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Sample records for etch rate measurements

  1. Comparison and limitations of three different bulk etch rate measurement methods used for gamma irradiated PM-355 detectors

    Energy Technology Data Exchange (ETDEWEB)

    Fazal-ur-Rehman E-mail: fazalr@kfupm.edu.sa; Abu-Jarad, F.; Al-Jarallah, M.I.; Farhat, M

    2001-06-01

    Samples of Nuclear Track Detectors (PM-355) were exposed to high gamma doses from 1x10{sup 5} Gy (10 Mrad) up to 1.2x10{sup 6} Gy (120 Mrad) at an incremental dose of 1x10{sup 5} Gy (10 Mrad). The gamma source was a 9.03 PBq (244 kCi) Co-60 source used for sterilization of medical syringes. The bulk etch rate (V{sub b}) was measured for various high gamma doses by three different methods: 1--thickness change method; 2--mass change method; 3--fission track diametric method. The study gives a comparison and limitations of these three methods used for bulk etch rate measurements in the detectors as a function of high gamma doses. The track etch rate (V{sub t}) and the sensitivity (V) of the detector were also measured using the fission track diametric method. It was observed that V{sub b} increases with the increase of the gamma absorbed dose at a fixed etching time in each bulk etch measuring method. The bulk etch rate decreases exponentially with the etching time at a fixed gamma absorbed dose in all three methods. The thickness change and mass change methods have successfully been applied to measure V{sub b} at higher gamma doses up to 1.2x10{sup 6} Gy (120 Mrad). The bulk etch rate determined by the mass change and thickness change methods was almost the same at a certain gamma dose and etching time whereas it was quite low in the case of the fission track diametric method due to its limitations at higher doses. Also in this method it was not possible to measure the fission fragment track diameters at higher doses due to the quick disappearance of the fission tracks and therefore the V{sub b} could not be estimated at higher gamma doses.

  2. Measurement of the variable track-etch rate of hydrogen, carbon and oxygen Ions in CR-39

    International Nuclear Information System (INIS)

    Lengar, I.; Skvarc, J.; Ilic, R.

    2003-01-01

    The ratio of the track-etch rate to the bulk-etch rate for hydrogen, carbon and oxygen ions was studied for the CR-39 detector with addition of dioctylphthalate. The response was reconstructed from etch-pit growth curves obtained by the multi-step etching technique. A theoretical analysis of the correctness of the method due to the 'missing track segment' is assessed and utilisation of the results obtained for the calibration of fast neutron dosimetry is discussed. (author)

  3. Influence factors on etching rate of PET nuclear pore membrane

    International Nuclear Information System (INIS)

    Zuo Zhenzhong; Wu Zhendong; Liang Haiying; Ju Wei; Chen Dongfeng; Fu Yuanyong; Qu Guopu

    2014-01-01

    Background: The nuclear pore membrane is a kind of liquid filtration material manufactured by irradiation and chemical etching. Various conditions in etch process have a great influence on etch rate. Purpose: The influence factors of concentration and temperature of etch solution and the irradiation energy of heavy ions on etch rate was studied. Methods: Four layers of PET (polyethylene terephthalate) films were stacked together and were irradiated with 140-MeV 32 S ions at room temperature under vacuum conditions. Utilizing conductivity measurement technique, the electrical current changes through the u:radiated PET film were monitored during etching, from which the breakthrough time and therefore the track etching rate was calculated. Results: The results show that there is an exponential correlation between etch rate and temperature, and a linear correlation between etch rate and concentration. The track etching rate increases linearly with energy loss rate. Empirical formula for the bulk etching rate as a function of etchant concentration and temperature was also established via fitting of measurements. Conclusion: It is concluded that by using 1.6-MeV·u -1 32 S ions, PET nuclear pore membrane with cylindrical pore shape can be prepared at 85℃ with etchant concentration of l mol·L -1 . (authors)

  4. Interrelated temperature dependence of bulk etch rate and track length saturation time in CR-39 detector

    International Nuclear Information System (INIS)

    Azooz, A.A.; Al-Jubbori, M.A.

    2013-01-01

    Highlights: • New empirical parameterization of CR-39 bulk etch rate. • Bulk etch rates measurements using two different methods give consistent results. • Temperature independence of track saturation length. • Two empirical relation between bulk etch rate and temperature are suggested. • Simple inverse relation between bulk etch rate and track saturation time. -- Abstract: Experimental measurements of the etching solution temperature dependence of bulk etch rate using two independent methods revealed a few interesting properties. It is found that while the track saturation length is independent of etching temperature, the etching time needed to reach saturation is strongly temperature-dependent. It is demonstrated that there is systematic simple inverse relation between track saturation time, and etching solution temperature. In addition, and although, the relation between the bulk etch rate and etching solution temperature can be reasonably described by a modified form of the Arrhenius equation, better fits can be obtained by another equation suggested in this work

  5. Direct determination of bulk etching rate for LR-115-II solid state ...

    Indian Academy of Sciences (India)

    The thickness of the removed layer of the LR-115-II solid state nuclear track detector during etching is measured directly with a rather precise instrument. Dependence of bulk etching rate on temperature of the etching solution is investigated. It has been found that the bulk etching rate is 3.2 m/h at 60°C in 2.5 N NaOH of ...

  6. Measurement of bulk etch rates for poly-allyl-diglycol carbonate (PADC) and cellulose nitrate in a broad range of concentration and temperature of NaOH etching solution

    International Nuclear Information System (INIS)

    Hermsdorf, D.; Hunger, M.; Starke, S.; Weickert, F.

    2007-01-01

    In the present work the dependence of the bulk etch rate v B for solid state nuclear track detectors (SSNTD) on the concentration c and the temperature T of the NaOH etching solution has been studied for material types PADC and cellulose nitrate. As commonly applied exponents of PADC and cellulose nitrate material, the commercial products CR-39 and LR-115 were investigated. The concentration and temperature have been varied in the ranges 0.5moll -1 -1 and 313 -1 and T between 313 and 333K for cellulose nitrate, respectively. The application of a simple Arrhenius-law of chemical reactions fails in the interpretation of the dependence on the concentration. A constant activation energy cannot describe the behaviour of v B (c,T) over the whole range of concentration. To understand the deviation, more qualified models treating the superposition of chemical and physical processes including reaction kinetics and material transport phenomena by diffusion have to be developed and tested

  7. High rate dry etching of InGaZnO by BCl3/O2 plasma

    Science.gov (United States)

    Park, Wanjae; Whang, Ki-Woong; Gwang Yoon, Young; Hwan Kim, Jeong; Rha, Sang-Ho; Seong Hwang, Cheol

    2011-08-01

    This paper reports the results of the high-rate dry etching of indium gallium zinc oxide (IGZO) at room temperature using BCl3/O2 plasma. We achieved an etch rate of 250 nm/min. We inferred from the x-ray photoelectron spectroscopy analysis that BOx or BOClx radicals generated from BCl3/O2 plasma cause the etching of the IGZO material. O2 initiates the etching of IGZO, and Ar removes nonvolatile byproducts from the surface during the etching process. Consequently, a smooth etched surface results when these gases are added to the etch gas.

  8. Bulk etch rate of LR-115 cellulose nitrate film

    International Nuclear Information System (INIS)

    Harris, M.J.; Schlenker, R.A.

    1977-01-01

    Bulk etch rate (V/sub b/) of Kodak LR-115 cellulose nitrate film has been studied, and values for the parameter are presented. An interesting variability of V/sub b/ has been found which has implications for microdosimetry using this type of integrating nuclear track detector. Short-term and longer-term thickness changes have been observed which may increase the uncertainty in estimations of dose using this type of detector

  9. Angular dependence of the redeposition rates during SiO2 etching in a CF4 plasma

    International Nuclear Information System (INIS)

    Cho, Byeong-Ok; Hwang, Sung-Wook; Lee, Gyeo-Re; Moon, Sang Heup

    2001-01-01

    The angular dependence of the redeposition rates during SiO 2 etching in a CF 4 plasma was studied using three types of Faraday cages located in a transformer coupled plasma etcher. The SiO 2 substrates were fixed on sample holder slopes that have different angles to the cathode. The substrate was subjected to one of three processes depending on the design of the Faraday cage, i.e., redeposition of sputtered particles from the SiO 2 bottom surface (case I), substrate etching by incident ions (case II), or simultaneous etching and redeposition (case III). Both the redeposition and the etch rates were measured by changing the substrate-surface angle and the self-bias voltage in the range of -100 to -800 V. The redeposition-only rates (case I) at -450 and -800 V closely followed the quadratic curve of the angle whereas the rates at -100 V followed the cubic curve, indicating different mechanisms of the bottom SiO 2 etching depending on the energy regimes. The steep increase of the redeposition rate with the angle was attributed to three factors: the substrate-bottom distance, the angular distribution of emitted particles from the bottom surface, and the particle incident angle on the substrate surface. The etch-only rate curves (case II) closely followed the cosine of the surface angle. The etch-rate curve changed into a reverse-S shape when the substrate was subjected to simultaneous etching and redeposition (case III). The net etch rate for case III decreased drastically above 60 deg. , showing a negative value, i.e., a net redeposition, beyond 75 deg. . The drastic decrease in the net etch rate coincided with the steep increase in the redeposition rate, implying the significant effect of redeposition

  10. Etched track radiometers in radon measurements: a review

    CERN Document Server

    Nikolaev, V A

    1999-01-01

    Passive radon radiometers, based on alpha particle etched track detectors, are very attractive for the assessment of radon exposure. The present review considers various devices used for measurement of the volume activity of radon isotopes and their daughters and determination of equilibrium coefficients. Such devices can be classified into 8 groups: (i) open or 'bare' detectors, (ii) open chambers, (iii) sup 2 sup 2 sup 2 Rn chambers with an inlet filter, (iv) advanced sup 2 sup 2 sup 2 Rn radiometers, (v) multipurpose radiometers, (vi) radiometers based on a combination of etched track detectors and an electrostatic field, (vii) radiometers based on etched track detectors and activated charcoal and (viii) devices for the measurement of radon isotopes and/or radon daughters by means of track parameter measurements. Some of them such as the open detector and the chamber with an inlet filter have a variety of modifications and are applied widely both in geophysical research and radon dosimetric surveys. At the...

  11. Effect of track etch rate on geometric track characteristics for polymeric track detectors

    International Nuclear Information System (INIS)

    Abdel-Naby, A.A.; El-Akkad, F.A.

    2001-01-01

    Analysis of the variable track etch rate on geometric track characteristic for polymeric track detectors has been applied to the case of LR-155 II SSNTD. Spectrometric characteristics of low energy alpha particles response by the polymeric detector have been obtained. The track etching kinematics theory of development of minor diameter of the etched tracks has been applied. The calculations show that, for this type of detector, the energy dependence of the minor track diameter d is linear for small-etched removal layer h. The energy resolution gets better for higher etched removal layer

  12. Evolution of titanium residue on the walls of a plasma-etching reactor and its effect on the polysilicon etching rate

    Energy Technology Data Exchange (ETDEWEB)

    Hirota, Kosa, E-mail: hirota-kousa@sme.hitachi-hitec.com; Itabashi, Naoshi; Tanaka, Junichi [Hitachi, Ltd., Central Research Laboratory, 1-280, Higashi-Koigakubo, Kokubunji, Tokyo 185-8601 (Japan)

    2014-11-01

    The variation in polysilicon plasma etching rates caused by Ti residue on the reactor walls was investigated. The amount of Ti residue was measured using attenuated total reflection Fourier transform infrared spectroscopy with the HgCdTe (MCT) detector installed on the side of the reactor. As the amount of Ti residue increased, the number of fluorine radicals and the polysilicon etching rate increased. However, a maximum limit in the etching rate was observed. A mechanism of rate variation was proposed, whereby F radical consumption on the quartz reactor wall is suppressed by the Ti residue. The authors also investigated a plasma-cleaning method for the removal of Ti residue without using a BCl{sub 3} gas, because the reaction products (e.g., boron oxide) on the reactor walls frequently cause contamination of the product wafers during etching. CH-assisted chlorine cleaning, which is a combination of CHF{sub 3} and Cl{sub 2} plasma treatment, was found to effectively remove Ti residue from the reactor walls. This result shows that CH radicals play an important role in deoxidizing and/or defluorinating Ti residue on the reactor walls.

  13. Unbiased roughness measurements: the key to better etch performance

    Science.gov (United States)

    Liang, Andrew; Mack, Chris; Sirard, Stephen; Liang, Chen-wei; Yang, Liu; Jiang, Justin; Shamma, Nader; Wise, Rich; Yu, Jengyi; Hymes, Diane

    2018-03-01

    Edge placement error (EPE) has become an increasingly critical metric to enable Moore's Law scaling. Stochastic variations, as characterized for lines by line width roughness (LWR) and line edge roughness (LER), are dominant factors in EPE and known to increase with the introduction of EUV lithography. However, despite recommendations from ITRS, NIST, and SEMI standards, the industry has not agreed upon a methodology to quantify these properties. Thus, differing methodologies applied to the same image often result in different roughness measurements and conclusions. To standardize LWR and LER measurements, Fractilia has developed an unbiased measurement that uses a raw unfiltered line scan to subtract out image noise and distortions. By using Fractilia's inverse linescan model (FILM) to guide development, we will highlight the key influences of roughness metrology on plasma-based resist smoothing processes. Test wafers were deposited to represent a 5 nm node EUV logic stack. The patterning stack consists of a core Si target layer with spin-on carbon (SOC) as the hardmask and spin-on glass (SOG) as the cap. Next, these wafers were exposed through an ASML NXE 3350B EUV scanner with an advanced chemically amplified resist (CAR). Afterwards, these wafers were etched through a variety of plasma-based resist smoothing techniques using a Lam Kiyo conductor etch system. Dense line and space patterns on the etched samples were imaged through advanced Hitachi CDSEMs and the LER and LWR were measured through both Fractilia and an industry standard roughness measurement software. By employing Fractilia to guide plasma-based etch development, we demonstrate that Fractilia produces accurate roughness measurements on resist in contrast to an industry standard measurement software. These results highlight the importance of subtracting out SEM image noise to obtain quicker developmental cycle times and lower target layer roughness.

  14. Pulsed laser-assisted focused electron-beam-induced etching of titanium with XeF2: enhanced reaction rate and precursor transport.

    Science.gov (United States)

    Noh, J H; Fowlkes, J D; Timilsina, R; Stanford, M G; Lewis, B B; Rack, P D

    2015-02-25

    In order to enhance the etch rate of electron-beam-induced etching, we introduce a laser-assisted focused electron-beam-induced etching (LA-FEBIE) process which is a versatile, direct write nanofabrication method that allows nanoscale patterning and editing. The results demonstrate that the titanium electron stimulated etch rate via the XeF2 precursor can be enhanced up to a factor of 6 times with an intermittent pulsed laser assist. The evolution of the etching process is correlated to in situ stage current measurements and scanning electron micrographs as a function of time. The increased etch rate is attributed to photothermally enhanced Ti-F reaction and TiF4 desorption and in some regimes enhanced XeF2 surface diffusion to the reaction zone.

  15. Spatially-Resolved Ion Trajectory Measurements During Cl2 Reactive Ion Beam Etching and Ar Ion Beam Etching

    International Nuclear Information System (INIS)

    Vawter, G. Allen; Woodworth, Joseph R.; Zubrzycki, Walter J.

    1999-01-01

    The angle of ion incidence at the etched wafer location during RIBE and IBE using Cl 2 , Ar and O 2 ion beams has been characterized using an ion energy and angle analyzer. Effects of beam current and accelerator grid bias on beam divergence and the spatial uniformity of the spread of incident angles are measured. It is observed that increased total beam current can lead to reduced current density at the sample stage due to enhanced beam divergence at high currents. Results are related to preferred etch system design for uniform high-aspect-ratio etching across semiconductor wafers

  16. Dependence of wet etch rate on deposition, annealing conditions and etchants for PECVD silicon nitride film

    International Nuclear Information System (INIS)

    Tang Longjuan; Zhu Yinfang; Yang Jinling; Li Yan; Zhou Wei; Xie Jing; Liu Yunfei; Yang Fuhua

    2009-01-01

    The influence of deposition, annealing conditions, and etchants on the wet etch rate of plasma enhanced chemical vapor deposition (PECVD) silicon nitride thin film is studied. The deposition source gas flow rate and annealing temperature were varied to decrease the etch rate of SiN x :H by HF solution. A low etch rate was achieved by increasing the SiH 4 gas flow rate or annealing temperature, or decreasing the NH 3 and N2 gas flow rate. Concentrated, buffered, and dilute hydrofluoric acid were utilized as etchants for SiO 2 and SiN x :H. A high etching selectivity of SiO 2 over SiN x :H was obtained using highly concentrated buffered HF.

  17. Wet etching rates of InGaZnO for the fabrication of transparent thin-film transistors on plastic substrates

    International Nuclear Information System (INIS)

    Lee, Chi-Yuan; Chang, Chienliu; Shih, Wen-Pin; Dai, Ching-Liang

    2010-01-01

    The wet etch process for amorphous indium gallium zinc oxide (a-IGZO or a-InGaZnO) by using various etchants is reported. The etch rates of a-IGZO, compared to another indium-based oxides including indium gallium oxide (IGO), indium zinc oxide (IZO), and indium tin oxide (ITO), are measured by using acetic acid, citric acid, hydrochloric acid, perchloric acid, and aqua ammonia as etchants, respectively. In our experimental results, the etch rate of the transparent oxide semiconductor (TOS) films by using acid solutions ranked accordingly from high to low are IZO, IGZO, IGO and ITO. Comparatively, the etch rate of the TOS films by using alkaline ammonia solution ranked from high to low are IGZO, IZO, IGO and ITO, in that order. Using the proposed wet etching process with high etch selectivity, bottom-gate-type thin-film transistors (TFTs) based on a-IGZO channels and Y 2 O 3 gate-insulators were fabricated by radio-frequency sputtering on plastic substrates. The wet etch processed TFT with 30 μm gate length and 120 μm gate width exhibits a saturation mobility of 46.25 cm 2 V -1 s -1 , a threshold voltage of 1.3 V, a drain current on-off ratio > 10 6 , and subthreshold gate voltage swing of 0.29 V decade -1 . The performance of the TFTs ensures the applicability of the wet etching process for IGZO to electronic devices on organic polymer substrates.

  18. Dominant rate process of silicon surface etching by hydrogen chloride gas

    International Nuclear Information System (INIS)

    Habuka, Hitoshi; Suzuki, Takahiro; Yamamoto, Sunao; Nakamura, Akio; Takeuchi, Takashi; Aihara, Masahiko

    2005-01-01

    Silicon surface etching and its dominant rate process are studied using hydrogen chloride gas in a wide concentration range of 1-100% in ambient hydrogen at atmospheric pressure in a temperature range of 1023-1423 K, linked with the numerical calculation accounting for the transport phenomena and the surface chemical reaction in the entire reactor. The etch rate, the gaseous products and the surface morphology are experimentally evaluated. The dominant rate equation accounting for the first-order successive reactions at silicon surface by hydrogen chloride gas is shown to be valid. The activation energy of the dominant surface process is evaluated to be 1.5 x 10 5 J mol - 1 . The silicon deposition by the gaseous by-product, trichlorosilane, is shown to have a negligible influence on the silicon etch rate

  19. Characterisation of anisotropic etching in KOH using network etch rate function model: influence of an applied potential in terms of microscopic properties

    International Nuclear Information System (INIS)

    Nguyen, Q D; Elwenspoek, M

    2006-01-01

    Using the network etch rate function model, the anisotropic etch rate of p-type single crystal silicon was characterised in terms of microscopic properties including step velocity, step and terrace roughening. The anisotropic etch rate data needed have been obtained using a combination of 2 wagon wheel patterns on different substrate and 1 offset trench pattern. Using this procedure the influence of an applied potential has been investigated in terms of microscopic properties. Model parameter trends show a good correlation with chemical/electrochemical reaction mechanism and mono- and dihydride terminated steps reactivity difference. Results also indicate a minimum in (111) terrace roughening which results in a peak in anisotropic ratio at the non-OCP applied potential of -1250 mV vs OCP

  20. Image analysis used to count and measure etched tracks from ionizing radiation

    Science.gov (United States)

    Blanford, George E.; Schulz, Cindy K.

    1995-01-01

    of plastic dosimeters is at an early stage of development, results are encouraging. The dosimeter was etched in 6.25 N NaOH at 70 deg C for 16 h. We took 200x secondary electron images of the sample and used the NIH Image software to count and measure major and minor diameters of the etched tracks. We calculated the relative track etch rate from a formula that relates it to the major and minor diameters. We made a histogram of the number of tracks versus their relative etch rate. The relative track etching rate is proportional to the linear energy transfer of the particle. With appropriate calibration experiments, the histogram could be used to calculate the radiation dose.

  1. A Study of Parameters Related to the Etch Rate for a Dry Etch Process Using NF3/O2 and SF6/O2

    Directory of Open Access Journals (Sweden)

    Seon-Geun Oh

    2014-01-01

    Full Text Available The characteristics of the dry etching of SiNx:H thin films for display devices using SF6/O2 and NF3/O2 were investigated using a dual-frequency capacitively coupled plasma reactive ion etching (CCP-RIE system. The investigation was carried out by varying the RF power ratio (13.56 MHz/2 MHz, pressure, and gas flow ratio. For the SiNx:H film, the etch rates obtained using NF3/O2 were higher than those obtained using SF6/O2 under various process conditions. The relationships between the etch rates and the usual monitoring parameters—the optical emission spectroscopy (OES intensity of atomic fluorine (685.1 nm and 702.89 nm and the voltages VH and VL—were investigated. The OES intensity data indicated a correlation between the bulk plasma density and the atomic fluorine density. The etch rate was proportional to the product of the OES intensity of atomic fluorine (I(F and the square root of the voltages (Vh+Vl on the assumption that the velocity of the reactive fluorine was proportional to the square root of the voltages.

  2. In-situ virtual metrology for the silicon-dioxide etch rate by using optical emission spectroscopy data

    International Nuclear Information System (INIS)

    Kim, Boomsoo; Hong, Sangjeen

    2014-01-01

    As a useful tool for process control in a high volume semiconductor manufacturing environment, virtual metrology for the etch rate in a plasma etch process is investigated using optical emission spectroscopy (OES) data. Virtual metrology is a surrogate measurement taken from the process instead of from direct measurement, and it can provide in-situ metrology of a wafer's geometry from a predictive model. A statistical regression model that correlates the selected wavelengths of the optical emission spectra to the etch rate is established using the OES data collected over 20 experimental runs. In addition, an argon actinometry study is employed to quantify the OES data, and it provides valuable insight into the analysis of the OES data. The established virtual metrology model is further verified with an additional 20 runs of data. As a result, the virtual metrology model with both process recipe tool data and in-situ data shows higher prediction accuracy by as much as 56% compared with either the process recipe tool data or the in-situ data alone.

  3. Effect of deposition temperature and thermal annealing on the dry etch rate of a-C: H films for the dry etch hard process of semiconductor devices

    International Nuclear Information System (INIS)

    Lee, Seung Moo; Won, Jaihyung; Yim, Soyoung; Park, Se Jun; Choi, Jongsik; Kim, Jeongtae; Lee, Hyeondeok; Byun, Dongjin

    2012-01-01

    The effect of deposition and thermal annealing temperatures on the dry etch rate of a-C:H films was investigated to increase our fundamental understanding of the relationship between thermal annealing and dry etch rate and to obtain a low dry etch rate hard mask. The hydrocarbon contents and hydrogen concentration were decreased with increasing deposition and annealing temperatures. The I(D)/I(G) intensity ratio and extinction coefficient of the a-C:H films were increased with increasing deposition and annealing temperatures because of the increase of sp 2 bonds in the a-C:H films. There was no relationship between the density of the unpaired electrons and the deposition temperature, or between the density of the unpaired electrons and the annealing temperature. However, the thermally annealed a-C:H films had fewer unpaired electrons compared with the as-deposited ones. Transmission electron microscopy analysis showed the absence of any crystallographic change after thermal annealing. The density of the as-deposited films was increased with increasing deposition temperature. The density of the 600 °C annealed a-C:H films deposited under 450 °C was decreased but at 550 °C was increased, and the density of all 800 °C annealed films was increased. The dry etch rate of the as-deposited a-C:H films was negatively correlated with the deposition temperature. The dry etch rate of the 600 °C annealed a-C:H films deposited at 350 °C and 450 °C was faster than that of the as-deposited film and that of the 800 °C annealed a-C:H films deposited at 350 °C and 450 °C was 17% faster than that of the as-deposited film. However, the dry etch rate of the 550 °C deposited a-C:H film was decreased after annealing at 600 °C and 800 °C. The dry etch rate of the as-deposited films was decreased with increasing density but that of the annealed a-C:H films was not. These results indicated that the dry etch rate of a-C:H films for dry etch hard masks can be further decreased by

  4. Passivation of mechanically polished, chemically etched and anodized zirconium in various aqueous solutions: Impedance measurements

    International Nuclear Information System (INIS)

    Abo-Elenien, G.M.; Abdel-Salam, O.E.

    1987-01-01

    Zirconium and its alloys are finding increasing applications especially in water-cooled nuclear reactors. Because of the fact that zirconium is electronegative (E 0 = -1.529V) its corrosion resistance in aqueous solutions is largely determined by the existence of a thin oxide film on its surface. The structure and properties of this film depend in the first place on the method of surface pre-treatment. This paper presents an experimental study of the nature of the oxide film on mechanically polished, chemically etched and anodized zirconium. Ac impedance measurements carried out in various acidic, neutral and alkaline solutions show that the film thickness depends on the method of surface pre-treatment and the type of electrolyte solution. The variation of the potential and impedance during anodization of zirconium at low current density indicates that the initial stages of polarization consist of oxide build-up at a rate dependent on the nature of the electrode surface and the electrolyte. Oxygen evolution commences at a stage where oxide thickening starts to decline. The effect of frequency on the measured impedance indicates that the surface reactivity, and hence the corrosion rate, decreases in the following order: mechanically polished > chemically etched > anodized

  5. Angular dependence of etch rates in the etching of poly-Si and fluorocarbon polymer using SF6, C4F8, and O2 plasmas

    International Nuclear Information System (INIS)

    Min, Jae-Ho; Lee, Gyeo-Re; Lee, Jin-Kwan; Moon, Sang Heup; Kim, Chang-Koo

    2004-01-01

    The dependences of etch rates on the angle of ions incident on the substrate surface in four plasma/substrate systems that constitute the advanced Bosch process were investigated using a Faraday cage designed for the accurate control of the ion-incident angle. The four systems, established by combining discharge gases and substrates, were a SF 6 /poly-Si, a SF 6 /fluorocarbon polymer, an O 2 /fluorocarbon polymer, and a C 4 F 8 /Si. In the case of SF 6 /poly-Si, the normalized etch rates (NERs), defined as the etch rates normalized by the rate on the horizontal surface, were higher at all angles than values predicted from the cosine of the ion-incident angle. This characteristic curve shape was independent of changes in process variables including the source power and bias voltage. Contrary to the earlier case, the NERs for the O 2 /polymer decreased and eventually reached much lower values than the cosine values at angles between 30 deg. and 70 deg. when the source power was increased and the bias voltage was decreased. On the other hand, the NERs for the SF 6 /polymer showed a weak dependence on the process variables. In the case of C 4 F 8 /Si, which is used in the Bosch process for depositing a fluorocarbon layer on the substrate surface, the deposition rate varied with the ion incident angle, showing an S-shaped curve. These characteristic deposition rate curves, which were highly dependent on the process conditions, could be divided into four distinct regions: a Si sputtering region, an ion-suppressed polymer deposition region, an ion-enhanced polymer deposition region, and an ion-free polymer deposition region. Based on the earlier characteristic angular dependences of the etch (or deposition) rates in the individual systems, ideal process conditions for obtaining an anisotropic etch profile in the advanced Bosch process are proposed

  6. Dose-rate effects on the bulk etch-rate of CR-39 track detector exposed to low-LET radiations

    CERN Document Server

    Yamauchi, T; Oda, K; Ikeda, T; Honda, Y; Tagawa, S

    1999-01-01

    The effect of gamma-rays and pulsed electrons has been investigated on the bulk etch rate of CR-39 detector at doses up to 100 kGy under various dose-rate between 0.0044 and 35.0 Gy/s. The bulk etch rate increased exponentially with the dose at every examined dose-rates. It was reveled to be strongly depend on the dose-rate: the bulk etch rate was decreased with increasing dose-rate at the same total dose. A primitive model was proposed to explain the dose-rate effect in which oxygen dissolved was assumed to dominate the damage formation process.

  7. Bend measurement using an etched fiber incorporating a fiber Bragg grating.

    Science.gov (United States)

    Rauf, Abdul; Zhao, Jianlin; Jiang, Biqiang; Jiang, Yajun; Jiang, Wei

    2013-01-15

    A fiber Bragg grating (FBG) based bend measurement method using an etched fiber is proposed that utilizes the coupling of the core mode to the cladding and radiation modes at the bending region. An etching region of 99 µm diameter that serves as bend sensing head is achieved at 10 mm upstream the FBG through processing in 40% hydrofluoric acid, while the FBG acts as a narrowband reflector to enhance the sensitivity. The power variation curves are obtained for a wide range of bend angles, but the performance is limited due to the presence of the loss peaks. The sensing response is improved by immersing the etching region in a refractive index matching gel. The results are analyzed by using curve fitting formulas and are in good agreement. A large dynamic range of -27° to +27° and sensitivity of 0.43 dBm/deg is achieved, which can be enhanced by reducing the etched diameter.

  8. Plasma etching of niobium-SiO/sub x/ layers

    International Nuclear Information System (INIS)

    Schelle, D.; Tiller, H.J.

    1986-01-01

    CF 4 -plasma etching of niobium and SiO/sub x/ layers has been investigated in a r.f. diode reactor. Etch rates increase linearly with increasing power density and also increase with pressure. The etch rate ratio can be changed using different etch gases or operating in different plasma modes (PE or IEPE). Changing from the ion enhanced plasma etching mode (IEPE) to plasma etching mode (PE) the etch rate ratio is changing by a factor of ten. On the basis of etch rate dependences on process parametes and thermodynamic data it has been suggested the generation of fluorine radicals as the rate limiting step. A general etching model has been proposed, which explains qualitatively and quantitatively (on account of data from literature) the measured results. (author)

  9. Angular dependence of SiO2 etch rate at various bias voltages in a high density CHF3 plasma

    International Nuclear Information System (INIS)

    Lee, Gyeo-Re; Hwang, Sung-Wook; Min, Jae-Ho; Moon, Sang Heup

    2002-01-01

    The dependence of the SiO 2 etch rate on the angle of ions incident on the substrate surface was studied over a bias voltage range from -20 to -600 V in a high-density CHF 3 plasma using a Faraday cage to control the ion incident angle. The effect of the bottom plane on the sidewall etching was also examined. Differences in the characteristics of the etch rate as a function of the ion angle were observed for different bias voltage regions. When the absolute value of the bias voltage was smaller than 200 V, the normalized etch rate (NER) defined as the etch rate normalized by the rate on the horizontal surface, changed following a cosine curve with respect to the ion incident angle, defined as the angle between the ion direction and the normal of the substrate surface. When the magnitude of the bias voltage was larger than 200 V, the NER was deviated to higher values from those given by a cosine curve at ion angles between 30 deg. and 70 deg. , and then drastically decreased at angles higher than 70 deg. until a net deposition was observed at angles near 90 deg. . The characteristic etch-rate patterns at ion angles below 70 deg. were determined by the ion energy transferred to the surface, which affected the SiO 2 etch rate and, simultaneously, the rate of removal of a fluorocarbon polymer film formed on the substrate surface. At high ion angles, particles emitted from the bottom plane contributed to polymer formation on and affected the etching characteristics of the substrate

  10. Measurement of low neutron fluences with polycarbonate foils electrochemically etched with methyl alcohol-KOH solution

    International Nuclear Information System (INIS)

    Kumamoto, Y.

    1982-01-01

    Electrochemical etching of polycarbonate foils was performed using a KOH solution with a high concentration of methyl alcohol under different conditions of field strength, frequency, temperature and etching time. These studies showed that the highest neutron sensitivity relative to the inherent background in the foil was obtained under the following etching conditions: 52 kV/cm, 1 kHz, 30 0 C, 30 min in a solution of 45 gm KOH + 80 cc CH 3 OH + 20 cc H 2 O. Under these conditions, 100 mrem of neutrons from a Ra-Be source gave 70 pits per cm 2 while background was 7 +- 3 pits per cm 2 (10 +- 5 mrem). The pit diameters were about 90 μm. This sensitivity (giving lowest measurable dose of 15 mrem) is quite sufficient for personnel neutron dosimetry applications and the size of the pits is large enough for easy counting using a microscope at magnification of 40X. (author)

  11. Measurement of low neutron-fluences using electrochemically etched PC and PET track detectors

    International Nuclear Information System (INIS)

    Somogyi, G.; Dajko, G.; Turek, K.; Spurny, F.

    1979-01-01

    Systematic investigations have been carried out to study different properties of electrochemically etched (ECE) polycarbonate (PC) and polyethylene-terephthalate (PET) foils. The dependence of the density of background discharge spots on surface-thickness removal, electrical field strength and frequency of voltage is given. The effect of these parameters on the neutron sensitivity of polycarbonate and polyethylene-terephthalate foils irradiated at right angles to 14.7 MeV, 241 Am-Be and 252 Cf neutrons is also studied. With knowledge of the background and sensitivity data, the etching and electrical parameters are optimized for low neutron-fluence measurements. (author)

  12. The effect of hydroxyapatite presence on the degree of conversion and polymerization rate in a model self-etching adhesive

    Science.gov (United States)

    Zhang, Ying; Wang, Yong

    2011-01-01

    Objective The effect of hydroxyapatite (HAp) content on photopolymerization of a model self-etching adhesive was studied by using attenuated total reflectance Fourier transform infrared (ATR/FT-IR) spectroscopy. Materials and methods The model adhesive contained two monomers: bis[2-(methacryloyloxy)ethyl] phosphate (2MP) and 2-hydroxyethyl methacrylate (HEMA) using a 1:1 mass ratio, representing an acidic formulation. Camphorquinone and ethyl 4-dimethylaminobenzoate were added to enable visible light photopolymerization in a constant concentration of 0.022 mmol per gram monomer. HAp [Ca10(OH)2(PO4)6] powder were added to the test solutions to obtain mass fraction of 0, 1, 2, 3, 4 wt%. The degree of conversion (DC) and the polymerization rate (PR) with/without HAp were determined using ATR/FT-IR with a time-based spectrum analysis. Results Monomer DC and PR were significantly enhanced by addition of HAp. Incorporation of 4 wt% of HAp increased DC from 20.8 (±0.3) % to 93.4 (±1.1) %, and PR from 0.42 (±0.01) %/s to 3.21 (±0.07) %/s. The pH of adhesive solutions was measured and correlated with DC and PR. The pH of test solutions was also controlled using a base (sodium hydroxide, NaOH) to similar values as when using HAp. Results indicated that both the DC and PR increased with increasing pH, regardless of additive, confirming the role of pH on polymerization. From the IR spectral comparison, changes in molecular structures of the self-etching adhesive after the addition of HAp were observed, which were correlated with the specific interaction between 2MP and HAp. The effect of viscosity was also proposed to be another possible reason for the improved polymerization. Significance The photopolymerization of a self-etching adhesive was enhanced / accelerated in the presence of HAp. The results provide the critical information for understanding the interactions/bonding between self-etching adhesives and tooth substrates. PMID:22032933

  13. Radon Measurements in Egypt using passive etched track detectors. A Review

    Energy Technology Data Exchange (ETDEWEB)

    Gomaa, M A [National Network of Radiation Physics. Atomic Energy Authority (Egypt); Hussein, A S [Radiation Protection Department, Nuclear Power Plants Authority, (Egypt); El-Arabi, A M [Physics Department, Faculty of Science, South Valley University, Qena, (Egypt)

    2005-04-01

    Radon and its progeny may cause serious radiation harm to human health such as lung cancer and other types. Radon measurements based on alpha particles etched track detectors (LR-115, CR-39) are very attractive for assessment of radon exposure. This is due to their high sensitivity, low cost, easy to handle and retain a permanent record of data. Also these detectors can incorporate the effects of seasonal and diurnal fluctuation of radon activity concentrations due to physical, geological and meteorological factors. The present review is based mainly on the topic of passive etched track detectors for the measurements of radon in Egypt in the recent years. Published papers includes the measurements of radon in dwellings, working places, Cairo Metro stations, ancient Pharaonic places and uranium exploration galleries as well as assessment of radon in drinking water.

  14. Radon Measurements in Egypt using passive etched track detectors. A Review

    International Nuclear Information System (INIS)

    Gomaa, M.A.; Hussein, A.S.; El-Arabi, A.M.

    2005-01-01

    Radon and its progeny may cause serious radiation harm to human health such as lung cancer and other types. Radon measurements based on alpha particles etched track detectors (LR-115, CR-39) are very attractive for assessment of radon exposure. This is due to their high sensitivity, low cost, easy to handle and retain a permanent record of data. Also these detectors can incorporate the effects of seasonal and diurnal fluctuation of radon activity concentrations due to physical, geological and meteorological factors. The present review is based mainly on the topic of passive etched track detectors for the measurements of radon in Egypt in the recent years. Published papers includes the measurements of radon in dwellings, working places, Cairo Metro stations, ancient Pharaonic places and uranium exploration galleries as well as assessment of radon in drinking water

  15. Elemental depth profiles and plasma etching rates of positive-tone electron beam resists after sequential infiltration synthesis of alumina

    Science.gov (United States)

    Ozaki, Yuki; Ito, Shunya; Hiroshiba, Nobuya; Nakamura, Takahiro; Nakagawa, Masaru

    2018-06-01

    By scanning transmission electron microscopy and energy dispersive X-ray spectroscopy (STEM–EDS), we investigated the elemental depth profiles of organic electron beam resist films after the sequential infiltration synthesis (SIS) of inorganic alumina. Although a 40-nm-thick poly(methyl methacrylate) (PMMA) film was entirely hybridized with alumina, an uneven distribution was observed near the interface between the substrate and the resist as well as near the resist surface. The uneven distribution was observed around the center of a 100-nm-thick PMMA film. The thicknesses of the PMMA and CSAR62 resist films decreased almost linearly as functions of plasma etching period. The comparison of etching rate among oxygen reactive ion etching, C3F8 reactive ion beam etching (RIBE), and Ar ion beam milling suggested that the SIS treatment enhanced the etching resistance of the electron beam resists to chemical reactions rather than to ion collisions. We proposed oxygen- and Ar-assisted C3F8 RIBE for the fabrication of silica imprint molds by electron beam lithography.

  16. Etching characteristics of a CR-39 track detector at room temperature in different etching solutions

    International Nuclear Information System (INIS)

    Dajko, G.

    1991-01-01

    Investigations were carried out to discover how the etching characteristics of CR-39 detectors change with varying conditions of the etching process. Measurements were made at room temperature in pure NaOH and KOH solutions; in different alcoholic KOH solutions (PEW solution, i.e. potassium hydroxide, ethyl alcohol, water); and in NaOH and KOH solutions containing different additives. The bulk etching rate of the detector (V B ) and the V (= V T /V B ) function, i.e. track to bulk etch rates ratio, for 6.1 MeV α-particles, were measured systematically. (author)

  17. Thermal etching rate of GaN during MOCVD growth interruption in hydrogen and ammonia ambient determined by AlGaN/GaN superlattice structures

    Science.gov (United States)

    Zhang, Feng; Ikeda, Masao; Zhang, Shuming; Liu, Jianping; Tian, Aiqin; Wen, Pengyan; Cheng, Yang; Yang, Hui

    2017-10-01

    Thermal etching effect of GaN during growth interruption in the metalorganic chemical vapor deposition reactor was investigated in this paper. The thermal etching rate was determined by growing a series of AlGaN/GaN superlattice structures with fixed GaN growth temperature at 735 °C and various AlGaN growth temperature changing from 900 °C to 1007 °C. It was observed that the GaN layer was etched off during the growth interruption when the growth temperature ramped up to AlGaN growth temperature. The etching thickness was determined by high resolution X-ray diffractometer and the etching rate was deduced accordingly. An activation energy of 2.53 eV was obtained for the thermal etching process.

