conventional vertical double implanted metal–oxide–semiconductor structure contains two n +  regions beneath two symmetrically posed source biases. These n +  regions are surrounded by a p-doped layer, which itself has an abrupt transition to the vertical drift region. Owing to the existence of these p-layers, the ‘drift’ region has varying cross sections: it is reduced going upward from the bottom (drain bias) to the top. Such a drift region is usually described either by a three piecewise model, which begins with constant cross section that at some point starts narrowing until at some other point it becomes reduced to the region between two p-regions, or by a two piecewise model, whose narrowing region starts right above the drain bias and finishes in the manner described before. The crucial geometrical parameters of the flow profile in the drift region, such as the slope of the cross-section reducing region and the length of the narrowest (accumulation) region are widely used but never determined, or even estimated, in the available literature. In this paper, the least-action principle has been utilized successfully in order to determine the exact values of these parameters and so make the existing models closed. The proof has also been provided, which shows that the three piecewise model described the flow profile better than a two piecewise model more adequately as long as it was permitted by the length of the entire drift region (the energy necessary to restore the specific value of drain current is smaller than for the three piecewise model). The two piecewise model can be accepted in practical calculations only for higher values of drain current far from a triode regime. (paper)

  5. Biocompatibility property of 100% strontium-substituted SiO2 -Al2 O3 -P2 O5 -CaO-CaF2 glass ceramics over 26 weeks implantation in rabbit model: Histology and micro-Computed Tomography analysis.

    Science.gov (United States)

    Basu, Bikramjit; Sabareeswaran, A; Shenoy, S J

    2015-08-01

    One of the desired properties for any new biomaterial composition is its long-term stability in a suitable animal model and such property cannot be appropriately assessed by performing short-term implantation studies. While hydroxyapatite (HA) or bioglass coated metallic biomaterials are being investigated for in vivo biocompatibility properties, such study is not extensively being pursued for bulk glass ceramics. In view of their inherent brittle nature, the implant stability as well as impact of long-term release of metallic ions on bone regeneration have been a major concern. In this perspective, the present article reports the results of the in vivo implantation experiments carried out using 100% strontium (Sr)-substituted glass ceramics with the nominal composition of 4.5 SiO2 -3Al2 O3 -1.5P2 O5 -3SrO-2SrF2 for 26 weeks in cylindrical bone defects in rabbit model. The combination of histological and micro-computed tomography analysis provided a qualitative and quantitative understanding of the bone regeneration around the glass ceramic implants in comparison to the highly bioactive HA bioglass implants (control). The sequential polychrome labeling of bone during in vivo osseointegration using three fluorochromes followed by fluorescence microscopy observation confirmed homogeneous bone formation around the test implants. The results of the present study unequivocally confirm the long-term implant stability as well as osteoconductive property of 100% Sr-substituted glass ceramics, which is comparable to that of a known bioactive implant, that is, HA-based bioglass. © 2014 Wiley Periodicals, Inc.

  6. Anisotropic deformation of metallo-dielectric core-shell colloids under MeV ion irradiation

    International Nuclear Information System (INIS)

    Penninkhof, J.J.; Dillen, T. van; Roorda, S.; Graf, C.; Blaaderen, A. van; Vredenberg, A.M.; Polman, A.

    2006-01-01

    We have studied the deformation of metallo-dielectric core-shell colloids under 4 MeV Xe, 6 and 16 MeV Au, 30 MeV Si and 30 MeV Cu ion irradiation. Colloids of silica surrounded by a gold shell, with a typical diameter of 400 nm, show anisotropic plastic deformation under MeV ion irradiation, with the metal flowing conform the anisotropically deforming silica core. The 20 nm thick metal shell imposes a mechanical constraint on the deforming silica core, reducing the net deformation strain rate compared to that of pure silica. In colloids consisting of a Au core and a silica shell, the silica expands perpendicular to the ion beam, while the metal core shows a large elongation along the ion beam direction, provided the silica shell is thick enough (>40 nm). A minimum electronic energy loss of 3.3 keV/nm is required for shape transformation of the metal core. Silver cores embedded in a silica shell show no elongation, but rather disintegrate. Also in planar SiO 2 films, Au and Ag colloids show entirely different behavior under MeV irradiation. We conclude that the deformation model of core-shell colloids must include ion-induced particle disintegration in combination with thermodynamical effects, possibly in combination with mechanical effects driven by stresses around the ion tracks

  7. Anisotropic deformation of metallo-dielectric core shell colloids under MeV ion irradiation

    Science.gov (United States)

    Penninkhof, J. J.; van Dillen, T.; Roorda, S.; Graf, C.; van Blaaderen, A.; Vredenberg, A. M.; Polman, A.

    2006-01-01

    We have studied the deformation of metallo-dielectric core-shell colloids under 4 MeV Xe, 6 and 16 MeV Au, 30 MeV Si and 30 MeV Cu ion irradiation. Colloids of silica surrounded by a gold shell, with a typical diameter of 400 nm, show anisotropic plastic deformation under MeV ion irradiation, with the metal flowing conform the anisotropically deforming silica core. The 20 nm thick metal shell imposes a mechanical constraint on the deforming silica core, reducing the net deformation strain rate compared to that of pure silica. In colloids consisting of a Au core and a silica shell, the silica expands perpendicular to the ion beam, while the metal core shows a large elongation along the ion beam direction, provided the silica shell is thick enough (>40 nm). A minimum electronic energy loss of 3.3 keV/nm is required for shape transformation of the metal core. Silver cores embedded in a silica shell show no elongation, but rather disintegrate. Also in planar SiO2 films, Au and Ag colloids show entirely different behavior under MeV irradiation. We conclude that the deformation model of core-shell colloids must include ion-induced particle disintegration in combination with thermodynamical effects, possibly in combination with mechanical effects driven by stresses around the ion tracks.

  8. Reorientation effects for 52 MeV vector polarized deuterons

    International Nuclear Information System (INIS)

    Nurzynski, J.; Kihm, T.; Knopfle, K.T.; Mairle, G.; Clement, H.

    1987-01-01

    The differential cross sections and the vector analysing powers were measured for the elastic and inelastic scattering of 52 MeV vector polarized deuterons from 20 Ne, 22 Ne, 26 Mg, 28 Si, 32 S, 34 S, 36 Ar and 40 Ar nuclei. Coupled channels analysis was carried out using an axially symmetric rotational model with either prolate or oblate quadrupole deformations for each isotope. Calculations assuming harmonic vibrator model were also carried out. In general, reorientation effects were found to be weak. A global optical model potential containing an imaginary spin-orbit component was found to be the most suitable in describing the experimental data at this energy

  9. Central moments of ion implantation distributions derived by the backward Boltzmann transport equation compared with Monte Carlo simulations

    International Nuclear Information System (INIS)

    Bowyer, M.D.J.; Ashworth, D.G.; Oven, R.