  18. Angular dependence of Si3N4 etch rates and the etch selectivity of SiO2 to Si3N4 at different bias voltages in a high-density C4F8 plasma

    International Nuclear Information System (INIS)

    Lee, Jin-Kwan; Lee, Gyeo-Re; Min, Jae-Ho; Moon, Sang Heup

    2007-01-01

    The dependence of Si 3 N 4 etch rates and the etch selectivity of SiO 2 to Si 3 N 4 on ion-incident angles was studied for different bias voltages in a high-density C 4 F 8 plasma. A Faraday cage and specially designed substrate holders were used to accurately control the angles of incident ions on the substrate surface. The normalized etch yield (NEY), defined as the etch yield obtained at a given ion-incident angle normalized to that obtained on a horizontal surface, was unaffected by the bias voltage in Si 3 N 4 etching, but it increased with the bias voltage in SiO 2 etching in the range of -100 to -300 V. The NEY changed showing a maximum with an increase in the ion-incident angle in the etching of both substrates. In the Si 3 N 4 etching, a maximum NEY of 1.7 was obtained at 70 deg. in the above bias voltage range. However, an increase in the NEY at high ion-incident angles was smaller for SiO 2 than for Si 3 N 4 and, consequently, the etch selectivity of SiO 2 to Si 3 N 4 decreased with an increase in the ion-incident angle. The etch selectivity decreased to a smaller extent at high bias voltage because the NEY of SiO 2 had increased. The characteristic changes in the NEY for different substrates could be correlated with the thickness of a steady-state fluorocarbon (CF x ) film formed on the substrates

  19. Vacuum pump age effects by the exposure to the corrosive gases on the Cr etch rate as observed using optical emission spectroscopy in an Ar/O{sub 2}/Cl{sub 2} mixed plasma

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seolhye; Roh, Hyun-Joon; Jang, Yunchang; Jeong, Sangmin; Ryu, Sangwon; Choe, Jae-Myung; Kim, Gon-Ho, E-mail: ghkim@snu.ac.kr

    2016-03-31

    Vacuum pumps of different ages were used to prepare Cl{sub 2} based plasmas for use in Cr etching. The effects of the vacuum pump age on the etching results were investigated using optical emission spectroscopy analysis. The composition of gas at the base pressure was mainly nitrogen and oxygen, although the ratio depended on the vacuum pump age and therefore, modulated the etch rate in a manner that was difficult to monitor. The effects of the pump age on the etch rate were clearly observed in the Cl{sub 2} plasma-assisted chromium film etching process, in which oxygen and chlorine radicals were responsible for the etching process. The electron energy distribution function (EEDF), which provided a proxy for the thermal equilibrium properties of the etching plasmas, was monitored. The shape of EEDF was derived from an analysis of the optical emission spectral data using an analysis model described previously. Because molecular nitrogen has a higher threshold energy and a larger cross-section of inelastic collisional processes than oxygen, the tail of the EEDF depends on the mixing ratio between nitrogen and oxygen. The various mechanisms that contribute to the chromium etch rate varied with subtle differences in the vacuum conditions, which were determined by age of the turbo molecular pump. The rates at which oxygen and chlorine radicals were generated were estimated using the measured EEDF, and the estimated oxygen radical and etching product contents were verified by comparing the residual gas analyzer data. The results revealed that the residual nitrogen partial pressures in two etchers equipped with either a new or an aged pump differed by 0.18%, and the EEDF tail areas differed by 10{sup −4}. Importantly, the chromium etch rates in these two instruments differed by 30%. These results suggest that the chamber-to-chamber mismatch should be monitored during plasma-assisted device fabrication processes. - Highlights: • We observed the vacuum pump age effect

  20. Single Mode Optical Fiber based Refractive Index Sensor using Etched Cladding

    OpenAIRE

    Kumar, Ajay; Gupta, Geeta; Mallik, Arun; Bhatnagar, Anuj

    2011-01-01

    The use of optical fiber for sensor applications is a topic of current interest. We report the fabrication of etched single mode optical fiber based refractive index sensor. Experiments are performed to determine the etch rate of fiber in buffered hydrofluoric acid, which can be high or low depending upon the temperature at which etching is carried out. Controlled wet etching of fiber cladding is performed using these measurements and etched fiber region is tested for refractive index sensing...

  1. Long-term measurements of equilibrium factor with electrochemically etched CR-39 SSNTD

    International Nuclear Information System (INIS)

    Ng, F.M.F.; Nikezic, D.; Yu, K.N.

    2007-01-01

    Recently, our group proposed a method (proxy equilibrium factor method) using a bare LR 115 detector for long-term monitoring of the equilibrium factor. Due to the presence of an upper alpha-particle energy threshold for track formation in the LR 115 detector, the partial sensitivities to 222 Rn, 218 Po and 214 Po were the same, which made possible measurements of a proxy equilibrium factor F p that was well correlated with the equilibrium factor. In the present work, the method is extended to CR-39 detectors which have better-controlled etching properties but do not have an upper energy threshold. An exposed bare CR-39 detector is first pre-etched in 6.25 N NaOH solution at 70 o C for 6 h, and then etched electrochemically in a 6.25 N NaOH solution with ac voltage of 400 V (peak to peak) and 5 kHz applied across the detectors for 1 h at room temperature. Under these conditions, for tracks corresponding to incident angles larger than or equal to 50 deg., the treeing efficiency is 0% and 100% for incident energies smaller than and larger than 4 MeV, respectively. A simple method is then proposed to obtain the total number of tracks formed below the upper energy threshold of 4 MeV, from which the proxy equilibrium factor method can apply

  2. Estimation of track registration efficiency in solution medium and study of gamma irradiation effects on the bulk-etch rate and the activation energy for bulk etching of CR-39 (DOP) Solid State Nuclear Track Detector

    International Nuclear Information System (INIS)

    Kalsi, P.C.

    2010-01-01

    The fission track registration efficiency of diethylene glycol bis allyl carbonate (dioctyl phthalate doped) (CR-39 (DOP)) solid state nuclear track detector (SSNTD) in solution medium (K wet ) has been experimentally determined and is found to be (9.7 ± 0.5).10 -4 cm. This is in good agreement with the values of other SSNTDs. The gamma irradiation effects in the dose range of 50.0-220.0 kGy on the bulk etch rate, V b and the activation energy for bulk etching, E of this solid state nuclear track detector (SSNTD) have also been studied. It is observed that the bulk etch rates increase and the activation energies for bulk etching decrease with the increase in gamma dose. These results have been explained on the basis of scission of the detector due to gamma irradiation

  3. Precision Recess of AlGaN/GaN with Controllable Etching Rate Using ICP-RIE Oxidation and Wet Etching

    NARCIS (Netherlands)

    Sokolovskij, R.; Sun, J.; Santagata, F.; Iervolino, E.; Li, S.; Zhang, G.Y.; Sarro, P.M.; Zhang, G.Q.

    2016-01-01

    A method for highly controllable etching of AlGaN/GaN for the fabrication of high sensitivity HEMT based sensors is developed. The process consists of cyclic oxidation of nitride with O2 plasma using ICP-RIE etcher followed by wet etching of the oxidized layer. Previously reported

  4. Device fabrication by plasma etching

    International Nuclear Information System (INIS)

    Mogab, C.J.

    1980-01-01

    Plasma etching as applied to many of the materials encountered in the fabrication of LSI's is complicated by loading effect-the dependence of etch rate on the integrated surface area to be etched. This problem is alleviated by appropriate choice of etchant and etching conditions. Appropriate choice of system parameters, generally most concerned with the inherent lifetime of etchant species, may also result in improvement of etch rate uniformity on a wafer-by-wafer basis

  5. Radon measurements by etched track detectors applications in radiation protection, earth sciences and the environment

    CERN Document Server

    Durrani, Saeed A

    1997-01-01

    Exposure to radon gas, which is present in the environment naturally, constitutes over half the radiation dose received by the general public annually. At present, the most widely used method of measuring radon concentration levels throughout the world, both in dwellings and in the field, is by etched track detectors - also known as Solid State Nuclear Detectors (SSNTDs). Although this is not only the most widely used method but is also the simplest and the cheapest, yet there is at present no book available on the market globally, devoted exclusively or largely to the methodology of, and deal

  6. Measurement of nanosize etched pits in SiO2 optical fiber conduit using AFM

    International Nuclear Information System (INIS)

    Espinosa, G.; Golzarri, J.I.; Vazquez, C.; Fragoso, R.

    2003-01-01

    Fission fragment tracks from 252 Cf have been observed in SiO 2 optical fiber, using an atomic force microscope (AFM), after a very short chemical etching in hydrofluoric acid solution at normal temperature. The nuclear track starting and evolution process is followed by the AFM direct measurements on the material surface and beyond a fine layer of the surface material. The images of the scanned cones were determined observing the two predominant energies from 252 Cf fission fragments and the development of the tracks in the 150 μm diameter optical fiber conduit

  7. Properties and etching rates of negative ions in inductively coupled plasmas and dc discharges produced in Ar/SF6

    International Nuclear Information System (INIS)

    Draghici, M.; Stamate, E.

    2010-01-01

    Negative ion production is investigated in a chamber with transversal magnetic filter operated in dc or inductively coupled plasma (ICP) modes in Ar/SF 6 gas mixtures. Plasma parameters are evaluated by mass spectrometry and Langmuir probe for different discharge conditions. The density ratio of negative ion to electron exceeded 300 in dc mode while it was below 100 in the ICP mode. The possibility to apply a large positive bias to an electrode without affecting the plasma potential and the transition from a negative sheath to anodic glow are also investigated. The etching rates by positive and negative ions are evaluated on silicon substrate for different Ar/SF 6 gas ratios. The etching rate by negative ions was with less than 5% smaller than that by positive ions.

  8. Properties and etching rates of negative ions in inductively coupled plasmas and dc discharges produced in Ar/SF6

    DEFF Research Database (Denmark)

    Draghici, Mihai; Stamate, Eugen

    2010-01-01

    of negative ion to electron exceeded 300 in dc mode while it was below 100 in the ICP mode. The possibility to apply a large positive bias to an electrode without affecting the plasma potential and the transition from a negative sheath to anodic glow are also investigated. The etching rates by positive...... and negative ions are evaluated on silicon substrate for different Ar/SF6 gas ratios. The etching rate by negative ions was with less than 5% smaller than that by positive ions.......Negative ion production is investigated in a chamber with transversal magnetic filter operated in dc or inductively coupled plasma (ICP) modes in Ar/SF6 gas mixtures. Plasma parameters are evaluated by mass spectrometry and Langmuir probe for different discharge conditions. The density ratio...

  9. Track etch detectors with air gap for measurements of radon in soil

    Energy Technology Data Exchange (ETDEWEB)

    Turek, K; Bednar, J [Czech Academy of Sciences, 18086 Prague (Czech Republic). Nuclear Research Inst., Dept. of Radiation Dosimetry; Neznal, M [Radon Corp., 28922 Lysa nad Labem (Czech Republic)

    1996-12-31

    The main aim of this study was to develop a method of radon concentration measurements in soil using track etch detectors without cups. Our approach enables to minimize the detector dimensions resulting into smaller diameter of drilled holes, more rigid construction, easier handling and mailing, lower consumption of material and consequently in lower costs. The parallel arrangement of two track etch detectors in the open metallic holder seems to be promising as the complementary method to the commonly used cup-technique for radon measurement. The firmness, simple and compact construction, small size as well as low costs could be successfully utilized mainly in field measurement. The possibility of a variable sensitivity by the distance between the detectors makes the system versatile for many applications, 2 detectors with different h can practically exclude of under- or overexposure. The more precise calibrations including exposures in radon-chamber and study of an eventual influence of humidity are supposed to be done in the nearest future. (J.K) 2 tabs.

  10. Bulk and track etching of PET studied by spectrophotometer

    International Nuclear Information System (INIS)

    Zhu, Z.Y.; Duan, J.L.; Maekawa, Y.; Koshikawa, H.; Yoshida, M.

    2004-01-01

    UV-VIS spectra of poly(ethylene terephthalate) (PET) solutions formed by etching PET in NaOH solution were analyzed with respect to the etching time. A linear relationship between absorptions centered at 4.45 and 5.11 eV with weight loss of PET in NaOH solution was established. The relation was applied to study the influence of UV light illumination on bulk etching of PET and to evaluate pore size of etched-through tracks. It is found that bulk etching of PET can be greatly enhanced by UV illumination in air in the wavelength range around 313 nm. A surface area of about 350 nm in thickness shows a 23 times increase in bulk-etching rate after illuminated for 6 h. The phenomenon is attributed to the oxygen-assisted photo-degradation through generating of new photo-unstable species. The enhancement in bulk etching was immediately reduced as the etching proceeds below the surface with an exponential decay constant of about 1.5 μm -1 . Etching of Xe ion irradiated PET films gives extra etching products with similar chemical structure as revealed by spectrophotometer measurements. Quantitative analysis of etching products from latent tracks implies that pores of about 14.6 nm in radius are formed after etching in 0.74 N NaOH at 40 deg. C for 35 min, which is in agreement with the conductometric measurement

  11. Plasmonic nanoshell functionalized etched fiber Bragg gratings for highly sensitive refractive index measurements.

    Science.gov (United States)

    Burgmeier, Jörg; Feizpour, Amin; Schade, Wolfgang; Reinhard, Björn M

    2015-02-15

    A novel fiber optical refractive index sensor based on gold nanoshells immobilized on the surface of an etched single-mode fiber including a Bragg grating is demonstrated. The nanoparticle coating induces refractive index dependent waveguide losses, because of the variation of the evanescently guided part of the light. Hence the amplitude of the Bragg reflection is highly sensitive to refractive index changes of the surrounding medium. The nanoshell functionalized fiber optical refractive index sensor works in reflectance mode, is suitable for chemical and biochemical sensing, and shows an intensity dependency of 4400% per refractive index unit in the refractive index range between 1.333 and 1.346. Furthermore, the physical length of the sensor is smaller than 3 mm with a diameter of 6 μm, and therefore offers the possibility of a localized refractive index measurement.

  12. Simultaneous measurement of magnetic field and temperature based on an etched TCFMI cascaded with an FBG

    Science.gov (United States)

    Yan, Guofeng; Zhang, Liang; He, Sailing

    2016-04-01

    In this paper, a dual-parameter measurement scheme based on an etched thin core fiber modal interferometer (TCMI) cascaded with a fiber Bragg grating (FBG) is proposed and experimentally demonstrated for simultaneous measurement of magnetic field and temperature. The magnetic field and temperature responses of the packaged TCFMI were first investigated, which showed that the magnetic field sensitivity could be highly enhanced by decreasing of the TCF diameter and the temperature-cross sensitivities were up to 3-7 Oe/°C at 1550 nm. Then, the theoretical analysis and experimental demonstration of the proposed dual-parameter sensing scheme were conducted. Experimental results show that, the reflection of the FBG has a magnetic field intensity and temperature sensitivities of -0.017 dB/Oe and 0.133 dB/°C, respectively, while the Bragg wavelength of the FBG is insensitive to magnetic field and has a temperature sensitivity of 13.23 pm/°C. Thus by using the sensing matrix method, the intensity of the magnetic field and the temperature variance can be measured, which enables magnetic field sensing under strict temperature environments. In the on-off time response test, the fabricated sensor exhibited high repeatability and short response time of ∼19.4 s. Meanwhile the reflective sensing probe type is more compact and practical for applications in hard-to-reach conditions.

  13. Radon and radon-daughter exposure measurements by through-etched track registration in cellulose nitrate

    International Nuclear Information System (INIS)

    Knoefell, T.M.J.; Silva Estrada, J.J. da; Tavares, O.A.P.; Martins, J.B.

    1981-01-01

    The use of cellulose nitrate films LR-115 type II (Kodak-Pathe) as a practical, exposure integrating device to measure the level of exposure to alpha particles in atmospheres which contain radon and radon-daughter products is investigated. The analysis of a number of cellulose nitrate films that have been exposed to calibrated radon test-chamber atmospheres has indicated good correlations between through-etched track density p and integrated alpha-particle exposure Σa (Working-Level-Hour). It is shown that the response of the cellulose nitrate detector to radon-daughter alpha-particle exposures is linear, and that reliable conservative estimations of the Working-Level-Hour can be obtained from Σa = 3.0(p-b), where p is expressed in tracks/mm 2 (b is the background level). These results recommend the use of the special red cellulose nitrate films as a convenient dosimeter for monitoring radioactive contaminants in mine atmospheres. (Author) [pt

  14. Polymer degradation in reactive ion etching and its possible application to all dry processes

    International Nuclear Information System (INIS)

    Hiraoka, H.; Welsh, L.W. Jr.

    1981-01-01

    Dry etching processes involving CF 4 -plasma and reactive ion etching become increasingly important for microcircuit fabrication techniques. In these techniques polymer degradation and etch resistance against reactive species like F atoms and CF 3 + ions are the key factors in the processes. It is well-known that classical electron beam resists like poly(methyl methacrylate) and poly(1-butene sulfone) are not suitable for dry etching processes because they degrade rapidly under these etching conditions. In order to find a correlation of etching rate and polymer structures the thickness loss of polymer films have been measured for a variety of polymer films in reactive ion etching conditions, where CF 3 + ions are the major reactive species with an accelerating potential of 500 volts. Because of its high CF 4 -plasma and reactive ion etch resistance, and because of its high electron beam sensitivity, poly(methacrylonitrile) provides a positive working electron beam resist uniquely suited for all dry processes. (author)

  15. Controlled ion track etching

    Science.gov (United States)

    George, J.; Irkens, M.; Neumann, S.; Scherer, U. W.; Srivastava, A.; Sinha, D.; Fink, D.

    2006-03-01

    It is a common practice since long to follow the ion track-etching process in thin foils via conductometry, i.e . by measurement of the electrical current which passes through the etched track, once the track breakthrough condition has been achieved. The major disadvantage of this approach, namely the absence of any major detectable signal before breakthrough, can be avoided by examining the track-etching process capacitively. This method allows one to define precisely not only the breakthrough point before it is reached, but also the length of any non-transient track. Combining both capacitive and conductive etching allows one to control the etching process perfectly. Examples and possible applications are given.

  16. Ion-beam etching of ramps in thin film heterostructures

    International Nuclear Information System (INIS)

    Mozhaev, P. B.; Mozhaeva, Ju. E.; Komissinskii, P. V.

    2002-01-01

    Ion-beam patterning of thin films and heterostructures is one of the most common processes of fabrication of thin film devices and structures. 'Directed' nature of ion-beam etching provides a possibility to form certain profiles on the films surface, like shallow ramps, when etching is performed at some inclination angle. A simple geometrical model is presented, describing the formation of a ramp as a shadow of the mask on the film surface. Good agreement with the experiment can be obtained if the mask etching is taken into account. The etching at the opposite direction ('high-angle etching') also can be satisfactory described by the model. The profile of the slope - positive or negative curvature, pits near the end of the ramp - is discussed as a function of the etch rate dependence on the incidence angle. Such etch rate dependences for some often used materials were measured. An area of instability of the resulting ramp shape is found for the 'high-angle etching'. The model is compared with the experimental data reported by other groups. Finally ion-beam etching of a rotating sample at non-normal incidence is discussed, the results are compared with experimental data. (Authors)

  17. Dry Etching

    DEFF Research Database (Denmark)

    Stamate, Eugen; Yeom, Geun Young

    2016-01-01

    generation) to 2,200 × 2,500 mm (eighth generation), and the substrate size is expected to increase further within a few years. This chapter aims to present relevant details on dry etching including the phenomenology, materials to be etched with the different recipes, plasma sources fulfilling the dry...

  18. Power ultrasound irradiation during the alkaline etching process of the 2024 aluminum alloy

    Science.gov (United States)

    Moutarlier, V.; Viennet, R.; Rolet, J.; Gigandet, M. P.; Hihn, J. Y.

    2015-11-01

    Prior to any surface treatment on an aluminum alloy, a surface preparation is necessary. This commonly consists in performing an alkaline etching followed by acid deoxidizing. In this work, the use of power ultrasound irradiation during the etching step on the 2024 aluminum alloy was studied. The etching rate was estimated by weight loss, and the alkaline film formed during the etching step was characterized by glow discharge optical emission spectrometry (GDOES) and scanning electron microscope (SEM). The benefit of power ultrasound during the etching step was confirmed by pitting potential measurement in NaCl solution after a post-treatment (anodizing).

  19. Etching of fused silica fiber by metallic laser-induced backside wet etching technique

    Energy Technology Data Exchange (ETDEWEB)

    Vass, Cs., E-mail: vasscsaba@physx.u-szeged.hu [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dóm tér 9 (Hungary); Kiss, B.; Kopniczky, J.; Hopp, B. [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dóm tér 9 (Hungary)

    2013-08-01

    The tip of multimode fused silica fiber (core diameter: 550 μm) was etched by metallic laser-induced backside wet etching (M-LIBWE) method. Frequency doubled, Q-switched Nd:YAG laser (λ = 532 nm; τ{sub FWHM} = 8 ns) was used as laser source. The laser beam was coupled into the fiber by a fused silica lens with a focal length of 1500 mm. The other tip of the fiber was dipped into liquid gallium metallic absorber. The etching threshold fluence was measured to be 475 mJ/cm{sup 2}, while the highest fluence, which resulted etching without breaking the fiber, was 1060 mJ/cm{sup 2}. The progress of etching was followed by optical microscopy, and the etch rate was measured to be between 20 and 37 nm/pulse depending on the applied laser energy. The surface morphologies of the etched tips were studied by scanning electron microscopy. A possible application of the structured fibers was also tested.

  20. Etching of fused silica fiber by metallic laser-induced backside wet etching technique

    International Nuclear Information System (INIS)

    Vass, Cs.; Kiss, B.; Kopniczky, J.; Hopp, B.

    2013-01-01

    The tip of multimode fused silica fiber (core diameter: 550 μm) was etched by metallic laser-induced backside wet etching (M-LIBWE) method. Frequency doubled, Q-switched Nd:YAG laser (λ = 532 nm; τ FWHM = 8 ns) was used as laser source. The laser beam was coupled into the fiber by a fused silica lens with a focal length of 1500 mm. The other tip of the fiber was dipped into liquid gallium metallic absorber. The etching threshold fluence was measured to be 475 mJ/cm 2 , while the highest fluence, which resulted etching without breaking the fiber, was 1060 mJ/cm 2 . The progress of etching was followed by optical microscopy, and the etch rate was measured to be between 20 and 37 nm/pulse depending on the applied laser energy. The surface morphologies of the etched tips were studied by scanning electron microscopy. A possible application of the structured fibers was also tested.

  1. Measurement of radon and thoron present in the environment using nuclear track etch detector technique

    International Nuclear Information System (INIS)

    Ramachandran, T.V.; Lalit, B.Y.; Mishra, U.C.

    1986-01-01

    The use of solid state nuclear track detectors (SSNTD) is one of the most convenient techniques to assess the average radiation levels of alpha activities in the environment. This technique has been used to assess the radon and thoron concentrations in some high background areas of South India and underground non-uranium mines in Bihar State. Exposed SSNTD films are chemically etched in an alkali solution and the alpha tracks are evaluated under an optical microscope. The detailed procedure for this study and the calibration of the etched films for conversion of alpha track density to radon and thoron concentrations in pCi l -1 are given in this paper. It was found that 1.9 tracks cm -2 day -1 and 6.2 tracks cm -2 day -1 were produced by exposing the LR-115 foils to 1 pCi l -1 of thoron and radon respectively. (author)

  2. CONTRIBUTION OF DIFFERENT PARTICLES MEASURED WITH TRACK ETCHED DETECTORS ONBOARD ISS.

    Science.gov (United States)

    Ambrožová, I; Davídková, M; Brabcová, K Pachnerová; Tolochek, R V; Shurshakov, V A

    2017-09-29

    Cosmic radiation consists of primary high-energy galactic and solar particles. When passing through spacecraft walls and astronauts' bodies, the spectrum becomes even more complex due to generating of secondary particles through fragmentation and nuclear interactions. Total radiation exposure is contributed by both these components. With an advantage, space research uses track etched detectors from the group of passive detectors visualizing the tracks of particles, in this case by etching. The detectors can discriminate between various components of cosmic radiation. A method is introduced for the separation of the different types of particles according to their range using track etched detectors. The method is demonstrated using detectors placed in Russian segment of the International Space Station in 2009. It is shown that the primary high-energy heavy ions with long range contribute up to 56% of the absorbed dose and up to 50% to the dose equivalent. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Anisotropic etching of silicon for application in micro machine using plasma of SF6/CH4/O2/Ar and SF6/CF4/O2/Ar

    International Nuclear Information System (INIS)

    Reyes B, C.; Moshkalyov, S.A.; Swart, J.W.

    2004-01-01

    We investigated the reactive ion etching of silicon using SF 6 /CH 4 (CF 4 )/O 2 /Ar gas mixtures containing fluorine for MEMS applications. Etch rates and anisotropy of etch profiles were examined as a function of gas composition, material of electrode, and RF power. Etch depths were measured using a profilometers, and etch profiles were analyzed by scanning electron microscope. As a mask material, an aluminium film deposited by evaporation, was used. High anisotropy of etching of 0.95 was achieved at etch depths up to 20-30 micrometers and etch rates of approximately 0.3-0.6 μm/min. Highly anisotropic etching is based on a mechanism that enhance the ion bombarding and protects the sidewalls due to polymerization and/or oxidation mechanisms in order to avoid the lateral etch. However, under the anisotropic etching conditions, considerable damages of the etched surfaces (roughness formation), were observed. After etching experiments, wet / dry cleaning procedures were applied to remove surface residues resulting from the reactive ion etching and to improve the etched surface morphology. (Author)

  4. Growth and Etch Rate Study of Low Temperature Anodic Silicon Dioxide Thin Films

    Directory of Open Access Journals (Sweden)

    Akarapu Ashok

    2014-01-01

    Full Text Available Silicon dioxide (SiO2 thin films are most commonly used insulating films in the fabrication of silicon-based integrated circuits (ICs and microelectromechanical systems (MEMS. Several techniques with different processing environments have been investigated to deposit silicon dioxide films at temperatures down to room temperature. Anodic oxidation of silicon is one of the low temperature processes to grow oxide films even below room temperature. In the present work, uniform silicon dioxide thin films are grown at room temperature by using anodic oxidation technique. Oxide films are synthesized in potentiostatic and potentiodynamic regimes at large applied voltages in order to investigate the effect of voltage, mechanical stirring of electrolyte, current density and the water percentage on growth rate, and the different properties of as-grown oxide films. Ellipsometry, FTIR, and SEM are employed to investigate various properties of the oxide films. A 5.25 Å/V growth rate is achieved in potentiostatic mode. In the case of potentiodynamic mode, 160 nm thickness is attained at 300 V. The oxide films developed in both modes are slightly silicon rich, uniform, and less porous. The present study is intended to inspect various properties which are considered for applications in MEMS and Microelectronics.

  5. Correlation of film density and wet etch rate in hydrofluoric acid of plasma enhanced atomic layer deposited silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Provine, J., E-mail: jprovine@stanford.edu; Schindler, Peter; Kim, Yongmin; Walch, Steve P.; Kim, Hyo Jin [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Kim, Ki-Hyun [Manufacturing Technology Center, Samsung Electronics, Suwon, Gyeonggi-Do (Korea, Republic of); Prinz, Fritz B. [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

    2016-06-15

    The continued scaling in transistors and memory elements has necessitated the development of atomic layer deposition (ALD) of silicon nitride (SiN{sub x}), particularly for use a low k dielectric spacer. One of the key material properties needed for SiN{sub x} films is a low wet etch rate (WER) in hydrofluoric (HF) acid. In this work, we report on the evaluation of multiple precursors for plasma enhanced atomic layer deposition (PEALD) of SiN{sub x} and evaluate the film’s WER in 100:1 dilutions of HF in H{sub 2}O. The remote plasma capability available in PEALD, enabled controlling the density of the SiN{sub x} film. Namely, prolonged plasma exposure made films denser which corresponded to lower WER in a systematic fashion. We determined that there is a strong correlation between WER and the density of the film that extends across multiple precursors, PEALD reactors, and a variety of process conditions. Limiting all steps in the deposition to a maximum temperature of 350 °C, it was shown to be possible to achieve a WER in PEALD SiN{sub x} of 6.1 Å/min, which is similar to WER of SiN{sub x} from LPCVD reactions at 850 °C.

  6. Feedback control of chlorine inductively coupled plasma etch processing

    International Nuclear Information System (INIS)

    Lin Chaung; Leou, K.-C.; Shiao, K.-M.

    2005-01-01

    Feedback control has been applied to poly-Si etch processing using a chlorine inductively coupled plasma. Since the positive ion flux and ion energy incident upon the wafer surface are the key factors that influence the etch rate, the ion current and the root mean square (rms) rf voltage on the wafer stage, which are measured using an impedance meter connected to the wafer stage, are adopted as the controlled variables to enhance etch rate. The actuators are two 13.56 MHz rf power generators, which adjust ion density and ion energy, respectively. The results of closed-loop control show that the advantages of feedback control can be achieved. For example, with feedback control, etch rate variation under the transient chamber wall condition is reduced roughly by a factor of 2 as compared to the open-loop case. In addition, the capability of the disturbance rejection was also investigated. For a gas pressure variation of 20%, the largest etch rate variation is about 2.4% with closed-loop control as compared with as large as about 6% variation using open-loop control. Also the effect of ion current and rms rf voltage on etch rate was studied using 2 2 factorial design whose results were used to derive a model equation. The obtained formula was used to adjust the set point of ion current and rf voltage so that the desired etch rate was obtained

  7. Etched colloidal LiFePO4 nanoplatelets toward high-rate capable Li-ion battery electrodes.

    Science.gov (United States)

    Paolella, Andrea; Bertoni, Giovanni; Marras, Sergio; Dilena, Enrico; Colombo, Massimo; Prato, Mirko; Riedinger, Andreas; Povia, Mauro; Ansaldo, Alberto; Zaghib, Karim; Manna, Liberato; George, Chandramohan

    2014-12-10

    LiFePO4 has been intensively investigated as a cathode material in Li-ion batteries, as it can in principle enable the development of high power electrodes. LiFePO4, on the other hand, is inherently "plagued" by poor electronic and ionic conductivity. While the problems with low electron conductivity are partially solved by carbon coating and further by doping or by downsizing the active particles to nanoscale dimensions, poor ionic conductivity is still an issue. To develop colloidally synthesized LiFePO4 nanocrystals (NCs) optimized for high rate applications, we propose here a surface treatment of the NCs. The particles as delivered from the synthesis have a surface passivated with long chain organic surfactants, and therefore can be dispersed only in aprotic solvents such as chloroform or toluene. Glucose that is commonly used as carbon source for carbon-coating procedure is not soluble in these solvents, but it can be dissolved in water. In order to make the NCs hydrophilic, we treated them with lithium hexafluorophosphate (LiPF6), which removes the surfactant ligand shell while preserving the structural and morphological properties of the NCs. Only a roughening of the edges of NCs was observed due to a partial etching of their surface. Electrodes prepared from these platelet NCs (after carbon coating) delivered a capacity of ∼ 155 mAh/g, ∼ 135 mAh/g, and ∼ 125 mAh/g, at 1 C, 5 C, and 10 C, respectively, with significant capacity retention and remarkable rate capability. For example, at 61 C (10.3 A/g), a capacity of ∼ 70 mAh/g was obtained, and at 122 C (20.7 A/g), the capacity was ∼ 30 mAh/g. The rate capability and the ease of scalability in the preparation of these surface-treated nanoplatelets make them highly suitable as electrodes in Li-ion batteries.

  8. Comparison of neutron dose measured by Albedo TLD and etched tracks detector at PNC plutonium fuel facilities

    International Nuclear Information System (INIS)

    Tsujimura, N.; Momose, T.; Shinohara, K.; Ishiguro, H.

    1996-01-01

    Power Reactor and Nuclear Fuel Development Corporation (PNC) has fabricated Plutonium and Uranium Mixed OXide (MOX) fuel for FBR MONJU at Tokai works. In this site, PNC/Panasonic albedo TLDs/1/ are used for personnel neutron monitoring. And a part of workers wore Etched Tracks Detector (ETD) combined with TLD in order to check the accuracy of the neutron dose estimated by albedo TLD. In this paper, the neutron dose measured by TLD and ETD in the routine monitoring is compared at PNC plutonium fuel facilities. (author)

  9. High-etch-rate bottom-antireflective coating and gap-fill materials using dextrin derivatives in via first dual-Damascene lithography process

    Science.gov (United States)

    Takei, Satoshi; Sakaida, Yasushi; Shinjo, Tetsuya; Hashimoto, Keisuke; Nakajima, Yasuyuki

    2008-03-01

    The present paper describes a novel class of bottom antireflective coating (BARC) and gap fill materials using dextrin derivatives. The general trend of interconnect fabrication for such a high performance LSI is to apply cupper (Cu)/ low-dielectric-constant (low-k) interconnect to reduce RC delay. A via-first dual damascene process is one of the most promising processes to fabricate Cu/ low-k interconnect due to its wide miss-alignment margin. The sacrificial materials containing dextrin derivatives under resist for lithography were developed in via-first dual damascene process. The dextrin derivatives in this study was obtained by the esterification of the hydroxyl groups of dextrin resulting in improved solubility in the resist solvents such as propylene glycol monomethylether, propylene glycol monomethylether acetate, and ethyl lactate due to avoid the issue of defects that were caused by incompatability. The etch rate of our developed BARC and gap fill materials using dextrin derivatives was more than two times faster than one of the ArF resists evaluated in a CF4 gas condition using reactive ion etching. The improved etch performance was also verified by comparison with poly(hydroxystyrene), acrylate-type materials and latest low-k materials as a reference. In addition to superior etch performance, these materials showed good resist profiles and via filling performance without voids in via holes.

  10. Development of etched nuclear tracks

    International Nuclear Information System (INIS)

    Somogyi, G.

    1980-01-01

    The theoretical description of the evolution of etched tracks in solid state nuclear track detectors is considered for different initial conditions, for the cases of constant and varying track etch rates, isotropic and anisotropic bulk etching as well as for thick and thin detectors. It is summarized how one can calculate the main parameters of etch-pit geometry, the track length, the axes of a surface track opening, track profile and track contour. The application of the theory of etch-track evolution is demonstrated with selected practical problems. Attention is paid to certain questions related to the determination of unknown track parameters and calculation of surface track sizes. Finally, the theory is extended to the description of the perforation and etch-hole evolution process in thin detectors, which is of particular interest for track radiography and nuclear filter production. (orig.)

  11. Development of etched nuclear tracks

    International Nuclear Information System (INIS)

    Somogyi, G.

    1979-01-01

    The theoretical description of the evolution of etched tracks in solid state nuclear track detectors is considered for different initial conditions, for the cases of constant and varying track etch rates, isotopic and unisotropic bulk etching as well as for thick and thin detectors. It is summarized how the main parameters of etch-pit geometry, the track length, the axes of a surface track opening, the track profile and the track contour can be calculated. The application of the theory of etch-track evolution is demonstrated with selected practical problems. Attention is paid to certain questions related to the determination of unknown track parameters and calculation of surface track sizes. Finally, the theory is extended to the description of the perforation and etch-hole evolution process in thin detectors, which is of particular interest for track radiography and nuclear filter production. (author)

  12. Introducing etch kernels for efficient pattern sampling and etch bias prediction

    Science.gov (United States)

    Weisbuch, François; Lutich, Andrey; Schatz, Jirka

    2018-01-01

    Successful patterning requires good control of the photolithography and etch processes. While compact litho models, mainly based on rigorous physics, can predict very well the contours printed in photoresist, pure empirical etch models are less accurate and more unstable. Compact etch models are based on geometrical kernels to compute the litho-etch biases that measure the distance between litho and etch contours. The definition of the kernels, as well as the choice of calibration patterns, is critical to get a robust etch model. This work proposes to define a set of independent and anisotropic etch kernels-"internal, external, curvature, Gaussian, z_profile"-designed to represent the finest details of the resist geometry to characterize precisely the etch bias at any point along a resist contour. By evaluating the etch kernels on various structures, it is possible to map their etch signatures in a multidimensional space and analyze them to find an optimal sampling of structures. The etch kernels evaluated on these structures were combined with experimental etch bias derived from scanning electron microscope contours to train artificial neural networks to predict etch bias. The method applied to contact and line/space layers shows an improvement in etch model prediction accuracy over standard etch model. This work emphasizes the importance of the etch kernel definition to characterize and predict complex etch effects.

  13. True mean rate measuring system

    International Nuclear Information System (INIS)

    Eichenlaub, D.P.

    1980-01-01

    A digital radiation-monitoring system for nuclear power plants uses digital and microprocessor circuitry to enable rapid processing of pulse information from remote radiation monitors. The pulse rates are analyzed to determine whether new pulse-rate information is statisticaly the same as that previously received and to determine the best possible averaging time, which can be changed so that the statistical error remains below a specified level while the system response time remains short. Several data modules each process the pulse-rate information from several remote radiation monitors. Each data module accepts pulse data from each radiation monitor and measures the true average or mean pulse rate of events occurring with a Poisson distribution to determine the radiation level. They then develop digital output signals which indciate the respective radiation levels and which can be transmitted via multiplexer circuits for additional processing and display. The data modules can accept signals from remote control stations or computer stations via the multiplexer circuit to change operating thresholds and alarm levels in their memories. A check module scans the various data modules to determine whether the output signals are valid. It also acts as a redundant data module and will automatically replace an inoperative unit. (DN)

  14. Defect sensitive etching of hexagonal boron nitride single crystals

    Science.gov (United States)

    Edgar, J. H.; Liu, S.; Hoffman, T.; Zhang, Yichao; Twigg, M. E.; Bassim, Nabil D.; Liang, Shenglong; Khan, Neelam

    2017-12-01

    Defect sensitive etching (DSE) was developed to estimate the density of non-basal plane dislocations in hexagonal boron nitride (hBN) single crystals. The crystals employed in this study were precipitated by slowly cooling (2-4 °C/h) a nickel-chromium flux saturated with hBN from 1500 °C under 1 bar of flowing nitrogen. On the (0001) planes, hexagonal-shaped etch pits were formed by etching the crystals in a eutectic mixture of NaOH and KOH between 450 °C and 525 °C for 1-2 min. There were three types of pits: pointed bottom, flat bottom, and mixed shape pits. Cross-sectional transmission electron microscopy revealed that the pointed bottom etch pits examined were associated with threading dislocations. All of these dislocations had an a-type burgers vector (i.e., they were edge dislocations, since the line direction is perpendicular to the [ 2 11 ¯ 0 ]-type direction). The pit widths were much wider than the pit depths as measured by atomic force microscopy, indicating the lateral etch rate was much faster than the vertical etch rate. From an Arrhenius plot of the log of the etch rate versus the inverse temperature, the activation energy was approximately 60 kJ/mol. This work demonstrates that DSE is an effective method for locating threading dislocations in hBN and estimating their densities.

  15. Optical diagnostics for plasma etching

    NARCIS (Netherlands)

    Bisschops, T.H.J.; Kroesen, G.M.W.; Veldhuizen, van E.M.; de Zeeuw, C.J.H.; Timmermans, C.J.

    1985-01-01

    Several optical diagnostics were used to det. plasma properties and etch rates in an single wafer etch reactor. Results of UV-visible spectroscopy and IR absorption spectroscopy, indicating different mol. species and their densities are presented. The construction of an interferometer to det. the

  16. Etching properties of BLT films in CF4/Ar plasma

    International Nuclear Information System (INIS)

    Kim, Dong Pyo; Kim, Kyoung Tae; Kim, Chang Il

    2003-01-01

    CF 4 /Ar plasma mass content and etching rate behavior of BLT thin films were investigated in inductively coupled plasma (ICP) reactor as functions of CF 4 /Ar gas mixing ratio, rf power, and dc bias voltage. The variation of relative volume densities for F and Ar atoms were measured by the optical emission spectroscopy (OES). The etching rate as functions of Ar content showed the maximum of 803 A/min at 80 % Ar addition into CF 4 plasma. The presence of maximum etch rate may be explained by the concurrence of two etching mechanisms such as physical sputtering and chemical reaction. The role of Ar ion bombardment includes destruction of metal (Bi, La, Ti)-O bonds as well as support of chemical reaction of metals with fluorine atoms

  17. Etching characteristics of Si{110} in 20 wt% KOH with addition of hydroxylamine for the fabrication of bulk micromachined MEMS

    Science.gov (United States)

    Rao, A. V. Narasimha; Swarnalatha, V.; Pal, P.

    2017-12-01

    Anisotropic wet etching is a most widely employed for the fabrication of MEMS/NEMS structures using silicon bulk micromachining. The use of Si{110} in MEMS is inevitable when a microstructure with vertical sidewall is to be fabricated using wet anisotropic etching. In most commonly employed etchants (i.e. TMAH and KOH), potassium hydroxide (KOH) exhibits higher etch rate and provides improved anisotropy between Si{111} and Si{110} planes. In the manufacturing company, high etch rate is demanded to increase the productivity that eventually reduces the cost of end product. In order to modify the etching characteristics of KOH for the micromachining of Si{110}, we have investigated the effect of hydroxylamine (NH2OH) in 20 wt% KOH solution. The concentration of NH2OH is varied from 0 to 20% and the etching is carried out at 75 °C. The etching characteristics which are studied in this work includes the etch rates of Si{110} and silicon dioxide, etched surface morphology, and undercutting at convex corners. The etch rate of Si{110} in 20 wt% KOH + 15% NH2OH solution is measured to be four times more than that of pure 20 wt% KOH. Moreover, the addition of NH2OH increases the undercutting at convex corners and enhances the etch selectivity between Si and SiO2.

  18. Etching behaviour of alpha-recoil tracks in natural dark mica studied via artificial ion tracks

    International Nuclear Information System (INIS)

    Lang, M.; Glasmacher, U.A.; Neumann, R.; Wagner, G.A.

    2003-01-01

    Alpha-recoil tracks (ARTs) created by the α-decay of U, Th, and their daughter nuclei, are used by a new dating method to determine the formation age of dark mica bearing Quaternary and Neogene volcanic rocks and the cooling age of plutonic and metamorphic rocks [Chem. Geol. 166 (2000) 127, Science 155 (1967) 1103]. The age equation combines the volumetric density of ARTs with the U and Th contents. Etching latent ARTs (diameter 30-100 nm) in the mica mineral phlogopite by HF and measuring the areal density of triangular etch pits by optical and scanning force microscopy (SFM) leads to a linear growth of ART areal density versus etching time. The ART volume density is a function of the slope of the areal density and the etching rate (v eff ). Therefore, the determination of v eff is essential for the calculation of an age value. To determine the etching parameters such as etching efficiency and v eff , phlogopite samples were irradiated with 80 keV Au ions. Irradiated surfaces were etched with 4% HF at 23±2 deg. C during successive time intervals and after each interval studied with SFM. The etching rate v eff was determined by different techniques. To evaluate the threshold of etchability, the energy losses of the Au ions and α-recoil nuclei in phlogopite were calculated with the SRIM00 code. The etching efficiency of the Au ion tracks was then used to predict the corresponding etching efficiency of the natural radioactive nuclei

  19. Radiation dose rate measuring device

    International Nuclear Information System (INIS)

    Sorber, R.

    1987-01-01

    A portable device is described for in-field usage for measuring the dose rate of an ambient beta radiation field, comprising: a housing, substantially impervious to beta radiation, defining an ionization chamber and having an opening into the ionization chamber; beta radiation pervious electrically-conductive window means covering the opening and entrapping, within the ionization chamber, a quantity of gaseous molecules adapted to ionize upon impact with beta radiation particles; electrode means disposed within the ionization chamber and having a generally shallow concave surface terminating in a generally annular rim disposed at a substantially close spacing to the window means. It is configured to substantially conform to the window means to define a known beta radiation sensitive volume generally between the window means and the concave surface of the electrode means. The concave surface is effective to substantially fully expose the beta radiation sensitive volume to the radiation field over substantially the full ambient area faced by the window means

  20. Saddle-fin cell transistors with oxide etch rate control by using tilted ion implantation (TIS-fin) for sub-50-nm DRAMs

    International Nuclear Information System (INIS)

    Yoo, Min Soo; Choi, Kang Sik; Sun, Woo Kyung

    2010-01-01

    As DRAM cell pitch size decreases, the need for a high performance transistor is increasing. Though saddle-fin (S-fin) transistors have superior characteristics, S-fin transistors are well known to be more sensitive to process variation. To make uniform S-fin transistors, for the first time, we developed a new fin formation method using tilted ion implantation along the wordline direction after a recess gate etch. Due to the increased etch rate of the oxide film by ion implantation damage, fins are made at the bottom channel of the recess gate after wet etching. The resulting tilt implanted saddle-fin (TIS-fin) transistor has remarkably improved characteristics, such as ∼8% subthreshold swing (SS) and a 40% drain induced barrier lowering (DIBL) decrease. Especially, the TIS-fin with a neutral dopant has a reduced threshold voltage (Vth) variation within a wafer (<100 mV), which is comparable with that of a mass-produced sphere-shaped recessed channel array transistor (SRCAT).

  1. Qualification of a new defect revealing etch for CdTe using cathodoluminescence microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Watson, C.C.R.; Durose, K. (Dept. of Physics, Univ. of Durham (United Kingdom)); Banister, A.J. (Dept. of Chemistry, Univ. of Durham (United Kingdom)); O' Keefe, E.; Bains, S.K. (Philips Infrared Defence Components, Southampton (United Kingdom))

    1993-01-30

    The action of a new defect revealing etch comprising a saturated FeCl[sub 3] solution has been investigated. The etch was found suitable for use on (111)A, (anti 1anti 1anti 1)B and other surface orientations of CdTe, and (111)A and (anti 1anti 1anti 1)B surfaces of Cd[sub 0.96]Zn[sub 0.04] Te. Direct correlations with cathodoluminescence and infra-red microscopy have shown the etch to successfully reveal twin boundaries, precipitates and dislocations. A background etch rate of approximately 2 [mu]m min[sup -1] has been measured. (orig.).

  2. Single-crystal silicon trench etching for fabrication of highly integrated circuits

    Science.gov (United States)

    Engelhardt, Manfred

    1991-03-01

    The development of single crystal silicon trench etching for fabrication of memory cells in 4 16 and 64Mbit DRAMs is reviewed in this paper. A variety of both etch tools and process gases used for the process development is discussed since both equipment and etch chemistry had to be improved and changed respectively to meet the increasing requirements for high fidelity pattern transfer with increasing degree of integration. In additon to DRAM cell structures etch results for deep trench isolation in advanced bipolar ICs and ASICs are presented for these applications grooves were etched into silicon through a highly doped buried layer and at the borderline of adjacent p- and n-well areas respectively. Shallow trench etching of large and small exposed areas with identical etch rates is presented as an approach to replace standard LOCOS isolation by an advanced isolation technique. The etch profiles were investigated with SEM TEM and AES to get information on contathination and damage levels and on the mechanism leading to anisotropy in the dry etch process. Thermal wave measurements were performed on processed single crystal silicon substrates for a fast evaluation of the process with respect to plasma-induced substrate degradation. This useful technique allows an optimization ofthe etch process regarding high electrical performance of the fully processed memory chip. The benefits of the use of magnetic fields for the development of innovative single crystal silicon dry

  3. Plasma etching of polymers like SU8 and BCB

    Science.gov (United States)

    Mischke, Helge; Gruetzner, Gabi; Shaw, Mark

    2003-01-01

    Polymers with high viscosity, like SU8 and BCB, play a dominant role in MEMS application. Their behavior in a well defined etching plasma environment in a RIE mode was investigated. The 40.68 MHz driven bottom electrode generates higher etch rates combined with much lower bias voltages by a factor of ten or a higher efficiency of the plasma with lower damaging of the probe material. The goal was to obtain a well-defined process for the removal and structuring of SU8 and BCB using fluorine/oxygen chemistry, defined using variables like electron density and collision rate. The plasma parameters are measured and varied using a production proven technology called SEERS (Self Excited Electron Resonance Spectroscopy). Depending on application and on Polymer several metals are possible (e.g., gold, aluminum). The characteristic of SU8 and BCB was examined in the case of patterning by dry etching in a CF4/O2 chemistry. Etch profile and etch rate correlate surprisingly well with plasma parameters like electron density and electron collision rate, thus allowing to define to adjust etch structure in situ with the help of plasma parameters.

  4. Shallow surface etching of organic and inorganic compounds by electrospray droplet impact

    International Nuclear Information System (INIS)

    Hiraoka, Kenzo; Sakai, Yuji; Iijima, Yoshitoki; Asakawa, Daiki; Mori, Kunihiko

    2009-01-01

    The electrospray droplet impact (EDI) was applied to bradykinin, polyethylene terephthalate (PET), SiO 2 /Si, and indium phosphide (InP). It was found that bradykinin deposited on the stainless steel substrate was ionized/desorbed without the accumulation of radiation products. The film thickness desorbed by a single collisional event was found to be less than 10 monolayers. In the EDI mass spectra for PET, several fragment ions were observed but the XPS spectra did not change with prolonged cluster irradiation. The etching rate for SiO 2 by EDI was measured to be ∼0.2 nm/min. The surface roughness of InP etched by EDI was found to be one order of magnitude smaller than that etched by 3 keV Ar + for about the same etching depths. EDI is capable of shallow surface etching with little damage left on the etched surface.

  5. Power ultrasound irradiation during the alkaline etching process of the 2024 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Moutarlier, V.; Viennet, R.; Rolet, J.; Gigandet, M.P.; Hihn, J.Y., E-mail: jean-yves.hihn@univ-fcomte.fr

    2015-11-15

    Graphical abstract: Result of an etching step in ultrasound presence on intermetallic particles on a 2024 aluminum alloy. - Highlights: • Etching step prior to anodization on 2024 aluminum alloy. • Etching rate measurement and hydroxide film characterization by GDOES and SEM. • Various etching parameters (temperature, presence or absence of ultrasound). • Improvement of corrosion resistance show by electrochemical tests. - Abstract: Prior to any surface treatment on an aluminum alloy, a surface preparation is necessary. This commonly consists in performing an alkaline etching followed by acid deoxidizing. In this work, the use of power ultrasound irradiation during the etching step on the 2024 aluminum alloy was studied. The etching rate was estimated by weight loss, and the alkaline film formed during the etching step was characterized by glow discharge optical emission spectrometry (GDOES) and scanning electron microscope (SEM). The benefit of power ultrasound during the etching step was confirmed by pitting potential measurement in NaCl solution after a post-treatment (anodizing).

  6. Power ultrasound irradiation during the alkaline etching process of the 2024 aluminum alloy

    International Nuclear Information System (INIS)

    Moutarlier, V.; Viennet, R.; Rolet, J.; Gigandet, M.P.; Hihn, J.Y.

    2015-01-01

    Graphical abstract: Result of an etching step in ultrasound presence on intermetallic particles on a 2024 aluminum alloy. - Highlights: • Etching step prior to anodization on 2024 aluminum alloy. • Etching rate measurement and hydroxide film characterization by GDOES and SEM. • Various etching parameters (temperature, presence or absence of ultrasound). • Improvement of corrosion resistance show by electrochemical tests. - Abstract: Prior to any surface treatment on an aluminum alloy, a surface preparation is necessary. This commonly consists in performing an alkaline etching followed by acid deoxidizing. In this work, the use of power ultrasound irradiation during the etching step on the 2024 aluminum alloy was studied. The etching rate was estimated by weight loss, and the alkaline film formed during the etching step was characterized by glow discharge optical emission spectrometry (GDOES) and scanning electron microscope (SEM). The benefit of power ultrasound during the etching step was confirmed by pitting potential measurement in NaCl solution after a post-treatment (anodizing).

  7. A comparative clinical study of the failure rate of orthodontic brackets bonded with two adhesive systems: conventional and self-etching primer (SEP).

    Science.gov (United States)

    Dominguez, Gladys Cristina; Tortamano, André; Lopes, Luiz Vicente de Moura; Catharino, Priscilla Campanatti Chibebe; Morea, Camillo

    2013-01-01

    This study compared the clinical performance of orthodontic brackets bonded with Transbond adhesive paste after two primer systems: a two-stage conventional system (acid etching + Transbond XT adhesive primer) and a single-stage self-etching primer (SEP) (Transbond Plus). The sample comprised 480 metal brackets bonded to the teeth of 24 consecutive patients treated for 36 to 48 months. A split-mouth design was used for bonding, and both systems were used in each patient. Bracket failure rates for each system were analyzed; and failure causes as reported by the patients and the quadrant of teeth for which brackets failed were recorded. The conventional system group had a failure rate of 5.41%, whereas the rate for SEP was 4.58%. In this group, there were 5 failures (38.4%) in the right maxillary quadrant, 2 (15.4%) in the left maxillary quadrant, 4 (30.8%) in the right mandibular quadrant, and 2 (15.4%) in the left mandibular quadrant. In the SEP group, there were 4 (36.4%) failures in the right maxillary quadrant, 1 (9%) in the left maxillary quadrant, 3 (27.3%) in the right mandibular quadrant, and 3 (27.3%) in the left mandibular quadrant. Results of descriptive statistical analysis and odds ratio did not show any significant differences between rates (p = 0.67). The clinical efficiency of SEP was similar to that of the conventional system.

  8. A comparative clinical study of the failure rate of orthodontic brackets bonded with two adhesive systems: conventional and self-etching primer (SEP

    Directory of Open Access Journals (Sweden)

    Gladys Cristina Dominguez

    2013-04-01

    Full Text Available OBJECTIVE: This study compared the clinical performance of orthodontic brackets bonded with Transbond adhesive paste after two priming systems: a two-stage conventional system (acid etching + Transbond XT adhesive primer and a singlestage self-etching primer (SEP (Transbond Plus. METHODS: The sample comprised 480 metal brackets bonded to the teeth of 24 consecutive patients treated for 36 to 48 months. A split-mouth design was used for bonding, and both systems were used in each patient. Bracket failure rates for each system were analyzed; and failure causes as reported by the patients and the quadrant of teeth for which brackets failed were recorded. RESULTS: The conventional system group had a failure rate of 5.41%, whereas the rate for SEP was 4.58%. In this group, there were 5 failures (38.4% in the right maxillary quadrant, 2 (15.4% in the left maxillary quadrant, 4 (30.8% in the right mandibular quadrant, and 2 (15.4% in the left mandibular quadrant. In the SEP group, there were 4 (36.4% failures in the right maxillary quadrant, 1 (9% in the left maxillary quadrant, 3 (27.3% in the right mandibular quadrant, and 3 (27.3% in the left mandibular quadrant. Results of descriptive statistical analysis and odds ratio did not show any significant differences between rates (p = 0.67. CONCLUSION: The clinical efficiency of SEP was similar to that of the conventional system.

  9. Relevance of LiPF6 as Etching Agent of LiMnPO4 Colloidal Nanocrystals for High Rate Performing Li-ion Battery Cathodes.

    Science.gov (United States)

    Chen, Lin; Dilena, Enrico; Paolella, Andrea; Bertoni, Giovanni; Ansaldo, Alberto; Colombo, Massimo; Marras, Sergio; Scrosati, Bruno; Manna, Liberato; Monaco, Simone

    2016-02-17

    LiMnPO4 is an attractive cathode material for the next-generation high power Li-ion batteries, due to its high theoretical specific capacity (170 mA h g(-1)) and working voltage (4.1 V vs Li(+)/Li). However, two main drawbacks prevent the practical use of LiMnPO4: its low electronic conductivity and the limited lithium diffusion rate, which are responsible for the poor rate capability of the cathode. The electronic resistance is usually lowered by coating the particles with carbon, while the use of nanosize particles can alleviate the issues associated with poor ionic conductivity. It is therefore of primary importance to develop a synthetic route to LiMnPO4 nanocrystals (NCs) with controlled size and coated with a highly conductive carbon layer. We report here an effective surface etching process (using LiPF6) on colloidally synthesized LiMnPO4 NCs that makes the NCs dispersible in the aqueous glucose solution used as carbon source for the carbon coating step. Also, it is likely that the improved exposure of the NC surface to glucose facilitates the formation of a conductive carbon layer that is in intimate contact with the inorganic core, resulting in a high electronic conductivity of the electrode, as observed by us. The carbon coated etched LiMnPO4-based electrode exhibited a specific capacity of 118 mA h g(-1) at 1C, with a stable cycling performance and a capacity retention of 92% after 120 cycles at different C-rates. The delivered capacities were higher than those of electrodes based on not etched carbon coated NCs, which never exceeded 30 mA h g(-1). The rate capability here reported for the carbon coated etched LiMnPO4 nanocrystals represents an important result, taking into account that in the electrode formulation 80% wt is made of the active material and the adopted charge protocol is based on reasonable fast charge times.

  10. Process for etching zirconium metallic objects

    International Nuclear Information System (INIS)

    Panson, A.J.

    1988-01-01

    In a process for etching of zirconium metallic articles formed from zirconium or a zirconium alloy, wherein the zirconium metallic article is contacted with an aqueous hydrofluoric acid-nitric acid etching bath having an initial ratio of hydrofluoric acid to nitric acid and an initial concentration of hydrofluoric and nitric acids, the improvement, is described comprising: after etching of zirconium metallic articles in the bath for a period of time such that the etching rate has diminished from an initial rate to a lesser rate, adding hydrofluoric acid and nitric acid to the exhausted bath to adjust the concentration and ratio of hydrofluoric acid to nitric acid therein to a value substantially that of the initial concentration and ratio and thereby regenerate the etching solution without removal of dissolved zirconium therefrom; and etching further zirconium metallic articles in the regenerated etching bath

  11. Effects of temperature on the etching properties of Bi4-xLaxTi3O12 thin films

    International Nuclear Information System (INIS)

    Kim, Dong-Pyo; Kim, Kyoung-Tae; Koo, Seong-Mo; Kim, Chang-Il

    2004-01-01

    The etching properties of Bi 4-x La x Ti 3 O 12 (BLT) films etched in an inductively coupled Ar/Cl 2 plasma were investigated in terms of the gas mixing ratio, the rf power, and the substrate temperature. We obtained a high etch rate of 433 A/min at 30 .deg. C and 344 A/min at 80 .deg. C in Ar (15 sccm)/Cl 2 (15 sccm). As the rf power was increased, the ion current density increased, resulting in an increase in the etch rate. To understand the etch mechanism of BLT in a Cl 2 /Ar plasma, we performed the plasma diagnostics using a Langmuir probe (LP). The LP measurement indicated that the maximum ion density decreased with Cl 2 addition, but increased with the rf power. X-ray photoelectron spectroscopy (XPS) narrow scan analysis showed that La-chlorides remained on the etched surface and that the high accumulation of nonvolatile etch byproducts increased at high substrate temperatures. The analysis of surface reactions and the plasma diagnostics in the frameworks of an ion-assisted etching mechanism confirmed the possibility of non-monotonic etch rate behavior due to the concurrence of physical sputtering and chemical etching activated by ion bombardment.

  12. Influence of Pre-etching Times on Fatigue Strength of Self-etch Adhesives to Enamel.

    Science.gov (United States)

    Takamizawa, Toshiki; Barkmeier, Wayne W; Tsujimoto, Akimasa; Endo, Hajime; Tsuchiya, Kenji; Erickson, Robert L; Latta, Mark A; Miyazaki, Masashi

    To use shear bond strength (SBS) and shear fatigue strength (SFS) testing to determine the influence of phosphoric acid pre-etching times prior to application of self-etch adhesives on enamel bonding. Two single-step self-etch universal adhesives (Prime&Bond Elect and Scotchbond Universal), a conventional single-step self-etch adhesive (G-ӕnial Bond), and a conventional two-step self-etch adhesive (OptiBond XTR) were used. The SBS and SFS were obtained with phosphoric acid pre-etching for 3, 10, or 15 s prior to application of the adhesives, and without pre-etching (0 s) as a control. A staircase method was used to determine the SFS with 10 Hz frequency for 50,000 cycles or until failure occurred. The mean demineralization depth for each treated enamel surface was also measured using a profilometer. For all the adhesives, the groups with pre-etching showed significantly higher SBS and SFS than groups without pre-etching. However, there was no significant difference in SBS and SFS among groups with > 3 s of preetching. In addition, although the groups with pre-etching showed significantly deeper demineralization depths than groups without pre-etching, there was no significant difference in depth among groups with > 3 s of pre-etching. Three seconds of phosphoric acid pre-etching prior to application of self-etch adhesive can enhance enamel bonding effectiveness.

  13. Optimisation of elevated radon concentration measurement by using electro-chemical etching of nuclear track detectors

    International Nuclear Information System (INIS)

    Celikovic, I.; Ujic, P.; Fujimoto, K.; Tommasino, L.; Demajo, A.; Zunic, Z.; Celikovic, I.)

    2007-01-01

    In the paper, two methods for adjusting of passive radon-thoron discriminative dosimeters (UFO detector) for enhanced radon concentration measurement are presented. Achieved upper limit of detection is 5.94 MBq m-3 d [sr

  14. Acid-catalyzed kinetics of indium tin oxide etching

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jae-Hyeok; Kim, Seong-Oh; Hilton, Diana L. [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Centre for Biomimetic Sensor Science, Nanyang Technological University, 50 Nanyang Drive, 637553 (Singapore); Cho, Nam-Joon, E-mail: njcho@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Centre for Biomimetic Sensor Science, Nanyang Technological University, 50 Nanyang Drive, 637553 (Singapore); School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459 (Singapore)

    2014-08-28

    We report the kinetic characterization of indium tin oxide (ITO) film etching by chemical treatment in acidic and basic electrolytes. It was observed that film etching increased under more acidic conditions, whereas basic conditions led to minimal etching on the time scale of the experiments. Quartz crystal microbalance was employed in order to track the reaction kinetics as a function of the concentration of hydrochloric acid and accordingly solution pH. Contact angle measurements and atomic force microscopy experiments determined that acid treatment increases surface hydrophilicity and porosity. X-ray photoelectron spectroscopy experiments identified that film etching is primarily caused by dissolution of indium species. A kinetic model was developed to explain the acid-catalyzed dissolution of ITO surfaces, and showed a logarithmic relationship between the rate of dissolution and the concentration of undisassociated hydrochloric acid molecules. Taken together, the findings presented in this work verify the acid-catalyzed kinetics of ITO film dissolution by chemical treatment, and support that the corresponding chemical reactions should be accounted for in ITO film processing applications. - Highlights: • Acidic conditions promoted indium tin oxide (ITO) film etching via dissolution. • Logarithm of the dissolution rate depended linearly on the solution pH. • Acid treatment increased ITO surface hydrophilicity and porosity. • ITO film etching led to preferential dissolution of indium species over tin species.

  15. The deconvolution of sputter-etching surface concentration measurements to determine impurity depth profiles

    International Nuclear Information System (INIS)

    Carter, G.; Katardjiev, I.V.; Nobes, M.J.

    1989-01-01

    The quasi-linear partial differential continuity equations that describe the evolution of the depth profiles and surface concentrations of marker atoms in kinematically equivalent systems undergoing sputtering, ion collection and atomic mixing are solved using the method of characteristics. It is shown how atomic mixing probabilities can be deduced from measurements of ion collection depth profiles with increasing ion fluence, and how this information can be used to predict surface concentration evolution. Even with this information, however, it is shown that it is not possible to deconvolute directly the surface concentration measurements to provide initial depth profiles, except when only ion collection and sputtering from the surface layer alone occur. It is demonstrated further that optimal recovery of initial concentration depth profiles could be ensured if the concentration-measuring analytical probe preferentially sampled depths near and at the maximum depth of bombardment-induced perturbations. (author)

  16. Dry etching of LaNiO3 thin films using inductively coupled plasma

    International Nuclear Information System (INIS)

    Kim, Gwan-Ha; Kim, Dong-Pyo; Kim, Kyoung-Tae; Kim, Chang-Il; Lee, Cheol-In; Kim, Tae-Hyung

    2006-01-01

    The etching characteristics of LaNiO 3 (LNO) thin films and SiO 2 in Cl 2 /Ar plasma were investigated. LNO etch rates decreased with increasing Cl 2 fraction in Ar plasma and the working pressure. Langmuir probe measurement showed a noticeable influence of Cl 2 /Ar mixing ratio on electron temperature, electron density, and ion current density. The modeling of volume kinetics for charged particles and OES measurements for neutral atoms indicated monotonous changes of both densities and fluxes of active species such as chlorine atoms and positive ions. The LNO etch rate behavior may be explained by physical mechanisms

  17. Study of the reduction in detection limits of track detectors used for {sup 10}B(n,α){sup 7}Li reaction rate measure through annealing and chemical etching experiments; Estudo da reducao nos limites de deteccao de detectores de tracos utilizados na medida de taxa de reacao {sup 10}B(n, α){sup 7}Li atraves de experimentos de annealing e ataque quimico

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcellos, Herminiane L.; Smilgys, Barbara; Guedes, Sandro, E-mail: hluizav@ifi.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Instituto de Fisica Gleb Wataghin; Castro, Vinicius A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear

    2013-08-15

    The Boron Neutron Capture Therapy (BNCT) is an experimental radiotherapy for cancer treatment. It is based on {sup 10}B(n, α){sup 7}Li reaction, which can be measured by track detectors capable of recording events that strike them. With this recording, it is possible to determine the number of alpha particles and recoiling Lithium-7 nucleus, reaction products, and from this information, which amount of radiation dose a patient is exposed to. In this work, PADC detectors were characterized, irradiated at the IEA-R1 IPEN/CNEN reactor to assess the contribution of the{sup 10}B(n, α){sup 7}Li reaction and protons from fast neutron scattering with the elements that compounds the tissue. With the aim of reducing the proton background, the detectors were subjected to heating experiments at 80°C for periods in the range 0-100 hours. This was done in order to restore partially modified structure of the detector, causing a reduction in the size and density of tracks. This effect is known as annealing. For the visualization of tracks at microscope, detectors were made three chemical attacks with sodium hydroxide (NaOH) for 30, 60 and 90 minutes at 70°C. It was observed a reduction in the track density achieving a plateau heating time of 50 hours. For detectors that have not undergone annealing and were etched with another etchant, PEW solution, a reduction of 87% in track density was obtained. (author)

  18. Etching of Niobium Sample Placed on Superconducting Radio Frequency Cavity Surface in Ar/CL2 Plasma

    International Nuclear Information System (INIS)

    Upadhyay, Janardan; Phillips, Larry; Valente, Anne-Marie

    2011-01-01

    Plasma based surface modification is a promising alternative to wet etching of superconducting radio frequency (SRF) cavities. It has been proven with flat samples that the bulk Niobium (Nb) removal rate and the surface roughness after the plasma etchings are equal to or better than wet etching processes. To optimize the plasma parameters, we are using a single cell cavity with 20 sample holders symmetrically distributed over the cell. These holders serve the purpose of diagnostic ports for the measurement of the plasma parameters and for the holding of the Nb sample to be etched. The plasma properties at RF (100 MHz) and MW (2.45 GHz) frequencies are being measured with the help of electrical and optical probes at different pressures and RF power levels inside of this cavity. The niobium coupons placed on several holders around the cell are being etched simultaneously. The etching results will be presented at this conference.

  19. Etching of Niobium Sample Placed on Superconducting Radio Frequency Cavity Surface in Ar/CL2 Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Janardan Upadhyay, Larry Phillips, Anne-Marie Valente

    2011-09-01

    Plasma based surface modification is a promising alternative to wet etching of superconducting radio frequency (SRF) cavities. It has been proven with flat samples that the bulk Niobium (Nb) removal rate and the surface roughness after the plasma etchings are equal to or better than wet etching processes. To optimize the plasma parameters, we are using a single cell cavity with 20 sample holders symmetrically distributed over the cell. These holders serve the purpose of diagnostic ports for the measurement of the plasma parameters and for the holding of the Nb sample to be etched. The plasma properties at RF (100 MHz) and MW (2.45 GHz) frequencies are being measured with the help of electrical and optical probes at different pressures and RF power levels inside of this cavity. The niobium coupons placed on several holders around the cell are being etched simultaneously. The etching results will be presented at this conference.

  20. Deep reactive ion etching of fused silica using a single-coated soft mask layer for bio-analytical applications

    International Nuclear Information System (INIS)

    Ray, Tathagata; Zhu, Haixin; Meldrum, Deirdre R

    2010-01-01

    In this note, we present our results from process development and characterization of reactive ion etching (RIE) of fused silica using a single-coated soft masking layer (KMPR® 1025, Microchem Corporation, Newton, MA). The effects of a number of fluorine-radical-based gaseous chemistries, the gas flow rate, RF power and chamber pressure on the etch rate and etching selectivity of fused silica were studied using factorial experimental designs. RF power and pressure were found to be the most important factors in determining the etch rate. The highest fused silica etch rate obtained was about 933 Å min −1 by using SF 6 -based gas chemistry, and the highest etching selectivity between the fused silica and KMPR® 1025 was up to 1.2 using a combination of CF 4 , CHF 3 and Ar. Up to 30 µm deep microstructures have been successfully fabricated using the developed processes. The average area roughness (R a ) of the etched surface was measured and results showed it is comparable to the roughness obtained using a wet etching technique. Additionally, near-vertical sidewalls (with a taper angle up to 85°) have been obtained for the etched microstructures. The processes developed here can be applied to any application requiring fabrication of deep microstructures in fused silica with near-vertical sidewalls. To our knowledge, this is the first note on deep RIE of fused silica using a single-coated KMPR® 1025 masking layer and a non-ICP-based reactive ion etcher. (technical note)

  1. Interpretation of Mason's equation in terms of measurable electrochemical-etching parameters governing the dielectric breakdown phenomenon

    International Nuclear Information System (INIS)

    Al-Najjar, S.A.R.; Durrani, S.A.

    1986-01-01

    A new interpretation of Mason's equation, as applicable to the electrochemical etching (ECE) of tracks in polymers, is presented in terms of physically meaningful track-etching parameters. The values of these parameters have been experimentally obtained by irradiating CR-39 foils with heavy ions ( 238 U and 129 Xe) and α-particles of various energies, and applying chemical pre-etching (CPE), followed by ECE in steps, with increasing electric field until the 'treeing' breakdown is initiated. A value of 1.19 MV cm -1 is obtained for the intrinsic electrical breakdown stress of CR-39. It is found that the track radius r used in Mason's equation is related to the radius rsub(Θ) of a sphere, inscribed within the etch cone, whose lowest point is at a fixed distance lsub(o) above the cone tip, with lsub(o) ≅ 1.75 μm for α-particle tracks of energies 2-5.5 MeV, such that r = 0.43 + rsub(Θ) (in μm). (author)

  2. Reactive ion etching of GaSb, (Al,Ga)Sb, and InAs for novel device applications

    International Nuclear Information System (INIS)

    LaTulipe, D.C.; Frank, D.J.; Munekata, H.

    1991-01-01

    Although a variety of novel device proposals for GaSb/(Al,Ga)Sb/InAs heterostructures have been made, relatively little is known about processing these materials. The authors of this paper have studied the reactive ion etching characteristics of GaSb, (Al,Ga)Sb, and InAs in both methane/hydrogen and chlorine gas chemistries. At conditions similar to those reported elsewhere for RIE of InP and GaAs in CH 4 /H 2 , the etch rate of (Al,Ga)Sb was found to be near zero, while GaSb and InAs etched at 200 Angstrom/minute. Under conditions where the etch mechanism is primarily physical sputtering, the three compounds etch at similar rates. Etching in Cl 2 was found to yield anistropic profiles, with the etch rate of (Al,Ga)Sb increasing with Al mole fraction, while InAs remains unetched. Damage to the InAs stop layer was investigated by sheet resistance and mobility measurements. These etching techniques were used to fabricate a novel InAs- channel FET composed of these materials. Several scanning electron micrographs of etching results are shown along with preliminary electrical characteristics

  3. Track profile and range studies of heavy and light ions in CR-39: effect of thermal pre-treatment on etching characteristics

    International Nuclear Information System (INIS)

    Al-Najjar, S.A.R.; Bull, R.K.; Durrani, S.A.

    1982-01-01

    Sheets of CR 39 have been irradiated with 20 Ne, 32 S, 40 Ar, 56 Fe and 63 Cu ions at normal incidence to the surface of the sheets and at normal incidence to the edges. The profiles of the etched tracks have been observed side-on and measurements made of the variation of V (the ratio of track to bulk etching velocities) along the tracks and of the fully etched range of the tracks. Heating the plastic at 100 0 C prior to etching produces zones within the plastic having different bulk etching rates Vsub(B). An outer zone of low Vsub(B) is followed by a zone of much higher Vsub(B). This allows tracks to be readily etched to very large diameters, comparable in size to the breakdown spots produced by electrochemical etching. (author)

  4. Plasma etching of electrospun polymeric nanofibres

    Energy Technology Data Exchange (ETDEWEB)

    Verdonck, Patrick [LSI-PSI-EPUSP, Av. Prof. Luciano Gualberto trav 3, 158, 05508-900 Sao Paulo, SP (Brazil)]. E-mail: verdonck@imec.be; Braga Caliope, Priscila [LSI-PSI-EPUSP, Av. Prof. Luciano Gualberto trav 3, 158, 05508-900 Sao Paulo, SP (Brazil); Moral Hernandez, Emilio del [LSI-PSI-EPUSP, Av. Prof. Luciano Gualberto trav 3, 158, 05508-900 Sao Paulo, SP (Brazil); Silva, Ana Neilde R. da [LSI-PSI-EPUSP, Av. Prof. Luciano Gualberto trav 3, 158, 05508-900 Sao Paulo, SP (Brazil); FATEC-SP, Pca Fernando Prestes, 30 Sao Paulo, SP (Brazil)

    2006-10-25

    Electrospun polymeric nanofibres have several applications because of their high surface area to volume and high length to diameter ratios. This paper investigates the influence of plasma etching on these fibres and the etching mechanisms. For the characterization, SEM analysis was performed to determine the forms and shapes of the fibres and SEM photos were analysed by the technique of mathematical morphology, in order to determine the area on the sample occupied by the fibres and the frequency distribution of the nanofibre diameters. The results showed that the oxygen plasma etches the nanofibres much faster when ion bombardment is present. The form of the fibres is not altered by the etching, indicating the possibility of transport of oxygen atoms over the fibre surface. The most frequent diameter, somewhat surprisingly, is not significantly dependent on the etching process, and remains of the order of 80 nm, indicating that fibres with smaller diameters are etched at high rates.

  5. Measurement of inertial confinement fusion reaction rate

    International Nuclear Information System (INIS)

    Peng Xiaoshi; Wang Feng; Tang Daorun; Liu Shenye; Huang Tianxuan; Liu Yonggang; Xu Tao; Chen Ming; Mei Yu

    2011-01-01

    Fusion reaction rate is an important parameter for measuring compression during the implosion in inertial confinement fusion experiment. We have developed a system for fusion reaction history measurement with high temporal resolution. The system is composed of plastic scintillator and nose cone, optical system and streak camera. We have applied this system on the SG-III prototype for fusion reaction rate measuring. For the first time, fusion reaction rate history have been measured for deuterium-tritium filled targets with neutrons yields about 10 10 . We have analyzed possible influence factor during fusion reaction rate measuring. It indicates that the instrument measures fusion reaction bang time at temporal resolutions as low as 30 ps.(authors)

  6. Texture-Etched SnO2 Glasses Applied to Silicon Thin-Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Bing-Rui Wu

    2014-01-01

    Full Text Available Transparent electrodes of tin dioxide (SnO2 on glasses were further wet-etched in the diluted HCl:Cr solution to obtain larger surface roughness and better light-scattering characteristic for thin-film solar cell applications. The process parameters in terms of HCl/Cr mixture ratio, etching temperature, and etching time have been investigated. After etching process, the surface roughness, transmission haze, and sheet resistance of SnO2 glasses were measured. It was found that the etching rate was increased with the additions in etchant concentration of Cr and etching temperature. The optimum texture-etching parameters were 0.15 wt.% Cr in 49% HCl, temperature of 90°C, and time of 30 sec. Moreover, silicon thin-film solar cells with the p-i-n structure were fabricated on the textured SnO2 glasses using hot-wire chemical vapor deposition. By optimizing the texture-etching process, the cell efficiency was increased from 4.04% to 4.39%, resulting from the increment of short-circuit current density from 14.14 to 15.58 mA/cm2. This improvement in cell performances can be ascribed to the light-scattering effect induced by surface texturization of SnO2.

  7. Modeling of block copolymer dry etching for directed self-assembly lithography

    Science.gov (United States)

    Belete, Zelalem; Baer, Eberhard; Erdmann, Andreas

    2018-03-01

    Directed self-assembly (DSA) of block copolymers (BCP) is a promising alternative technology to overcome the limits of patterning for the semiconductor industry. DSA exploits the self-assembling property of BCPs for nano-scale manufacturing and to repair defects in patterns created during photolithography. After self-assembly of BCPs, to transfer the created pattern to the underlying substrate, selective etching of PMMA (poly (methyl methacrylate)) to PS (polystyrene) is required. However, the etch process to transfer the self-assemble "fingerprint" DSA patterns to the underlying layer is still a challenge. Using combined experimental and modelling studies increases understanding of plasma interaction with BCP materials during the etch process and supports the development of selective process that form well-defined patterns. In this paper, a simple model based on a generic surface model has been developed and an investigation to understand the etch behavior of PS-b-PMMA for Ar, and Ar/O2 plasma chemistries has been conducted. The implemented model is calibrated for etch rates and etch profiles with literature data to extract parameters and conduct simulations. In order to understand the effect of the plasma on the block copolymers, first the etch model was calibrated for polystyrene (PS) and poly (methyl methacrylate) (PMMA) homopolymers. After calibration of the model with the homopolymers etch rate, a full Monte-Carlo simulation was conducted and simulation results are compared with the critical-dimension (CD) and selectivity of etch profile measurement. In addition, etch simulations for lamellae pattern have been demonstrated, using the implemented model.

  8. Sources of error in etched-track radon measurements and a review of passive detectors using results from a series of radon intercomparisons

    International Nuclear Information System (INIS)

    Ibrahimi, Z.-F.; Howarth, C.B.; Miles, J.C.H.

    2009-01-01

    Etched-track passive radon detectors are a well established and apparently simple technology. As with any measurement system, there are multiple sources of uncertainty and potential for error. The authors discuss these as well as good quality assurance practices. Identification and assessment of sources of error is crucial to maintain high quality standards by a measurement laboratory. These sources can be found both within and outside the radon measurement laboratory itself. They can lead to changes in track characteristics and ultimately detector response to radon exposure. Changes don't just happen during etching, but can happen during the recording or counting of etched-tracks (for example ageing and fading effects on track sensitivity, or focus and image acquisition variables). Track overlap means the linearity of response of detectors will vary as exposure increases. The laboratory needs to correct the calibration curve due to this effect if it wishes to offer detectors that cover a range of exposures likely to be observed in the field. Extrapolation of results to estimate annual average concentrations also has uncertainty associated with it. Measurement systems need to be robust, reliable and stable. If a laboratory is not actively and constantly monitoring for anomalies via internal testing, the laboratory may not become aware of a problem until some form of external testing occurs, eg an accreditation process, performance test, interlaboratory comparison exercise or when a customer has cause to query results. Benchmark standards of accuracy and precision achievable with passive detectors are discussed drawing on trends from the series of intercomparison exercises for passive radon detectors which began in 1982, organised by the National Radiological Protection Board (NRPB), subsequently the Health Protection Agency (HPA).

  9. Model etch profiles for ion energy distribution functions in an inductively coupled plasma reactor

    International Nuclear Information System (INIS)

    Chen, W.; Abraham-Shrauner, B.; Woodworth, J.R.

    1999-01-01

    Rectangular trench profiles are modeled with analytic etch rates determined from measured ion distribution functions. The pattern transfer step for this plasma etch is for trilayer lithography. Argon and chlorine angular ion energy distribution functions measured by a spherical collector ring analyzer are fit to a sum of drifting Maxwellian velocity distribution functions with anisotropic temperatures. The fit of the model ion distribution functions by a simulated annealing optimization procedure converges adequately for only two drifting Maxwellians. The etch rates are proportional to analytic expressions for the ion energy flux. Numerical computation of the etch profiles by integration of the characteristic equations for profile points and connection of the profiles points is efficient. copyright 1999 American Vacuum Society

  10. Etching conditions and shape of tracks

    International Nuclear Information System (INIS)

    Kudo, Shuichi

    1979-01-01

    The etching effect of hydrogen fluoride (HF) solution of 5%, 10%, 20% and 46% was investigated, using the perlite dug out at Wada-toge, Japan. They were studied by the progressive etching at 30 deg C, after the perlite was subjected to thermal neutron irradiation for 8 hours in the research reactor of the Institute for Atomic Energy of St. Paul (Rikkyo) University. Observation was performed mainly by replica, and false tracks, which are difficult to be judged whether they are the tracks or not, didn't appear as far as this experiment was concerned. Measurements of etch-pits and track density were carried out. The results of these investigations were considered and analyzed to describe them in five sections. The conclusions are as follows: (1) Regarding the ease of etch-pit observation and the adjustment of etching time, etching with 5% HF solution is most advantageous among four solutions of 5, 10, 20 and 46% HF. (2) The measurement of track density is more affected by the difference in counting criteria than the difference in etching conditions. The data on the size of etch-pits are required to discuss the problems of track density and counting efficiency. (3) If linear tracks are to be observed using hydrogen fluoride, it is necessary to investigate the etching characteristics with the solution of lower concentration. (Wakatsuki, Y.)

  11. Influence of redeposition on the plasma etching dynamics

    International Nuclear Information System (INIS)

    Stafford, L.; Margot, J.; Delprat, S.; Chaker, M.; Pearton, S. J.