    1992-01-01

    In this paper we study solutions to the backward Boltzmann transport equation (BBTE) specialized to equations governing moments of the distribution of ions implanted into amorphous targets. A central moment integral equation set has been derived starting from the classical plane source BBTE for non-central moments. A full generator equation is provided to allow construction of equation sets of an arbitrary size, thus allowing computation of moments of arbitrary order. A BBTE solver program has been written that uses the residual correction technique proposed by Winterbon. A simple means is presented to allow direct incorporation of Biersack's two-parameter ''magic formula'' into a BBTE solver program. Results for non-central and central moment integral equation sets are compared with Monte Carlo simulations, using three different formulae for the mean free flight path between collisions. Comparisons are performed for the ions B and As, implanted into the target a-Si, over the energy range 1 keV-1 MeV. The central moment integral equation set is found to have superior convergence properties to the non-central moment equation set. For As ions implanted into a-Si, at energies below ∼ 30 keV, significant differences are observed, for third- and fourth-order moments, when using alternative versions for the mean free flight path. Third- and fourth-order moments derived using one- and two-parameter scattering mechanisms also show significant differences over the same energy range. (Author)

  10. Thermoluminescence response of Ge-, Al- and Nd- doped optical fibers by 6 MeV - electron and 6 MeV - photon irradiations

    International Nuclear Information System (INIS)

    Hossain, I.; Moburak, A. A.; Saeed, M.A.; Wagiran, H.; Hida, N.; Yaakob, H.N.

    2015-01-01

    In this paper, we report the prediction of thermoluminescence responses of Neodymium-doped SiO 2 optical fibre with various dose ranges from 0.5 Gy to 4.0 Gy by 6 MeV - electron irradiations without requirement for experimental measurements. A technique has been developed to calculate prediction of 6 MeV - electron response of Neodymium-doped SiO 2 optical fibre by observing the measured TL response of 6 MV - photon and the ratio of known measured photon/electron yield ratio distribution for Ge-doped, Al-doped optical fibre and standard TLD 100 dosimeter. The samples were kept in gelatin capsule an irradiated with 6 MV - photon at the dose range from 0.5 Gy to 4.0 Gy. Siemens model Primus 3368 linear accelerator located at Hospital Sultan Ismail, Johor Bahru has been used to deliver the photon beam to the samples. We found the average response ratio of 6 MV - photon and 6 MeV - electron in Ge-doped, Al-doped optical fibre and standard TLD-100 dosimeter are 0.83(3). Observing the measured value of 6 MV - photon irradiation this average ratio is useful to find the prediction of thermoluminescence responses by 6 MeV - electron irradiation of Neodymium-doped SiO 2 optical fibre by the requirement for experimental measurements with various dose ranges from 0.5 Gy to 4.0 Gy by 6 MV - photon irradiations.

  11. Bias dependent charge trapping in MOSFETs during 1 and 6 MeV electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, N.S. [Department of Chemical Engineering, Mie University, 5148507 (Japan); Kulkarni, V.R.; Mathakari, N.L.; Bhoraskar, V.N. [Department of Physics, Univeristy of Pune, Pune 411007 (India); Dhole, S.D. [Department of Physics, Univeristy of Pune, Pune 411007 (India)], E-mail: sanjay@physics.unipune.ernet.in

    2008-06-15

    To study irradiation-induced charge trapping in SiO{sub 2} and around the SiO{sub 2}-Si interface, depletion n-MOSFETs (metal-oxide-semiconductor field effect transistor) were used. The devices were gate biased during 1 and 6 MeV pulsed electron irradiation. The I{sub D}-V{sub DS} (drain current versus drain voltage) and I{sub D}-V{sub GS} (drain current versus gate voltage) characteristics were measured before and after irradiation. The shift in threshold voltage {delta}V{sub T} (difference in threshold voltage V{sub T} before and after irradiation) exhibited trends depending on the applied gate bias during 1 MeV electron irradiation. This behavior can be associated to the contribution of irradiation-induced negative charge {delta}N{sub IT} buildup around the SiO{sub 2}-Si interface to {delta}V{sub T}, which is sensitive to the electron tunneling from the substrates. However, only weak gate bias dependence was observed in 6 MeV electron irradiated devices. Independent of the energy loss and applied bias, the positive oxide trapped charge {delta}N{sub OT} is marginal and can be associated to thin and good quality of SiO{sub 2}. These results are explained using screening of free and acceptor states by the applied bias during irradiation, thereby reducing the total irradiation-induced charges.

  12. Effect of oxygen on the processes of ion beam synthesis of buried SiC layers in silicon

    International Nuclear Information System (INIS)

    Artamonov, V.V.; Valakh, M.Ya.; Klyuj, N.I.; Mel'nik, V.P.; Romanyuk, A.B.; Romanyuk, B.N.; Yukhimchuk, V.A.

    1998-01-01

    The properties of Si-structures with buried silicon carbide (SiC) layers created by high dose carbon implantation into Cz-Si or Fz-Si wafers followed by high-temperature annealing were studied by Raman and infrared spectroscopy. Effect of additional oxygen implantation on the peculiarities of SiC layer formation was also studied. It was shown that under the same implantation and post-implantation annealing conditions the buried SiC layers are more effectively formed in Cz-Si or in Si subjected to additional oxygen implantation. Thus, oxygen in silicon promotes the SiC layer formation due to SiO x precipitate creation and accommodation of the crystal volume in the region where SiC phase is formed

  13. Quartz modification by Zn ion implantation and swift Xe ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Privezentsev, Vladimir [Institute of Physics and Technology, Russian Academy of Sciences, Moscow (Russian Federation); Kulikauskas, Vaclav [Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University (Russian Federation); Didyk, Alexander; Skuratov, Vladimir [Joint Institute of Nuclear Research, Dubna (Russian Federation); Steinman, Edward; Tereshchenko, Alexey; Kolesnikov, Nikolay [Institute of Solid-State Physics, Russian Academy of Sciences, Chernogolovka (Russian Federation); Trifonov, Alexey; Sakharov, Oleg [National Research University ' ' MIET' ' , Zelenograd, Moscow (Russian Federation); Ksenich, Sergey [National University of Science and Technology ' ' MISiS' ' , Moscow (Russian Federation)