    2007-01-01

    This work reports on measurements of the degree of redeposition of sputtered species during the etching of platinum (Pt), barium-strontium-titanate (BST), strontium-bismuth-tantalate (SBT), and photoresist (PR) in a high-density argon plasma. While PR exhibits a redeposition-free behavior, the degree of redeposition of Pt, BST, and SBT species increases from 10% to 95% as the argon pressure increases from 0.5 to 10 mTorr. These results are in good agreement with the predictions of a simple model accounting for the backscattering of sputtered species following their interaction with the gas phase. Based on these results and using other experimental data reported in the literature, it is further demonstrated that, depending on the plasma etching conditions, redeposition effects can induce misinterpretation of the etch rate data

  12. Glass dissolution rate measurement and calculation revisited

    Energy Technology Data Exchange (ETDEWEB)

    Fournier, Maxime, E-mail: maxime.fournier@cea.fr [CEA, DEN, DTCD, SECM, F-30207, Bagnols sur Cèze (France); Ull, Aurélien; Nicoleau, Elodie [CEA, DEN, DTCD, SECM, F-30207, Bagnols sur Cèze (France); Inagaki, Yaohiro [Department of Applied Quantum Physics & Nuclear Engineering, Kyushu University, Fukuoka, 819-0395 (Japan); Odorico, Michaël [ICSM-UMR5257 CEA/CNRS/UM2/ENSCM, Site de Marcoule, BP17171, F-30207, Bagnols sur Cèze (France); Frugier, Pierre; Gin, Stéphane [CEA, DEN, DTCD, SECM, F-30207, Bagnols sur Cèze (France)

    2016-08-01

    Aqueous dissolution rate measurements of nuclear glasses are a key step in the long-term behavior study of such waste forms. These rates are routinely normalized to the glass surface area in contact with solution, and experiments are very often carried out using crushed materials. Various methods have been implemented to determine the surface area of such glass powders, leading to differing values, with the notion of the reactive surface area of crushed glass remaining vague. In this study, around forty initial dissolution rate measurements were conducted following static and flow rate (SPFT, MCFT) measurement protocols at 90 °C, pH 10. The international reference glass (ISG), in the forms of powders with different particle sizes and polished monoliths, and soda-lime glass beads were examined. Although crushed glass grains clearly cannot be assimilated with spheres, it is when using the samples geometric surface (S{sub geo}) that the rates measured on powders are closest to those found for monoliths. Overestimation of the reactive surface when using the BET model (S{sub BET}) may be due to small physical features at the atomic scale—contributing to BET surface area but not to AFM surface area. Such features are very small compared with the thickness of water ingress in glass (a few hundred nanometers) and should not be considered in rate calculations. With a S{sub BET}/S{sub geo} ratio of 2.5 ± 0.2 for ISG powders, it is shown here that rates measured on powders and normalized to S{sub geo} should be divided by 1.3 and rates normalized to S{sub BET} should be multiplied by 1.9 in order to be compared with rates measured on a monolith. The use of glass beads indicates that the geometric surface gives a good estimation of glass reactive surface if sample geometry can be precisely described. Although data clearly shows the repeatability of measurements, results must be given with a high uncertainty of approximately ±25%. - Highlights: • Initial dissolution

  13. SU-8 etching in inductively coupled oxygen plasma

    DEFF Research Database (Denmark)

    Rasmussen, Kristian Hagsted; Keller, Stephan Sylvest; Jensen, Flemming

    2013-01-01

    Structuring or removal of the epoxy based, photo sensitive polymer SU-8 by inductively coupled plasma reactive ion etching (ICP-RIE) was investigated as a function of plasma chemistry, bias power, temperature, and pressure. In a pure oxygen plasma, surface accumulation of antimony from the photo......-initiator introduced severe roughness and reduced etch rate significantly. Addition of SF6 to the plasma chemistry reduced the antimony surface concentration with lower roughness and higher etch rate as an outcome. Furthermore the etch anisotropy could be tuned by controlling the bias power. Etch rates up to 800 nm...

  14. Bulk etching characteristics of CR-39 track detectors in hydroxide solutions

    International Nuclear Information System (INIS)

    Fonseca, E.S. da; Knoefel, T.M.J.; Tavares, O.A.P.

    1983-01-01

    A systematic study of the bulk etch rate of CR-39 track detectors in KOH and NaOH aqueous solutions is presented. A number of unirradiated and non-thermally treated CR-39 samples were chemically attacked in KOH and NaOH solutions of concentration and temperature in the range 2-10 N and 50-90 0 C, respectively. From measurements of the thickness of layers removed as a function of the etching time, the bulk etch rate υ β and the induction time T ο for surface removal were obtained for each etching condition. For both NaOH and KOH solution the activation energy of the process was derived as E = 0.76 ± 0.05 eV. It was observed that the induction time decreases both with increasing normality and temperature of the solution. (author) [pt

  15. HANARO core channel flow-rate measurement

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Heon Il; Chae, Hee Tae; Im, Don Soon; Kim, Seon Duk [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1996-06-01

    HANARO core consists of 23 hexagonal flow tubes and 16 cylindrical flow tubes. To get the core flow distribution, we used 6 flow-rate measuring dummy fuel assemblies (instrumented dummy fuel assemblies). The differential pressures were measured and converted to flow-rates using the predetermined relationship between AP and flow-rate for each instrumented dummy fuel assemblies. The flow-rate for the cylindrical flow channels shows +-7% relative errors and that for the hexagonal flow channels shows +-3.5% relative errors. Generally the flow-rates of outer core channels show smaller values compared to those of inner core. The channels near to the core inlet pipe and outlet pipes also show somewhat lower flow-rates. For the lower flow channels, the thermal margin was checked by considering complete linear power histories. From the experimental results, the gap flow-rate was estimated to be 49.4 kg/s (cf. design flow of 50 kg/s). 15 tabs., 9 figs., 10 refs. (Author) .new.

  16. Characterization of silicon isotropic etch by inductively coupled plasma etcher for microneedle array fabrication

    International Nuclear Information System (INIS)

    Ji, J; Tay, F E H; Miao Jianmin; Sun Jianbo

    2006-01-01

    This work investigates the isotropic etching properties in inductively coupled plasma (ICP) etcher for microneedle arrays fabrication. The effects of process variables including powers, gas and pressure on needle structure generation are characterized by factorial design of experiment (DOE). The experimental responses of vertical etching depth, lateral etching length, ratio of vertical etching depth to lateral etching length and photoresist etching rate are reported. The relevance of the etching variables is also presented. The obtained etching behaviours for microneedle structure generation will be applied to develop recipes to fabricate microneedles in designed dimensions

  17. Characterization of silicon isotropic etch by inductively coupled plasma etcher for microneedle array fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Ji, J [Mechanical Engineering National University of Singapore, 119260, Singapore (Singapore); Tay, F E H [Mechanical Engineering National University of Singapore, 119260, Singapore (Singapore); Miao Jianmin [MicroMachines Center, School of Mechanical and Aerospace Engineering, Nanyang Technologica l University, 50 Nanyang Avenue, 639798 (Singapore); Sun Jianbo [MicroMachines Center, School of Mechanical and Aerospace Engineering, Nanyang Technologica l University, 50 Nanyang Avenue, 639798 (Singapore)

    2006-04-01

    This work investigates the isotropic etching properties in inductively coupled plasma (ICP) etcher for microneedle arrays fabrication. The effects of process variables including powers, gas and pressure on needle structure generation are characterized by factorial design of experiment (DOE). The experimental responses of vertical etching depth, lateral etching length, ratio of vertical etching depth to lateral etching length and photoresist etching rate are reported. The relevance of the etching variables is also presented. The obtained etching behaviours for microneedle structure generation will be applied to develop recipes to fabricate microneedles in designed dimensions.

  18. In situ reflectivity investigations of solid/liquid interface during laser backside etching

    International Nuclear Information System (INIS)

    Boehme, R.; Otto, T.; Zimmer, K.

    2006-01-01

    In situ reflectivity measurements of the solid/liquid interface with a pump-probe setup were performed during laser-induced backside wet etching (LIBWE) of fused silica with KrF excimer laser using toluene as absorbing liquid. The intensity, the temporal shape, and the duration of the reflected light measured in dependence on the laser fluence are discussed referring to the surface modification and the bubble formation. The vaporisation of the superheated liquid at the solid interface causes a considerable increase of the reflectivity and gives information about the bubble lifetime. The alterations of the reflectivity after bubbles collapse can be explained with the changed optical properties due to surface modifications of the solid surface. Comparative studies of the reflectivity at different times and the etch rate behaviour in dependence on the laser fluence show that the in situ measured surface modification begins just at the etch threshold fluence and correlates further with etch rate behaviour and the etched surface appearance. The already observed surface modification at LIBWE due to a carbon deposition and structural changes of the near surface region are approved by the changes of the interface reflectivity and emphasizes the importance of the modified surface region in the laser-induced backside wet etching process

  19. Inductively coupled plasma etching of III-V antimonides in BCl3/SiCl4 etch chemistry

    International Nuclear Information System (INIS)

    Swaminathan, K.; Janardhanan, P.E.; Sulima, O.V.

    2008-01-01

    Inductively coupled plasma etching of GaSb using BCl 3 /SiCl 4 etch chemistry has been investigated. The etch rates were studied as a function of bias power, inductively coupled plasma source power, plasma chemistry and chamber pressure. The etched surfaces remain smooth and stoichiometric over the entire range of plasma conditions investigated. The knowledge gained in etching GaSb was applied to etching AlGaAsSb and InGaAsSb in order to fabricate heterojunction phototransistors. As expected, InGaAsSb etch rate was much lower compared to the corresponding value for GaSb, mainly due to the relatively low volatility of indium chlorides. For a wide range of plasma conditions, the selectivity between GaSb and AlGaAsSb was close to unity, which is desirable for fabricating etched mirrors and gratings for Sb-based mid-infrared laser diodes. The surface roughness and the etch profile were examined for the etched GaSb, AlGaAsSb and InGaAsSb samples using scanning electron microscope. The high etch rates achieved (∼ 4 μm/min) facilitated deep etching of GaSb. A single layer, soft mask (AZ-4903 photoresist) was used to etch GaSb, with etch depth ∼ 90 μm. The deep dry etching of GaSb has many important applications including etching substrate windows for backside-illuminated photodetectors for the mid-infrared wavelength range

  20. Using an energized oxygen micro-jet for improved graphene etching by focused electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Songkil; Henry, Mathias [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Fedorov, Andrei G., E-mail: agf@gatech.edu [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

    2015-12-07

    We report on an improved Focused Electron Beam Induced Etching (FEBIE) process, which exploits heated oxygen delivery via a continuous supersonic micro-jet resulting in faster graphene patterning and better etch feature definition. Positioning a micro-jet in close proximity to a graphene surface with minimal jet spreading due to a continuous regime of gas flow at the exit of the 10 μm inner diameter capillary allows for focused exposure of the surface to reactive oxygen at high mass flux and impingement energy of a supersonic gas stream localized to a small etching area exposed to electron beam. These unique benefits of focused supersonic oxygen delivery to the surface enable a dramatic increase in the etch rate of graphene with no parasitic carbon “halo” deposition due to secondary electrons from backscattered electrons (BSE) in the area surrounding the etched regions. Increase of jet temperature via local nozzle heating provides means for enhancing kinetic energy of impinging oxygen molecules, which further speed up the etch, thus minimizing the beam exposure time and required electron dose, before parasitic carbon film deposition due to BSE mediated decomposition of adsorbed hydrocarbon contaminants has a measurable impact on quality of graphene etched features. Interplay of different physical mechanisms underlying an oxygen micro-jet assisted FEBIE process is discussed with support from experimental observations.

  1. Using an energized oxygen micro-jet for improved graphene etching by focused electron beam

    International Nuclear Information System (INIS)

    Kim, Songkil; Henry, Mathias; Fedorov, Andrei G.

    2015-01-01

    We report on an improved Focused Electron Beam Induced Etching (FEBIE) process, which exploits heated oxygen delivery via a continuous supersonic micro-jet resulting in faster graphene patterning and better etch feature definition. Positioning a micro-jet in close proximity to a graphene surface with minimal jet spreading due to a continuous regime of gas flow at the exit of the 10 μm inner diameter capillary allows for focused exposure of the surface to reactive oxygen at high mass flux and impingement energy of a supersonic gas stream localized to a small etching area exposed to electron beam. These unique benefits of focused supersonic oxygen delivery to the surface enable a dramatic increase in the etch rate of graphene with no parasitic carbon “halo” deposition due to secondary electrons from backscattered electrons (BSE) in the area surrounding the etched regions. Increase of jet temperature via local nozzle heating provides means for enhancing kinetic energy of impinging oxygen molecules, which further speed up the etch, thus minimizing the beam exposure time and required electron dose, before parasitic carbon film deposition due to BSE mediated decomposition of adsorbed hydrocarbon contaminants has a measurable impact on quality of graphene etched features. Interplay of different physical mechanisms underlying an oxygen micro-jet assisted FEBIE process is discussed with support from experimental observations

  2. Using an energized oxygen micro-jet for improved graphene etching by focused electron beam

    Science.gov (United States)

    Kim, Songkil; Henry, Mathias; Fedorov, Andrei G.

    2015-12-01

    We report on an improved Focused Electron Beam Induced Etching (FEBIE) process, which exploits heated oxygen delivery via a continuous supersonic micro-jet resulting in faster graphene patterning and better etch feature definition. Positioning a micro-jet in close proximity to a graphene surface with minimal jet spreading due to a continuous regime of gas flow at the exit of the 10 μm inner diameter capillary allows for focused exposure of the surface to reactive oxygen at high mass flux and impingement energy of a supersonic gas stream localized to a small etching area exposed to electron beam. These unique benefits of focused supersonic oxygen delivery to the surface enable a dramatic increase in the etch rate of graphene with no parasitic carbon "halo" deposition due to secondary electrons from backscattered electrons (BSE) in the area surrounding the etched regions. Increase of jet temperature via local nozzle heating provides means for enhancing kinetic energy of impinging oxygen molecules, which further speed up the etch, thus minimizing the beam exposure time and required electron dose, before parasitic carbon film deposition due to BSE mediated decomposition of adsorbed hydrocarbon contaminants has a measurable impact on quality of graphene etched features. Interplay of different physical mechanisms underlying an oxygen micro-jet assisted FEBIE process is discussed with support from experimental observations.

  3. Experiences in integrated leak rate measurements

    International Nuclear Information System (INIS)

    Shirk, R.E.

    1982-01-01

    During a hypothetical design basis accident for nuclear power plants, the reactor containment system is relied upon to maintain radioactive exposure limits below acceptable limits. Integrated leak rate testing is a means of verifying that the leakage of radioactivity material from the reactor containment will be below allowable limits. Leakage rate computations are based on the ideal gas law. The absolute method of leakage rate testing utilizing mass point method of data analysis is recommended. Integrated leak rate testing data is obtained from pressure, drybulb temperature, dewpoint temperature, and flow measuring systems. Test data does not support the usual leakage (flow) - pressure square root relationship. The major source of potential leakage from the reactor containment is reactor containment isolation valves

  4. Silicon etch process

    International Nuclear Information System (INIS)

    Day, D.J.; White, J.C.

    1984-01-01

    A silicon etch process wherein an area of silicon crystal surface is passivated by radiation damage and non-planar structure produced by subsequent anisotropic etching. The surface may be passivated by exposure to an energetic particle flux - for example an ion beam from an arsenic, boron, phosphorus, silicon or hydrogen source, or an electron beam. Radiation damage may be used for pattern definition and/or as an etch stop. Ethylenediamine pyrocatechol or aqueous potassium hydroxide anisotropic etchants may be used. The radiation damage may be removed after etching by thermal annealing. (author)

  5. Problems in continuous dose rate measurement

    International Nuclear Information System (INIS)

    Yoshioka, Mitsuo

    1983-01-01

    The system of continuous dose rate measurement in Fukui Prefecture is described. A telemeter system was constructed in October, 1976, and it has been operated since 1977. Observation has been made at 11 observation stations in the Prefecture. In addition to the continuous measurement of dose rate by using NaI(T1)-DBM systems, the ionization chambers for high dose rate were installed, and also meteorological data have been collected. The detectors are covered with 1 mm thick aluminum designed so that the absorption of external radiation is kept as small as possible. To keep the environmental temperature of the detectors constant, constant temperature wind blow is made. With these consideration, the measurement of Xe-133 is possible, and the standard deviation of yearly dose is around 0.4 mR/Y. By measuring DBM transmission rate, the contribution of Xe-133, which comes from the exhaust pumps in power plants, can be detected. The problems of this system are as follows. First of all, the characteristics of the system must meet the purpose of dose monitoring. The system must detect the dose less than the target value to be achieved. The second is the selection of measuring systems to be set. The system is still not unified, and it is difficult to exchange data between different stations. Finally, the method of data analysis is not yet unified. Manuals or guide-books for this purpose are necessary for the mutual comparison of the data from the stations in different districts. (Kato, T.)

  6. Etched track technique to measure sup 2 sup 2 sup 2 Rn and sup 2 sup 2 sup 0 Rn fluxes on soil surface

    CERN Document Server

    Csige, I

    2003-01-01

    sup 2 sup 2 sup 2 Rn and sup 2 sup 2 sup 0 Rn in the human environment are considered to be a risk factor because of the radiation dose due to the inhalation of their short-lived daughters. Main source of radon is usually the soil; therefore the measurement of fluxes of sup 2 sup 2 sup 2 Rn and sup 2 sup 2 sup 0 Rn on soil surfaces is often a relevant parameter to characterise building site radon potential. An etched track detector technique was developed to measure long-time average sup 2 sup 2 sup 2 Rn and sup 2 sup 2 sup 0 Rn fluxes. (R.P.)

  7. Determination of nuclear tracks parameters on sequentially etched PADC detectors

    Science.gov (United States)

    Horwacik, Tomasz; Bilski, Pawel; Koerner, Christine; Facius, Rainer; Berger, Thomas; Nowak, Tomasz; Reitz, Guenther; Olko, Pawel

    Polyallyl Diglycol Carbonate (PADC) detectors find many applications in radiation protection. One of them is the cosmic radiation dosimetry, where PADC detectors measure the linear energy transfer (LET) spectra of charged particles (from protons to heavy ions), supplementing TLD detectors in the role of passive dosemeter. Calibration exposures to ions of known LET are required to establish a relation between parameters of track observed on the detector and LET of particle creating this track. PADC TASTRAK nuclear track detectors were exposed to 12 C and 56 Fe ions of LET in H2 O between 10 and 544 keV/µm. The exposures took place at the Heavy Ion Medical Accelerator (HIMAC) in Chiba, Japan in the frame of the HIMAC research project "Space Radiation Dosimetry-Ground Based Verification of the MATROSHKA Facility" (20P-240). Detectors were etched in water solution of NaOH with three different temperatures and for various etching times to observe the appearance of etched tracks, the evolution of their parameters and the stability of the etching process. The applied etching times (and the solution's concentrations and temperatures) were: 48, 72, 96, 120 hours (6.25 N NaOH, 50 O C), 20, 40, 60, 80 hours (6.25 N NaOH, 60 O C) and 8, 12, 16, 20 hours (7N NaOH, 70 O C). The analysis of the detectors involved planimetric (2D) measurements of tracks' entrance ellipses and mechanical measurements of bulk layer thickness. Further track parameters, like angle of incidence, track length and etch rate ratio were then calculated. For certain tracks, results of planimetric measurements and calculations were also compared with results of optical track profile (3D) measurements, where not only the track's entrance ellipse but also the location of the track's tip could be directly measured. All these measurements have been performed with the 2D/3D measurement system at DLR. The collected data allow to create sets of V(LET in H2 O) calibration curves suitable for short, intermediate and

  8. Heartbeat Rate Measurement from Facial Video

    DEFF Research Database (Denmark)

    Haque, Mohammad Ahsanul; Irani, Ramin; Nasrollahi, Kamal

    2016-01-01

    Heartbeat Rate (HR) reveals a person’s health condition. This paper presents an effective system for measuring HR from facial videos acquired in a more realistic environment than the testing environment of current systems. The proposed method utilizes a facial feature point tracking method...... by combining a ‘Good feature to track’ and a ‘Supervised descent method’ in order to overcome the limitations of currently available facial video based HR measuring systems. Such limitations include, e.g., unrealistic restriction of the subject’s movement and artificial lighting during data capture. A face...

  9. Effect of various etching conditions on the response of Cr-39 plastic track detector applied for radon dosimetry in environment

    International Nuclear Information System (INIS)

    Maged, A.F.; Ashraf, F.A.

    1997-01-01

    A solid state nuclear track detector Cr-39 has been used for measuring the radon concentration in the soil air and indoor concentration. The bulk etch rate, C B of Cr-39 has been measured in various concentrations of NaOH in the range (6-8 mole) at temperature 70 degree C. In addition, the track etch rate, V T , and the ratio V = V T /V B , of alpha particles emitted from radon gas exists in nature have been measured in a similar range of etching conditions. This study shows that 8 M NaOH at 70 degree C represent the optimum etching conditions for Cr-39, with the range of the present study. The equilibrium factor and gamma-dose equivalent were calculated by using the track densities of open and filtered solid state nuclear track detectors

  10. High dose rate brachytherapy source measurement intercomparison.

    Science.gov (United States)

    Poder, Joel; Smith, Ryan L; Shelton, Nikki; Whitaker, May; Butler, Duncan; Haworth, Annette

    2017-06-01

    This work presents a comparison of air kerma rate (AKR) measurements performed by multiple radiotherapy centres for a single HDR 192 Ir source. Two separate groups (consisting of 15 centres) performed AKR measurements at one of two host centres in Australia. Each group travelled to one of the host centres and measured the AKR of a single 192 Ir source using their own equipment and local protocols. Results were compared to the 192 Ir source calibration certificate provided by the manufacturer by means of a ratio of measured to certified AKR. The comparisons showed remarkably consistent results with the maximum deviation in measurement from the decay-corrected source certificate value being 1.1%. The maximum percentage difference between any two measurements was less than 2%. The comparisons demonstrated the consistency of well-chambers used for 192 Ir AKR measurements in Australia, despite the lack of a local calibration service, and served as a valuable focal point for the exchange of ideas and dosimetry methods.

  11. Si etching with reactive neutral beams of very low energy

    Energy Technology Data Exchange (ETDEWEB)

    Hara, Yasuhiro [Organization for Research and Development of Innovative Science and Technology, Kansai University, 3-3-35 Yamate-chou, Suita, Osaka 565-0871 (Japan); Hamagaki, Manabu; Mise, Takaya [RIKEN, 2-1, Hirosawa, Wako, Saitama 351-0198 (Japan); Iwata, Naotaka; Hara, Tamio [Toyota Technological Institute, 2-12-1 Hisakata, Tenpaku-ku, Nagoya 468-8511 (Japan)

    2014-12-14

    A Si etching process has been investigated with reactive neutral beams (NBs) extracted using a low acceleration voltage of less than 100 V from CF{sub 4} and Ar mixed plasmas. The etched Si profile shows that the etching process is predominantly anisotropic. The reactive NB has a constant Si etching rate in the acceleration voltage range from 20 V to 80 V. It is considered that low-energy NBs can trigger Si etching because F radicals adsorb onto the Si surface and weaken Si–Si bonds. The etching rate per unit beam flux is 33 times higher than that with Ar NB. These results show that the low-energy reactive NB is useful for damage-free high speed Si etching.

  12. Optimization of KOH etching parameters for quantitative defect recognition in n- and p-type doped SiC

    Science.gov (United States)

    Sakwe, S. A.; Müller, R.; Wellmann, P. J.

    2006-04-01

    We have developed a KOH-based defect etching procedure for silicon carbide (SiC), which comprises in situ temperature measurement and control of melt composition. As benefit for the first time reproducible etching conditions were established (calibration plot, etching rate versus temperature and time); the etching procedure is time independent, i.e. no altering in KOH melt composition takes place, and absolute melt temperature values can be set. The paper describes this advanced KOH etching furnace, including the development of a new temperature sensor resistant to molten KOH. We present updated, absolute KOH etching parameters of n-type SiC and new absolute KOH etching parameters for low and highly p-type doped SiC, which are used for quantitative defect analysis. As best defect etching recipes we found T=530 °C/5 min (activation energy: 16.4 kcal/mol) and T=500 °C/5 min (activation energy: 13.5 kcal/mol) for n-type and p-type SiC, respectively.

  13. Surface kinetics of Bi4-xLaxTi3O12 films etched in a CF4/Ar gas chemistry

    International Nuclear Information System (INIS)

    Kim, Dong-Pyo; Kim, Kyoung-Tae; Efremov, A. M.; Kim, Chang-Il

    2004-01-01

    The surface reactions and the etch rate of Bi 4-x La x Ti 3 O 12 (BLT) films in a CF 4 /Ar plasma were investigated in an inductively coupled plasma (ICP) reactor in terms of the gas mixing ratio. The variation of relative volume densities for the F and the Ar atoms were measured with optical emission spectroscopy (OES). The maximum etch rate of 803 A/min was obtained in a CF 4 (20 %)/Ar(80 %) plasma. The presence of a maximum in the BLT etch rate at CF 4 (20 %)/Ar(80 %) may be explained by the concurrence of two etching mechanisms, physical sputtering and chemical reaction. Ar-ion bombardment played roles of destroying the metal (Bi, La, Ti)-O bonds and assisting the chemical reaction between metal and fluorine atoms. The chemical states of BLT were investigated using X-ray photoelectron spectroscopy (XPS), which confirmed the existence of nonvolatile etch byproducts (La-fluorides).

  14. Self-etching adhesive on intact enamel, with and without pre-etching.

    Science.gov (United States)

    Devarasa, G M; Subba Reddy, V V; Chaitra, N L; Swarna, Y M

    2012-05-01

    Bond strengths of composite resin to enamel using self-etch adhesive (SEA) Clearfil SE bond system on intact enamel and enamel pre-etched with phosphoric acid were compared. The objective was to determine if the pre-etching would increase the bond strengths of the SEA systems to intact enamel and to evaluate the effect of pre-etching on bond formation of self-etch adhesives on intact enamel. Labial surfaces of 40 caries free permanent upper central and lateral incisors were cleaned, sectioned of their roots. All specimens were mounted on acrylic block and divided randomly into four groups. In two groups the application of self-etch adhesive, Clearfil SE bond was carried as per manufacturer's instructions, composite cylinders were built, whereas in the other two groups, 37% phosphoric acid etching was done before the application of self-etching adhesives. Then the resin tags were analyzed using scanning electron microscope and shear bond strength was measured using Instron universal testing machine. When phosphoric acid was used, there was significant increase in the depth of penetration of resin tags and in the Shear Bond Strength of composite to enamel. The results indicate that out of both treatment groups, pre-etching the intact enamel with 37% phosphoric acid resulted in formation of longer resin tags and higher depth of penetration of resin tags of the Clearfil SE bond, and attaining higher bond strength of the Clearfil SE bond to intact enamel. Copyright © 2011 Wiley Periodicals, Inc.

  15. Shear bond strength of self-etch adhesives to enamel with additional phosphoric acid etching.

    Science.gov (United States)

    Lührs, Anne-Katrin; Guhr, Silke; Schilke, Reinhard; Borchers, Lothar; Geurtsen, Werner; Günay, Hüsamettin

    2008-01-01

    This study evaluated the shear bond strength of self-etch adhesives to enamel and the effect of additional phosphoric acid etching. Seventy sound human molars were randomly divided into three test groups and one control group. The enamel surfaces of the control group (n=10) were treated with Syntac Classic (SC). Each test group was subdivided into two groups (each n=10). In half of each test group, ground enamel surfaces were coated with the self-etch adhesives AdheSe (ADH), Xeno III (XE) or Futurabond NR (FNR). In the remaining half of each test group, an additional phosphoric acid etching of the enamel surface was performed prior to applying the adhesives. The shear bond strength was measured with a universal testing machine at a crosshead speed of 1 mm/minute after storing the samples in distilled water at 37 degrees C for 24 hours. Fracture modes were determined by SEM examination. For statistical analysis, one-way ANOVA and the two-sided Dunnett Test were used (p>0.05). Additional phosphoric etching significantly increased the shear bond strength of all the examined self-etch adhesives (padhesive fractures. For all the self-etch adhesives, a slight increase in mixed fractures occurred after conditioning with phosphoric acid. An additional phosphoric acid etching of enamel should be considered when using self-etch adhesives. More clinical studies are needed to evaluate the long-term success of the examined adhesives.

  16. Plasma etching of patterned tungsten

    International Nuclear Information System (INIS)

    Franssila, S.

    1993-01-01

    Plasma etching of tungsten is discussed from the viewpoint of thin film structure and integrated circuit process engineering. The emphasis is on patterned tungsten etching for silicon device and X-ray mask fabrication. After introducing tungsten etch chemistries and mechanisms, microstructural aspects of tungsten films (crystal structure, grain size, film density, defects, impurities) in relation to etching are discussed. Approaches to etch process optimization are presented, and the current state-of-the-art of patterned tungsten etching is reviewed. (orig.)

  17. Measurement of leach rates: a review

    International Nuclear Information System (INIS)

    Mendel, J.E.

    1982-01-01

    A historical perspective of the techniques that can be used to measure the leach rate of radioactive waste forms is presented. The achievement of leach rates that are as low as possible has been an important goal ever since the development of solidification processes for liquid radioactive wastes began in the 1950's. Leach tests can be divided into two major categories, dynamic and static, based on whether or not the leachant in contact with the test specimen is changed during the course of the test. Both types of tests have been used extensively. The results of leach tests can be used to compare waste forms, and that has been a major purpose of leach data heretofore; increasingly, however, the data now are needed for predicting long-term leaching behavior during geologic disposal. This requirement is introducing new complexities into leach testing methodology. 3 figures, 2 tables

  18. Flow rate measurement in a volume

    Energy Technology Data Exchange (ETDEWEB)

    Galvez, Cristhian

    2018-04-17

    A system for measuring flow rate within a volume includes one or more transmission devices that transmit one or more signals through fluid contained within the volume. The volume may be bounded, at least in part, by an outer structure and by an object at least partially contained within the outer structure. A transmission device located at a first location of the outer structure transmits a first signal to a second location of the outer structure. A second signal is transmitted through the fluid from the second location to a third location of the outer structure. The flow rate of the fluid within the volume may be determined based, at least in part, on the time of flight of both the first signal and the second signal.

  19. Dry etching of thin chalcogenide films

    Energy Technology Data Exchange (ETDEWEB)

    Petkov, Kiril [Acad. J. Malinowski Central Laboratory of Photoprocesses, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 109, 1113 Sofia (Bulgaria); Vassilev, Gergo; Vassilev, Venceslav, E-mail: kpetkov@clf.bas.b [Department of Semiconductors, University of Chemical Technology and Metallurgy, 8 Kl. Ohridsky Blvd., 1756 Sofia (Bulgaria)

    2010-04-01

    Fluorocarbon plasmas (pure and mixtures with Ar) were used to investigate the changes in the etching rate depending on the chalcogenide glasses composition and light exposure. The experiments were performed on modified commercial HZM-4 vacuum equipment in a diode electrode configuration. The surface microstructure of thin chalcogenide layers and its change after etching in CCl{sub 2}F{sub 2} and CF{sub 4} plasmas were studied by SEM. The dependence of the composition of As-S-Ge, As-Se and multicomponent Ge-Se-Sb-Ag-I layers on the etching rate was discussed. The selective etching of some glasses observed after light exposure opens opportunities for deep structure processing applications.

  20. Molecular dynamics simulations and thermochemistry of reactive ion etching of silicon by chlorine, chlorine dimer, bromine, and bromine dimer cations

    Energy Technology Data Exchange (ETDEWEB)

    Valone, S.M.; Hanson, D.E.; Kress, J.D.

    1998-05-08

    Simulations of Cl plasma etch of Si surfaces with MD techniques agree reasonably well with the available experimental information on yields and surface morphologies. This information has been supplied to a Monte Carlo etch profile resulting in substantial agreement with comparable inputs provided through controlled experiments. To the extent that more recent measurements of etch rates are more reliable than older ones, preliminary MD simulations using bond-order corrections to the atomic interactions between neighboring Si atoms on the surface improves agreement with experiment through an increase in etch rate and improved agreement with XPS measurements of surface stoichiometry. Thermochemical and geometric analysis of small Si-Br molecules is consistent with the current notions of the effects of including brominated species in etchant gases.

  1. Determination of etching parameters for pulsed XeF2 etching of silicon using chamber pressure data

    Science.gov (United States)

    Sarkar, Dipta; Baboly, M. G.; Elahi, M. M.; Abbas, K.; Butner, J.; Piñon, D.; Ward, T. L.; Hieber, Tyler; Schuberth, Austin; Leseman, Z. C.

    2018-04-01

    A technique is presented for determination of the depletion of the etchant, etched depth, and instantaneous etch rate for Si etching with XeF2 in a pulsed etching system in real time. The only experimental data required is the pressure data collected temporally. Coupling the pressure data with the knowledge of the chemical reactions allows for the determination of the etching parameters of interest. Using this technique, it is revealed that pulsed etching processes are nonlinear, with the initial etch rate being the highest and monotonically decreasing as the etchant is depleted. With the pulsed etching system introduced in this paper, the highest instantaneous etch rate of silicon was recorded to be 19.5 µm min-1 for an initial pressure of 1.2 Torr for XeF2. Additionally, the same data is used to determine the rate constant for the reaction of XeF2 with Si; the reaction is determined to be second order in nature. The effect of varying the exposed surface area of Si as well as the effect that pressure has on the instantaneous etch rate as a function of time is shown applying the same technique. As a proof of concept, an AlN resonator is released using XeF2 pulses to remove a sacrificial poly-Si layer.

  2. Etching characteristics of nuclear tracks in CR-39 plastics

    International Nuclear Information System (INIS)

    Tsuruta, Takao; Isobe, Ginko.

    1984-01-01

    In using CR-39 plastics for individual neutron dosimeters, changes of etching efficiency cause significant error in dose estimation. Etching efficiency is subject to a number of parameters. In this study the influences of the parameters were examined by measuring the diameters of etch-pits formed by alpha-particles and enlarged by aqueous solutions of 25-35% KOH at 55-65 0 C for 4 hr. It has been observed that diameter changes at the rate of 8.3%/ 0 C in temperature, 8.2%/wt% in concentration and -0.60%/day in time after preparation of etchant. The diameter is unaffected by the supplying of up to 280ml/l, of distilled water for evaporation of etchant or by increase up to 5g/l of CR-39 dissolved in etchant. The magnitude of possible error has been estimated by parameter as well as in general, so as to obtain suggestions for improving etching treatment. (author)

  3. Comparative study of resist stabilization techniques for metal etch processing

    Science.gov (United States)

    Becker, Gerry; Ross, Matthew F.; Wong, Selmer S.; Minter, Jason P.; Marlowe, Trey; Livesay, William R.

    1999-06-01

    This study investigates resist stabilization techniques as they are applied to a metal etch application. The techniques that are compared are conventional deep-UV/thermal stabilization, or UV bake, and electron beam stabilization. The electron beam tool use din this study, an ElectronCure system from AlliedSignal Inc., ELectron Vision Group, utilizes a flood electron source and a non-thermal process. These stabilization techniques are compared with respect to a metal etch process. In this study, two types of resist are considered for stabilization and etch: a g/i-line resist, Shipley SPR-3012, and an advanced i-line, Shipley SPR 955- Cm. For each of these resist the effects of stabilization on resist features are evaluated by post-stabilization SEM analysis. Etch selectivity in all cases is evaluated by using a timed metal etch, and measuring resists remaining relative to total metal thickness etched. Etch selectivity is presented as a function of stabilization condition. Analyses of the effects of the type of stabilization on this method of selectivity measurement are also presented. SEM analysis was also performed on the features after a compete etch process, and is detailed as a function of stabilization condition. Post-etch cleaning is also an important factor impacted by pre-etch resist stabilization. Results of post- etch cleaning are presented for both stabilization methods. SEM inspection is also detailed for the metal features after resist removal processing.

  4. Dry etching for microelectronics

    CERN Document Server

    Powell, RA

    1984-01-01

    This volume collects together for the first time a series of in-depth, critical reviews of important topics in dry etching, such as dry processing of III-V compound semiconductors, dry etching of refractory metal silicides and dry etching aluminium and aluminium alloys. This topical format provides the reader with more specialised information and references than found in a general review article. In addition, it presents a broad perspective which would otherwise have to be gained by reading a large number of individual research papers. An additional important and unique feature of this book

  5. Etching in microsystem technology

    CERN Document Server

    Kohler, Michael

    2008-01-01

    Microcomponents and microdevices are increasingly finding application in everyday life. The specific functions of all modern microdevices depend strongly on the selection and combination of the materials used in their construction, i.e., the chemical and physical solid-state properties of these materials, and their treatment. The precise patterning of various materials, which is normally performed by lithographic etching processes, is a prerequisite for the fabrication of microdevices.The microtechnical etching of functional patterns is a multidisciplinary area, the basis for the etching p

  6. Characterization of the high density plasma etching process of CCTO thin films for the fabrication of very high density capacitors

    International Nuclear Information System (INIS)

    Altamore, C; Tringali, C; Sparta', N; Marco, S Di; Grasso, A; Ravesi, S

    2010-01-01

    In this work the feasibility of CCTO (Calcium Copper Titanate) patterning by etching process is demonstrated and fully characterized in a hard to etch materials etcher. CCTO sintered in powder shows a giant relative dielectric constant (10 5 ) measured at 1 MHz at room temperature. This feature is furthermore coupled with stability from 10 1 Hz to 10 6 Hz in a wide temperature range (100K - 600K). In principle, this property can allow to fabricate very high capacitance density condenser. Due to its perovskite multi-component structure, CCTO can be considered a hard to etch material. For high density capacitor fabrication, CCTO anisotropic etching is requested by using high density plasma. The behavior of etched CCTO was studied in a HRe- (High Density Reflected electron) plasma etcher using Cl 2 /Ar chemistry. The relationship between the etch rate and the Cl 2 /Ar ratio was also studied. The effects of RF MHz, KHz Power and pressure variation, the impact of HBr addiction to the Cl 2 /Ar chemistry on the CCTO etch rate and on its selectivity to Pt and photo resist was investigated.

  7. Characterization of the high density plasma etching process of CCTO thin films for the fabrication of very high density capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Altamore, C; Tringali, C; Sparta' , N; Marco, S Di; Grasso, A; Ravesi, S [STMicroelectronics, Industial and Multi-segment Sector R and D, Catania (Italy)

    2010-02-15

    In this work the feasibility of CCTO (Calcium Copper Titanate) patterning by etching process is demonstrated and fully characterized in a hard to etch materials etcher. CCTO sintered in powder shows a giant relative dielectric constant (10{sup 5}) measured at 1 MHz at room temperature. This feature is furthermore coupled with stability from 10{sup 1} Hz to 10{sup 6} Hz in a wide temperature range (100K - 600K). In principle, this property can allow to fabricate very high capacitance density condenser. Due to its perovskite multi-component structure, CCTO can be considered a hard to etch material. For high density capacitor fabrication, CCTO anisotropic etching is requested by using high density plasma. The behavior of etched CCTO was studied in a HRe- (High Density Reflected electron) plasma etcher using Cl{sub 2}/Ar chemistry. The relationship between the etch rate and the Cl{sub 2}/Ar ratio was also studied. The effects of RF MHz, KHz Power and pressure variation, the impact of HBr addiction to the Cl{sub 2}/Ar chemistry on the CCTO etch rate and on its selectivity to Pt and photo resist was investigated.

  8. Etching method employing radiation

    International Nuclear Information System (INIS)

    Chapman, B.N.; Winters, H.F.

    1982-01-01

    This invention provides a method for etching a silicon oxide, carbide, nitride, or oxynitride surface using an electron or ion beam in the presence of a xenon or krypton fluoride. No additional steps are required after exposure to radiation

  9. Synchrotron radiation induced direct photo-etching and surface modification of PTFE

    International Nuclear Information System (INIS)

    Oshima, Akihiro; Washio, Masakazu

    2003-01-01

    In the first part of this article, we have described and discussed the measurement results of etching rates by direct photo-etching using Synchrotron Radiation (SR) for various kind of crosslinked PTFEs, which were prepared by different crosslinking doses, comparing with the non-crosslinked PTFE. It has been found that the etching rates obtained for crosslinked PTFE were much larger than that of non-crosslinked one. These results are not described by simple consideration such as the G values of main chain scission. We propose that the etching rates should be discussed by the complex mechanism through at least two different steps such as polymer decomposition and fragment desorption. In the second part of the article, we have described and discussed the abnormal reaction induced at the surface region after the SR etching for non-crosslinked PTFE. Through the measurements using DSC and solid state 19 F-NMR, we have confirmed the crosslinking reaction of PTFE even in solid state PTFE. This should be induced by the very high density radical formation in very thin area of PTFE films by SR radiation. (author)

  10. Flux based modeling and simulation of dry etching for fabrication of silicon deep trench structures

    Energy Technology Data Exchange (ETDEWEB)

    Malik Rizwan [State Key Laboratory of Digital Manufacturing Equipment and technology, Huazhong University of Science and Technology, 1037 Luoyu road, Wuhan, China 43007 (China); Shi Tielin; Tang Zirong; Liu Shiyuan, E-mail: zirong@mail.hust.edu.cn, E-mail: rizwanmalik@smail.hust.edu.cn [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu road Wuhan, 430074 (China)

    2011-02-01

    Deep reactive ion etching (DRIE) process is a key growth for fabrication of micro-electromechanical system (MEMS) devices. Due to complexity of this process, including interaction of the process steps, full analytical modeling is complex. Plasma process holds deficiency of understanding because it is very easy to measure the results empirically. However, as device parameters shrink, this issue is more critical. In this paper, our process was modeled qualitatively based on 'High Density Plasma Etch Model'. Deep trench solutions of etch rate based on continuity equation were successfully generated first time through mathematical analysis. It was also proved that the product of fluorine and gas phase concentration in SF{sub 6} remains identical during both deposition and etching stages. The etching process was treated as a combination of isotropic, directional and angle-dependent component parts. It exploited a synergistic balance of chemical as well as physical etching for promoting silicon trenches and high aspect ratio structures. Simulations were performed for comprehensive analysis of fluxes coming towards the surface during chemical reaction of gas. It is observed that near the surface, the distribution of the arrival flux follows a cosine distribution. Our model is feasible to analyze various parameters like gas delivery, reactor volume and temperature that help to assert large scale effects and to optimize equipment design.

  11. Low-voltage electroosmotic pumping using polyethylene terephthalate track-etched membrane

    Energy Technology Data Exchange (ETDEWEB)

    Wang Ceming; Wang Lin [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Xue Jianming, E-mail: jmxue@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China)

    2012-09-01

    We present experimental investigations of electroosmotic (EO) pumping using polyethylene terephthalate (PET) track-etched membrane at a low applied voltage. An EO pump based on PET track-etched membrane has been designed and fabricated. Pumping performance of the device is experimentally studied in terms of flow rate as a function of applied voltage and KCl aqueous concentration. The PET track-etched membrane EO pump can generate flow rates on the order of 10 {mu}l min{sup -1} cm{sup -2} at several applied volts. The measured flow rate tends to decrease with increasing KCl aqueous concentration. In addition, we study the EO flow in cylindrical nanopore with use of a continuum model, composed of Nernst Planck equations, Poisson equation and Navier Stokes equations.

  12. Dose rate measuring device and dose rate measuring method using the same

    International Nuclear Information System (INIS)

    Urata, Megumu; Matsushita, Takashi; Hanazawa, Sadao; Konno, Takahiro; Chiba, Yoshinori; Yumitate, Tadahiro

    1998-01-01

    The device of the present invention comprises a scintillation fiber scope having a shape elongated in the direction of the height of a pressure vessel and emitting light by incident of radiation to detect radiation, a radioactivity measuring device for measuring a dose rate based on the detection of the fiber scope and a reel means for dispensing and taking up the fiber scope, and it constituted such that the dose rate of the pressure vessel and that of a shroud are determined independently. Then, when the taken out shroud is contained in an container, excessive shielding is not necessary, in addition, this device can reliably be inserted to or withdrawn from complicated places between the pressure vessel and the shroud, and further, the dose rate of the pressure vessel and that of the shroud can be measured approximately accurately even when the thickness of them is different greatly. (N.H.)

  13. Dose rate measuring device and dose rate measuring method using the same

    Energy Technology Data Exchange (ETDEWEB)

    Urata, Megumu; Matsushita, Takashi; Hanazawa, Sadao; Konno, Takahiro; Chiba, Yoshinori; Yumitate, Tadahiro

    1998-11-13

    The device of the present invention comprises a scintillation fiber scope having a shape elongated in the direction of the height of a pressure vessel and emitting light by incident of radiation to detect radiation, a radioactivity measuring device for measuring a dose rate based on the detection of the fiber scope and a reel means for dispensing and taking up the fiber scope, and it constituted such that the dose rate of the pressure vessel and that of a shroud are determined independently. Then, when the taken out shroud is contained in an container, excessive shielding is not necessary, in addition, this device can reliably be inserted to or withdrawn from complicated places between the pressure vessel and the shroud, and further, the dose rate of the pressure vessel and that of the shroud can be measured approximately accurately even when the thickness of them is different greatly. (N.H.)

  14. Chemical etching of fission tracks in ethylene-tetrafluoroethylene copolymer

    International Nuclear Information System (INIS)

    Komaki, Y.; Tsujimura, S.; Seguchi, T.

    1979-01-01

    The chemical etching of fission tracks in ethylene-tetrafluoroethylene copolymer was studied. Etched holes 3000 to 4000 A in diameter were recognized by electron microscopy for a film bombarded by fission fragments in oxygen and etched in a 12N sodium hydroxide solution at 125 0 C. The radial etching rate at 125 0 C was 6 to 8 A/hr, which is less than 17 A/hr for polyvinylidene fluoride in the same sodium hydroxide concentration at 85 0 C. The smaller rate is a reflection of the larger chemical resistivity of ethylene-tetrafluoroethylene copolymer than polyvinylidene fluoride. (author)

  15. Measuring the costs of exchange rate volatility

    OpenAIRE

    Paul R. Bergin

    2004-01-01

    Many countries go to great lengths to manage their exchange rates. Probably the most prominent recent example is the European Monetary Union, where all the members abandoned their national currencies and adopted the euro. A number of developing countries maintain other kinds of regimes of managed exchange rates, even though they face potent market pressures to let their exchange rates float. One of the main motives for these arrangements stems from the extreme volatility of exchange rates. Th...

  16. Measuring Implicit Rental Rates for Farm Capital

    OpenAIRE

    Hrubovcak, James

    1986-01-01

    Developing implicit rental rates for capital inputs is an Important step in understanding the Impact of tax law changes on agricultural investments This article develops a methodology for estimating implicit rental rates and presents annual estimates of rental rates for seven categories of farm equipment and structures from 1955 to 1979 This article also compares these rental rates With those estimated under a no-tax alternative The author developed a method for estimating marginal Federal In...

  17. Growth and etching characteristics of gallium oxide thin films by pulsed laser deposition

    International Nuclear Information System (INIS)

    Ou, Sin-Liang; Wuu, Dong-Sing; Fu, Yu-Chuan; Liu, Shu-Ping; Horng, Ray-Hua; Liu, Lei; Feng, Zhe-Chuan

    2012-01-01

    Highlights: ► The β-Ga2O3 thin films are prepared by pulsed laser deposition. ► The substrate temperature affects the structural, optical and etching properties of the grown films. ► The optical transmittance and band gap of the films increased with increasing the substrate temperature. ► The etching treatments for gallium oxide are performed in 49 mol% HF solution at room temperature. ► The gallium oxide thin film grown at 400 °C has the highest etching rate of 490 nm s −1 . - Abstract: The gallium oxide films were deposited on (0 0 1) sapphire at various substrate temperatures from 400 to 1000 °C by pulsed laser deposition using a KrF excimer laser. The etching treatments for as-grown gallium oxide were performed in a 49 mol% HF solution at room temperature. The structural, optical and etching properties of the grown films were investigated in terms of high resolution X-ray diffraction, optical transmittance, atomic force microscopy, and X-ray photoelectron spectroscopy. The phase transition from amorphous to polycrystalline β-Ga 2 O 3 structure was observed with increasing growth temperature. From the optical transmittance measurements, the films grown at 550–1000 °C exhibit a clear absorption edge at deep ultraviolet region around 250–275 nm wavelength. It was found that the optical band gap of gallium oxide films increased from 4.56 to 4.87 eV when the substrate temperature increased from 400 to 1000 °C. As the substrate temperature increases, the crystallinity of gallium oxide film is enhanced and the etching rate is decreased. The high etching rate of 490 nm s −1 for gallium oxide film grown at 400 °C could be due to its amorphous phase, which is referred to higher void ratio and looser atomic structure.

  18. Plasma etching: Yesterday, today, and tomorrow

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, Vincent M.; Kornblit, Avinoam [Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204 (United States)

    2013-09-15

    The field of plasma etching is reviewed. Plasma etching, a revolutionary extension of the technique of physical sputtering, was introduced to integrated circuit manufacturing as early as the mid 1960s and more widely in the early 1970s, in an effort to reduce liquid waste disposal in manufacturing and achieve selectivities that were difficult to obtain with wet chemistry. Quickly, the ability to anisotropically etch silicon, aluminum, and silicon dioxide in plasmas became the breakthrough that allowed the features in integrated circuits to continue to shrink over the next 40 years. Some of this early history is reviewed, and a discussion of the evolution in plasma reactor design is included. Some basic principles related to plasma etching such as evaporation rates and Langmuir–Hinshelwood adsorption are introduced. Etching mechanisms of selected materials, silicon, silicon dioxide, and low dielectric-constant materials are discussed in detail. A detailed treatment is presented of applications in current silicon integrated circuit fabrication. Finally, some predictions are offered for future needs and advances in plasma etching for silicon and nonsilicon-based devices.

  19. Plasma etching: Yesterday, today, and tomorrow

    International Nuclear Information System (INIS)

    Donnelly, Vincent M.; Kornblit, Avinoam

    2013-01-01

    The field of plasma etching is reviewed. Plasma etching, a revolutionary extension of the technique of physical sputtering, was introduced to integrated circuit manufacturing as early as the mid 1960s and more widely in the early 1970s, in an effort to reduce liquid waste disposal in manufacturing and achieve selectivities that were difficult to obtain with wet chemistry. Quickly, the ability to anisotropically etch silicon, aluminum, and silicon dioxide in plasmas became the breakthrough that allowed the features in integrated circuits to continue to shrink over the next 40 years. Some of this early history is reviewed, and a discussion of the evolution in plasma reactor design is included. Some basic principles related to plasma etching such as evaporation rates and Langmuir–Hinshelwood adsorption are introduced. Etching mechanisms of selected materials, silicon, silicon dioxide, and low dielectric-constant materials are discussed in detail. A detailed treatment is presented of applications in current silicon integrated circuit fabrication. Finally, some predictions are offered for future needs and advances in plasma etching for silicon and nonsilicon-based devices

  20. A multi-step electrochemical etching process for a three-dimensional micro probe array

    International Nuclear Information System (INIS)

    Kim, Yoonji; Youn, Sechan; Cho, Young-Ho; Park, HoJoon; Chang, Byeung Gyu; Oh, Yong Soo

    2011-01-01

    We present a simple, fast, and cost-effective process for three-dimensional (3D) micro probe array fabrication using multi-step electrochemical metal foil etching. Compared to the previous electroplating (add-on) process, the present electrochemical (subtractive) process results in well-controlled material properties of the metallic microstructures. In the experimental study, we describe the single-step and multi-step electrochemical aluminum foil etching processes. In the single-step process, the depth etch rate and the bias etch rate of an aluminum foil have been measured as 1.50 ± 0.10 and 0.77 ± 0.03 µm min −1 , respectively. On the basis of the single-step process results, we have designed and performed the two-step electrochemical etching process for the 3D micro probe array fabrication. The fabricated 3D micro probe array shows the vertical and lateral fabrication errors of 15.5 ± 5.8% and 3.3 ± 0.9%, respectively, with the surface roughness of 37.4 ± 9.6 nm. The contact force and the contact resistance of the 3D micro probe array have been measured to be 24.30 ± 0.98 mN and 2.27 ± 0.11 Ω, respectively, for an overdrive of 49.12 ± 1.25 µm.

  1. Determination of the depth of an etch pit through studies of diffraction rings

    Energy Technology Data Exchange (ETDEWEB)

    Basu, B. [Department of Physics, Bose Institute, 93/1 APC Road, Kolkata 700 009 (India); Centre for Astroparticle Physics and Space Science, Bose institute, Kolkata 700 091 (India); Dey, S.; Maulik, A. [Centre for Astroparticle Physics and Space Science, Bose institute, Kolkata 700 091 (India); Raha, Sibaji [Department of Physics, Bose Institute, 93/1 APC Road, Kolkata 700 009 (India); Centre for Astroparticle Physics and Space Science, Bose institute, Kolkata 700 091 (India); Saha, S. [Nuclear and Atomic Physics Division, Saha Institute of Nuclear Physics, Kolkata 700 064 (India); Saha, Swapan K. [Department of Physics, Bose Institute, 93/1 APC Road, Kolkata 700 009 (India); Centre for Astroparticle Physics and Space Science, Bose institute, Kolkata 700 091 (India)], E-mail: swapan@bosemain.boseinst.ac.in; Syam, D. [Department of Physics, Presidency College, Kolkata 700 073 (India)

    2009-04-15

    A Solid State Nuclear Track Detector (SSNTD) can be used to identify an impinging ion as well as to determine the energy of that ion. The track of the ion is made visible by chemically 'etching' the detector after exposure. By finding out the ratio of the track-etch rate (V{sub t}) to the bulk-etch rate (V{sub g}), together with the range of the ion in the detector, the identity and the energy of the ion can be ascertained. The required measurements can be conveniently made with the help of a microscope when the angle of incidence of the ion, with respect to the normal direction to the detector surface, is more than 15 deg.. For normal or near normal incidence, uncertainties plague the measurement of the depth of the etch pit and hence the range of the particle. Through this article we wish to suggest an alternative method of assessment, based on the observation of diffraction rings, of the depth of an etch pit.

  2. Cyclic etching of tin-doped indium oxide using hydrogen-induced modified layer

    Science.gov (United States)

    Hirata, Akiko; Fukasawa, Masanaga; Nagahata, Kazunori; Li, Hu; Karahashi, Kazuhiro; Hamaguchi, Satoshi; Tatsumi, Tetsuya

    2018-06-01

    The rate of etching of tin-doped indium oxide (ITO) and the effects of a hydrogen-induced modified layer on cyclic, multistep thin-layer etching were investigated. It was found that ITO cyclic etching is possible by precisely controlling the hydrogen-induced modified layer. Highly selective etching of ITO/SiO2 was also investigated, and it was suggested that cyclic etching by selective surface adsorption of Si can precisely control the etch rates of ITO and SiO2, resulting in an almost infinite selectivity for ITO over SiO2 and in improved profile controllability.

  3. Etching mechanism of MgO thin films in inductively coupled Cl2/Ar plasma

    International Nuclear Information System (INIS)

    Efremov, A.M.; Koo, Seong-Mo; Kim, Dong-Pyo; Kim, Kyoung-Tae; Kim, Chang-Il

    2004-01-01

    The etching mechanism of MgO thin films in Cl 2 /Ar plasma was investigated. It was found that the increasing Ar in the mixing ratio of Cl 2 /Ar plasma causes nonmonotonic MgO etch rate, which reaches a maximum value at 70%Ar+30%Cl 2 . Langmuir probe measurement showed the noticeable influence of Cl 2 /Ar mixing ratio on electron temperature and electron density. The zero-dimensional plasma model indicated monotonic changes of both densities and fluxes of active species. At the same time, analyses of surface kinetics showed the possibility of nonmonotonic etch rate behavior due to the concurrence of physical and chemical pathways in ion-assisted chemical reaction

  4. Measuring heart rate with optical sensor

    NARCIS (Netherlands)

    Barachi, M. (Mitra)

    2014-01-01

    The problem addressed in this report is to verify the possibility of using an optical sensor in the SaxShirt in order to extract the heart rate. There are specifically three questions that we try to address. 1) How is it possible to extract heart rate (BPM) from the optical sensor? 2) Is it

  5. Advanced dry etching studies for micro- and nano-systems

    DEFF Research Database (Denmark)

    Rasmussen, Kristian Hagsted

    and even contaminate the surface with metal flakes after resist removal. Ion beam etching has also been used for etching of steel without any problems with redeposition. For steel the etch rate was low which reduced the selectivity to the photo resist. Sapphire, a crystal of aluminum oxide, has a very low....... However, just generating an oxygen plasma does not result in a controllable etch and may give rise to a poor surface for later use. It may be necessary to introduce other gases such as SF6 to reduce surface roughness. Roughness can also be introduced by the mask in the form of redeposition of material...

  6. Preparation of Track Etch Membrane Filters Using Polystyrene Film

    International Nuclear Information System (INIS)

    Kaewsaenee, Jerawut; Ratanatongchai, Wichian; Supaphol, Pitt; Visal-athaphand, Pinpan

    2007-08-01

    Full text: Polystyrene nuclear track etch membrane filters was prepared by exposed 13 .m thin film polystyrene with fission fragment. Nuclear latent track was enlarged to through hole on the film by etching with 80 o C 40% H 2 SO 4 with K 2 Cr 2 O 7 solution for 6-10 hour. The hole size was depend on concentration of etching solution and etching time with 1.3-3.4 .m hole diameter. The flow rate test of water was 0.79-1.56 mm cm-2 min-1 at 109.8-113.7 kPa pressure

  7. Measurements of Protein Crystal Face Growth Rates

    Science.gov (United States)

    Gorti, S.

    2014-01-01

    Protein crystal growth rates will be determined for several hyperthermophile proteins.; The growth rates will be assessed using available theoretical models, including kinetic roughening.; If/when kinetic roughening supersaturations are established, determinations of protein crystal quality over a range of supersaturations will also be assessed.; The results of our ground based effort may well address the existence of a correlation between fundamental growth mechanisms and protein crystal quality.

  8. Silicon etching of difluoromethane atmospheric pressure plasma jet combined with its spectroscopic analysis

    Science.gov (United States)

    Sung, Yu-Ching; Wei, Ta-Chin; Liu, You-Chia; Huang, Chun

    2018-06-01

    A capacitivly coupled radio-frequency double-pipe atmospheric-pressure plasma jet is used for etching. An argon carrier gas is supplied to the plasma discharge jet; and CH2F2 etch gas is inserted into the plasma discharge jet, near the silicon substrate. Silicon etchings rate can be efficiently-controlled by adjusting the feeding etching gas composition and plasma jet operating parameters. The features of silicon etched by the plasma discharge jet are discussed in order to spatially spreading plasma species. Electronic excitation temperature and electron density are detected by increasing plasma power. The etched silicon profile exhibited an anisotropic shape and the etching rate was maximum at the total gas flow rate of 4500 sccm and CH2F2 concentration of 11.1%. An etching rate of 17 µm/min was obtained at a plasma power of 100 W.

  9. Etching of polymers, proteins and bacterial spores by atmospheric pressure DBD plasma in air

    Science.gov (United States)

    Kuzminova, A.; Kretková, T.; Kylián, O.; Hanuš, J.; Khalakhan, I.; Prukner, V.; Doležalová, E.; Šimek, M.; Biederman, H.

    2017-04-01

    Many studies proved that non-equilibrium discharges generated at atmospheric pressure are highly effective for the bio-decontamination of surfaces of various materials. One of the key processes that leads to a desired result is plasma etching and thus the evaluation of etching rates of organic materials is of high importance. However, the comparison of reported results is rather difficult if impossible as different authors use diverse sources of atmospheric plasma that are operated at significantly different operational parameters. Therefore, we report here on the systematic study of the etching of nine different common polymers that mimic the different structures of more complicated biological systems, bovine serum albumin (BSA) selected as the model protein and spores of Bacillus subtilis taken as a representative of highly resistant micro-organisms. The treatment of these materials was performed by means of atmospheric pressure dielectric barrier discharge (DBD) sustained in open air at constant conditions. All tested polymers, BSA and spores, were readily etched by DBD plasma. However, the measured etching rates were found to be dependent on the chemical structure of treated materials, namely on the presence of oxygen in the structure of polymers.

  10. A study on electric properties for pulse laser annealing of ITO film after wet etching

    International Nuclear Information System (INIS)

    Lee, C.J.; Lin, H.K.; Li, C.H.; Chen, L.X.; Lee, C.C.; Wu, C.W.; Huang, J.C.

    2012-01-01

    The electric properties of ITO thin film after UV or IR laser annealing and wet etching was analyzed via grazing incidence in-plane X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectra and residual stress measurement. The laser annealing process readily induced microcracks or quasi-microcracks on the ITO thin film due to the residual tension stress of crystalline phase transformation between irradiated and non-irradiated areas, and these defects then became the preferred sites for a higher etching rate, resulting in discontinuities in the ITO thin film after the wet etching process. The discontinuities in the residual ITO thin film obstruct carrier transmission and further result in electric failure. - Highlights: ► The laser annealing process induces microcracks in InSnO 2 thin films. ► The defects result in higher local etching rate during wet etching. ► These process defects originate from residual tension stress. ► Decreasing the thermal shock is suggested in order to reduce these process defects.

  11. Measuring Change with the Rating Scale Model.

    Science.gov (United States)

    Ludlow, Larry H.; And Others

    The Rehabilitation Research and Development Laboratory at the United States Veterans Administration Hines Hospital is engaged in a long-term evaluation of blind rehabilitation. One aspect of the evaluation project focuses on the measurement of attitudes toward blindness. Our aim is to measure changes in attitudes toward blindness from…

  12. Effects of gas-flow structures on radical and etch-product density distributions on wafers in magnetomicrowave plasma etching reactors

    International Nuclear Information System (INIS)

    Ikegawa, Masato; Kobayashi, Jun'ichi; Fukuyama, Ryoji

    2001-01-01

    To achieve high etch rate, uniformity, good selectivity, and etch profile control across large diameter wafers, the distributions of ions, radicals, and etch products in magnetomicrowave high-etch-rate plasma etching reactors must be accurately controlled. In this work the effects of chamber heights, a focus ring around the wafer, and gas supply structures (or gas flow structures) on the radicals and etch products flux distribution onto the wafer were examined using the direct simulation Monte Carlo method and used to determine the optimal reactor geometry. The pressure uniformity on the wafer was less than ±1% when the chamber height was taller than 60 mm. The focus ring around the wafer produced uniform radical and etch-product fluxes but increased the etch-product flux on the wafer. A downward-flow gas-supply structure (type II) produced a more uniform radical distribution than that produced by a radial gas-supply structure (type I). The impact flow of the type II structure removed etch products from the wafer effectively and produced a uniform etch-product distribution even without the focus ring. Thus the downward-flow gas-supply structure (type II) was adopted in the design for the second-generation of a magnetomicrowave plasma etching reactor with a higher etching rate

  13. Automated Speech Rate Measurement in Dysarthria

    Science.gov (United States)

    Martens, Heidi; Dekens, Tomas; Van Nuffelen, Gwen; Latacz, Lukas; Verhelst, Werner; De Bodt, Marc

    2015-01-01

    Purpose: In this study, a new algorithm for automated determination of speech rate (SR) in dysarthric speech is evaluated. We investigated how reliably the algorithm calculates the SR of dysarthric speech samples when compared with calculation performed by speech-language pathologists. Method: The new algorithm was trained and tested using Dutch…

  14. Inductively coupled plasma etching of III-V antimonides in BCl{sub 3}/SiCl{sub 4} etch chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Swaminathan, K. [Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware 19716 (United States)], E-mail: swaminak@ece.osu.edu; Janardhanan, P.E.; Sulima, O.V. [Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware 19716 (United States)

    2008-10-01

    Inductively coupled plasma etching of GaSb using BCl{sub 3}/SiCl{sub 4} etch chemistry has been investigated. The etch rates were studied as a function of bias power, inductively coupled plasma source power, plasma chemistry and chamber pressure. The etched surfaces remain smooth and stoichiometric over the entire range of plasma conditions investigated. The knowledge gained in etching GaSb was applied to etching AlGaAsSb and InGaAsSb in order to fabricate heterojunction phototransistors. As expected, InGaAsSb etch rate was much lower compared to the corresponding value for GaSb, mainly due to the relatively low volatility of indium chlorides. For a wide range of plasma conditions, the selectivity between GaSb and AlGaAsSb was close to unity, which is desirable for fabricating etched mirrors and gratings for Sb-based mid-infrared laser diodes. The surface roughness and the etch profile were examined for the etched GaSb, AlGaAsSb and InGaAsSb samples using scanning electron microscope. The high etch rates achieved ({approx} 4 {mu}m/min) facilitated deep etching of GaSb. A single layer, soft mask (AZ-4903 photoresist) was used to etch GaSb, with etch depth {approx} 90 {mu}m. The deep dry etching of GaSb has many important applications including etching substrate windows for backside-illuminated photodetectors for the mid-infrared wavelength range.

  15. Features of copper etching in chlorine-argon plasma

    International Nuclear Information System (INIS)

    Efremov, A.M.; Svettsov, V.I.

    1995-01-01

    Chlorine mixtures with inert gases including argon exhibit promise as plasma feed gases for etching metals and semiconductors in the microelectronics industry. It was shown that even strong dilution of reactive gas with an inert gas (up to 80-90% of the latter) has virtually no effect in decreasing the rate of plasma etching of materials such as silicon and gallium arsenide, compared to etching in pure chlorine. The principal reactive species responsible for etching these substrates are chlorine atoms therefore, a possible explanation of the effect is an increase in the rate of bulk generation of chlorine atoms in the presence of argon. In this work the authors studied the influence of argon on the rate of copper etching in chlorine, because copper, unlike the above substrates, reacts effectively not only with the atoms but with the ground-state molecules of chlorine

  16. Physical chemistry of wet chemical anisotropic etching of silicon

    NARCIS (Netherlands)

    Elwenspoek, Michael Curt

    1995-01-01

    In this paper we explain a view to understand the anisotropy of the etching of silicon in certain wet chemical agents (such as KOH). The starting point is the assumption that the [Left angle bracket]111[Right Angle Bracket] face of silicon is a flat face, the etch rate of which is then governed by a

  17. Optimization of some electrochemical etching parameters for cellulose derivatives

    International Nuclear Information System (INIS)

    Chowdhury, Annis; Gammage, R.B.

    1978-01-01

    Electrochemical etching of fast neutron induced recoil particle tracks in cellulose derivatives and other polymers provides an inexpensive and sensitive means of fast neutron personnel dosimetry. A study of the shape, clarity, and size of the tracks in Transilwrap polycarbonate indicated that the optimum normality of the potassium hydroxide etching solution is 9 N. Optimizations have also been attempted for cellulose nitrate, triacetate, and acetobutyrate with respect to such electrochemical etching parameters as frequency, voltage gradient, and concentration of the etching solution. The measurement of differential leakage currents between the undamaged and the neutron damaged foils aided in the selection of optimum frequencies. (author)

  18. Dry etching technology for semiconductors

    CERN Document Server

    Nojiri, Kazuo

    2015-01-01

    This book is a must-have reference to dry etching technology for semiconductors, which will enable engineers to develop new etching processes for further miniaturization and integration of semiconductor integrated circuits.  The author describes the device manufacturing flow, and explains in which part of the flow dry etching is actually used. The content is designed as a practical guide for engineers working at chip makers, equipment suppliers and materials suppliers, and university students studying plasma, focusing on the topics they need most, such as detailed etching processes for each material (Si, SiO2, Metal etc) used in semiconductor devices, etching equipment used in manufacturing fabs, explanation of why a particular plasma source and gas chemistry are used for the etching of each material, and how to develop etching processes.  The latest, key technologies are also described, such as 3D IC Etching, Dual Damascene Etching, Low-k Etching, Hi-k/Metal Gate Etching, FinFET Etching, Double Patterning ...

  19. Leak rate measurements and detection systems

    International Nuclear Information System (INIS)

    Kupperman, D.; Shack, W.J.; Claytor, T.

    1983-10-01

    A research program is under way to evaluate and develop improve leak detection systems. The primary focus of the work has been on acoustic emission detection of leaks. Leaks from artificial flaws, laboratory-generated IGSCCs and thermal fatigue cracks, and field-induced intergranular stress corrosion cracks (IGSCCs) from reactor piping have been examined. The effects of pressure, temperature, and leak rate and geometry on the acoustic signature are under study. The use of cross-correlation techniques for leak location and pattern recognition and autocorrelation for source discrimination is also being considered

  20. ECE laboratory in the Vinca Institute - its basic characteristics and fundamentals of electrochemical etching on polycarbonate

    International Nuclear Information System (INIS)

    Zunic, Z.S.; Ujic, P.; Celikovic, I.; Fujimoto, K.

    2003-01-01

    This paper deals with the introductory aspects of the Electrochemical Etching Laboratory installed at the VINCA Institute in the year 2003. The main purpose of the laboratory is its field application for radon and thoron large-scale survey using passive radon/thoron UFO type detectors. Since the etching techniques together with the laboratory equipment were transferred from the National Institute of Radiological Sciences, Chiba, Japan, it was necessary for both etching conditions to be confirmed and to be checked up, i. e., bulk etching speeds of chemical etching and electrochemical etching in the VINCA Electrochemical Etching Laboratory itself. Beside this initial step, other concerns were taken into consideration in this preliminary experimental phase such as the following: the measurable energy range of the polycarbonate film, background etch pit density of the film and its standard deviation and reproducibility of the response to alpha particles for different sets of etchings. (author)

  1. Fabrication, measurement and tuning of a photonic crystal H1-cavity in deeply etched InP/InGaAsP/InP

    NARCIS (Netherlands)

    Kicken, H.H.J.E.; Barbu, I.; Gabriels, J.; Heijden, van der R.W.; Nötzel, R.; Karouta, F.; Salemink, H.W.M.; Drift, van der E.W.J.M.

    2008-01-01

    A point defect cavity (H1) was fabricated by deep etching in the InP/InGaAsP/InP system. The optical properties of the devices were experimentally investigated by transmission spectroscopy yielding a Q-factor of ~65. The resonance frequency of the defect cavity was shifted, by infiltrating the

  2. Measuring Transpiration to Regulate Winter Irrigation Rates

    Energy Technology Data Exchange (ETDEWEB)

    Samuelson, Lisa [Auburn University

    2006-11-08

    Periodic transpiration (monthly sums) in a young loblolly pine plantation between ages 3 and 6 was measured using thermal dissipation probes. Fertilization and fertilization with irrigation were better than irrigation alone in increasing transpiration of young loblolly pines during winter months, apparently because of increased leaf area in fertilized trees. Irrigation alone did not significantly increase transpiration compared with the non-fertilized and non-irrigated control plots.

  3. Pattern transfer with stabilized nanoparticle etch masks

    International Nuclear Information System (INIS)

    Hogg, Charles R; Majetich, Sara A; Picard, Yoosuf N; Narasimhan, Amrit; Bain, James A

    2013-01-01

    Self-assembled nanoparticle monolayer arrays are used as an etch mask for pattern transfer into Si and SiO x substrates. Crack formation within the array is prevented by electron beam curing to fix the nanoparticles to the substrate, followed by a brief oxygen plasma to remove excess carbon. This leaves a dot array of nanoparticle cores with a minimum gap of 2 nm. Deposition and liftoff can transform the dot array mask into an antidot mask, where the gap is determined by the nanoparticle core diameter. Reactive ion etching is used to transfer the dot and antidot patterns into the substrate. The effect of the gap size on the etching rate is modeled and compared with the experimental results. (paper)

  4. Etching radical controlled gas chopped deep reactive ion etching

    Science.gov (United States)

    Olynick, Deidre; Rangelow, Ivo; Chao, Weilun

    2013-10-01

    A method for silicon micromachining techniques based on high aspect ratio reactive ion etching with gas chopping has been developed capable of producing essentially scallop-free, smooth, sidewall surfaces. The method uses precisely controlled, alternated (or chopped) gas flow of the etching and deposition gas precursors to produce a controllable sidewall passivation capable of high anisotropy. The dynamic control of sidewall passivation is achieved by carefully controlling fluorine radical presence with moderator gasses, such as CH.sub.4 and controlling the passivation rate and stoichiometry using a CF.sub.2 source. In this manner, sidewall polymer deposition thicknesses are very well controlled, reducing sidewall ripples to very small levels. By combining inductively coupled plasmas with controlled fluorocarbon chemistry, good control of vertical structures with very low sidewall roughness may be produced. Results show silicon features with an aspect ratio of 20:1 for 10 nm features with applicability to nano-applications in the sub-50 nm regime. By comparison, previous traditional gas chopping techniques have produced rippled or scalloped sidewalls in a range of 50 to 100 nm roughness.

  5. Etch characteristics of BCB film using inductively coupled plasma

    International Nuclear Information System (INIS)

    Kang, Pil Seung; Kim, Dong Pyo; Kim, Kyoung Tae; Kim, Chang Il; Kim, Sang Gi

    2003-01-01

    The etching characteristics and mechanism of BCB thin films were investigated as a function of CF 4 /O 2 mixing ratio in ICP system. Maximum etch rate of 830 nm/min is obtained at the mixture of O 2 /CF 4 (=80%/20%). OES actinometry results showed that volume density of oxygen atoms fallows the same extreme behavior with the BCB etch rate, while the density of fluorine atoms changes monotonously. Therefore chemical destruction of BCB by oxygen atoms was proposed as the dominant etch mechanism. XPS analysis showed that the addition of CF 4 to O 2 helps to volatilize silicon atoms containing in BCB but leads to the formation of F-containing polymer layer. The profile of etched BCB film was close to 90 .deg. and the surface was clean

  6. Enlarging the fission fragment tracks in glass detectors by etching in weak solutions of HF - a safe etchant

    International Nuclear Information System (INIS)

    Singh, V.P.; Sharma, A.P.

    1982-01-01

    The effect of etchant concentration and temperature on track revelation properties of soda glass detectors has been studied. Etch rate ratio, maximum observable diameter and the energy resolution of the fission fragment tracks of 252 Cf in glasses are increased when the samples are etched in 1.25 vol% HF as compared to higher concentrations of HF and other etching solutions. The critical angle of etching is found to decrease with decrease in etchant concentration. The activation energies for bulk etching and track etching have also been estimated. Better results were obtained by using lower etching temperatures. (author)

  7. Comprehensive Study of SF_6/O_2 Plasma Etching for Mc-Silicon Solar Cells

    International Nuclear Information System (INIS)

    Li Tao; Zhou Chun-Lan; Wang Wen-Jing

    2016-01-01

    The mask-free SF_6/O_2 plasma etching technique is used to produce surface texturization of mc-silicon solar cells for efficient light trapping in this work. The SEM images and mc-silicon etching rate show the influence of plasma power, SF_6/O_2 flow ratios and etching time on textured surface. With the acidic-texturing samples as a reference, the reflection and IQE spectra are obtained under different experimental conditions. The IQE spectrum measurement shows an evident increase in the visible and infrared responses. By using the optimized plasma power, SF_6/O_2 flow ratios and etching time, the optimal efficiency of 15.7% on 50 × 50 mm"2 reactive ion etching textured mc-silicon silicon solar cells is achieved, mostly due to the improvement in the short-circuit current density. The corresponding open-circuit voltage, short-circuit current density and fill factor are 611 mV, 33.6 mA/cm"2, 76.5%, respectively. It is believed that such a low-cost and high-performance texturization process is promising for large-scale industrial silicon solar cell manufacturing. (paper)

  8. Surfactant-controlled etching of ion track nanopores and its practical applications in membrane technology

    International Nuclear Information System (INIS)

    Apel, P.Yu.; Blonskaya, I.V.; Dmitriev, S.N.; Mamonova, T.I.; Orelovitch, O.L.; Sartowska, B.; Yamauchi, Yu.

    2008-01-01

    The effect of surfactants on chemical development of ion tracks in polymers has been studied. It has been shown that surface-active agents added to an alkaline etching solution adsorb on the polymer surface at the pore entrances. This reduces the etch rate, which leads to the formation of pores tapered toward the surface. Self-assembly of surfactant molecules at the pore entrance creates a barrier for their penetration into the etched-out nanopores, whereas hydroxide ions diffuse freely. Due to this, the internal pore volume grows faster than the pore surface diameter. The ability to control pore shape is demonstrated with the fabrication of profiled nano- and micropores in polyethylene terephthalate, polycarbonate. Some earlier published data on small track-etched pores in polycarbonate (in particular, the pore diameter vs. etching time curves measured conductometrically) have been revised in light of the above findings. Adding surfactants to chemical etchants makes it possible to optimize the structure of track membranes, thus improving their retention and permeation properties. Asymmetric membranes with thin skin retention layers have been produced and their performance studied

  9. Uniform lateral etching of tungsten in deep trenches utilizing reaction-limited NF3 plasma process

    Science.gov (United States)

    Kofuji, Naoyuki; Mori, Masahito; Nishida, Toshiaki

    2017-06-01

    The reaction-limited etching of tungsten (W) with NF3 plasma was performed in an attempt to achieve the uniform lateral etching of W in a deep trench, a capability required by manufacturing processes for three-dimensional NAND flash memory. Reaction-limited etching was found to be possible at high pressures without ion irradiation. An almost constant etching rate that showed no dependence on NF3 pressure was obtained. The effect of varying the wafer temperature was also examined. A higher wafer temperature reduced the threshold pressure for reaction-limited etching and also increased the etching rate in the reaction-limited region. Therefore, the control of the wafer temperature is crucial to controlling the etching amount by this method. We found that the uniform lateral etching of W was possible even in a deep trench where the F radical concentration was low.

  10. Measurements of diameters of selectively etchable tracks produced in polymer by heavy ions

    International Nuclear Information System (INIS)

    Apel', P.Yu.

    1981-01-01

    The process of pore formation in polyethyleneterephtalate films irradiated by the 136 Xe, 84 Kr, 40 Ar ions was investigated by measuring the conductivity of the samples during etching. The diameters of the damaged tracks within which the local etching rate was larger than etching rate for non-destroyed polymer were determined. In the case of the 136 Xe ions measurements have been carried out at different ion energies [ru

  11. Track etch parameters and annealing kinetics assessment of protons of low energy in CR-39 detector

    International Nuclear Information System (INIS)

    Jain, R.K.; Kumar, Ashok; Singh, B.K.

    2012-01-01

    Highlights: ► We calibrate CR-39 detector with very low energy protons. ► We establish linear relationship between track diameter and time/energy up to 200 keV. ► We determine activation energy of annealing using different models. ► We justify concept of single annealing activation energy in CR-39. - Abstract: In this paper threshold of the registration sensitivity of very low energy proton in CR-39 is investigated. Irradiation of CR-39 (poly-allyl-diglycol carbonate) was carried out with very low energy mono energetic protons of 20–60 keV from a mini proton accelerator. Nearly 10 4 /cm 2 fluence of protons was used. The variation of track diameter with etching time as well as proton energy response curve was carefully calibrated. The bulk and track etch rates were measured by using proton track diameters. Bulk etch rate was also measured by the thickness of removed surface layer. The thermal annealing of proton track at temperatures ranging from 100 to 200 °C in CR-39 was studied by several models. Activation energy of annealed CR-39 detectors was calculated by slope of track etch rate and temperature plot. The data of proton tracks of 200, 250 and 300 keV from 400 kV Van-de-Graaff accelerator was also used and compared with the track diameters of different energies of proton.

  12. Model calculations for electrochemically etched neutron detectors

    International Nuclear Information System (INIS)

    Pitt, E.; Scharmann, A.; Werner, B.

    1988-01-01

    Electrochemical etching has been established as a common method for visualisation of nuclear tracks in solid state nuclear track detectors. Usually the Mason equation, which describes the amplification of the electrical field strength at the track tip, is used to explain the treeing effect of electrochemical etching. The yield of neutron-induced tracks from electrochemically etched CR-39 track detectors was investigated with respect to the electrical parameters. A linear dependence on the response from the macroscopic field strength was measured which could not be explained by the Mason equation. It was found that the reality of a recoil proton track in the detector does not fit the boundary conditions which are necessary when the Mason equation is used. An alternative model was introduced to describe the track and detector geometry in the case of a neutron track detector. The field strength at the track tip was estimated with this model and compared with the experimental data, yielding good agreement. (author)

  13. Longevity of Self-etch Dentin Bonding Adhesives Compared to Etch-and-rinse Dentin Bonding Adhesives: A Systematic Review.