    2017-07-15

    The quartz slides were implanted by {sup 64}Zn{sup +} ions with dose of 5 x 10{sup 16}/cm{sup 2} and energy of 100 keV. After implantation, the amorphous metallic Zn nanoparticles with an average radius of 3.5 nm were created. The sample surface becomes nonuniform, its roughness is increased and its values rise up to 6 nm compared to virgin state, and the roughness maximum is at a value of about 0.8 nm. The surface is made up of valleys and hillocks which have a round shape with an average diameter about 200 nm. At the center of these hillocks are pores with a depth up to 6 nm and a diameter of about 20 nm. After implantation in UV-vis diapason, the optical transmission decreases while PL peak (apparently due to oxygen deficient centers) at wavelength of 400 nm increases. Then the samples were subjected to swift Xe ion irradiation with the fluences of 1 x 10{sup 12}-7.5 x 10{sup 14}/cm{sup 2} and energy of 167 MeV. After Xe irradiation, the sample surface roughness shat down to values of 0.5 nm and the roughness maximum is at a value of about 0.1 nm. Optical transmission in UV-vis diapason increases. The PL peak at wavelength of 400 nm is decreased while a PL peak at wavelength of 660 nm is raised. This peak is presumably due to non-bridging oxygen hole centers or/and NPs with structure Si(core)/SiO{sub 2}(shell). HRTEM image of Zn-implanted quartz subsurface layer. One can see the Zn amorphous nanoparticles, which confirms the electron diffraction pattern (insert). (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Entrance channel excitations in the 28Si + 28Si reaction

    International Nuclear Information System (INIS)

    Decowski, P.; Gierlik, E.; Box, P.F.; Kamermans, R.; Nieuwenhuizen, G.J. van; Meijer, R.J.; Griffioen, K.A.; Wilschut, H.W.; Giorni, A.; Morand, C.; Demeyer, A.; Guinet, D.

    1991-01-01

    Velocity spectra of heavy ions produced in the 28 Si + 28 Si reaction at bombarding energies of 19.7 and 30 MeV/nucleon were measured and interpreted within the Q-optimum model extended by the inclusion of particle evaporation from excited fragments. Regions of forward angle spectra corresponding to the mutual excitation of the reaction partners with net mass transfer zero projected onto the Q-value variable show an enhancement at Q-values of -60 - -80 MeV (excitation energies of the reaction partners equal to 30 - 40 MeV). This energy range coincides with the region of 2ℎω - 3ℎω excitations characteristic for giant osciallations. This selective excitation, which occurs at a very early stage of the reaction (the cross section is the largest at very forward angles), provides an important doorway to other dissipative processes

  15. Scanning ion deep level transient spectroscopy: II. Ion irradiated Au-Si Schottky junctions

    International Nuclear Information System (INIS)

    Laird, J S; Jagadish, C; Jamieson, D N; Legge, G J F

    2006-01-01

    Here we introduce a new technique called scanning ion deep level transient spectroscopy (SIDLTS) for the spatial analysis of electrically active defects in devices. In the first part of this paper, a simple theory behind SIDLTS was introduced and factors determining its sensitivity and resolution were discussed. In this paper, we demonstrate the technique on MeV boron implantation induced defects in an Au-Si Schottky junction. SIDLTS measurements are compared with capacitance DLTS measurements over the temperature range, 100-300 K. SIDLTS analyses indicate the presence of two levels, one of which was positively identified as the E c - 0.23 eV divacancy level. The high sensitivity of SIDLTS is verified and the advantages and limitations of the technique are discussed in light of non-exponential components in the charge transient response. Reasons for several undetected levels are also discussed

  16. Swift heavy ion irradiation effects in SiC measured by positrons

    Energy Technology Data Exchange (ETDEWEB)

    Liszkay, L.; Kajcsos, Zs.; Szilagyi, E. [KFKI Research Inst. for Nuclear and Particle Physics, Budapest (Hungary); Havancsak, K. [Dept. for Solid State Physics, Eoetvoes Univ., Budapest (Hungary); Barthe, M.F.; Desgardin, P.; Henry, L. [CNRS Centre d' Etudes et de Recherches par Irradiation, Orleans (France); Battistig, G. [Research Inst. for Technical Physics and Materials Science, Budapest (Hungary); Skuratov, V.A. [Joint Inst. of Nuclear Research, Moscow (Russian Federation). Bogoliubov Lab. of Theoretical Physics

    2001-07-01

    N-type 6H SiC single crystals irradiated with swift (246 MeV) Kr ions at room temperature (the implantation depth being 21 {mu}m) were investigated by conventional positron lifetime and Doppler-broadening measurements as well as with the application of a slow positron beam. The fluence dependence of the irradiation-induced defects was studied in the 1 x 10{sup 10} - 1 x 10{sup 14} ion cm{sup -2} range. In the fluence and depth range studied, no sign of amorphization (or creation of large voids) was seen in the Kr irradiated crystals. The positron annihilation results were compared with atomic displacement calculations by TRIM. A simple model was used to describe the trapping effect and determine the relationship between the atomic displacement densities and the positron trapping. The 225 ps lifetime of the open-volume defects created suggests that the V{sub Si}-V{sub C} divacancy is the dominant trapping site in the implanted zone. (orig.)

  17. Surface Passivation and Junction Formation Using Low Energy Hydrogen Implants

    Science.gov (United States)

    Fonash, S. J.

    1985-01-01

    New applications for high current, low energy hydrogen ion implants on single crystal and polycrystal silicon grain boundaries are discussed. The effects of low energy hydrogen ion beams on crystalline Si surfaces are considered. The effect of these beams on bulk defects in crystalline Si is addressed. Specific applications of H+ implants to crystalline Si processing are discussed. In all of the situations reported on, the hydrogen beams were produced using a high current Kaufman ion source.

  18. Ion beam processes in Si

    International Nuclear Information System (INIS)

    Holland, O.W.; Narayan, J.; Fathy, D.

    1984-07-01

    Observation of the effects of implants of energetic ions at high dose rates into Si have produced some exciting and interesting results. The mechanism whereby displacement damage produced by ions self-anneals during high dose rate implantation is discussed. It is shown that ion beam annealing (IBA) offers in certain situations unique possibilities for damage annealing. Annealing results of the near surface in Si with a buried oxide layer, formed by high dose implantation, are presented in order to illustrate the advantages offered by IBA. It is also shown that ion irradiation can stimulate the epitaxial recrystallization of amorphous overlayers in Si. The nonequilibrium alloying which results from such epitaxial processes is discussed as well as mechanisms which limit the solid solubility during irradiation. Finally, a dose rate dependency for the production of stable damage by ion irradiation at a constant fluence has been observed. For low fluence implants, the amount of damage is substantially greater in the case of high flux rather than low flux implantation

  19. Simple fabrication of back contact heterojunction solar cells by plasma ion implantation

    Science.gov (United States)

    Koyama, Koichi; Yamaguchi, Noboru; Hironiwa, Daisuke; Suzuki, Hideo; Ohdaira, Keisuke; Matsumura, Hideki

    2017-08-01

    A back-contact amorphous-silicon (a-Si)/crystalline silicon (c-Si) heterojunction is one of the most promising structures for high-efficiency solar cells. However, the patterning of back-contact electrodes causes the increase in fabrication cost. Thus, to simplify the fabrication of back-contact cells, we attempted to form p-a-Si/i-a-Si/c-Si and n-a-Si/i-a-Si/c-Si regions by the conversion of a patterned area of p-a-Si/i-a-Si/c-Si to n-a-Si/i-a-Si/c-Si by plasma ion implantation. It is revealed that the conversion of the conduction type can be realized by the plasma ion implantation of phosphorus (P) atoms into p-a-Si/i-a-Si/c-Si regions, and also that the quality of passivation can be kept sufficiently high, the same as that before ion implantation, when the samples are annealed at around 250 °C and also when the energy and dose of ion implantation are appropriately chosen for fitting to a-Si layer thickness and bulk c-Si carrier density.