    Science.gov (United States)

    Masarwa, Nader; Mohamed, Ahmed; Abou-Rabii, Iyad; Abu Zaghlan, Rawan; Steier, Liviu

    2016-06-01

    A systematic review and meta-analysis were performed to compare longevity of Self-Etch Dentin Bonding Adhesives to Etch-and-Rinse Dentin Bonding Adhesives. The following databases were searched for PubMed, MEDLINE, Web of Science, CINAHL, the Cochrane Library complemented by a manual search of the Journal of Adhesive Dentistry. The MESH keywords used were: "etch and rinse," "total etch," "self-etch," "dentin bonding agent," "bond durability," and "bond degradation." Included were in-vitro experimental studies performed on human dental tissues of sound tooth structure origin. The examined Self-Etch Bonds were of two subtypes; Two Steps and One Step Self-Etch Bonds, while Etch-and-Rinse Bonds were of two subtypes; Two Steps and Three Steps. The included studies measured micro tensile bond strength (μTBs) to evaluate bond strength and possible longevity of both types of dental adhesives at different times. The selected studies depended on water storage as the aging technique. Statistical analysis was performed for outcome measurements compared at 24 h, 3 months, 6 months and 12 months of water storage. After 24 hours (p-value = 0.051), 3 months (p-value = 0.756), 6 months (p-value=0.267), 12 months (p-value=0.785) of water storage self-etch adhesives showed lower μTBs when compared to the etch-and-rinse adhesives, but the comparisons were statistically insignificant. In this study, longevity of Dentin Bonds was related to the measured μTBs. Although Etch-and-Rinse bonds showed higher values at all times, the meta-analysis found no difference in longevity of the two types of bonds at the examined aging times. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Optimization of silver-assisted nano-pillar etching process in silicon

    Science.gov (United States)

    Azhari, Ayu Wazira; Sopian, Kamaruzzaman; Desa, Mohd Khairunaz Mat; Zaidi, Saleem H.

    2015-12-01

    In this study, a respond surface methodology (RSM) model is developed using three-level Box-Behnken experimental design (BBD) technique. This model is developed to investigate the influence of metal-assisted chemical etching (MACE) process variables on the nanopillars profiles created in single crystalline silicon (Si) substrate. Design-Expert® software (version 7.1) is employed in formulating the RSM model based on five critical process variables: (A) concentration of silver (Ag), (B) concentration of hydrofluoric acid (HF), (C) concentration of hydrogen peroxide (H2O2), (D) deposition time, and (E) etching time. This model is supported by data from 46 experimental configurations. Etched profiles as a function of lateral etching rate, vertical etching rate, height, size and separation between the Si trenches and etching uniformity are characterized using field emission scanning electron microscope (FE-SEM). A quadratic regression model is developed to correlate critical process variables and is validated using the analysis of variance (ANOVA) methodology. The model exhibits near-linear dependence of lateral and vertical etching rates on both the H2O2 concentration and etching time. The predicted model is in good agreement with the experimental data where R2 is equal to 0.80 and 0.67 for the etching rate and lateral etching respectively. The optimized result shows minimum lateral etching with the average pore size of about 69 nm while the maximum etching rate is estimated at around 360 nm/min. The model demonstrates that the etching process uniformity is not influenced by either the etchant concentration or the etching time. This lack of uniformity could be attributed to the surface condition of the wafer. Optimization of the process parameters show adequate accuracy of the model with acceptable percentage errors of 6%, 59%, 1.8%, 38% and 61% for determination of the height, separation, size, the pore size and the etching rate respectively.

  15. Metal-assisted etch combined with regularizing etch

    Energy Technology Data Exchange (ETDEWEB)

    Yim, Joanne; Miller, Jeff; Jura, Michael; Black, Marcie R.; Forziati, Joanne; Murphy, Brian; Magliozzi, Lauren

    2018-03-06

    In an aspect of the disclosure, a process for forming nanostructuring on a silicon-containing substrate is provided. The process comprises (a) performing metal-assisted chemical etching on the substrate, (b) performing a clean, including partial or total removal of the metal used to assist the chemical etch, and (c) performing an isotropic or substantially isotropic chemical etch subsequently to the metal-assisted chemical etch of step (a). In an alternative aspect of the disclosure, the process comprises (a) performing metal-assisted chemical etching on the substrate, (b) cleaning the substrate, including removal of some or all of the assisting metal, and (c) performing a chemical etch which results in regularized openings in the silicon substrate.

  16. The chemical and electrochemical anisotropic etching of silicon

    International Nuclear Information System (INIS)

    Dixon, E.

    1997-06-01

    The success of silicon IC technology in producing a wide variety of microstructures relies heavily on the orientation dependant etching observed for silicon in alkaline media. Despite the rapid growth of this industry, the chemical and electrochemical mechanisms by which anisotropic etching occurs remain poorly understood. The most common etchant systems in use are ethylenediamine-pyrocatechol-water (EPW) and potassium hydroxide-isopropanol-water (KOH-IPA), and whilst these systems are highly plane selective they each have distinct disadvantages. The occurrence of inhomogeneities such as micropyramids and pits on the surface of etched substrates is a particularly disadvantageous characteristic of many alkaline etching systems. A complete understanding of the chemical and electrochemical anisotropic etching mechanisms is essential in order to obtain more reproducible etching, improved etch rate ratios and the development of more reliable etching baths. Wet chemical etching experiments to evaluate the etching rates for the different alkali metal cations have shown that similar etch rates are observed for LiOH, NaOH and KOH but those of RbOH and CsOH are significantly lower. The presence of impurities was shown to worsen the etched wafer's surface finish obtained in these etching baths. Additives have been shown to dramatically improve the surface finish with the presence of IPA in conjunction with etchant oxygenation virtually eliminating all surface defects. Electrochemical experiments were used to assess the electrochemical behaviour of Si p-(100) in of a wide variety of etchants and variations were seen according to the etchant used. A.C impedance spectroscopy showed a variation in the flat-band potential (V FB ) according to alkali metal hydroxide etchant used. These trends were similarly observed in the presence of isopropanol. Oxygenation was observed to reproducibly alter the flat-band potentials. A.c impedance spectroscopic studies additionally confirmed the

  17. Unveiling the wet chemical etching characteristics of polydimethylsiloxane film for soft micromachining applications

    International Nuclear Information System (INIS)

    Kakati, A; Maji, D; Das, S

    2017-01-01

    Micromachining of a polydimethylsiloxane (PDMS) microstructure by wet chemical etching is explored for microelectromechanical systems (MEMS) and microfluidic applications. A 100 µ m thick PDMS film was patterned with different microstructure designs by wet chemical etching using a N-methyl-2-pyrrolidone (C 16 H 36 FN) and tetra-n-butylammonium fluoride (C 5 H 9 NO) mixture solution with 3:1 volume ratio after lithography for studying etching characteristics. The patterning parameters, such as etch rate, surface roughness, pH of etchant solution with time, were thoroughly investigated. A detailed study of surface morphology with etching time revealed nonlinear behaviour of the PDMS surface roughness and etch rate. A maximum rate of 1.45 µ m min −1 for 10 min etching with surface roughness of 360 nm was achieved. A new approach of wet chemical etching with pH controlled doped etchant was introduced for lower surface roughness of etched microstructures, and a constant etch rate during etching. Variation of the etching rate and surface roughness by pH controlled etching was performed by doping 5–15 gm l −1 of silicic acid (SiO 2xH2 O) into the traditional etchant solution. PDMS etching by silicic acid doped etchant solution showed a reduction in surface roughness from 400 nm to 220 nm for the same 15 µ m etching. This study is beneficial for micromachining of various MEMS and microfluidic structures such as micropillars, microchannels, and other PDMS microstructures. (paper)

  18. Fabrication of high quality GaN nanopillar arrays by dry and wet chemical etching

    OpenAIRE

    Paramanik, Dipak; Motayed, Abhishek; King, Matthew; Ha, Jong-Yoon; Kryluk, Sergi; Davydov, Albert V.; Talin, Alec

    2013-01-01

    We study strain relaxation and surface damage of GaN nanopillar arrays fabricated using inductively coupled plasma (ICP) etching and post etch wet chemical treatment. We controlled the shape and surface damage of such nanopillar structures through selection of etching parameters. We compared different substrate temperatures and different chlorine-based etch chemistries to fabricate high quality GaN nanopillars. Room temperature photoluminescence and Raman scattering measurements were carried ...

  19. Dry etching of ITO by magnetic pole enhanced inductively coupled plasma for display and biosensing devices

    Energy Technology Data Exchange (ETDEWEB)

    Meziani, T. [European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (Vatican City State, Holy See,) (Italy)]. E-mail: tarik.meziani@jrc.it; Colpo, P. [European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (Va) (Italy)]. E-mail: pascal.colpo@jrc.it; Lambertini, V. [Centro Ricerche Fiat, Strada Torino 50, 10043 Orbassano (TO) (Italy); Ceccone, G. [European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (Va) (Italy); Rossi, F. [European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (Va) (Italy)

    2006-03-15

    The dry etching of indium tin oxide (ITO) layers deposited on glass substrates was investigated in a high density inductively coupled plasma (ICP) source. This innovative low pressure plasma source uses a magnetic core in order to concentrate the electromagnetic energy on the plasma and thus provides for higher plasma density and better uniformity. Different gas mixtures were tested containing mainly hydrogen, argon and methane. In Ar/H{sub 2} mixtures and at constant bias voltage (-100 V), the etch rate shows a linear dependence with input power varying the same way as the ion density, which confirms the hypothesis that the etching process is mainly physical. In CH{sub 4}/H{sub 2} mixtures, the etch rate goes through a maximum for 10% CH{sub 4} indicating a participation of the radicals to the etching process. However, the etch rate remains quite low with this type of gas mixture (around 10 nm/min) because the etching mechanism appears to be competing with a deposition process. With CH{sub 4}/Ar mixtures, a similar feature appeared but the etch rate was much higher, reaching 130 nm/min at 10% of CH{sub 4} in Ar. The increase in etch rate with the addition of a small quantity of methane indicates that the physical etching process is enhanced by a chemical mechanism. The etching process was monitored by optical emission spectroscopy that appeared to be a valuable tool for endpoint detection.

  20. Electron cyclotron resonance ion stream etching of tantalum for x-ray mask absorber

    International Nuclear Information System (INIS)

    Oda, Masatoshi; Ozawa, Akira; Yoshihara, Hideo

    1993-01-01

    Electron cyclotron resonance ion stream etching of Ta film was investigated for preparing x-ray mask absorber patterns. Ta is etched by the system at a high rate and with high selectivity. Using Cl 2 as etching gas, the etch rate decreases rapidly with decreasing pattern width below 0.5 μm and large undercutting is observed. The problems are reduced by adding Ar or O 2 gas to the Cl 2 . Etching with a mixture of Cl 2 and O 2 produces highly accurate Ta absorber patterns for x-ray masks. The pattern width dependence of the etch rate and the undercutting were simulated with a model that takes account of the angular distribution of active species incident on the sample. The experimental results agree well with those calculated assuming that the incidence angles are distributed between -36 degrees and 36 degrees. The addition of O 2 or Ar enhances ion assisted etching. 16 refs., 16 figs

  1. Heart Rate Measures of Flight Test and Evaluation

    National Research Council Canada - National Science Library

    Bonner, Malcolm A; Wilson, Glenn F

    2001-01-01

    .... Because flying is a complex task, several measures are required to derive the best evaluation. This article describes the use of heart rate to augment the typical performance and subjective measures used in test and evaluation...

  2. High temperature reactive ion etching of iridium thin films with aluminum mask in CF4/O2/Ar plasma

    Directory of Open Access Journals (Sweden)

    Chia-Pin Yeh

    2016-08-01

    Full Text Available Reactive ion etching (RIE technology for iridium with CF4/O2/Ar gas mixtures and aluminum mask at high temperatures up to 350 °C was developed. The influence of various process parameters such as gas mixing ratio and substrate temperature on the etch rate was studied in order to find optimal process conditions. The surface of the samples after etching was found to be clean under SEM inspection. It was also shown that the etch rate of iridium could be enhanced at higher process temperature and, at the same time, very high etching selectivity between aluminum etching mask and iridium could be achieved.

  3. Eddy-current flow rate meter for measuring sodium flow rates

    International Nuclear Information System (INIS)

    Knaak, J.

    1976-01-01

    For safety reasons flow rate meters for monitoring coolant flow rates are inserted in the core of sodium-cooled fast breeder reactors. These are so-called eddy-current flow rate meters which can be mounted directly above the fuel elements. In the present contribution the principle of measurement, the mechanical construction and the circuit design of the flow rate measuring device are described. Special problems and their solution on developing the measuring system are pointed out. Finally, results of measurement and experience with the apparatus in several experiments are reported, where also further possibilities of application were tested. (orig./TK) [de

  4. The Effect of Phosphoric Acid Pre-etching Times on Bonding Performance and Surface Free Energy with Single-step Self-etch Adhesives.

    Science.gov (United States)

    Tsujimoto, A; Barkmeier, W W; Takamizawa, T; Latta, M A; Miyazaki, M

    2016-01-01

    The purpose of this study was to evaluate the effect of phosphoric acid pre-etching times on shear bond strength (SBS) and surface free energy (SFE) with single-step self-etch adhesives. The three single-step self-etch adhesives used were: 1) Scotchbond Universal Adhesive (3M ESPE), 2) Clearfil tri-S Bond (Kuraray Noritake Dental), and 3) G-Bond Plus (GC). Two no pre-etching groups, 1) untreated enamel and 2) enamel surfaces after ultrasonic cleaning with distilled water for 30 seconds to remove the smear layer, were prepared. There were four pre-etching groups: 1) enamel surfaces were pre-etched with phosphoric acid (Etchant, 3M ESPE) for 3 seconds, 2) enamel surfaces were pre-etched for 5 seconds, 3) enamel surfaces were pre-etched for 10 seconds, and 4) enamel surfaces were pre-etched for 15 seconds. Resin composite was bonded to the treated enamel surface to determine SBS. The SFEs of treated enamel surfaces were determined by measuring the contact angles of three test liquids. Scanning electron microscopy was used to examine the enamel surfaces and enamel-adhesive interface. The specimens with phosphoric acid pre-etching showed significantly higher SBS and SFEs than the specimens without phosphoric acid pre-etching regardless of the adhesive system used. SBS and SFEs did not increase for phosphoric acid pre-etching times over 3 seconds. There were no significant differences in SBS and SFEs between the specimens with and without a smear layer. The data suggest that phosphoric acid pre-etching of ground enamel improves the bonding performance of single-step self-etch adhesives, but these bonding properties do not increase for phosphoric acid pre-etching times over 3 seconds.

  5. Device accurately measures and records low gas-flow rates

    Science.gov (United States)

    Branum, L. W.

    1966-01-01

    Free-floating piston in a vertical column accurately measures and records low gas-flow rates. The system may be calibrated, using an adjustable flow-rate gas supply, a low pressure gage, and a sequence recorder. From the calibration rates, a nomograph may be made for easy reduction. Temperature correction may be added for further accuracy.

  6. Technique for etching monolayer and multilayer materials

    Science.gov (United States)

    Bouet, Nathalie C. D.; Conley, Raymond P.; Divan, Ralu; Macrander, Albert

    2015-10-06

    A process is disclosed for sectioning by etching of monolayers and multilayers using an RIE technique with fluorine-based chemistry. In one embodiment, the process uses Reactive Ion Etching (RIE) alone or in combination with Inductively Coupled Plasma (ICP) using fluorine-based chemistry alone and using sufficient power to provide high ion energy to increase the etching rate and to obtain deeper anisotropic etching. In a second embodiment, a process is provided for sectioning of WSi.sub.2/Si multilayers using RIE in combination with ICP using a combination of fluorine-based and chlorine-based chemistries and using RF power and ICP power. According to the second embodiment, a high level of vertical anisotropy is achieved by a ratio of three gases; namely, CHF.sub.3, Cl.sub.2, and O.sub.2 with RF and ICP. Additionally, in conjunction with the second embodiment, a passivation layer can be formed on the surface of the multilayer which aids in anisotropic profile generation.

  7. Resistive Wall Growth Rate Measurements in the Fermilab Recycler

    Energy Technology Data Exchange (ETDEWEB)

    Ainsworth, R. [Fermilab; Adamson, P. [Fermilab; Burov, A. [Fermilab; Kourbanis, I. [Fermilab

    2016-10-05

    Impedance could represent a limitation of running high intensity beams in the Fermilab recycler. With high intensity upgrades foreseen, it is important to quantify the impedance. To do this,studies have been performed measuring the growth rate of presumably the resistive wall instability. The growth rates at varying intensities and chromaticities are shown. The measured growth rates are compared to ones calculated with the resistive wall impedance.

  8. Low-k SiOCH Film Etching Process and Its Diagnostics Employing Ar/C5F10O/N2 Plasma

    Science.gov (United States)

    Nagai, Mikio; Hayashi, Takayuki; Hori, Masaru; Okamoto, Hidekazu

    2006-09-01

    We proposed an environmental harmonic etching gas of C5F10O (CF3CF2CF2OCFCF2), and demonstrated the etching of low-k SiOCH films employing a dual-frequency capacitively coupled etching system. Dissociative ionization cross sections for the electron impact ionizations of C5F10O and c-C4F8 gases have been measured by quadrupole mass spectroscopy (QMS). The dissociative ionization cross section of CF3+ from C5F10O gas was much higher than those of other ionic species, and 10 times higher than that of CF3+ from C4F8 gas. CF3+ is effective for increasing the etching rate of SiO2. As a result, the etching rate of SiOCH films using Ar/C5F10O/N2 plasma was about 1000 nm/min, which is much higher than that using Ar/C4F8/N2 plasma. The behaviours of fluorocarbon radicals in Ar/C5F10O/N2 plasma, which were measured by infrared diode laser absorption spectroscopy, were similar to those in Ar/C4F8/N2 plasma. The densities of CF and CF3 radicals were markedly decreased with increasing N2 flow rate. Etching rate was controlled by N2 flow rate. A vertical profile of SiOCH with a high etching rate and less microloading was realized using Ar/C5F10O/N2 plasma chemistry.

  9. Model of wet chemical etching of swift heavy ions tracks

    Science.gov (United States)

    Gorbunov, S. A.; Malakhov, A. I.; Rymzhanov, R. A.; Volkov, A. E.

    2017-10-01

    A model of wet chemical etching of tracks of swift heavy ions (SHI) decelerated in solids in the electronic stopping regime is presented. This model takes into account both possible etching modes: etching controlled by diffusion of etchant molecules to the etching front, and etching controlled by the rate of a reaction of an etchant with a material. Olivine ((Mg0.88Fe0.12)2SiO4) crystals were chosen as a system for modeling. Two mechanisms of chemical activation of olivine around the SHI trajectory are considered. The first mechanism is activation stimulated by structural transformations in a nanometric track core, while the second one results from neutralization of metallic atoms by generated electrons spreading over micrometric distances. Monte-Carlo simulations (TREKIS code) form the basis for the description of excitations of the electronic subsystem and the lattice of olivine in an SHI track at times up to 100 fs after the projectile passage. Molecular dynamics supplies the initial conditions for modeling of lattice relaxation for longer times. These simulations enable us to estimate the effects of the chemical activation of olivine governed by both mechanisms. The developed model was applied to describe chemical activation and the etching kinetics of tracks of Au 2.1 GeV ions in olivine. The estimated lengthwise etching rate (38 µm · h-1) is in reasonable agreement with that detected in the experiments (24 µm · h-1).

  10. The electrochemistry of InP in Br2/HBr solutions and its relevance to etching behaviour

    NARCIS (Netherlands)

    Notten, P.H.L.; Damen, A.A.J.M.

    1987-01-01

    Etch rate-potential curves of p-InP in HBr and Br2/HBr solutions in the dark and under illumination were correlated with current-potential curves. It was found that InP is etched via a "chemical" mechanism both by HBr and Br2. In aqueous HBr solutions InP is only etched at a significant rate at

  11. Dry Etching Characteristics of Amorphous Indium-Gallium-Zinc-Oxide Thin Films

    International Nuclear Information System (INIS)

    Zheng Yanbin; Li Guang; Wang Wenlong; Li Xiuchang; Jiang Zhigang

    2012-01-01

    Amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT) backplane technology is the best candidate for flat panel displays (FPDs). In this paper, a-IGZO TFT structures are described. The effects of etch parameters (rf power, dc-bias voltage and gas pressure) on the etch rate and etch profile are discussed. Three kinds of gas mixtures are compared in the dry etching process of a-IGZO thin films. Lastly, three problems are pointed out that need to be addressed in the dry etching process of a-IGZO TFTs. (plasma technology)

  12. Isolating GaSb Membranes Grown Metamorphically on GaAs Substrates Using Highly Selective Substrate Removal Etch Processes

    Science.gov (United States)

    Renteria, E. J.; Muniz, A. J.; Addamane, S. J.; Shima, D. M.; Hains, C. P.; Balakrishnan, G.

    2015-05-01

    The etch rates of NH4OH:H2O2 and C6H8O7:H2O2 for GaAs and GaSb have been investigated to develop a selective etch for GaAs substrates and to isolate GaSb epilayers grown on GaAs. The NH4OH:H2O2 solution has a greater etch rate differential for the GaSb/GaAs material system than C6H8O7:H2O2 solution. The selectivity of NH4OH:H2O2 for GaAs/GaSb under optimized etch conditions has been observed to be as high as 11,000 ± 2000, whereas that of C6H8O7:H2O2 has been measured up to 143 ± 2. The etch contrast has been verified by isolating 2- μm-thick GaSb epilayers that were grown on GaAs substrates. GaSb membranes were tested and characterized with high- resolution x-ray diffraction and atomic force microscopy.

  13. Etching of uranium dioxide in nitrogen trifluoride RF plasma glow discharge

    Science.gov (United States)

    Veilleux, John Mark

    1999-10-01

    A series of room temperature, low pressure (10.8 to 40 Pa), low power (25 to 210 W) RF plasma glow discharge experiments with UO2 were conducted to demonstrate that plasma treatment is a viable method for decontaminating UO2 from stainless steel substrates. Experiments were conducted using NF3 gas to decontaminate depleted uranium dioxide from stainless-steel substrates. Results demonstrated that UO2 can be completely removed from stainless-steel substrates after several minutes processing at under 200 W. At 180 W and 32.7 Pa gas pressure, over 99% of all UO2 in the samples was removed in just 17 minutes. The initial etch rate in the experiments ranged from 0.2 to 7.4 mum/min. Etching increased with the plasma absorbed power and feed gas pressure in the range of 10.8 to 40 Pa. A different pressure effect on UO2 etching was also noted below 50 W in which etching increased up to a maximum pressure, ˜23 Pa, then decreased with further increases in pressure. A computer simulation, CHEMKIN, was applied to predict the NF3 plasma species in the experiments. The code was validated first by comparing its predictions of the NF3 plasma species with mass spectroscopy etching experiments of silicon. The code predictions were within +/-5% of the measured species concentrations. The F atom radicals were identified as the primary etchant species, diffusing from the bulk plasma to the UO2 surface and reacting to form a volatile UF6, which desorbed into the gas phase to be pumped away. Ions created in the plasma were too low in concentration to have a major effect on etching, but can enhance the etch rate by removing non-volatile reaction products blocking the reaction of F with UO2. The composition of these non-volatile products were determined based on thermodynamic analysis and the electronic structure of uranium. Analysis identified possible non-volatile products as the uranium fluorides, UF2-5, and certain uranium oxyfluorides UO2F, UO2F2, UOF3, and UOF 4 which form over the

  14. A method for the measurement of fission rates in fast neutron fields using solid state track detectors

    International Nuclear Information System (INIS)

    Hansen, W.; Vogel, W.

    1984-04-01

    Solid state track detectors (SSTDs) are increasingly used for the registration of radiation in different fields of nuclear physics. Because of their small sizes and masses and the absence of any electronics during exposure SSTDs do not cause distortions in the system to be investigated and are useful for measurements at such places being difficult of access. The elaboration of a method is described for fission rate measurements in fast neutron fields applying SSTDs and different fissionable isotopes which were electrodeposited on stainless steel backings. Experiences of the electrodeposition and results of quality checks are presented. The evaluation of the etched tracks is performed with spark counter technique. The dependence of the counting result on essential influence parameters is discussed. (author)

  15. High-throughput anisotropic plasma etching of polyimide for MEMS

    International Nuclear Information System (INIS)

    Bliznetsov, Vladimir; Manickam, Anbumalar; Ranganathan, Nagarajan; Chen, Junwei

    2011-01-01

    This note describes a new high-throughput process of polyimide etching for the fabrication of MEMS devices with an organic sacrificial layer approach. Using dual frequency superimposed capacitively coupled plasma we achieved a vertical profile of polyimide with an etching rate as high as 3.5 µm min −1 . After the fabrication of vertical structures in a polyimide material, additional steps were performed to fabricate structural elements of MEMS by deposition of a SiO 2 layer and performing release etching of polyimide. (technical note)

  16. Colorimetric detection of Hg(II) by measurement the color alterations from the "before" and "after" RGB images of etched triangular silver nanoplates.

    Science.gov (United States)

    Li, Li; Zhang, Laiping; Zhao, Yan; Chen, Zhengbo

    2018-03-22

    It is shown that triangular silver nanoplates (TAgNPs) are viable colorimetric probes for the fast, sensitive and selective detection of Hg(II). Detection is accomplished by reducing Hg(II) ions to elemental Hg so that an Ag/Hg amalgam is formed on the surface of the TAgNPs. This leads to the inhibition of the etching TAgNPs by chloride ions. Correspondingly, a distinct color transition can be observed that goes from yellow to brown, purple, and blue. The color alterations extracted from the red, green, and blue part of digital (RGB) images can be applied to the determination of Hg(II). The relationship between the Euclidean distances (EDs), i.e. the square roots of the sums of the squares of the ΔRGB values, vary in the 5 nM to 100 nM Hg(II) concentration range, and the limit of detection is as low as 0.35 nM. The color changes also allow for a visual estimation of the concentrations of Hg(II). The method is simple in that it only requires a digital camera for data acquisition and a Photoshop software for extracting RGB variations and data processing. Graphical abstract Hg 2+ detection was achieved by anti-etching of TAgNPs caused by the formation of silver amalgam, along with vivid multicolor variations from yellow to brown, purple, and eventually to be blue.

  17. In situ measurements of dose rates from terrestrial gamma rays

    International Nuclear Information System (INIS)

    Horng, M.C.; Jiang, S.H.

    2002-01-01

    A portable, high purity germanium (HPGe) detector was employed for the performance of in situ measurements of radionuclide activity concentrations in the ground in Taiwan, at altitudes ranging from sea level to 3900 m. The absolute peak efficiency of the HPGe detector for a gamma-ray source uniformly distributed in the semi-infinite ground was determined using a semi-empirical method. The gamma-ray dose rates from terrestrial radionuclides were calculated from the measured activity levels using recently published dose rate conversion factors. The absorbed dose rate in air due to cosmic rays was derived by subtracting the terrestrial gamma-ray dose rate from the overall absorbed dose rate in air measured using a high-pressure ionization chamber. The cosmic-ray dose rate calculated as a function of altitude, was found to be in good agreement with the data reported by UNSCEAR. (orig.)

  18. Aquatic respiration rate measurements at low oxygen concentrations.

    Directory of Open Access Journals (Sweden)

    Moritz Holtappels

    Full Text Available Despite its huge ecological importance, microbial oxygen respiration in pelagic waters is little studied, primarily due to methodological difficulties. Respiration measurements are challenging because of the required high resolution of oxygen concentration measurements. Recent improvements in oxygen sensing techniques bear great potential to overcome these limitations. Here we compare 3 different methods to measure oxygen consumption rates at low oxygen concentrations, utilizing amperometric Clark type sensors (STOX, optical sensors (optodes, and mass spectrometry in combination with (18-18O2 labeling. Oxygen concentrations and consumption rates agreed well between the different methods when applied in the same experimental setting. Oxygen consumption rates between 30 and 400 nmol L(-1 h(-1 were measured with high precision and relative standard errors of less than 3%. Rate detection limits in the range of 1 nmol L(-1 h(-1 were suitable for rate determinations in open ocean water and were lowest at the lowest applied O2 concentration.

  19. Rating PV Power and Energy: Cell, Module, and System Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Emery, Keith

    2016-06-02

    A summary of key points related to research-level measurements of current vs. voltage measurement theory including basic PV operation, equivalent circuit, and concept of spectral error; PV power performance including PV irradiance sensors, simulators and commercial and generic I-V systems; PV measurement artifacts, intercomparisons, and alternative rating methods.

  20. Summary of Chalcogenide Glass Processing: Wet-Etching and Photolithography

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Brian J.; Sundaram, S. K.; Johnson, Bradley R.; Saraf, Laxmikant V.

    2006-12-01

    This report describes a study designed to explore the different properties of two different chalcogenide materials, As2S3 and As24S38Se38, when subjected to photolithographic wet-etching techniques. Chalcogenide glasses are made by combining chalcogen elements S, Se, and Te with Group IV and/or V elements. The etchant was selected from the literature and was composed of sodium hydroxide, isopropyl alcohol, and deionized water and the types of chalcogenide glass for study were As2S3 and As24S38Se38. The main goals here were to obtain a single variable etch rate curve of etch depth per time versus NaOH overall solution concentration in M and to see the difference in etch rate between a given etchant when used on the different chalcogenide stoichiometries. Upon completion of these two goals, future studies will begin to explore creating complex, integrated photonic devices via these methods.

  1. Development of deep silicon plasma etching for 3D integration technology

    Directory of Open Access Journals (Sweden)

    Golishnikov А. А.

    2014-02-01

    Full Text Available Plasma etch process for thought-silicon via (TSV formation is one of the most important technological operations in the field of metal connections creation between stacked circuits in 3D assemble technology. TSV formation strongly depends on parameters such as Si-wafer thickness, aspect ratio, type of metallization material, etc. The authors investigate deep silicon plasma etch process for formation of TSV with controllable profile. The influence of process parameters on plasma etch rate, silicon etch selectivity to photoresist and the structure profile are researched in this paper. Technology with etch and passivation steps alternation was used as a method of deep silicon plasma etching. Experimental tool «Platrane-100» with high-density plasma reactor based on high-frequency ion source with transformer coupled plasma was used for deep silicon plasma etching. As actuation gases for deep silicon etching were chosen the following gases: SF6 was used for the etch stage and CHF3 was applied on the polymerization stage. As a result of research, the deep plasma etch process has been developed with the following parameters: silicon etch rate 6 µm/min, selectivity to photoresist 60 and structure profile 90±2°. This process provides formation of TSV 370 µm deep and about 120 µm in diameter.

  2. The mechanism of selective corrugation removal by KOH anisotropic wet etching

    International Nuclear Information System (INIS)

    Shikida, M; Inagaki, N; Sasaki, H; Amakawa, H; Fukuzawa, K; Sato, K

    2010-01-01

    The mechanism of selective corrugation removal by anisotropic wet etching—which reduces a periodic corrugation, called 'scalloping', formed on the sidewalls of microstructures by the Bosch process in deep reactive-ion etching (D-RIE)—was investigated. In particular, the corrugation-removal mechanism was analyzed by using the etching rate distribution pattern, and two equations for predicting the corrugation-removal time by the etching were derived. A Si{1 0 0} wafer was first etched by D-RIE at a depth of 29.4 µm (60 cycles) to form the corrugation on the sidewall surface. The height and pitch of the corrugation were 196 and 494 nm, respectively. Selective removal of the corrugation by using 50% KOH (40 °C) was experimentally tried. The corrugation formed on Si{1 0 0} sidewall surfaces was gradually reduced in size as the etching progressed, and it was completely removed after 5 min of etching. Similarly, the corrugation formed on a Si{1 1 0} sidewall surface was also selectively removed by KOH etching (etching time: 3 min). The roughness value of the sidewall surface was reduced from 17.6 nm to a few nanometers by the etching. These results confirm that the corrugation-removal mechanism using anisotropic wet etching can be explained in terms of the distribution pattern of etching rate

  3. Infinitely high etch selectivity during CH4/H2/Ar inductively coupled plasma (ICP) etching of indium tin oxide (ITO) with photoresist mask

    International Nuclear Information System (INIS)

    Kim, D.Y.; Ko, J.H.; Park, M.S.; Lee, N.-E.

    2008-01-01

    Under certain conditions during ITO etching using CH 4 /H 2 /Ar inductively coupled plasmas, the etch rate selectivity of ITO to photoresist (PR) was infinitely high because the ITO films continued to be etched, but a net deposition of the α-C:H layer occurred on the top of the PR. Analyses of plasmas and etched ITO surfaces suggested that the continued consumption of the carbon and hydrogen in the deposited α-C:H layer by their chemical reaction with In and Sn atoms in the ITO resulting in the generation of volatile metal-organic etch products and by the ion-enhanced removal of the α-C:H layer presumably play important roles in determining the ITO etch rate and selectivity

  4. Etch bias inversion during EUV mask ARC etch

    Science.gov (United States)

    Lajn, Alexander; Rolff, Haiko; Wistrom, Richard

    2017-07-01

    The introduction of EUV lithography to high volume manufacturing is now within reach for 7nm technology node and beyond (1), at least for some steps. The scheduling is in transition from long to mid-term. Thus, all contributors need to focus their efforts on the production requirements. For the photo mask industry, these requirements include the control of defectivity, CD performance and lifetime of their masks. The mask CD performance including CD uniformity, CD targeting, and CD linearity/ resolution, is predominantly determined by the photo resist performance and by the litho and etch processes. State-of-the-art chemically amplified resists exhibit an asymmetric resolution for directly and indirectly written features, which usually results in a similarly asymmetric resolution performance on the mask. This resolution gap may reach as high as multiple tens of nanometers on the mask level in dependence of the chosen processes. Depending on the printing requirements of the wafer process, a reduction or even an increase of this gap may be required. A potential way of tuning via the etch process, is to control the lateral CD contribution during etch. Aside from process tuning knobs like pressure, RF powers and gases, which usually also affect CD linearity and CD uniformity, the simplest knob is the etch time itself. An increased over etch time results in an increased CD contribution in the normal case. , We found that the etch CD contribution of ARC layer etch on EUV photo masks is reduced by longer over etch times. Moreover, this effect can be demonstrated to be present for different etch chambers and photo resists.

  5. Study of gamma irradiation effects on the etching and optical properties of CR-39 solid state nuclear track detector and its application to uranium assay in soil samples

    International Nuclear Information System (INIS)

    Amol Mhatre; Kalsi, P.C.

    2011-01-01

    The gamma irradiation effects in the dose range of 2.5-43.0 Mrad on the etching and optical characteristics of CR-39 solid state nuclear track detector (SSNTD) have been studied by using etching and UV-Visible spectroscopic techniques. From the measured bulk etch rates at different temperatures, the activation energies for bulk etching at different doses have also been determined. It is seen that the bulk etch rates increase and the activation energies for bulk etching decrease with the increase in gamma dose. The optical band gaps of the unirradiated and the gamma -irradiated detectors determined from the UV-Visible spectra were found to decrease with the increase in gamma dose. These results have been explained on the basis of scission of the detector due to gamma irradiation. The present studies can be used for the estimation of gamma dose in the range of 2.5-43.0 Mrad and can also be used for estimating track registration efficiency in the presence of gamma dose. The CR-39 detector has also been applied for the assay of uranium in some soil samples of Jammu city. (author)

  6. Method of plastic track detector electrochemical etching

    International Nuclear Information System (INIS)

    D'yakov, A.A.

    1984-01-01

    The review of studies dealing with the development of the method for the electro-chemical etching (ECE) of the plastic track detectors on the base of polyethy-leneterephthalate (PET) and polycarbonate (PC) is given. Physical essence of the method, basic parameters of the processes, applied equipment and methods of measurement automation are considered. The advantages of the method over the traditional chemical etching are pointed out. Recommendations on the detector operation modes when detecting fission fragments, α-particles and fast neutrons are given. The ECE method is based on the condition that during chemical etching the high-voltage sound frequency alternating electric field is applied to the detector. In this case the detector serves as an isolating layer betWeen two vessels with etching solution in which high-voltage electrode are submerged. At a fixed electric field potential higher (over than the threshold value) at the end of the etching track cone atree-like discharge spot arises. It is shown that when PET is used for fast neutron detection it is advisable to apply for ECE the PEW solution (15g KOH+40 g C 2 H 2 OH + 45g H 2 O) the field potential should constitute 30 kVxcm -1 at the freqUency of 9 kHz. In the case of fission fragment detection Using ECE and PC the following ECE conditions are recommended: 30% KOH etcher, field potential of 10 kVxcm -1 , 2-4 kHz frequency. It is concluded that the ECE method permits considerably eXtend the sphere of plastic track detector application for detecting ionizing particles,

  7. Fission rate measurements in fuel plate type assembly reactor cores

    International Nuclear Information System (INIS)

    Rogers, J.W.

    1988-01-01

    The methods, materials and equipment have been developed to allow extensive and precise measurement of fission rate distributions in water moderated, U-Al fuel plate assembly type reactor cores. Fission rate monitors are accurately positioned in the reactor core, the reactor is operated at a low power for a short time, the fission rate monitors are counted with detectors incorporating automated sample changers and the measurements are converted to fission rate distributions. These measured fission rate distributions have been successfully used as baseline information related to the operation of test and experimental reactors with respect to fission power and distribution, fuel loading and fission experiments for approximately twenty years at the Idaho National Engineering Laboratory (INEL). 7 refs., 8 figs

  8. Sodium flow rate measurement method of annular linear induction pump

    International Nuclear Information System (INIS)

    Araseki, Hideo

    2011-01-01

    This report describes a method for measuring sodium flow rate of annular linear induction pumps arranged in parallel and its verification result obtained through an experiment and a numerical analysis. In the method, the leaked magnetic field is measured with measuring coils at the stator end on the outlet side and is correlated with the sodium flow rate. The experimental data and the numerical result indicate that the leaked magnetic field at the stator edge keeps almost constant when the sodium flow rate changes and that the leaked magnetic field change arising from the flow rate change is small compared with the overall leaked magnetic field. It is shown that the correlation between the leaked magnetic field and the sodium flow rate is almost linear due to this feature of the leaked magnetic field, which indicates the applicability of the method to small-scale annular linear induction pumps. (author)

  9. Natural stream flow-rates measurements by tracer techniques

    International Nuclear Information System (INIS)

    Cuellar Mansilla, J.

    1982-01-01

    This paper presents the study of the precision obtained measuring the natural stream flow rates by tracer techniques, especially when the system presents a great slope and a bed constituted by large and extended particle size. The experiences were realized in laboratory pilot channels with flow-rates between 15 and 130 [1/s]; and in natural streams with flow-rates from 1 to 25 m 3 /s. Tracer used were In-133m and Br-82 for laboratory and field measurements respectively. In both cases the tracer was injected as a pulse and its dilution measured collecting samples in the measured section, at constant flow-rates, of 5[1] in laboratory experiences and 60[1] of water in field experiences. Precisions obtained at a 95% confidence level were about 2% for laboratory and 3% for field. (I.V.)

  10. ECE laboratory in the Vinča institute: Its basic characteristics and fundamentals of electrochemic etching on polycarbonate

    Directory of Open Access Journals (Sweden)

    Žunić Zora S.

    2003-01-01

    Full Text Available This paper deals with the introductory aspects of the Electrochemical Etching Laboratory installed at the VINČA Institute in the year 2003. The main purpose of the laboratory is its field application for radon and thoron large-scale survey using passive radon/thoron UFO type detectors. Since the etching techniques together with the laboratory equipment were transferred from the National Institute of Radiological Sciences, Chiba, Japan, it was necessary for both etching conditions to be confirmed and to be checked up^ i. e., bulk etching speeds of chemical etching and electrochemical etching in the VINCA Electrochemical Etching Laboratory itself. Beside this initial step, other concerns were taken into consideration in this preliminary experimental phase such as the following: the measurable energy range of the polycarbonate film, background etch pit density of the film and its standard deviation and reproducibility of the response to alpha particles for different sets of etchings.

  11. Development and application of the electrochemical etching technique. Annual progress report

    International Nuclear Information System (INIS)

    1979-08-01

    This report documents advances in the development and application of the electrochemical etching technique for thermal and epithermal neutron dosimetry as well as track geometry determinations. The bulk and track etching rates were studied by evaluating the track geometry during electrochemical etching. The foil surface removed versus etching time for two different etchants at 1000 V, 2 kHz, and 22 0 C were studied. Results indicated that the bulk etching rates were constant for the two etchants, i.e. 45% KOH and 45% KOH mixed with an equal volume of C 2 H 5 OH 5 and were equal to 0.20 +- 0.14 μm/hr and 2.7 +- 0.27 μm/hr from each side of the foil. The track etching rate (as contrasted with the bulk etching rate) can be determined by the microscope focus at various depths. The increase of track depth values as a function of etching time for the two etchants are plotted. The track cone angles were determined and found to be much larger for electrochemically etched polycarbonate foils than for most plastics etched with passive chemical techniques

  12. Absolute rate measurement by light modulation - ESR technique

    Energy Technology Data Exchange (ETDEWEB)

    Choo, K Y; Gaspar, P P

    1977-01-01

    A rate constant is deduced for the reaction of tert-butoxy radicals and trimethylsilane from the measurement of the phase shift between the modulated light source and the ESR signal of trimethylsilyl radical. The rate constant was found to be 3 x 10/sup -2/M/sup -1/. sec/sup -1/ at -50/sup 0/C.