  20. Ion implantation

    International Nuclear Information System (INIS)

    Johnson, E.

    1986-01-01

    It is the purpose of the present paper to give a review of surface alloy processing by ion implantation. However, rather than covering this vast subject as a whole, the survey is confined to a presentation of the microstructures that can be found in metal surfaces after ion implantation. The presentation is limited to alloys processed by ion implantation proper, that is to processes in which the alloy compositions are altered significantly by direct injection of the implanted ions. The review is introduced by a presentation of the processes taking place during development of the fundamental event in ion implantation - the collision cascade, followed by a summary of the various microstructures which can be formed after ion implantation into metals. This is compared with the variability of microstructures that can be achieved by rapid solidification processing. The microstructures are subsequently discussed in the light of the processes which, as the implantations proceed, take place during and immediately after formation of the individual collision cascades. These collision cascades define the volumes inside which individual ions are slowed down in the implanted targets. They are not only centres for vigorous agitation but also the sources for formation of excess concentrations of point defects, which will influence development of particular microstructures. A final section presents a selection of specific structures which have been observed in different alloy systems. (orig./GSCH)

  1. Using 3.05 MeV resonance for determination of oxygen impurities

    International Nuclear Information System (INIS)

    Burkova, I.E.; Polyanskij, V.N.; Yatis, A.A.

    1983-01-01

    The method of determining oxygen impurities behind thin films using the isolated resonance in the 16 O(α, α) 16 O reaction at E=3.048 MeV with the width GITA approximately 20 keV, is considered. Cross section in resonance is σsUb(R) = 0.95 b apd it increases cross section of Rutherford scattering by the factor of 25. The conclusion is made on the possibility of using 3.048 MeV resonance when investigating Me-Si film structures

  2. Analyses of the As doping of SiO{sub 2}/Si/SiO{sub 2} nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Ruffino, Francesco; Miritello, Maria [CNR-IMM MATIS, via S. Sofia 64, 95123 Catania (Italy); Tomasello, Mario Vincenzo [Scuola Superiore di Catania, via San Nullo 5/i, 95123 Catania (Italy); De Bastiani, Riccardo; Grimaldi, Maria Grazia [Dipartimento di Fisica ed Astronomia, Universita di Catania, via S. Sofia 64, 95123 Catania (Italy); CNR-IMM MATIS, via S. Sofia 64, 95123 Catania (Italy); Nicotra, Giuseppe; Spinella, Corrado [Consiglio Nazionale delle Ricerche-Istituto per la Microelettronica e Microsistemi (CNR-IMM), VIII Strada 5, 95121 Catania (Italy)

    2011-03-15

    We illustrate the behaviour of As when it is confined, by the implantation technique, in a SiO{sub 2}(70nm)/Si(30nm)/SiO{sub 2}(70nm) multilayer and its spatial redistribution when annealing processes are performed. By Rutherford backscattering spectrometry and Z-contrast transmission electron microscopy we found an As accumulation at the Si/SiO{sub 2} interfaces and at the Si grain boundaries with no segregation of the As in the Si layer. Such an effect is in agreement with a model that assumes a traps distribution in the Si in the first 2-3 nm above the SiO{sub 2}/Si interfaces and along the Si grain boundaries. The traps concentration at the Si/SiO{sub 2} interfaces was estimated in 10{sup 14} traps/cm{sup 2}. The outlined results can open perspectives on the doping properties of As in Si nanocrystals, whose applications in nanoelectronics and optoelectronics are widely investigated (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. A study of channeling patterns from strained Si1-xGex/Si bilayers close to (011) axes

    NARCIS (Netherlands)

    Breese, MBH; Smulders, PJM

    This paper characterises the angular intensity distribution of MeV protons transmitted through strained Si1-xGex/Si bilayers close to the axis. The ring-like intensity distribution produced by the front layer axis when it is aligned close to the beam direction is projected either towards or away

  4. Additional evaluation of alpha induced neutron production nuclear data. 9Be, 27Al, 28,29,30Si

    International Nuclear Information System (INIS)

    Murata, Toru; Shibata, Keiichi

    2005-01-01

    Alpha particle induced neutron production cross sections, emitted neutron energy spectrum and angular distributions were evaluated for the target nucleus 9 Be, 27 Al and Si isotopes; 28 Si, 29 Si and 30 Si in the incident energy region below 15 MeV. (author)

  5. Propagation of misfit dislocations from buffer/Si interface into Si

    Science.gov (United States)

    Liliental-Weber, Zuzanna [El Sobrante, CA; Maltez, Rogerio Luis [Porto Alegre, BR; Morkoc, Hadis [Richmond, VA; Xie, Jinqiao [Raleigh, VA

    2011-08-30

    Misfit dislocations are redirected from the buffer/Si interface and propagated to the Si substrate due to the formation of bubbles in the substrate. The buffer layer growth process is generally a thermal process that also accomplishes annealing of the Si substrate so that bubbles of the implanted ion species are formed in the Si at an appropriate distance from the buffer/Si interface so that the bubbles will not migrate to the Si surface during annealing, but are close enough to the interface so that a strain field around the bubbles will be sensed by dislocations at the buffer/Si interface and dislocations are attracted by the strain field caused by the bubbles and move into the Si substrate instead of into the buffer epi-layer. Fabrication of improved integrated devices based on GaN and Si, such as continuous wave (CW) lasers and light emitting diodes, at reduced cost is thereby enabled.

  6. Carmustine Implant

    Science.gov (United States)

    ... works by slowing or stopping the growth of cancer cells in your body. ... are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while receiving carmustine implant, call your doctor. Carmustine may harm the fetus.

  7. Cochlear Implants

    Science.gov (United States)

    ... NIDCD A cochlear implant is a small, complex electronic device that can help to provide a sense ... Hearing Aids Retinitis Pigmentosa - National Eye Institute Telecommunications Relay Services Usher Syndrome Your Baby's Hearing Screening News ...