  13. Evaluation of Pentafluoroethane and 1,1-Difluoroethane for a Dielectric Etch Application in an Inductively Coupled Plasma Etch Tool

    Science.gov (United States)

    Karecki, Simon; Chatterjee, Ritwik; Pruette, Laura; Reif, Rafael; Sparks, Terry; Beu, Laurie; Vartanian, Victor

    2000-07-01

    In this work, a combination of two hydrofluorocarbon compounds, pentafluoroethane (FC-125, C2HF5) and 1,1-difluoroethane (FC-152a, CF2H-CH3), was evaluated as a potential replacement for perfluorocompounds in dielectric etch applications. A high aspect ratio oxide via etch was used as the test vehicle for this study, which was conducted in a commercial inductively coupled high density plasma etch tool. Both process and emissions data were collected and compared to those provided by a process utilizing a standard perfluorinated etch chemistry (C2F6). Global warming (CF4, C2F6, CHF3) and hygroscopic gas (HF, SiF4) emissions were characterized using Fourier transform infrared (FTIR) spectroscopy. FC-125/FC-152a was found to produce significant reductions in global warming emissions, on the order of 68 to 76% relative to the reference process. Although etch stopping, caused by a high degree of polymer deposition inside the etched features, was observed, process data otherwise appeared promising for an initial study, with good resist selectivity and etch rates being achieved.

  14. Measurement of flow rate in the third loop of PWR

    International Nuclear Information System (INIS)

    Gao Shufan.

    1986-01-01

    The range of flow rate was 14000-50000 m 3 /h. The diameter of main tube was 2.6 m. A special made pitot set was placed on the main tube in order to accurately measure the flow rate. A cross slideway and a guide devicc were used to prevent the pitot vibration. Method of equal annular area was used in the measurement. The error was less than 4.2%. A pitot cylinder flowmeter was set also on the main tube to supervise the total flow rate of the third loop

  15. Influence of neutron irradiation on etching of SiC in KOH

    Science.gov (United States)

    Mokhov, E. N.; Kazarova, O. P.; Soltamov, V. A.; Nagalyuk, S. S.

    2017-07-01

    The effect of reactor neutron irradiation on the etch rate of SiC in potassium hydroxide has been studied. In the case of high irradiation doses (1019-1021 cm-2), the etch rate of silicon carbide has been shown to drastically rise, especially in the [0001]Si direction. This considerably mitigates the orientation anisotropy of polar face etching. After high-temperature annealing (up to 1200-1400°C), a higher etch rate of irradiated crystals persists. The results have been explained by the high concentration of radiation-induced (partially clustered) defects they contain.

  16. Assessment of salivary flow rate: biologic variation and measure error.

    NARCIS (Netherlands)

    Jongerius, P.H.; Limbeek, J. van; Rotteveel, J.J.

    2004-01-01

    OBJECTIVE: To investigate the applicability of the swab method in the measurement of salivary flow rate in multiple-handicap drooling children. To quantify the measurement error of the procedure and the biologic variation in the population. STUDY DESIGN: Cohort study. METHODS: In a repeated

  17. Formation of plasma induced surface damage in silica glass etching for optical waveguides

    International Nuclear Information System (INIS)

    Choi, D.Y.; Lee, J.H.; Kim, D.S.; Jung, S.T.

    2004-01-01

    Ge, B, P-doped silica glass films are widely used as optical waveguides because of their low losses and inherent compatibility with silica optical fibers. These films were etched by ICP (inductively coupled plasma) with chrome etch masks, which were patterned by reactive ion etching (RIE) using chlorine-based gases. In some cases, the etched surfaces of silica glass were very rough (root-mean square roughness greater than 100 nm) and we call this phenomenon plasma induced surface damage (PISD). Rough surface cannot be used as a platform for hybrid integration because of difficulty in alignment and bonding of active devices. PISD reduces the etch rate of glass and it is very difficult to remove residues on a rough surface. The objective of this study is to elucidate the mechanism of PISD formation. To achieve this goal, PISD formation during different etching conditions of chrome etch mask and silica glass was investigated. In most cases, PISD sources are formed on a glass surface after chrome etching, and metal compounds are identified in theses sources. Water rinse after chrome etching reduces the PISD, due to the water solubility of metal chlorides. PISD is decreased or even disappeared at high power and/or low pressure in glass etching, even if PISD sources were present on the glass surface before etching. In conclusion, PISD sources come from the chrome etching process, and polymer deposition on these sources during the silica etching cause the PISD sources to grow. In the area close to the PISD source there is a higher ion flux, which causes an increase in the etch rate, and results in the formation of a pit

  18. Mechanisms and selectivity for etching of HfO2 and Si in BCl3 plasmas

    International Nuclear Information System (INIS)

    Wang Chunyu; Donnelly, Vincent M.

    2008-01-01

    The authors have investigated plasma etching of HfO 2 , a high dielectric constant material, and poly-Si in BCl 3 plasmas. Etching rates were measured as a function of substrate temperature (T s ) at several source powers. Activation energies range from 0.2 to 1.0 kcal/mol for HfO 2 and from 0.8 to 1.8 kcal/mol for Si, with little or no dependence on source power (20-200 W). These low activation energies suggest that product removal is limited by chemical sputtering of the chemisorbed Hf or Si-containing layer, with a higher T s only modestly increasing the chemical sputtering rate. The slightly lower activation energy for HfO 2 results in a small improvement in selectivity over Si at low temperature. The surface layers formed on HfO 2 and Si after etching in BCl 3 plasmas were also investigated by vacuum-transfer x-ray photoelectron spectroscopy. A thin boron-containing layer was observed on partially etched HfO 2 and on poly-Si after etching through HfO 2 films. For HfO 2 , a single B(1s) feature at 194 eV was ascribed to a heavily oxidized species with bonding similar to B 2 O 3 . B(1s) features were observed for poly-Si surfaces at 187.6 eV (B bound to Si), 189.8 eV, and 193 eV (both ascribed to BO x Cl y ). In the presence of a deliberately added 0.5% air, the B-containing layer on HfO 2 is largely unaffected, while that on Si converts to a thick layer with a single B(1s) peak at 194 eV and an approximate stoichiometry of B 3 O 4 Cl

  19. Fabrication of SiC nanopillars by inductively coupled SF6/O2 plasma etching

    International Nuclear Information System (INIS)

    Choi, J H; Bano, E; Latu-Romain, L; Dhalluin, F; Chevolleau, T; Baron, T

    2012-01-01

    In this paper, we demonstrate a top-down fabrication technique for nanometre scale silicon carbide (SiC) pillars using inductively coupled plasma etching. A set of experiments in SF 6 -based plasma was carried out in order to realize high aspect ratio SiC nanopillars. The etched SiC nanopillars using a small circular mask pattern (115 nm diameter) show high aspect ratio (7.4) with a height of 2.2 µm at an optimum bias voltage (300 V) and pressure (6 mTorr). Under the optimal etching conditions using a large circular mask pattern with 370 nm diameter, the obtained SiC nanopillars exhibit high anisotropy features (6.4) with a large etch depth (>7 µm). The etch characteristic of the SiC nanopillars under these conditions shows a high etch rate (550 nm min -1 ) and a high selectivity (over 60 for Ni). We also studied the etch profile of the SiC nanopillars and mask evolution over the etching time. As the mask pattern size shrinks in nanoscale, vertical and lateral mask erosion plays a crucial role in the etch profile of the SiC nanopillars. Long etching process makes the pillars appear with a hexagonal shape, coming from the crystallographic structure of α-SiC. It is found that the feature of pillars depends not only on the etching process parameters, but also on the crystallographic structure of the SiC phase. (paper)

  20. QT measurement and heart rate correction during hypoglycemia

    DEFF Research Database (Denmark)

    Christensen, Toke Folke; Randløv, Jette; Christensen, Leif Engmann

    2010-01-01

    induced by intravenous injection of two insulin types in a cross-over design. QT measurements were done using the slope-intersect (SI) and manual annotation (MA) methods. Heart rate correction was done using Bazett's (QTcB) and Fridericia's (QTcF) formulas. Results. The SI method showed significant......Introduction. Several studies show that hypoglycemia causes QT interval prolongation. The aim of this study was to investigate the effect of QT measurement methodology, heart rate correction, and insulin types during hypoglycemia. Methods. Ten adult subjects with type 1 diabetes had hypoglycemia...... prolongation at hypoglycemia for QTcB (42(6) ms; P measuring the QT interval has...

  1. Measuring Outdoor Air Intake Rates into Existing Building

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William; Sullivan, Douglas; Cohen, Sebastian; Han, Hwataik

    2009-04-16

    Practical and accurate technologies are needed for continuously measuring and controlling outdoor air (OA) intake rates in commercial building heating, ventilating, and air conditioning (HVAC) systems. This project evaluated two new measurement approaches. Laboratory experiments determined that OA flow rates were measurable with errors generally less than 10 percent using electronic air velocity probes installed between OA intake louver blades or at the outlet face of louvers. High accuracy was maintained with OA flow rates as low as 15 percent of the maximum for the louvers. Thus, with this measurement approach HVAC systems do not need separate OA intakes for minimum OA supply. System calibration parameters are required for each unique combination of louver type and velocity sensor location but calibrations are not necessary for each system installation. The research also determined that the accuracy of measuring OA flow rates with velocity probes located in the duct downstream of the intake louver was not improved by installing honeycomb airflow straighteners upstream of the probes. Errors varied with type of upstream louver, were as high as 100 percent, and were often greater than 25 percent. In conclusion, use of electronic air velocity probes between the blades of OA intake louvers or at the outlet face of louvers is a highly promising means of accurately measuring rates of OA flow into HVAC systems. The use of electronic velocity probes downstream of airflow straighteners is less promising, at least with the relatively small OA HVAC inlet systems employed in this research.

  2. WO3 and W Thermal Atomic Layer Etching Using "Conversion-Fluorination" and "Oxidation-Conversion-Fluorination" Mechanisms.

    Science.gov (United States)

    Johnson, Nicholas R; George, Steven M

    2017-10-04

    The thermal atomic layer etching (ALE) of WO 3 and W was demonstrated with new "conversion-fluorination" and "oxidation-conversion-fluorination" etching mechanisms. Both of these mechanisms are based on sequential, self-limiting reactions. WO 3 ALE was achieved by a "conversion-fluorination" mechanism using an AB exposure sequence with boron trichloride (BCl 3 ) and hydrogen fluoride (HF). BCl 3 converts the WO 3 surface to a B 2 O 3 layer while forming volatile WO x Cl y products. Subsequently, HF spontaneously etches the B 2 O 3 layer producing volatile BF 3 and H 2 O products. In situ spectroscopic ellipsometry (SE) studies determined that the BCl 3 and HF reactions were self-limiting versus exposure. The WO 3 ALE etch rates increased with temperature from 0.55 Å/cycle at 128 °C to 4.19 Å/cycle at 207 °C. W served as an etch stop because BCl 3 and HF could not etch the underlying W film. W ALE was performed using a three-step "oxidation-conversion-fluorination" mechanism. In this ABC exposure sequence, the W surface is first oxidized to a WO 3 layer using O 2 /O 3 . Subsequently, the WO 3 layer is etched with BCl 3 and HF. SE could simultaneously monitor the W and WO 3 thicknesses and conversion of W to WO 3 . SE measurements showed that the W film thickness decreased linearly with number of ABC reaction cycles. W ALE was shown to be self-limiting with respect to each reaction in the ABC process. The etch rate for W ALE was ∼2.5 Å/cycle at 207 °C. An oxide thickness of ∼20 Å remained after W ALE, but could be removed by sequential BCl 3 and HF exposures without affecting the W layer. These new etching mechanisms will enable the thermal ALE of a variety of additional metal materials including those that have volatile metal fluorides.

  3. Dry etching characteristics of GaN for blue/green light-emitting diode fabrication

    International Nuclear Information System (INIS)

    Baik, K.H.; Pearton, S.J.

    2009-01-01

    The etch rates, surface morphology and sidewall profiles of features formed in GaN/InGaN/AlGaN multiple quantum well light-emitting diodes by Cl 2 -based dry etching are reported. The chlorine provides an enhancement in etch rate of over a factor of 40 relative to the physical etching provided by Ar and the etching is reactant-limited until chlorine gas flow rates of at least 50 standard cubic centimeters per minute. Mesa sidewall profile angle control is possible using a combination of Cl 2 /Ar plasma chemistry and SiO 2 mask. N-face GaN is found to etch faster than Ga-face surfaces under the same conditions. Patterning of the sapphire substrate for improved light extraction is also possible using the same plasma chemistry

  4. Fabrication of micromechanical structures on substrates selectively etched using a micropatterned ion-implantation method

    International Nuclear Information System (INIS)

    Nakano, Shizuka; Nakagawa, Sachiko; Ishikawa, Haruo; Ogiso, Hisato

    2001-01-01

    An advanced micromachining technique using ion implantation to modify materials was studied. Gold ion implantation into silicon decreased the etching rate when the silicon was etched in potassium hydroxide solution after the ion implantation; the implanted region remained, thus forming the microstructure. Observation of the cross-section of the resulting etched structure by transmission electron microscopy showed that the structure was made only from the ion-implanted region, and that gold was precipitated on the surface. To clarify the mechanism involved in the decrease in the etching rate, we varied the etching conditions. Our results show that precipitation of implanted gold on the surface decreased the etching rate, because solubility of gold is lower

  5. Dynamic Wet Etching of Silicon through Isopropanol Alcohol Evaporation

    Directory of Open Access Journals (Sweden)

    Tiago S. Monteiro

    2015-10-01

    Full Text Available In this paper, Isopropanol (IPA availability during the anisotropic etching of silicon in Potassium Hydroxide (KOH solutions was investigated. Squares of 8 to 40 µm were patterned to (100 oriented silicon wafers through DWL (Direct Writing Laser photolithography. The wet etching process was performed inside an open HDPE (High Density Polyethylene flask with ultrasonic agitation. IPA volume and evaporation was studied in a dynamic etching process, and subsequent influence on the silicon etching was inspected. For the tested conditions, evaporation rates for water vapor and IPA were determined as approximately 0.0417 mL/min and 0.175 mL/min, respectively. Results demonstrate that IPA availability, and not concentration, plays an important role in the definition of the final structure. Transversal SEM (Scanning Electron Microscopy analysis demonstrates a correlation between microloading effects (as a consequence of structure spacing and the angle formed towards the (100 plane.

  6. Room temperature inductively coupled plasma etching of InAs/InSb in BCl 3/Cl 2/Ar

    KAUST Repository

    Sun, Jian; Kosel, Jü rgen

    2012-01-01

    Inductively coupled plasma (ICP) etching of InAs and InSb at room temperature has been investigated using BCl 3/Cl 2/Ar plasma. Specifically, the etch rate and post-etching surface morphology were investigated as functions of the gas composition

  7. Optimization of silver-assisted nano-pillar etching process in silicon

    International Nuclear Information System (INIS)

    Azhari, Ayu Wazira; Sopian, Kamaruzzaman; Desa, Mohd Khairunaz Mat; Zaidi, Saleem H.

    2015-01-01

    Graphical abstract: - Highlights: • Statistical analysis for synthesis of nano-pillar in crystalline Si substrates is presented. • Model is in good agreement with experimental for the etching rate and lateral etching respectively. • Optimum values for all parameters in fabrication of nanostructured Si are attained. - Abstract: In this study, a respond surface methodology (RSM) model is developed using three-level Box–Behnken experimental design (BBD) technique. This model is developed to investigate the influence of metal-assisted chemical etching (MACE) process variables on the nanopillars profiles created in single crystalline silicon (Si) substrate. Design-Expert ® software (version 7.1) is employed in formulating the RSM model based on five critical process variables: (A) concentration of silver (Ag), (B) concentration of hydrofluoric acid (HF), (C) concentration of hydrogen peroxide (H 2 O 2 ), (D) deposition time, and (E) etching time. This model is supported by data from 46 experimental configurations. Etched profiles as a function of lateral etching rate, vertical etching rate, height, size and separation between the Si trenches and etching uniformity are characterized using field emission scanning electron microscope (FE-SEM). A quadratic regression model is developed to correlate critical process variables and is validated using the analysis of variance (ANOVA) methodology. The model exhibits near-linear dependence of lateral and vertical etching rates on both the H 2 O 2 concentration and etching time. The predicted model is in good agreement with the experimental data where R 2 is equal to 0.80 and 0.67 for the etching rate and lateral etching respectively. The optimized result shows minimum lateral etching with the average pore size of about 69 nm while the maximum etching rate is estimated at around 360 nm/min. The model demonstrates that the etching process uniformity is not influenced by either the etchant concentration or the etching time

  8. Optimization of silver-assisted nano-pillar etching process in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Azhari, Ayu Wazira, E-mail: ayuwazira@unimap.edu.my [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, Bangi, Selangor 43650 (Malaysia); School of Environmental Engineering, Universiti Malaysia Perlis, 01000, Kangar, Perlis (Malaysia); Sopian, Kamaruzzaman [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, Bangi, Selangor 43650 (Malaysia); Desa, Mohd Khairunaz Mat [School of Electrical and Electronic Engineering, Universiti Sains Malaysia, Nibong Tebal, Pulau Pinang, 14300 (Malaysia); Zaidi, Saleem H. [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, Bangi, Selangor 43650 (Malaysia)

    2015-12-01

    Graphical abstract: - Highlights: • Statistical analysis for synthesis of nano-pillar in crystalline Si substrates is presented. • Model is in good agreement with experimental for the etching rate and lateral etching respectively. • Optimum values for all parameters in fabrication of nanostructured Si are attained. - Abstract: In this study, a respond surface methodology (RSM) model is developed using three-level Box–Behnken experimental design (BBD) technique. This model is developed to investigate the influence of metal-assisted chemical etching (MACE) process variables on the nanopillars profiles created in single crystalline silicon (Si) substrate. Design-Expert{sup ®} software (version 7.1) is employed in formulating the RSM model based on five critical process variables: (A) concentration of silver (Ag), (B) concentration of hydrofluoric acid (HF), (C) concentration of hydrogen peroxide (H{sub 2}O{sub 2}), (D) deposition time, and (E) etching time. This model is supported by data from 46 experimental configurations. Etched profiles as a function of lateral etching rate, vertical etching rate, height, size and separation between the Si trenches and etching uniformity are characterized using field emission scanning electron microscope (FE-SEM). A quadratic regression model is developed to correlate critical process variables and is validated using the analysis of variance (ANOVA) methodology. The model exhibits near-linear dependence of lateral and vertical etching rates on both the H{sub 2}O{sub 2} concentration and etching time. The predicted model is in good agreement with the experimental data where R{sup 2} is equal to 0.80 and 0.67 for the etching rate and lateral etching respectively. The optimized result shows minimum lateral etching with the average pore size of about 69 nm while the maximum etching rate is estimated at around 360 nm/min. The model demonstrates that the etching process uniformity is not influenced by either the etchant

  9. Hybrid mask for deep etching

    KAUST Repository

    Ghoneim, Mohamed T.

    2017-01-01

    Deep reactive ion etching is essential for creating high aspect ratio micro-structures for microelectromechanical systems, sensors and actuators, and emerging flexible electronics. A novel hybrid dual soft/hard mask bilayer may be deposited during

  10. Accuracy of real time radiography burning rate measurement

    Science.gov (United States)

    Olaniyi, Bisola

    The design of a solid propellant rocket motor requires the determination of a propellant's burning-rate and its dependency upon environmental parameters. The requirement that the burning-rate be physically measured, establishes the need for methods and equipment to obtain such data. A literature review reveals that no measurement has provided the desired burning rate accuracy. In the current study, flash x-ray modeling and digitized film-density data were employed to predict motor-port area to length ratio. The pre-fired port-areas and base burning rate were within 2.5% and 1.2% of their known values, respectively. To verify the accuracy of the method, a continuous x-ray and a solid propellant rocket motor model (Plexiglas cylinder) were used. The solid propellant motor model was translated laterally through a real-time radiography system at different speeds simulating different burning rates. X-ray images were captured and the burning-rate was then determined. The measured burning rate was within 1.65% of the known values.

  11. Level Set Approach to Anisotropic Wet Etching of Silicon

    Directory of Open Access Journals (Sweden)

    Branislav Radjenović

    2010-05-01

    Full Text Available In this paper a methodology for the three dimensional (3D modeling and simulation of the profile evolution during anisotropic wet etching of silicon based on the level set method is presented. Etching rate anisotropy in silicon is modeled taking into account full silicon symmetry properties, by means of the interpolation technique using experimentally obtained values for the etching rates along thirteen principal and high index directions in KOH solutions. The resulting level set equations are solved using an open source implementation of the sparse field method (ITK library, developed in medical image processing community, extended for the case of non-convex Hamiltonians. Simulation results for some interesting initial 3D shapes, as well as some more practical examples illustrating anisotropic etching simulation in the presence of masks (simple square aperture mask, convex corner undercutting and convex corner compensation, formation of suspended structures are shown also. The obtained results show that level set method can be used as an effective tool for wet etching process modeling, and that is a viable alternative to the Cellular Automata method which now prevails in the simulations of the wet etching process.

  12. Thermodynamics of nuclear track chemical etching

    Science.gov (United States)

    Rana, Mukhtar Ahmed

    2018-05-01

    This is a brief paper with new and useful scientific information on nuclear track chemical etching. Nuclear track etching is described here by using basic concepts of thermodynamics. Enthalpy, entropy and free energy parameters are considered for the nuclear track etching. The free energy of etching is determined using etching experiments of fission fragment tracks in CR-39. Relationship between the free energy and the etching temperature is explored and is found to be approximately linear. The above relationship is discussed. A simple enthalpy-entropy model of chemical etching is presented. Experimental and computational results presented here are of fundamental interest in nuclear track detection methodology.

  13. Validating a new device for measuring tear evaporation rates.

    Science.gov (United States)

    Rohit, Athira; Ehrmann, Klaus; Naduvilath, Thomas; Willcox, Mark; Stapleton, Fiona

    2014-01-01

    To calibrate and validate a commercially available dermatology instrument to measure tear evaporation rate of contact lens wearers. A dermatology instrument was modified by attaching a swim goggle cup such that the cup sealed around the eye socket. Results for the unmodified instrument are dependent on probe area and enclosed volume. Calibration curves were established using a model eye, to account for individual variations in chamber volume and exposed area. Fifteen participants were recruited and the study included a contact lens wear and a no contact lens wear stage. Day and diurnal variation of the measurements were assessed by taking the measurement three times a day over 2 days. The coefficient of repeatability of the measurement was calculated and a linear mixed model assessed the influence of humidity, temperature, contact lens wear, day and diurnal variations on tear evaporation rate. The associations between variables were assessed using Pearson correlation coefficient. Absolute evaporation rates with and without contact lens wear were calculated based on the new calibration. The measurements were most repeatable during the evening with no lens wear (COR = 49 g m⁻² h) and least repeatable during the evening with contact lens wear (COR = 93 g m⁻² h). Humidity (p = 0.007), and contact lens wear (p evaporation rate. However, temperature (p = 0.54) diurnal variation (p = 0.85) and different days (p = 0.65) had no significant effect after controlling for humidity. Tear evaporation rates can be measured using a modified dermatology instrument. Measurements were higher and more variable with lens wear consistent with previous literature. Control of environmental conditions is important as a higher humidity results in a reduced evaporation rate. © 2013 The Authors Ophthalmic & Physiological Optics © 2013 The College of Optometrists.

  14. Measurement of viscosity of slush at high shear rates

    OpenAIRE

    小林, 俊一; 川村, 公之; 津川, 圭一; 和泉, 薫; Kobayashi, Shun'ichi; Kawamura, Kimiyuki; Tugawa, Keiichi; Izumi, Kaoru

    1988-01-01

    Measurements of viscosity of slush were carried out using a method of flow along an inclined smooth surface in a 0℃cold room. The method was used to get the values of viscosity under high shear rates (25 and 75s^). From our experiments two important results were obtained: 1) the viscosity of slush decreases with increasing shear rates; 2) The fluid behavior is pseudoplastic that the values of non-Newtonian index of viscosity were less than unity.

  15. Anisotropic diamond etching through thermochemical reaction between Ni and diamond in high-temperature water vapour.

    Science.gov (United States)

    Nagai, Masatsugu; Nakanishi, Kazuhiro; Takahashi, Hiraku; Kato, Hiromitsu; Makino, Toshiharu; Yamasaki, Satoshi; Matsumoto, Tsubasa; Inokuma, Takao; Tokuda, Norio

    2018-04-27

    Diamond possesses excellent physical and electronic properties, and thus various applications that use diamond are under development. Additionally, the control of diamond geometry by etching technique is essential for such applications. However, conventional wet processes used for etching other materials are ineffective for diamond. Moreover, plasma processes currently employed for diamond etching are not selective, and plasma-induced damage to diamond deteriorates the device-performances. Here, we report a non-plasma etching process for single crystal diamond using thermochemical reaction between Ni and diamond in high-temperature water vapour. Diamond under Ni films was selectively etched, with no etching at other locations. A diamond-etching rate of approximately 8.7 μm/min (1000 °C) was successfully achieved. To the best of our knowledge, this rate is considerably greater than those reported so far for other diamond-etching processes, including plasma processes. The anisotropy observed for this diamond etching was considerably similar to that observed for Si etching using KOH.

  16. Development of nondestructive measurement of cold work rate, (2)

    International Nuclear Information System (INIS)

    Kamimura, Hideaki; Igarashi, Miyuki; Satoh, Masakazu; Miura, Makoto

    1978-01-01

    Cold-worked type 316 stainless steel will be used as fuel cladding material for the proto-type fast reactor MONJU. Cold work rate is an important parameter in swelling behavior of fuel cladding. It has been shown that austenitic stainless steel undergoes martensitic transformation during cold working. Nondestructive evaluation of cold work rate will be expected by measuring residual magnetism produced in the presence of martensitic phase when cold worked austenitic stainless steel is magnetized. In the previous work, the residual magnetism of cladding tubes of type 316 stainless steel was measured. The results have shown high degree of the correlation between residual magnetism and cold work rate. This paper reports the results of measurement on cold-rolled type 316 stainless steel plate samples. Dimensions of the specimens are 100 mm long and 3.5 and 7 mm wide. The apparatus and experimental procedures were similar to the previous work. Good agreement was found between the estimated cold work rate obtained in the previous work and that for cold rolled plate specimens. Measurement of residual magnetism in identical direction with magnetization showed smaller dispersion of data as compared with that in transverse direction. The residual magnetism near specimen surface hardly decreased when the surface of specimen was chemically removed. The reason for the comparative decrease in residual magnetism at 10% and 15% cold work rate is not clear. (Wakatsuki, Y.)

  17. Estimating average glandular dose by measuring glandular rate in mammograms

    International Nuclear Information System (INIS)

    Goto, Sachiko; Azuma, Yoshiharu; Sumimoto, Tetsuhiro; Eiho, Shigeru

    2003-01-01

    The glandular rate of the breast was objectively measured in order to calculate individual patient exposure dose (average glandular dose) in mammography. By employing image processing techniques and breast-equivalent phantoms with various glandular rate values, a conversion curve for pixel value to glandular rate can be determined by a neural network. Accordingly, the pixel values in clinical mammograms can be converted to the glandular rate value for each pixel. The individual average glandular dose can therefore be calculated using the individual glandular rates on the basis of the dosimetry method employed for quality control in mammography. In the present study, a data set of 100 craniocaudal mammograms from 50 patients was used to evaluate our method. The average glandular rate and average glandular dose of the data set were 41.2% and 1.79 mGy, respectively. The error in calculating the individual glandular rate can be estimated to be less than ±3%. When the calculation error of the glandular rate is taken into consideration, the error in the individual average glandular dose can be estimated to be 13% or less. We feel that our method for determining the glandular rate from mammograms is useful for minimizing subjectivity in the evaluation of patient breast composition. (author)

  18. Rapid Measurement of Neutron Dose Rate for Transport Index

    International Nuclear Information System (INIS)

    Morris, R.L.

    2000-01-01

    A newly available neutron dose equivalent remmeter with improved sensitivity and energy response has been put into service at Rocky Flats Environmental Technology Site (RFETS). This instrument is being used to expedite measurement of the Transport Index and as an ALARA tool to identify locations where slightly elevated neutron dose equivalent rates exist. The meter is capable of measuring dose rates as low as 0.2 μSv per hour (20 μrem per hour). Tests of the angular response and energy response of the instrument are reported. Calculations of the theoretical instrument response made using MCNPtrademark are reported for materials typical of those being shipped

  19. Three-dimensional spatial imaging in multiphoton ionization rate measurements

    International Nuclear Information System (INIS)

    Bredy, Richard; Camp, Howard A.; Nguyen, Hai; Awata, Takaaki; Shan Bing; Chang Zhenghu; DePaola, B.D.

    2004-01-01

    An experiment is described in which an apparatus is used to demonstrate the feasibility of measuring multiphoton photoionization rates in the interaction of short pulsed lasers with atoms or molecules. With this methodology, the ionization rate is measured as a function of the spatial position in the beam-waist region of the laser through the direct three-dimensional spatial imaging of the ionization events. Thus, if the spatial dependence of the laser beam intensity were known, a series of experiments could yield the intensity dependence of multiphoton ionization without the assumptions or errors that are generally inherent in the integration over one or more dimensions in the laser focal volume

  20. Measurement of thoron exhalation rates from building materials.

    Science.gov (United States)

    de With, G; de Jong, P; Röttger, A

    2014-09-01

    Thoron (220Rn) exhalation from building materials has become increasingly recognized as a potential source for radiation exposure in dwellings. However, contrary to radon (220Rn), limited information on thoron exposure is available. The purpose of this study is to develop a test method for the determination of the thoron exhalation rate from building materials. The method is validated, and subsequently the thoron exhalation rates from 10 widely-applied concretes, gypsums, brick, limestone, and mortar are determined. The measured thoron exhalation rates of these materials range from 0.01 Bq m-2 s-1 to 0.43 Bq m-2 s-1, with relative standard uncertainties between 6% to 14%.

  1. Optimization of microwave-induced chemical etching for rapid development of neutron-induced recoil tracks in CR-39 detectors

    International Nuclear Information System (INIS)

    Sahoo, G.S.; Tripathy, S.P.; Bandyopadhyay, T.

    2014-01-01

    A systematic investigation is carried out to optimize the recently established microwave-induced chemical etching (MICE) parameters for rapid development of neutron-induced recoil tracks in CR-39 detectors. Several combinations of all available microwave powers with different etching durations were analysed to determine the most suitable etching condition. The etching duration was found to reduce with increasing microwave power and the tracks were observed at about 18, 15, 12, and 6 min for 300, 450, 600 and 900 W of microwave powers respectively compared to a few hours in chemical etching (CE) method. However, for complete development of tracks the etching duration of 30, 40, 50 and 60 min were found to be suitable for the microwave powers of 900, 600, 450 and 300 W, respectively. Temperature profiles of the etchant for all the available microwave powers at different etching durations were generated to regulate the etching process in a controlled manner. The bulk etch rates at different microwave powers were determined by 2 methods, viz., gravimetric and removed thickness methods. A logarithmic expression was used to fit the variation of bulk etch rate with microwave power. Neutron detection efficiencies were obtained for all the cases and the results on track parameters obtained with MICE technique were compared with those obtained from another detector processed with chemical etching. - Highlights: • Microwave-induced chemical etching method is optimized for rapid development of recoil tracks due to neutrons in CR-39 detector. • Several combinations of microwave powers and etching durations are investigated to standardize the suitable etching condition. • Bulk-etch rates are determined for all microwave powers by two different methods, viz. gravimetric and removed thickness method. • The method is found to be simple, effective and much faster compared to conventional chemical etching

  2. Flow Rate Measurement in Multiphase Flow Rig: Radiotracer and Conventional

    International Nuclear Information System (INIS)

    Nazrul Hizam Yusoff; Noraishah Othman; Nurliyana Abdullah; Amirul Syafiq Mohd Yunos; Rasif Mohd Zain; Roslan Yahya

    2015-01-01

    Applications of radiotracer technology are prevalent throughout oil refineries worldwide, and this industry is one of the main users and beneficiaries of the technology. Radioactive tracers have been used to a great extent in many applications i.e. flow rate measurement, RTD, plant integrity evaluation and enhancing oil production in oil fields. Chemical and petrochemical plants are generally continuously operating and technically complex where the radiotracer techniques are very competitive and largely applied for troubleshooting inspection and process analysis. Flow rate measurement is a typical application of radiotracers. For flow measurements, tracer data are important, rather than the RTD models. Research is going on in refining the existing methods for single phase flow measurement, and in developing new methods for multiphase flow without sampling. The tracer techniques for single phase flow measurements are recognized as ISO standards. This paper presents technical aspect of laboratory experiments, which have been carried out using Molybdenum-99 - Mo99 (radiotracer) to study and determine the flow rate of liquid in multiphase flow rig. The multiphase flow rig consists of 58.7 m long and 20 cm diameter pipeline that can accommodate about 0.296 m 3 of liquid. Tap water was used as liquid flow in pipeline and conventional flow meters were also installed at the flow rig. The flow rate results; radiotracer and conventional flow meter were compared. The total count method was applied for radiotracer technique and showed the comparable results with conventional flow meter. (author)

  3. Laser etching of polymer masked leadframes

    Science.gov (United States)

    Ho, C. K.; Man, H. C.; Yue, T. M.; Yuen, C. W.

    1997-02-01

    A typical electroplating production line for the deposition of silver pattern on copper leadframes in the semiconductor industry involves twenty to twenty five steps of cleaning, pickling, plating, stripping etc. This complex production process occupies large floor space and has also a number of problems such as difficulty in the production of rubber masks and alignment, generation of toxic fumes, high cost of water consumption and sometimes uncertainty on the cleanliness of the surfaces to be plated. A novel laser patterning process is proposed in this paper which can replace many steps in the existing electroplating line. The proposed process involves the application of high speed laser etching techniques on leadframes which were protected with polymer coating. The desired pattern for silver electroplating is produced by laser ablation of the polymer coating. Excimer laser was found to be most effective for this process as it can expose a pattern of clean copper substrate which can be silver plated successfully. Previous working of Nd:YAG laser ablation showed that 1.06 μm radiation was not suitable for this etching process because a thin organic and transparent film remained on the laser etched region. The effect of excimer pulse frequency and energy density upon the removal rate of the polymer coating was studied.

  4. Correlation measurements of sodium flow rate with magnetic sensors

    International Nuclear Information System (INIS)

    Kebadze, B.V.; Krasnoyarov, N.V.; Adamovskij, L.A.; Golushko, V.V.; Sroelov, V.S.

    1978-01-01

    The results of bench-mark experiments and those carried out at the BOR-60 reactor to measure the sodium coolant flow rate by a correlation method are presented. The method is based on detecting the eddy type flow hydraulic nonuniformities using magnetic flowmeters. The measurements were fulfilled in a broad range of flow rates (G=10-10 4 m 3 /h, Re=2x10 5 -2x10 7 ). The measured and calculated mutual correlation functions are presented with parallel and perpendicular orientations of the flowmeters magnetic fields. A good accord is stated. Prerequirements to the arrangement of the measuring systems are formulated. As an important advantage of the correlation method a possibility of the flowmeter calibration in situ is hydhlighted

  5. Self-assembled monolayer resists and nanoscale lithography of silicon dioxide thin films by chemically enhanced vapor etching (CEVE)

    Science.gov (United States)

    Pan, M.; Yun, M.; Kozicki, M. N.; Whidden, T. K.

    1996-10-01

    We report on the use of electron-beam exposed monolayers of undecylenic acid in the etch rate enhancement of silicon dioxide films in HF vapor for the formation of nanoscale features in the oxide. Variations of the etching characteristics with electron beam parameters are examined and the results analyzed in terms of proposed models of the etching mechanism. Apparent variations in the relative concentrations of etch initiator with the thermal history of the samples prior to etching provides support for the dominant etch initiator within this system as the carboxylic acid moiety bound at the oxide surface. Other variations in the etching characteristics are discussed in terms of differences in localized concentrations of hydrocarbon crosslinks and the effect that this has upon the etch initiation. The process has been employed in the production of features in silicon dioxide surface masks with sizes down to 50 nm.

  6. Growth, etching, and stability of sputtered ZnO:Al for thin-film silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Owen, Jorj Ian

    2011-07-01

    , temperature, and type holds true for single crystal ZnO. Planar and cross-sectional transmission electron microscopy (TEM) measurements confirmed grain boundaries as the most prevalent catalysts for etching. A three-postulate etching model is proposed, the basics of which are: (1) every grain boundary has certain potential to etch, and this potential depends on the compactness of the grain boundary;(2) the etchant solution and conditions define an etching threshold, and grain boundaries with etching potentials above the threshold are actively etched; and (3) the vertical and horizontal etch rates are defined by the solution, and vertically limited etching leads to the characteristic crater opening angles while a horizontal limited etch yields sharper structures. Examples on how the better understanding of ZnO:Al can lead to more efficient solar cells and more reliable ZnO:Al film preparation are also given.

  7. Etching of UO2 in NF3 RF Plasma Glow Discharge

    International Nuclear Information System (INIS)

    John M. Veilleux

    1999-01-01

    A series of room temperature, low pressure (10.8 to 40 Pa), low power (25 to 210 W) RF plasma glow discharge experiments with UO 2 were conducted to demonstrate that plasma treatment is a viable method for decontaminating UO 2 from stainless steel substrates. Experiments were conducted using NF 3 gas to decontaminate depleted uranium dioxide from stainless-steel substrates. Depleted UO 2 samples each containing 129.4 Bq were prepared from 100 microliter solutions of uranyl nitrate hexahydrate solution. The amorphous UO 2 in the samples had a relatively low density of 4.8 gm/cm 3 . Counting of the depleted UO 2 on the substrate following plasma immersion was performed using liquid scintillation counting with alpha/beta discrimination due to the presence of confounding beta emitting daughter products, 234 Th and 234 Pa. The alpha emission peak from each sample was integrated using a gaussian and first order polynomial fit to improve quantification. The uncertainties in the experimental measurement of the etched material were estimated at about ± 2%. Results demonstrated that UO 2 can be completely removed from stainless-steel substrates after several minutes processing at under 200 W. At 180 W and 32.7 Pa gas pressure, over 99% of all UO 2 in the samples was removed in just 17 minutes. The initial etch rate in the experiments ranged from 0.2 to 7.4 microm/min. Etching increased with the plasma absorbed power and feed gas pressure in the range of 10.8 to 40 Pa. A different pressure effect on UO 2 etching was also noted below 50 W in which etching increased up to a maximum pressure, approximately23 Pa, then decreased with further increases in pressure

  8. Measurement of droplet vaporization rate enhancement caused by acoustic disturbances

    Science.gov (United States)

    Anderson, T. J.; Winter, M.

    1992-10-01

    Advanced laser diagnostics are being applied to quantify droplet vaporization enhancement in the presence of acoustic fields which can lead to instability in liquid-fueled rockets. While models have been developed to describe the interactions between subcritical droplet vaporization and acoustic fields in the surrounding gases, they have not been verified experimentally. In the super critical environment of a rocket engine combustor, little is understood about how the injected fluid is distributed. Experiments in these areas have been limited because of the lack of diagnostic techniques capable of providing quantitative results. Recently, however, extremely accurate vaporization rate measurements have been performed on droplets in a subcritical environment using morphology-dependent resonances (MDR's) in which fluorescence from an individual droplet provides information about its diameter. Initial measurements on methanol droplets behind a pressure pulse with a pressure ratio of 1.2 indicated that the evaporation rate in the first few microsec after wave passage was extremely high. Subsequent measurements have been made to validate these results using MDR's acquired from similarly-sized droplets using a pulse with a 1.1 pressure ratio. A baseline measurement was also made using a non evaporative fluid under similar Weber and Reynolds number conditions. The MDR technique employed for these measurements is explained and the facilities are described. The evaporation measurement results are shown and the rates observed from different droplet materials and different wave strengths are compared.

  9. The etching of InP in HCl solutions : a chemical mechanism

    NARCIS (Netherlands)

    Notten, P.H.L.

    1984-01-01

    The etch rate of InP in solutions of high HCl concentration was shown to be independent of the applied potential ina wide potential range negative with respect to the flatband value. Dissolution of the solid led to the formation of PH3.The etch rate, which was not mass-transport controlled, was

  10. Measurement of rates of cholesterol synthesis using tritiated water

    International Nuclear Information System (INIS)

    Dietschy, J.M.; Spady, D.K.