  8. Defects and defect generation in oxide layer of ion implanted silicon-silicon dioxide structures

    CERN Document Server

    Baraban, A P

    2002-01-01

    One studies mechanism of generation of defects in Si-SiO sub 2 structure oxide layer as a result of implantation of argon ions with 130 keV energy and 10 sup 1 sup 3 - 3.2 x 10 sup 1 sup 7 cm sup - sup 2 doses. Si-SiO sub 2 structures are produced by thermal oxidation of silicon under 950 deg C temperature. Investigations were based on electroluminescence technique and on measuring of high-frequency volt-farad characteristics. Increase of implantation dose was determined to result in spreading of luminosity centres and in its maximum shifting closer to boundary with silicon. Ion implantation was shown, as well, to result in increase of density of surface states at Si-SiO sub 2 interface. One proposed model of defect generation resulting from Ar ion implantation into Si-SiO sub 2

  9. High current pelletron for ion implantation

    International Nuclear Information System (INIS)

    Schroeder, J.B.

    1989-01-01

    Since 1984, when the first production MeV ion implanter (an NEC model MV-T30) went on-line, interest in versatile electrostatic accelerator systems for MeV ion implantation has grown. The systems use a negative ion source to inject a tandem megavolt accelerator. In early systems the 0.4 mA of charging current from the two Pelletron charging chains in the accelerator was sufficient for the low intensity of beams from the ion source. This 2-chain system, however, is no longer adequate for the much higher beam intensities from today's improved ion sources. A 4-chain charging system, which delivers 1.3 mA to the high voltage terminal, was developed and is in operation in new models of NEC S Series Pelletron accelerators. This paper describes the latest beam performance of 1 MV and 1.7 MW Pelletron accelerators with this new 4-chain charging system. (orig.)

  10. Implantation, recoil implantation, and sputtering

    International Nuclear Information System (INIS)

    Kelly, R.

    1984-01-01

    The implantation and sputtering mechanisms which are relevant to ion bombardment of surfaces are described. These are: collision, thermal, electronic and photon-induced sputtering. 135 refs.; 36 figs.; 9 tabs

  11. Low dose irradiation performance of SiC interphase SiC/SiC composites

    International Nuclear Information System (INIS)

    Snead, L.L.; Lowden, R.A.; Strizak, J.; More, K.L.; Eatherly, W.S.; Bailey, J.; Williams, A.M.; Osborne, M.C.; Shinavski, R.J.

    1998-01-01

    Reduced oxygen Hi-Nicalon fiber reinforced composite SiC materials were densified with a chemically vapor infiltrated (CVI) silicon carbide (SiC) matrix and interphases of either 'porous' SiC or multilayer SiC and irradiated to a neutron fluence of 1.1 x 10 25 n m -2 (E>0.1 MeV) in the temperature range of 260 to 1060 C. The unirradiated properties of these composites are superior to previously studied ceramic grade Nicalon fiber reinforced/carbon interphase materials. Negligible reduction in the macroscopic matrix microcracking stress was observed after irradiation for the multilayer SiC interphase material and a slight reduction in matrix microcracking stress was observed for the composite with porous SiC interphase. The reduction in strength for the porous SiC interfacial material is greatest for the highest irradiation temperature. The ultimate fracture stress (in four point bending) following irradiation for the multilayer SiC and porous SiC interphase materials was reduced by 15% and 30%, respectively, which is an improvement over the 40% reduction suffered by irradiated ceramic grade Nicalon fiber materials fabricated in a similar fashion, though with a carbon interphase. The degradation of the mechanical properties of these composites is analyzed by comparison with the irradiation behavior of bare Hi-Nicalon fiber and Morton chemically vapor deposited (CVD) SiC. It is concluded that the degradation of these composites, as with the previous generation ceramic grade Nicalon fiber materials, is dominated by interfacial effects, though the overall degradation of fiber and hence composite is reduced for the newer low-oxygen fiber. (orig.)

  12. Microscopic analysis of proton elastic scattering in the range 80-200 MeV

    International Nuclear Information System (INIS)

    Dietrich, F.S.; Petrovich, F.

    1983-01-01

    A systematic comparison is made of differential cross-section and analyzing-power data on 12 C, 28 Si, 40 Ca, 90 Zr, and 208 Pb at 80-200 MeV with calculations based on the single-step folding-model approach to the optical potential. In these calculations, proton densities have been inferred from electron scattering results, with neutron densities either the same as for protons ( 12 C, 28 Si, 40 Ca) or with a small neutron skin consistent with 800-MeV proton scattering results ( 80 Zr, 208 Pb). The effective two-body interactions that have been used are the Love-Franey t-matrix, a density-dependent interaction based on the Paris potential (calculated by von Geramb), and finally the Brieva-Rook density-dependent central interaction used with the spin-orbit part of the Love-Franey interaction

  13. Effects of antimony (Sb) on electron trapping near SiO{sub 2}/4H-SiC interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Mooney, P. M.; Jiang, Zenan; Basile, A. F. [Physics Department, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada); Zheng, Yongju; Dhar, Sarit [Physics Department, Auburn University, Auburn, Alabama 36849 (United States)

    2016-07-21

    To investigate the mechanism by which Sb at the SiO{sub 2}/SiC interface improves the channel mobility of 4H-SiC MOSFETs, 1 MHz capacitance measurements and constant capacitance deep level transient spectroscopy (CCDLTS) measurements were performed on Sb-implanted 4H-SiC MOS capacitors. The measurements reveal a significant concentration of Sb donors near the SiO{sub 2}/SiC interface. Two Sb donor related CCDLTS peaks corresponding to shallow energy levels in SiC were observed close to the SiO{sub 2}/SiC interface. Furthermore, CCDLTS measurements show that the same type of near-interface traps found in conventional dry oxide or NO-annealed capacitors are present in the Sb implanted samples. These are O1 traps, suggested to be carbon dimers substituted for O dimers in SiO{sub 2}, and O2 traps, suggested to be interstitial Si in SiO{sub 2}. However, electron trapping is reduced by a factor of ∼2 in Sb-implanted samples compared with samples with no Sb, primarily at energy levels within 0.2 eV of the SiC conduction band edge. This trap passivation effect is relatively small compared with the Sb-induced counter-doping effect on the MOSFET channel surface, which results in improved channel transport.

  14. Annealing characteristics of SiO2-Si structures after incoherent light pulse processing

    International Nuclear Information System (INIS)

    Sieber, N.; Klabes, R.; Voelskow, M.; Fenske, F.

    1982-01-01

    The behaviour of oxide charges and interface charges in boron implanted and non-implanted SiO 2 -Si structures as well as the electrical activation of the dopants by the action of incoherent light pulses was studied. Depth profiles of electrically active boron ions are presented for different annealing conditions as measured by the pulsed C-V method. It can be concluded that exposure of MOS structures to intense radiation of flash lamps does not increase the fixed charge and the fast state density at the SiO 2 -Si interface if optimal annealing conditions (energy densities) are employed. Low dose boron implanted silicon can be electrically activated without diffusion or segregation of dopants

  15. Study of high energy ion implantation of boron and oxygen in silicon

    International Nuclear Information System (INIS)

    Thevenin, P.

    1991-06-01

    Three aspects of high energy (0.5-3 MeV) light ions ( 11 B + and 16 O + ) implantation in silicon are examined: (1)Spatial repartition; (2) Target damage and (3) Synthesis by oxygen implantation of a buried silicon oxide layer

  16. Interaction of implanted deuterium and helium with beryllium: radiation enhanced oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Langley, R.A.

    1979-01-01

    The interaction of implanted deuterium and helium with beryllium is of significant interest in the application of first wall coatings and other components of fusion reactors. Electropolished polycrystalline beryllium was first implanted with an Xe backscatter marker at 1.98 MeV followed by either implantation with 5 keV diatomic deuterium or helium. A 2.0 MeV He beam was used to analyze for impurity buildup; namely oxygen. The oxide layer thickness was found to increase linearly with increasing implant fluence. A 2.5 MeV H/sup +/ beam was used to depth profile the D and He by ion backscattering. In addition the retention of the implant was measured as a function of the implant fluence. The mean depth of the implant was found to agree with theoretical range calculations. Scanning electron microscopy was used to observe blister formation. No blisters were observed for implanted D but for implanted He blisters occurred at approx. 1.75 x 10/sup 17/ He cm/sup -2/. The blister diameter increased with increasing implant fluence from about 0.8 ..mu..m at 10/sup 18/ He cm/sup -2/ to 5.5 ..mu..m at 3 x 10/sup 18/ He cm/sup -2/.

  17. Interaction of implanted deuterium and helium with beryllium: radiation enhanced oxidation

    International Nuclear Information System (INIS)

    Langley, R.A.

    1979-01-01

    The interaction of implanted deuterium and helium with beryllium is of significant interest in the application of first wall coatings and other components of fusion reactors. Electropolished polycrystalline beryllium was first implanted with an Xe backscatter marker at 1.98 MeV followed by either implantation with 5 keV diatomic deuterium or helium. A 2.0 MeV He beam was used to analyze for impurity buildup; namely oxygen. The oxide layer thickness was found to increase linearly with increasing implant fluence. A 2.5 MeV H + beam was used to depth profile the D and He by ion backscattering. In addition the retention of the implant was measured as a function of the implant fluence. The mean depth of the implant was found to agree with theoretical range calculations. Scanning electron microscopy was used to observe blister formation. No blisters were observed for implanted D but for implanted He blisters occurred at approx. 1.75 x 10 17 He cm -2 . The blister diameter increased with increasing implant fluence from about 0.8 μm at 10 18 He cm -2 to 5.5 μm at 3 x 10 18 He cm -2

  18. Evaluation of electron beam stabilization for ion implant processing

    Science.gov (United States)

    Buffat, Stephen J.; Kickel, Bee; Philipps, B.; Adams, J.; Ross, Matthew F.; Minter, Jason P.; Marlowe, Trey; Wong, Selmer S.

    1999-06-01

    With the integration of high energy ion implant processes into volume CMOS manufacturing, the need for thick resist stabilization to achieve a stable ion implant process is critical. With new photoresist characteristics, new implant end station characteristics arise. The resist outgassing needs to be addressed as well as the implant profile to ensure that the dosage is correct and the implant angle does not interfere with other underlying features. This study compares conventional deep-UV/thermal with electron beam stabilization. The electron beam system used in this study utilizes a flood electron source and is a non-thermal process. These stabilization techniques are applied to a MeV ion implant process in a CMOS production process flow.

  19. Determination of phosphorus and potassium in sugar cane leaves by 14 MeV neutrons

    International Nuclear Information System (INIS)

    Diaz, R.A.; Nagy, A.Z.; Bakos, L.; Soria, J.C.

    1979-04-01

    The possibilities of N, P, K evaluation in samples of sugar cane leaves were discussed. A method for determining P and K content in this samples by 14 MeV neutron activation analysis is described. Corrections for K and Si were taken into account. The limit of detection for P was 0.1 mg and for K it was 4 mg. The precision for P and K was 10% in agreement with the values given by other authors. (author)

  20. RBS/NRA/channeling analysis of implanted immiscible species

    International Nuclear Information System (INIS)

    Naramoto, H.; Yamamoto, S.; Narumi, K.

    2000-01-01

    Ion implantation of immiscible elements was performed to prepare supersaturated substance for further heat treatment. 63 Cu ion implantation was made at low temperature into Nb(1 0 0), (1 1 0) and (1 1 1) single crystal films on sapphire, and the induced lattice damage and the lattice location of implanted Cu atoms were analyzed by 2.7 MeV 4 He + RBS/channeling. The coherent segregation of 63 Cu atoms with specific crystallographic orientations was found in the near surface region (Cu(1 0 0)/Nb(1 0 0), Cu(1 1 1)/Nb(1 1 0) and Cu(1 1 0)/Nb(1 1 1)). The same kind of study was also made in Ir(1 0 0)/MgO(1 0 0) implanted with 50 keV 12 C + ions. In addition to 2 MeV 4 He + RBS/channeling, 1.22 MeV d + RBS/NRA/channeling was employed to detect implanted 12 C atoms. The results suggest that 12 C atoms are aligned along Ir direction at least by low temperature implantation followed by thermal annealing

  1. Channeling ion implantation through palladium films

    International Nuclear Information System (INIS)

    Ishiwara, H.; Furukawa, S.

    1975-01-01

    The possibility of channeling ion implantation into semiconductors through polycrystalline metallic layers is studied. Minimum values and standard deviations of channeling angular yield in polycrystalline Pd 2 Si layers formed on Si have been measured by protons and 4 He, and 14 N ion backscattering and channeling measurements. Depth distributions of the spread of crystallite orientations and scattering centers such as lattice defects have been separately derived by using the above two quantities. It has been concluded that the channeling-ion-implantation technique will become a practical one by using the parallel scanning system

  2. Hip Implant Systems

    Science.gov (United States)

    ... Implants and Prosthetics Metal-on-Metal Hip Implants Hip Implants Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Hip implants are medical devices intended to restore mobility ...

  3. Breast reconstruction - implants

    Science.gov (United States)

    Breast implants surgery; Mastectomy - breast reconstruction with implants; Breast cancer - breast reconstruction with implants ... harder to find a tumor if your breast cancer comes back. Getting breast implants does not take as long as breast reconstruction ...

  4. Fluorine incorporation during Si solid phase epitaxy

    International Nuclear Information System (INIS)

    Impellizzeri, G.; Mirabella, S.; Romano, L.; Napolitani, E.; Carnera, A.; Grimaldi, M.G.; Priolo, F.

    2006-01-01

    We have investigated the F incorporation and segregation in preamorphized Si during solid phase epitaxy (SPE) at different temperatures and for several implanted-F energies and fluences. The Si samples were amorphized to a depth of 550 nm by implanting Si at liquid nitrogen temperature and then enriched with F at different energies (65-150 keV) and fluences (0.07-5 x 10 14 F/cm 2 ). Subsequently, the samples were regrown by SPE at different temperatures: 580, 700 and 800 deg. C. We have found that the amount of F incorporated after SPE strongly depends on the SPE temperature and on the energy and fluence of the implanted-F, opening the possibility to tailor the F profile during SPE

  5. SI Notes.

    Science.gov (United States)

    Nelson, Robert A.

    1983-01-01

    Discusses legislation related to SI (International Systems of Units) in the United States. Indicates that although SI metric units have been officially recognized by law in the United States, U.S. Customary Units have never received a statutory basis. (JN)

  6. Evidence for two narrow pp resonances at 2020 MeV and 2200 MeV

    CERN Document Server

    Benkheiri, P; Bouquet, B; Briandet, P; D'Almagne, B; Dang-Vu, C; De Rosny, G; Eisenstein, B I; Ferrer, A; Fleury, P; Grossetête, B; Irwin, G; Jacholkowski, A; Lahellec, A; Nguyen, H; Petroff, P; Richard, F; Rivet, P; Roudeau, P; Rougé, A; Rumpf, M; Six, J; Thénard, J M; Treille, D; Volte, A; Yaffe, D; Yiou, T P; Yoshida, H

    1977-01-01

    From the study of the reaction pi /sup -/p to p/sub F/pp pi /sup -/ using a fast proton (p/sub F/) trigger device in the CERN Omega spectrometer, the authors find evidence for two narrow pp states produced mainly in association with a Delta degrees (1232) and a N degrees (1520). The statistical significance of each peak is greater than 6 standard deviations. Masses and natural widths of these resonances are respectively M/sub 1/=2020+or-3 MeV, Gamma /sub 1 /=24+or-12 MeV and M/sub 2/=2204+or-5 MeV, Gamma /sub 2/=16/sub -16 //sup +20/ MeV. The data are consistent with a small production of the narrow approximately 1935 MeV resonance already reported. Production cross sections for these new pp resonances are given. (8 refs).

  7. Ion implantation methods for semiconductor substrates

    International Nuclear Information System (INIS)

    Matsushita, T.; Mamine, T.; Hayashi, H.; Nishiyama, K.

    1980-01-01

    A method of ion implantation for controlling the life time of minority carriers in a semiconductor substrate and hence to reduce the temperature dependency of the life time, comprises implanting iron ions into an N type semiconductor substrate with a dosage of 10 10 to 10 15 ions cm -2 , and then heat-treating the implanted substrate at 850 0 to 1250 0 C. The method is applicable to the production of diodes, transistors, Si controlled rectifiers and gate controlled switching devices. (author)

  8. The reliability studies of nano-engineered SiGe HBTs using Pelletron accelerator

    Science.gov (United States)

    Prakash, A. P. Gnana; Praveen, K. C.; Pushpa, N.; Cressler, John D.

    2015-05-01

    The effects of high energy ions on the electrical characteristics of silicon-germanium heterojunction bipolar transistors (SiGe HBTs) were studied in the total dose of ranging from 600 krad to 100 Mrad (Si). The two generations (50 GHz and 200 GHz) of SiGe HBTs were exposed to 50 MeV lithium, 75 MeV boron and 100 MeV oxygen ions. The electrical characteristics of SiGe HBTs were studied before and after irradiation. The SiGe HBTs were exposed to 60Co gamma radiation in the same total dose. The results are systematically compared in order to understand the interaction of ions and ionizing radiation with SiGe HBTs.

  9. The reliability studies of nano-engineered SiGe HBTs using Pelletron accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, A. P. Gnana, E-mail: gnanaprakash@physics.uni-mysore.ac.in; Praveen, K. C. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore, Karnataka-570006 (India); Pushpa, N. [Department of PG Studies in Physics, JSS College, Ooty Road, Mysore-570025 (India); Cressler, John D. [School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, 30332 (United States)

    2015-05-15

    The effects of high energy ions on the electrical characteristics of silicon-germanium heterojunction bipolar transistors (SiGe HBTs) were studied in the total dose of ranging from 600 krad to 100 Mrad (Si). The two generations (50 GHz and 200 GHz) of SiGe HBTs were exposed to 50 MeV lithium, 75 MeV boron and 100 MeV oxygen ions. The electrical characteristics of SiGe HBTs were studied before and after irradiation. The SiGe HBTs were exposed to {sup 60}Co gamma radiation in the same total dose. The results are systematically compared in order to understand the interaction of ions and ionizing radiation with SiGe HBTs.

  10. Positron acceleration to 200 MeV

    International Nuclear Information System (INIS)

    Leboutet, H.

    1983-01-01

    220 MeV is the energy that has to be obtained in routine operation. A standard 12m girder with SLED II can give 220 MeV minus a few percent due to not riding at the crest of the wave. In order to have the 200 MeV with only one girder, a klystron at full power all the time would be required - kept brand new. Then, for safety it is necessary to use two klystrons as designated in the SLC design. Having two klystrons gives freedom for the choice of the best arrangement. Since there will be excess rf power, it can be traded against higher gradient, shorter waveguides, larger apertures (lower shunt impedence)

  11. TOTAL NUCLEAR-REACTION PROBABILITY OF 270 TO 390 N-14 IONS IN SI AND CSI

    NARCIS (Netherlands)

    WARNER, RE; CARPENTER, CL; FETTER, JM; WAITE, WF; WILSCHUT, HW; HOOGDUIN, JM

    A magnetic spectrograph and position-sensitive detectors were used to measure the total nuclear reaction probability eta(R) for alpha + CsI at 116 MeV, N-14 + CsI at 265 and 385 MeV, and N-14 + Si at 271 and 390 MeV. From these eta(R)'s, average reaction cross sections sigma(R) were deduced for

  12. Endothelial cell adhesion to ion implanted polymers

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Y; Kusakabe, M [SONY Corp., Tokyo (Japan); Lee, J S; Kaibara, M; Iwaki, M; Sasabe, H [RIKEN (Inst. of Physical and Chemical Research), Saitama (Japan)

    1992-03-01

    The biocompatibility of ion implanted polymers has been studied by means of adhesion measurements of bovine aorta endothelial cells in vitro. The specimens used were polystyrene (PS) and segmented polyurethane (SPU). Na{sup +}, N{sub 2}{sup +}, O{sub 2}{sup +} and Kr{sup +} ion implantations were performed at an energy of 150 keV with fluences ranging from 1x10{sup 15} to 3x10{sup 17} ions/cm{sup 2} at room temperature. The chemical and physical structures of ion-implanted polymers have been investigated in order to analyze their tissue compatibility such as improvement of endothelial cell adhesion. The ion implanted SPU have been found to exhibit remarkably higher adhesion and spreading of endothelial cells than unimplanted specimens. By contrast, ion implanted PS demonstrated a little improvement of adhesion of cells in this assay. Results of FT-IR-ATR showed that ion implantation broke the original chemical bond to form new radicals such as OH, ....C=O, SiH and condensed rings. The results of Raman spectroscopy showed that ion implantation always produced a peak near 1500 cm{sup -1}, which indicated that these ion implanted PS and SPU had the same carbon structure. This structure is considered to bring the dramatic increase in the extent of cell adhesion and spreading to these ion implanted PS and SPU. (orig.).

  13. DPAC measurements on 129sup(m)TeSi

    International Nuclear Information System (INIS)

    Kemerink, G.J.; Pleiter, F.; Arendes, A.R.

    1981-01-01

    Using results of DPAC measurements on 129 sup(m)TeSi it is shown that the absorption lines in the Moessbauer spectra obtained with unannealed implanted sources must be ascribed mainly as belonging to a quadrupole split multiplet. (orig.)

  14. Buried injector logic, a vertical IIL using deep ion implantation

    NARCIS (Netherlands)

    Mouthaan, A.J.

    1987-01-01

    A vertically integrated alternative for integrated injection logic has been realized, named buried injector logic (BIL). 1 MeV ion implantations are used to create buried layers. The vertical pnp and npn transistors have thin base regions and exhibit a limited charge accumulation if a gate is

  15. Evaluation of electronic states of implanted materials by molecular orbital calculation

    International Nuclear Information System (INIS)

    Saito, Jun-ichi; Kano, Shigeki

    1997-07-01

    In order to understand the effect of implanted atom in ceramics and metals on the sodium corrosion, the electronic structures of un-implanted and implanted materials were calculated using DV-Xα cluster method which was one of molecular orbital calculations. The calculated materials were β-Si 3 N 4 , α-SiC and β-SiC as ceramics, and f.c.c. Fe, b.c.c. Fe and b.c.c. Nb as metals. An Fe, Mo and Hf atom for ceramics, and N atom for metals were selected as implanted atoms. Consequently, it is expected that the corrosion resistance of β-Si 3 N 4 is improved, because the ionic bonding reduced by the implantation. When the implanted atom is occupied at interstitial site in α-SiC and β-SiC, the ionic bonding reduced. Hence, there is a possibility to improve the corrosion resistance of α-SiC and β-SiC. It is clear that Hf is most effective element among implanted atoms in this study. As the covalent bond between N atom and surrounding Fe atoms increased largely in f.c.c. Fe by N implantation, it was expected that the corrosion resistance of f.c.c. Fe improved in liquid sodium. (J.P.N.)

  16. Polarized micro-Raman scattering characterization of Mg2Si nanolayers in (001) Si matrix

    International Nuclear Information System (INIS)

    Zlateva, G; Atanassov, A; Baleva, M; Nikolova, L; Abrashev, M V

    2007-01-01

    An orientational growth of the Mg 2 Si lattice relative to the Si lattice is considered assuming minimum mismatch of their lattice parameters. The Raman scattering cross-sections are calculated for the four possible orientations of the Mg 2 Si lattice positioned in this way. The integral intensity ratios for the F 2g mode of Mg 2 Si in different polarization configurations, obtained from the experimental spectra, are compared with the calculated ratios. It is found that the Mg 2 Si nanolayer's morphology is sensitive to the implantation energy, which determines both the peak Mg concentration in the initial implantation profile and its position in the sample depth. At a peak concentration of the order of the stoichiometric concentration, the layers are highly oriented. When the peak concentration is higher and the peak is placed closer to the surface, the layers are polycrystalline

  17. Excitation function for the population of the 4.51 MeV state of 27Al inelastic proton scattering. Evidence for 6- strength?

    International Nuclear Information System (INIS)

    Spicer, B.M.; Koutsoliotas, S.

    1995-01-01

    The excitation function for emission of 2.30 MeV gamma rays from the 4.51 MeV state of 27 Al formed in inelastic proton scattering has been measured for proton energies from 5.6 to 7.3 MeV. A resonance previously seen in both inelastic electron and proton scattering from 28 Si at 17.35 MeV has been observed as a resonance in the excitation function, as well as seven other resonances, all of which are narrow (i.e., less than 100 keV wide). It is suggested that these may represent fragments of 6 - strength in 28 Si. 6 refs., 1 tab., 2 figs

  18. Integrated picosecond photoconductors produced on bulk Si substrates

    International Nuclear Information System (INIS)

    Hammond, R.B.; Paulter, N.G.; Wagner, R.S.; Eisenstadt, W.R.

    1984-01-01

    We report optoelectronic cross-correlation measurements of the response of photoconductor pulsers and sampling gates formed on Si wafers. These photoconductors were fabricated with standard integrated circuit fabrication techniques followed by shadow-masked ion beam irradiation. Successful ion beam irradiations were performed with 2 MeV 2 H, 6 MeV He, and 30 MeV O with doses of 10 15 ion/cm 2 . Deep damage was necessary to eliminate long-lived background currents in the cross correlations. Carrier lifetimes of 96, 47, and 29 ps were observed in photoconductors with carrier mobilities of approx.250 cm 2 /Vs

  19. Implant damage and redistribution of indium in indium-implanted thin silicon-on-insulator

    International Nuclear Information System (INIS)

    Chen Peng; An Zhenghua; Zhu Ming; Fu, Ricky K.Y.; Chu, Paul K.; Montgomery, Neil; Biswas, Sukanta

    2004-01-01

    The indium implant damage and diffusion behavior in thin silicon-on-insulator (SOI) with a 200 nm top silicon layer were studied for different implantation energies and doses. Rutherford backscattering spectrometry in the channeling mode (RBS/C) was used to characterize the implant damage before and after annealing. Secondary ion mass spectrometry (SIMS) was used to study the indium transient enhanced diffusion (TED) behavior in the top Si layer of the SOI structure. An anomalous redistribution of indium after relatively high energy (200 keV) and dose (1 x 10 14 cm -2 ) implantation was observed in both bulk Si and SOI substrates. However, there exist differences in these two substrates that are attributable to the more predominant out-diffusion of indium as well as the influence of the buried oxide layer in the SOI structure

  20. MeV fullerene impacts on mica

    Energy Technology Data Exchange (ETDEWEB)

    Doebeli, M.; Scandella, L. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Ames, F. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1997-09-01

    Hillock heights on mica irradiated with MeV C{sub 60} ions have been investigated systematically. Results show that the small range of secondary particles along the track plays a crucial role in defect production. (author) figs., tab., refs.