    1984-01-01

    Rates of sterol synthesis in various tissues commonly are assessed by assaying levels of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase on isolated microsomes or by measuring the rates of incorporation of various 14 C-labeled substrates or [ 3 H]water into cholesterol by whole cell preparations in vitro or by the tissues of the whole animal in vivo. While measurement of activities of HMG-CoA reductase or rates of incorporation of 14 C-labeled substrates into cholesterol give useful relative rates of sterol production, neither method yields absolute rates of cholesterol synthesis. The use of [ 3 H]water circumvents the problem of variable and unknown dilution of the specific activity of the precursor pool encountered when 14 C-labeled substrates are used and does yield absolute rates of cholesterol synthesis provided that the 3 H/C incorporation ratio is known for a particular tissue. In 12 different experimental situations it has been found that from 21 to 27 micrograms atoms of 3 H are incorporated into cholesterol from [ 3 H]water in different tissues of several animal species, so that the 3 H/C incorporation ratio is similar under nearly all experimental conditions and varies from 0.78 to 1.00. When administered in vivo, [ 3 H]water rapidly equilibrates with intracellular water and is incorporated into sterols within the various organs at rates that are linear with respect to time. From such data it is possible to obtain absolute rates of cholesterol synthesis in the whole animal and in the various organs of the animal. Current data suggest, therefore, that use of [ 3 H]water yields the most accurate rates of cholesterol synthesis both in vitro and in vivo

  11. Heart rate measurement based on face video sequence

    Science.gov (United States)

    Xu, Fang; Zhou, Qin-Wu; Wu, Peng; Chen, Xing; Yang, Xiaofeng; Yan, Hong-jian

    2015-03-01

    This paper proposes a new non-contact heart rate measurement method based on photoplethysmography (PPG) theory. With this method we can measure heart rate remotely with a camera and ambient light. We collected video sequences of subjects, and detected remote PPG signals through video sequences. Remote PPG signals were analyzed with two methods, Blind Source Separation Technology (BSST) and Cross Spectral Power Technology (CSPT). BSST is a commonly used method, and CSPT is used for the first time in the study of remote PPG signals in this paper. Both of the methods can acquire heart rate, but compared with BSST, CSPT has clearer physical meaning, and the computational complexity of CSPT is lower than that of BSST. Our work shows that heart rates detected by CSPT method have good consistency with the heart rates measured by a finger clip oximeter. With good accuracy and low computational complexity, the CSPT method has a good prospect for the application in the field of home medical devices and mobile health devices.

  12. Sodium flow rate measurement method of annular linear induction pumps

    International Nuclear Information System (INIS)

    Araseki, Hideo; Kirillov, Igor R.; Preslitsky, Gennady V.

    2012-01-01

    Highlights: ► We found a new method of flow rate monitoring of electromagnetic pump. ► The method is very simple and does not require a large space. ► The method was verified with an experiment and a numerical analysis. ► The experimental data and the numerical results are in good agreement. - Abstract: The present paper proposes a method for measuring sodium flow rate of annular linear induction pumps. The feature of the method lies in measuring the leaked magnetic field with measuring coils near the stator end on the outlet side and in correlating it with the sodium flow rate. This method is verified through an experiment and a numerical analysis. The data obtained in the experiment reveals that the correlation between the leaked magnetic field and the sodium flow rate is almost linear. The result of the numerical analysis agrees with the experimental data. The present method will be particularly effective to sodium flow rate monitoring of each one of plural annular linear induction pumps arranged in parallel in a vessel which forms a large-scale pump unit.

  13. Etching of germanium-tin using ammonia peroxide mixture

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Yuan; Ong, Bin Leong; Wang, Wei; Gong, Xiao; Liang, Gengchiau; Yeo, Yee-Chia, E-mail: yeo@ieee.org [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore); Zhang, Zheng; Pan, Jisheng [Institute of Material Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, #08-03, Innovis, Singapore 138634 (Singapore); Tok, Eng-Soon [Department of Physics, National University of Singapore, Singapore 117551 (Singapore)

    2015-12-28

    The wet etching of germanium-tin (Ge{sub 1-x}Sn{sub x}) alloys (4.2% < x < 16.0%) in ammonia peroxide mixture (APM) is investigated. Empirical fitting of the data points indicates that the etch depth of Ge{sub 1-x}Sn{sub x} is proportional to the square root of the etch time t and decreases exponentially with increasing x for a given t. In addition, X-ray photoelectron spectroscopy results show that increasing t increases the intensity of the Sn oxide peak, whereas no obvious change is observed for the Ge oxide peak. This indicates that an accumulation of Sn oxide on the Ge{sub 1-x}Sn{sub x} surface decreases the amount of Ge atoms exposed to the etchant, which accounts for the decrease in etch rate with increasing etch time. Atomic force microscopy was used to examine the surface morphologies of the Ge{sub 0.918}Sn{sub 0.082} samples. Both root-mean-square roughness and undulation periods of the Ge{sub 1-x}Sn{sub x} surface were observed to increase with increasing t. This work provides further understanding of the wet etching of Ge{sub 1-x}Sn{sub x} using APM and may be used for the fabrication of Ge{sub 1-x}Sn{sub x}-based electronic and photonic devices.

  14. Inter-Observer Agreement in Measuring Respiratory Rate

    DEFF Research Database (Denmark)

    Nielsen, Louise Gramstrup; Folkestad, Lars; Brodersen, Jacob Broder

    2015-01-01

    BACKGROUND: Respiratory rate (RR) is an important vital sign which is strongly correlated with in-hospital mortality. At the same time, RR is the most likely vital sign to be omitted when assessing a patient. We believe that one reason for this could be the difficulty in measure the RR, since...

  15. High-temperature rate constant measurements for OH+xylenes

    KAUST Repository

    Elwardani, Ahmed Elsaid; Badra, Jihad; Farooq, Aamir

    2015-01-01

    The overall rate constants for the reactions of hydroxyl (OH) radicals with o-xylene (k 1), m-xylene (k 2), and p-xylene (k 3) were measured behind reflected shock waves over 890-1406K at pressures of 1.3-1.8atm using OH laser absorption near 306

  16. Intercalibration of mussel Mytilus edulis clearance rate measurements

    NARCIS (Netherlands)

    Kjerulf Petersen, J.; Bougrier, S.; Smaal, A.C.; Garen, P.; Robert, S.; Larsen, J.E.N.; Brummelhuis, E.B.M.

    2004-01-01

    Clearance rate (CR) was measured in blue mussels Mytilus edulis L. from Aiguillon Bay and the Oosterschelde using 3 different methods: the flow-through method, the bio-deposition method and the indirect or clearance method. CR differed significantly as a function of the method used and of the origin

  17. Influence of Application Time and Etching Mode of Universal Adhesives on Enamel Adhesion.

    Science.gov (United States)

    Sai, Keiichi; Takamizawa, Toshiki; Imai, Arisa; Tsujimoto, Akimasa; Ishii, Ryo; Barkmeier, Wayne W; Latta, Mark A; Miyazaki, Masashi

    2018-01-01

    To investigate the influence of application time and etching mode of universal adhesives on enamel adhesion. Five universal adhesives, Adhese Universal, Bondmer Lightless, Clearfil Universal Bond Quick, G-Premio Bond, and Scotchbond Universal, were used. Bovine incisors were prepared and divided into four groups of ten teeth each. SBS, Ra, and SFE were determined after the following procedures: 1. self-etch mode with immediate air blowing after application (IA); 2. self-etch mode with prolonged application time (PA); 3. etch-and-rinse mode with IA; 4. etch-and-rinse mode with PA. After 24-h water storage, the bonded assemblies were subjected to shear bond strength (SBS) tests. For surface roughness (Ra) and surface free energy (SFE) measurements, the adhesives were simply applied to the enamel and rinsed with acetone and water before the measurements were carried out. Significantly higher SBS and Ra values were obtained with etch-and-rinse mode than with self-etch mode regardless of the application time or type of adhesive. Although most adhesives showed decreased SFE values with increased application time in self-etch mode, SFE values in etch-and-rinse mode were dependent on the adhesive type and application time. Etching mode, application time, and type of adhesive significantly influenced the SBS, Ra, and SFE values.

  18. MEASURING TINY MASS ACCRETION RATES ONTO YOUNG BROWN DWARFS

    International Nuclear Information System (INIS)

    Herczeg, Gregory J.; Cruz, Kelle L.; Hillenbrand, Lynne A.

    2009-01-01

    We present low-resolution Keck I/LRIS spectra spanning from 3200 to 9000 A of nine young brown dwarfs and three low-mass stars in the TW Hya Association and in Upper Sco. The optical spectral types of the brown dwarfs range from M5.5 to M8.75, though two have near-IR spectral types of early L dwarfs. We report new accretion rates derived from excess Balmer continuum emission for the low-mass stars TW Hya and Hen 3-600A and the brown dwarfs 2MASS J12073347-3932540, UScoCTIO 128, SSSPM J1102-3431, USco J160606.29-233513.3, DENIS-P J160603.9-205644, and Oph J162225-240515B, and upper limits on accretion for the low-mass star Hen 3-600B and the brown dwarfs UScoCTIO 112, Oph J162225-240515A, and USco J160723.82-221102.0. For the six brown dwarfs in our sample that are faintest at short wavelengths, the accretion luminosity or upper limit is measurable only when the image is binned over large wavelength intervals. This method extends our sensitivity to accretion rate down to ∼10 -13 M sun yr -1 for brown dwarfs. Since the ability to measure an accretion rate from excess Balmer continuum emission depends on the contrast between excess continuum emission and the underlying photosphere, for objects with earlier spectral types the upper limit on accretion rate is much higher. Absolute uncertainties in our accretion rate measurements of ∼3-5 include uncertainty in accretion models, brown dwarf masses, and distance. The accretion rate of 2 x 10 -12 M sun yr -1 onto 2MASS J12073347-3932540 is within 15% of two previous measurements, despite large changes in the Hα flux.

  19. Waste tank ventilation rates measured with a tracer gas method

    International Nuclear Information System (INIS)

    Huckaby, J.L.; Evans, J.C.; Sklarew, D.S.; Mitroshkov, A.V.

    1998-08-01

    Passive ventilation with the atmosphere is used to prevent accumulation of waste gases and vapors in the headspaces of 132 of the 177 high-level radioactive waste Tanks at the Hanford Site in Southeastern Washington State. Measurements of the passive ventilation rates are needed for the resolution of two key safety issues associated with the rates of flammable gas production and accumulation and the rates at which organic salt-nitrate salt mixtures dry out. Direct measurement of passive ventilation rates using mass flow meters is not feasible because ventilation occurs va multiple pathways to the atmosphere (i.e., via the filtered breather riser and unsealed tank risers and pits), as well as via underground connections to other tanks, junction boxes, and inactive ventilation systems. The tracer gas method discussed in this report provides a direct measurement of the rate at which gases are removed by ventilation and an indirect measurement of the ventilation rate. The tracer gas behaves as a surrogate of the waste-generated gases, but it is only diminished via ventilation, whereas the waste gases are continuously released by the waste and may be subject to depletion mechanisms other than ventilation. The fiscal year 1998 tracer studies provide new evidence that significant exchange of air occurs between tanks via the underground cascade pipes. Most of the single-shell waste tanks are connected via 7.6-cm diameter cascade pipes to one or two adjacent tanks. Tracer gas studies of the Tank U-102/U-103 system indicated that the ventilation occurring via the cascade line could be a significant fraction of the total ventilation. In this two-tank cascade, air evidently flowed from Tank U-103 to Tank U-102 for a time and then was observed to flow from Tank U-102 to Tank U-103

  20. Temperature increase beneath etched dentin discs during composite polymerization.

    Science.gov (United States)

    Karaarslan, Emine Sirin; Secilmis, Asli; Bulbul, Mehmet; Yildirim, Cihan; Usumez, Aslihan

    2011-01-01

    The purpose of this in vitro study was to measure the temperature increase during the polymerization of a composite resin beneath acid-etched or laser-etched dentin discs. The irradiation of dentin with an Er:YAG laser may have a positive effect on the thermal conductivity of dentin. This technique has not been studied extensively. Forty dentin discs (5 mm in diameter and 0.5 or 1 mm in height) were prepared from extracted permanent third molars. These dentin discs were etched with 20% orthophosphoric acid or an Er:YAG laser, and were then placed on an apparatus developed to measure temperature increases. The composite resin was polymerized with a high-intensity quartz tungsten halogen (HQTH) or light-emitting diode unit (LED). The temperature increase was measured under the dentin disc with a J-type thermocouple wire that was connected to a data logger. Five measurements were made for each dentin disc, curing unit, and etching system combination. Differences between the initial and the highest temperature readings were taken, and the five calculated temperature changes were averaged to determine the value of the temperature increase. Statistical analysis was performed with a three-way ANOVA and Tukey HSD tests at a 0.05 level of significance. Further SEM examinations were performed. The temperature increase values varied significantly, depending on etching systems (p < 0.05), dentin thicknesses (p < 0.05), and curing units (p < 0.05). Temperature increases measured beneath laser-etched discs were significantly higher than those for acid-etched dentin discs (p < 0.05). The HQTH unit induced significantly higher temperature increases than the LED unit (p < 0.05). The LED unit induced the lowest temperature change (5.2°C) in the 1-mm, acid-etched dentin group. The HQTH unit induced the highest temperature change (10.4°C) for the 0.5-mm, laser-etched dentin group. The risk of heat-induced pulpal damage should be taken into consideration

  1. Measurement for the Leak Rate enhanced by a Improved Method

    International Nuclear Information System (INIS)

    Bae, Sang-Hoon; Choi, Young-San; Kim, Young-Ki; Lee, Yong-Sub; Jung, Hoan-Sung

    2007-01-01

    The leak rate measurement of the HANARO such as a research reactor that adopts a confinement concept for a reactor hall is very important one during a period inspection. This test verifies whether the reactor building could maintain the negative pressure or not when radiation is perceived by abnormal accidents. Of course, this may not cause a problem in a reactor operation only if it can satisfy the design requirement, but it is necessary to have some margin of a limitation value because a reactor hall should be managed more conservatively than the design reference. To meet the requirements of this strict design condition, previous method was changed to a new type of test with more stable and robust measuring method. The new leak rate measurement method is briefly introduced and the merits of this proposed method are shown through the data analyzed for last 3 years

  2. The effect of ArF laser irradiation (193 nm) on the photodegradation and etching properties of alpha-irradiated CR-39 detectors

    Energy Technology Data Exchange (ETDEWEB)

    Shakeri Jooybari, B. [Department of Energy Engineering and Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Nuclear Science and Technology Research Institute (NSRT), Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Ghergherehchi, M. [College of Information and Technology/ school of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon (Korea, Republic of); Afarideh, H., E-mail: hafarideh@aut.ac.ir [Department of Energy Engineering and Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Lamehi-Rachti, M. [Nuclear Science and Technology Research Institute (NSRT), Tehran, Islamic Republic of Iran (Iran, Islamic Republic of)

    2015-01-01

    The effects of ArF laser irradiation (λ=193nm) at various fluences (energy dose or energy density) on the etching properties of pre-exposed (laser + alpha) CR-39 detectors were studied. First, UV–Vis and Fourier transform infrared (FTIR) spectra were acquired for non-laser-irradiated and laser-irradiated samples to detect the influence of the ArF laser on the chemical modification of the CR-39. Changes observed in the spectra indicated that the predominant process that occurred upon ArF laser irradiation was a bond-scission process. Thereafter, the mean track and bulk etching parameters were experimentally measured in ArF-laser-irradiated CR-39 detectors exposed to an alpha source ({sup 241}Am, E = 5.49 MeV). Inhomogeneous regions in the laser-irradiated side of the CR-39 demonstrated a variable etching rate on only the front side of the CR-39 detector. New equations are also presented for the average bulk etching rate for these inhomogeneous regions (front side). The mean bulk and track etching rates and the mean track dimensions increased in a fluence range of 0–37.03 mJ/cm{sup 2} because of photodegradation and the scission of chemical bonds, which are the predominant processes in this range. When the fluence was increased from 37.03 to 123.45 mJ/cm{sup 2}, the bulk and track etching rates and the track dimensions slowly decreased because of the formation of cross-linked structures on the CR-39 surface. The behavior of the bulk and track etching rates and the track dimensions appears to be proportional to the dose absorbed on the detector surface. It was observed that as the etching time was increased, the bulk and track etching rates and the track dimensions of the laser-irradiated samples decreased because of the shallow penetration depth of the 193 nm laser and the reduction in the oxygen penetration depth.

  3. Etching of Niobium in an Argon-Chlorine Capacitively Coupled Plasma

    Science.gov (United States)

    Radovanov, Svetlana; Samolov, Ana; Upadhyay, Janardan; Peshl, Jeremy; Popovic, Svetozar; Vuskovic, Leposava; Applied Materials, Varian Semiconductor Team; Old Dominion University Team

    2016-09-01

    Ion assisted etching of the inner surfaces of Nb superconducting radio frequency (SRF) cavities requires control of incident ion energies and fluxes to achieve the desired etch rate and smooth surfaces. In this paper, we combine numerical simulation and experiment to investigate Ar /Cl2 capacitively coupled plasma (CCP) in cylindrical reactor geometry. Plasma simulations were done in the CRTRS 2D/3D code that self-consistently solves for CCP power deposition and electrostatic potential. The experimental results are used in combination with simulation predictions to understand the dependence of plasma parameters on the operating conditions. Using the model we were able to determine the ion current and flux at the Nb substrate. Our simulations indicate the relative importance of the current voltage phase shift and displacement current at different pressures and powers. For simulation and the experiment we have used a test structure with a pillbox cavity filled with niobium ring-type samples. The etch rate of these samples was measured. The probe measurements were combined with optical emission spectroscopy in pure Ar for validation of the model. The authors acknowledge Dr Shahid Rauf for developing the CRTRS code. Support DE-SC0014397.

  4. High-temperature rate constant measurements for OH+xylenes

    KAUST Repository

    Elwardani, Ahmed Elsaid

    2015-06-01

    The overall rate constants for the reactions of hydroxyl (OH) radicals with o-xylene (k 1), m-xylene (k 2), and p-xylene (k 3) were measured behind reflected shock waves over 890-1406K at pressures of 1.3-1.8atm using OH laser absorption near 306.7nm. Measurements were performed under pseudo-first-order conditions. The measured rate constants, inferred using a mechanism-fitting approach, can be expressed in Arrhenius form as:k1=2.93×1013exp(-1350.3/T)cm3mol-1s-1(890-1406K)k2=3.49×1013exp(-1449.3/T)cm3mol-1s-1(906-1391K)k3=3.5×1013exp(-1407.5/T)cm3mol-1s-1(908-1383K)This paper presents, to our knowledge, first high-temperature measurements of the rate constants of the reactions of xylene isomers with OH radicals. Low-temperature rate-constant measurements by Nicovich et al. (1981) were combined with the measurements in this study to obtain the following Arrhenius expressions, which are applicable over a wider temperature range:k1=2.64×1013exp(-1181.5/T)cm3mol-1s-1(508-1406K)k2=3.05×109exp(-400/T)cm3mol-1s-1(508-1391K)k3=3.0×109exp(-440/T)cm3mol-1s-1(526-1383K) © 2015 The Combustion Institute.

  5. Precedents For Authorization Of Contents Using Dose Rate Measurements

    International Nuclear Information System (INIS)

    Abramczyk, G.; Bellamy, S.; Nathan, S.; Loftin, B.

    2012-01-01

    For the transportation of Radioactive Material (RAM) packages, the requirements for the maximum allowed dose rate at the package surface and in its vicinity are given in Title 10 of the Code of Federal Regulations, Section 71.47. The regulations are based on the acceptable dose rates to which the public, workers, and the environment may be exposed. As such, the regulations specify dose rates, rather than quantity of radioactive isotopes and require monitoring to confirm the requirements are met. 10CFR71.47 requires that each package of radioactive materials offered for transportation must be designed and prepared for shipment so that under conditions normally incident to transportation the radiation level does not exceed 2 mSv/h (200 mrem/h) at any point on the external Surface of the package, and the transport index does not exceed 10. Before shipment, the dose rate of the package is determined by measurement, ensuring that it conforms to the regulatory limits, regardless of any analyses. This is the requirement for all certified packagings. This paper discusses the requirements for establishing the dose rates when shipping RAM packages and the precedents for meeting these requirements by measurement.

  6. MEASURING THE EVOLUTIONARY RATE OF COOLING OF ZZ Ceti

    Energy Technology Data Exchange (ETDEWEB)

    Mukadam, Anjum S.; Fraser, Oliver; Riecken, T. S.; Kronberg, M. E. [Department of Astronomy, University of Washington, Seattle, WA 98195 (United States); Bischoff-Kim, Agnes [Georgia College and State University, Milledgeville, GA 31061 (United States); Corsico, A. H. [Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata (Argentina); Montgomery, M. H.; Winget, D. E.; Hermes, J. J.; Winget, K. I.; Falcon, Ross E.; Reaves, D. [Department of Astronomy, University of Texas at Austin, Austin, TX 78759 (United States); Kepler, S. O.; Romero, A. D. [Universidade Federal do Rio Grande do Sul, Porto Alegre 91501-970, RS (Brazil); Chandler, D. W. [Meyer Observatory, Central Texas Astronomical Society, 3409 Whispering Oaks, Temple, TX 76504 (United States); Kuehne, J. W. [McDonald Observatory, Fort Davis, TX 79734 (United States); Sullivan, D. J. [Victoria University of Wellington, P.O. Box 600, Wellington (New Zealand); Von Hippel, T. [Embry-Riddle Aeronautical University, 600 South Clyde Morris Boulevard, Daytona Beach, FL 32114 (United States); Mullally, F. [SETI Institute, NASA Ames Research Center, MS 244-30, Moffet Field, CA 94035 (United States); Shipman, H. [Delaware Asteroseismic Research Center, Mt. Cuba Observatory, Greenville, DE 19807 (United States); and others

    2013-07-01

    We have finally measured the evolutionary rate of cooling of the pulsating hydrogen atmosphere (DA) white dwarf ZZ Ceti (Ross 548), as reflected by the drift rate of the 213.13260694 s period. Using 41 yr of time-series photometry from 1970 November to 2012 January, we determine the rate of change of this period with time to be dP/dt = (5.2 {+-} 1.4) Multiplication-Sign 10{sup -15} s s{sup -1} employing the O - C method and (5.45 {+-} 0.79) Multiplication-Sign 10{sup -15} s s{sup -1} using a direct nonlinear least squares fit to the entire lightcurve. We adopt the dP/dt obtained from the nonlinear least squares program as our final determination, but augment the corresponding uncertainty to a more realistic value, ultimately arriving at the measurement of dP/dt = (5.5 {+-} 1.0) Multiplication-Sign 10{sup -15} s s{sup -1}. After correcting for proper motion, the evolutionary rate of cooling of ZZ Ceti is computed to be (3.3 {+-} 1.1) Multiplication-Sign 10{sup -15} s s{sup -1}. This value is consistent within uncertainties with the measurement of (4.19 {+-} 0.73) Multiplication-Sign 10{sup -15} s s{sup -1} for another similar pulsating DA white dwarf, G 117-B15A. Measuring the cooling rate of ZZ Ceti helps us refine our stellar structure and evolutionary models, as cooling depends mainly on the core composition and stellar mass. Calibrating white dwarf cooling curves with this measurement will reduce the theoretical uncertainties involved in white dwarf cosmochronometry. Should the 213.13 s period be trapped in the hydrogen envelope, then our determination of its drift rate compared to the expected evolutionary rate suggests an additional source of stellar cooling. Attributing the excess cooling to the emission of axions imposes a constraint on the mass of the hypothetical axion particle.

  7. Evaporation rate measurement in the pool of IEAR-1 reactor

    International Nuclear Information System (INIS)

    Torres, Walmir Maximo; Cegalla, Miriam A.; Baptista Filho, Benedito Dias

    2000-01-01

    The surface water evaporation in pool type reactors affects the ventilation system operation and the ambient conditions and dose rates in the operation room. This paper shows the results of evaporation rate experiment in the pool of IEA-R1 research reactor. The experiment is based on the demineralized water mass variation inside cylindrical metallic recipients during a time interval. Other parameters were measured, such as: barometric pressure, relative humidity, environmental temperature, water temperature inside the recipients and water temperature in the reactor pool. The pool level variation due to water contraction/expansion was calculated. (author)

  8. Field measurement and interpretation of beta doses and dose rates

    International Nuclear Information System (INIS)

    Selby, J.M.; Swinth, K.L.; Hooker, C.D.; Kenoyer, J.L.

    1983-01-01

    A wide variety of portable survey instruments employing GM, ionization chamber and scintillation detectors exist for the measurement of gamma exposure rates. Often these same survey instruments are used for monitoring beta fields. This is done by making measurements with and without a removable shield which is intended to shield out the non-penetrating component (beta) of the radiation field. The difference does not correspond to an absorbed dose rate for the beta field due to a variety of factors. Among these factors are the dependence on beta energy, source-detector geometries, mixed fields and variable ambient conditions. Attempting to use such measurements directly can lead to errors as high as a factor of 100. In many instances correction factors have been derived, that if properly applied, can reduce these errors substantially. However, this requires some knowledge of the beta spectra, calibration techniques and source geometry. This paper discusses some aspects of the proper use of instruments for beta measurements including the application of appropriate correction factors. Ionization type instruments are commonly used to measure beta dose rates. Through design and calibration these instruments will give an accurate reading only for uniform irradiation of the detection volume. Often in the field it is not feasible to meet these conditions. Large area uniform distributions of activity are not generally encountered and it is not possible to use large source-to-detector distances due to beta particle absorption in air. An example of correction factors required for various point sources is presented when a cutie pie ionization chamber is employed. The instrument reading is multiplied by the appropriate correction factor to obtain the dose rate at the window. When a different detector is used or for other geometries, a different set of correction factors must be used

  9. Grafting on nuclear tracks using the active sites that remain after the etching process

    International Nuclear Information System (INIS)

    Mazzei, R.; Bermudez, G. Garcia; Chappa, V.C.; Grosso, M.F. del; Fernandez, A.

    2006-01-01

    Poly(propylene) foils were irradiated with Ag ions and then chemically etched to produce samples with structured surfaces. After the etching procedure the active sites that remain on the latent track were used to graft acrylic acid. Nuclear tracks before grafting were visualised using a transmission electron microscope. The grafting yields were determined by weight measurements as a function of ion fluence, etching and grafting time, and were also analysed using Fourier transform infrared spectroscopy. Both measurements suggest that the acrylic acid was grafted on etched tracks using the active sites produced by the swift heavy ion beam

  10. Grafting on nuclear tracks using the active sites that remain after the etching process

    Energy Technology Data Exchange (ETDEWEB)

    Mazzei, R. [Unidad de Aplicaciones Tecnologicas y Agropecuarias, CNEA, 1429 Buenos Aires (Argentina) and Universidad Tecnologica Nacional, Buenos Aires (Argentina)]. E-mail: mazzei@cae.cnea.gov.ar; Bermudez, G. Garcia [U. A. de Fisica, Tandar, CNEA, 1429 Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, UNSAM, 1653 Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Chappa, V.C. [U. A. de Fisica, Tandar, CNEA, 1429 Buenos Aires (Argentina); Grosso, M.F. del [U. A. de Fisica, Tandar, CNEA, 1429 Buenos Aires (Argentina); U. A. de Materiales, CNEA, 1429 Buenos Aires (Argentina); Fernandez, A. [Universidad Tecnologica Nacional, Buenos Aires (Argentina)

    2006-09-15

    Poly(propylene) foils were irradiated with Ag ions and then chemically etched to produce samples with structured surfaces. After the etching procedure the active sites that remain on the latent track were used to graft acrylic acid. Nuclear tracks before grafting were visualised using a transmission electron microscope. The grafting yields were determined by weight measurements as a function of ion fluence, etching and grafting time, and were also analysed using Fourier transform infrared spectroscopy. Both measurements suggest that the acrylic acid was grafted on etched tracks using the active sites produced by the swift heavy ion beam.

  11. High electronegativity multi-dipolar electron cyclotron resonance plasma source for etching by negative ions

    DEFF Research Database (Denmark)

    Stamate, Eugen; Draghici, M.

    2012-01-01

    A large area plasma source based on 12 multi-dipolar ECR plasma cells arranged in a 3 x 4 matrix configuration was built and optimized for silicon etching by negative ions. The density ratio of negative ions to electrons has exceeded 300 in Ar/SF6 gas mixture when a magnetic filter was used...... to reduce the electron temperature to about 1.2 eV. Mass spectrometry and electrostatic probe were used for plasma diagnostics. The new source is free of density jumps and instabilities and shows a very good stability for plasma potential, and the dominant negative ion species is F-. The magnetic field...... in plasma volume is negligible and there is no contamination by filaments. The etching rate by negative ions measured in Ar/SF6/O-2 mixtures was almost similar with that by positive ions reaching 700 nm/min. (C) 2012 American Institute of Physics...

  12. Etching and oxidation of InAs in planar inductively coupled plasma

    Energy Technology Data Exchange (ETDEWEB)

    Dultsev, F.N., E-mail: fdultsev@thermo.isp.nsc.ru [Institute of Semiconductor Physics SB RAS, Lavrentiev av. 13, Novosibirsk 630090 (Russian Federation); Kesler, V.G. [Institute of Semiconductor Physics SB RAS, Lavrentiev av. 13, Novosibirsk 630090 (Russian Federation)

    2009-10-15

    The surface of InAs (1 1 1)A was investigated under plasmachemical etching in the gas mixture CH{sub 4}/H{sub 2}/Ar. Etching was performed using the RF (13.56 MHz) and ICP plasma with the power 30-150 and 50-300 W, respectively; gas pressure in the reactor was 3-10 mTorr. It was demonstrated that the composition of the subsurface layer less than 5 nm thick changes during plasmachemical etching. A method of deep etching of InAs involving ICP plasma and hydrocarbon based chemistry providing the conservation of the surface relief is proposed. Optimal conditions and the composition of the gas phase for plasmachemical etching ensuring acceptable etch rates were selected.

  13. Etching and oxidation of InAs in planar inductively coupled plasma

    Science.gov (United States)

    Dultsev, F. N.; Kesler, V. G.

    2009-10-01

    The surface of InAs (1 1 1)A was investigated under plasmachemical etching in the gas mixture CH 4/H 2/Ar. Etching was performed using the RF (13.56 MHz) and ICP plasma with the power 30-150 and 50-300 W, respectively; gas pressure in the reactor was 3-10 mTorr. It was demonstrated that the composition of the subsurface layer less than 5 nm thick changes during plasmachemical etching. A method of deep etching of InAs involving ICP plasma and hydrocarbon based chemistry providing the conservation of the surface relief is proposed. Optimal conditions and the composition of the gas phase for plasmachemical etching ensuring acceptable etch rates were selected.

  14. Etching and oxidation of InAs in planar inductively coupled plasma

    International Nuclear Information System (INIS)

    Dultsev, F.N.; Kesler, V.G.

    2009-01-01

    The surface of InAs (1 1 1)A was investigated under plasmachemical etching in the gas mixture CH 4 /H 2 /Ar. Etching was performed using the RF (13.56 MHz) and ICP plasma with the power 30-150 and 50-300 W, respectively; gas pressure in the reactor was 3-10 mTorr. It was demonstrated that the composition of the subsurface layer less than 5 nm thick changes during plasmachemical etching. A method of deep etching of InAs involving ICP plasma and hydrocarbon based chemistry providing the conservation of the surface relief is proposed. Optimal conditions and the composition of the gas phase for plasmachemical etching ensuring acceptable etch rates were selected.

  15. A novel non-sequential hydrogen-pulsed deep reactive ion etching of silicon

    International Nuclear Information System (INIS)

    Gharooni, M; Mohajerzadeh, A; Sandoughsaz, A; Khanof, S; Mohajerzadeh, S; Asl-Soleimani, E

    2013-01-01

    A non-sequential pulsed-mode deep reactive ion etching of silicon is reported that employs continuous etching and passivation based on SF 6 and H 2 gases. The passivation layer, as an important step for deep vertical etching of silicon, is feasible by hydrogen pulses in proper time-slots. By adjusting the etching parameters such as plasma power, H 2 and SF 6 flows and hydrogen pulse timing, the process can be controlled for minimum underetch and high etch-rate at the same time. High-aspect-ratio features can be realized with low-density plasma power and by controlling the reaction chemistry. The so-called reactive ion etching lag has been minimized by operating the reactor at higher pressures. X-ray photoelectron spectroscopy and scanning electron microscopy have been used to study the formation of the passivation layer and the passivation mechanism. (paper)

  16. Surfactant-enhanced control of track-etch pore morphology

    International Nuclear Information System (INIS)

    Apel', P.Yu.; Blonskaya, I.V.; Didyk, A.Yu.; Dmitriev, S.N.; Orelovich, O.L.; Samojlova, L.I.; Vutsadakis, V.A.; Root, D.

    2000-01-01

    The influence of surfactants on the process of chemical development of ion tracks in polymers is studied. Based on the experimental data, a mechanism of the surfactant effect on the track-etch pore morphology is proposed. In the beginning of etching the surfactant is adsorbed on the surface and creates a layer that is quasi-solid and partially protects the surface from the etching agent. However, some etchant molecules diffuse through the barrier and react with the polymer surface. This results in the formation of a small hole at the entrance to the ion track. After the hole has attained a few annometers in diameter, the surfactant molecules penetrate into the track and cover its walls. Further diffusion of the surfactant into the growing pore is hindered. The adsorbed surfactant layer is not permeable for large molecules. In contrast, small alkali molecules and water molecules diffuse into the track and provide the etching process enlarging the pore. At this stage the transport of the surfactant into the pore channel can proceed only due to the lateral diffusion in the adsorbed layer. The volume inside the pore is free of surfactant molecules and grows at a higher rate than pore entrance. After a more prolonged etching the bottle-like (or 'cigar-like') pore channels are formed. The bottle-like shape of the pore channels depends on the etching conditions such as alkali and surfactant concentration, temperature, and type of the surfactant. The use of surfactants enables one to produce track-etch membranes with improved flow rate characteristics compared with those having cylindrical pores with the same nominal pore diameters

  17. Dosimetric measurement of the disintegration rate of fission products

    International Nuclear Information System (INIS)

    Solymosi, J.; Nagy, L.G.; Zagyvai, P.

    1992-01-01

    Investigations on the disintegration rate of fission products of 238 U and 239 Pu are presented. The intensity of the β-and γ-radiation of fission products were measured continously in an interval of 1-1300 hours following the fission, offering the possibility for determining the general and specific characteristics of the individual fission products. A universal measuring procedure was elaborated for the rapid in situ determination of the dosimetric features of fission products, which is suitable for the accurate evaluation and prediction of external absorbed dose even in case of fission products of various origin and unknown composition. (author) 6 refs.; 7 figs.; 1 tab

  18. Miniature electron bombardment evaporation source: evaporation rate measurement

    International Nuclear Information System (INIS)

    Nehasil, V.; Masek, K.; Matolin, V.; Moreau, O.

    1997-01-01

    Miniature electron beam evaporation sources which operate on the principle of vaporization of source material, in the form of a tip, by electron bombardment are produced by several companies specialized in UHV equipment. These sources are used primarily for materials that are normally difficult to deposit due to their high evaporation temperature. They are appropriate for special applications such as heteroepitaxial thin film growth requiring a very low and well controlled deposition rate. A simple and easily applicable method of evaporation rate control is proposed. The method is based on the measurement of ion current produced by electron bombardment of evaporated atoms. The absolute evaporation flux values were measured by means of the Bayard-Alpert ion gauge, which enabled the ion current vs evaporation flux calibration curves to be plotted. (author). 1 tab., 4 figs., 6 refs

  19. In situ measurements of thoron exhalation rate in Okinawa (Japan)

    International Nuclear Information System (INIS)

    Shiroma, Y.; Isa, N.; Hosoda, M.; Sorimachi, A.; Ishikawa, T.; Tokonami, S.; Furukawa, M.

    2010-01-01

    Thoron exhalation rates from the ground surface were measured at 57 sites on Okinawa Island (Japan), using a ZnS(Ag) scintillation detector equipped with photomultiplier. The arithmetic means ± SD, median ± SD, minimum and maximum of the rates (unit: Bq m -2 s -1 ) were estimated to be 1.9 ± 1.4, 1.6 ± 0.3, 0.04 and 6.2, respectively. The soils distributed on the island are generally classified into dark red soils, residual regosols, as well as red and yellow soils. While it was assumed that the soils were originated from the bedrock, recent studies suggested that the main material of dark red soils is the East Asian eolian dust. In the dark red soils area, the exhalation rate is relatively higher than that in the other areas. This suggested that the eolian dust was an enhancer for the environmental thoron concentration on Okinawa Island. (authors)

  20. Etching mechanism of niobium in coaxial Ar/Cl2 radio frequency plasma

    International Nuclear Information System (INIS)

    Upadhyay, J.; Im, Do; Popović, S.; Vušković, L.; Valente-Feliciano, A.-M.; Phillips, L.

    2015-01-01

    The understanding of the Ar/Cl 2 plasma etching mechanism is crucial for the desired modification of inner surface of the three dimensional niobium (Nb) superconductive radio frequency cavities. Uniform mass removal in cylindrical shaped structures is a challenging task because the etch rate varies along the direction of gas flow. The study is performed in the asymmetric coaxial radio-frequency (rf) discharge with two identical Nb rings acting as a part of the outer electrode. The dependence of etch rate uniformity on pressure, rf power, dc bias, Cl 2 concentration, diameter of the inner electrode, temperature of the outer cylinder, and position of the samples in the structure is determined. To understand the plasma etching mechanisms, we have studied several factors that have important influence on the etch rate and uniformity, which include the plasma sheath potential, Nb surface temperature, and the gas flow rate

  1. Etching mechanism of niobium in coaxial Ar/Cl2 radio frequency plasma

    Energy Technology Data Exchange (ETDEWEB)

    Upadhyay, Janardan [Old Dominion Univ., Norfolk, VA (United States); Im, Do [Old Dominion Univ., Norfolk, VA (United States); Popovic, Svetozar [Old Dominion Univ., Norfolk, VA (United States); Valente-Feliciano, Anne -Marie [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Phillips, H. Larry [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Vuskovic, Leposova [Old Dominion Univ., Norfolk, VA (United States)

    2015-03-18

    The understanding of the Ar/Cl2 plasma etching mechanism is crucial for the desired modification of inner surface of the three dimensional niobium (Nb) superconductive radio frequency cavities. Uniform mass removal in cylindrical shaped structures is a challenging task because the etch rate varies along the direction of gas flow. The study is performed in the asymmetric coaxial radio-frequency (rf) discharge with two identical Nb rings acting as a part of the outer electrode. The dependence of etch rate uniformity on pressure, rf power, dc bias, Cl2 concentration, diameter of the inner electrode, temperature of the outer cylinder, and position of the samples in the structure is determined. Furthermore, to understand the plasma etching mechanisms, we have studied several factors that have important influence on the etch rate and uniformity, which include the plasma sheath potential, Nb surface temperature, and the gas flow rate.

  2. Comparison between Medgem and Deltatrac resting metabolic rate measurements.

    Science.gov (United States)

    Compher, C; Hise, M; Sternberg, A; Kinosian, B P

    2005-10-01

    The primary aims of this trial were to evaluate the reproducibility of a portable handheld calorimeter (Medgem) in a clinical population, and to compare its measures with a calorimeter in typical use with these patients. Cross-sectional clinical validation study. Outpatient Clinical Research Center. A total of 24 stable home nutrition support patients. In random order three measures of resting metabolic rate (RMR) were taken after a 4-h fast, 15 min rest and 2-h abstention from exercise. Two measures were taken with the same Medgem (MG) and one with the traditional calorimeter (Deltatrac). Reproducibility of MG measures and their comparability to a Deltatrac measure were assessed by Bland-Altman analysis, with >+/-250 kcal/day established a priori as a clinically unacceptable error. In addition, disagreement between the two types of measures was defined as greater than 10% difference. The mean difference between two MG measures was -6.8 kcal/day, with limits of agreement between 233 and -247 kcal/day and clinically acceptable. The mean difference between the Deltatrac and mean of two MG measures was -162 kcal/day, with limits of agreement between 577 and -253 kcal/day and clinically unacceptable. In all, 80% of the repeated MG RMR measures agreed within 10%, and the mean MG reading agreed with the Deltatrac in 60% of cases. RMR obtained using the MG calorimeter has an acceptable degree of reproducibility, and is acceptable to patients. The MG measures, however, are frequently lower than traditional measures and require further validation prior to application to practice in this vulnerable patient group.

  3. Measurement of soluble nuclide dissolution rates from spent fuel

    International Nuclear Information System (INIS)

    Wilson, C.N.; Gray, W.J.

    1990-01-01

    Gaining a better understanding of the potential release behavior of water-soluble radionuclides is the focus of new laboratory spent fuel dissolution studies being planned in support of the Yucca Mountain Project. Previous studies have suggested that maximum release rates for actinide nuclides, which account for most of the long-term radioactivity in spent fuel, should be solubility-limited and should not depend on the characteristics or durability of the spent fuel waste form. Maximum actinide concentrations should be sufficiently low to meet the NRC (Nuclear Regulatory Commission) annual release limits. Potential release rates for soluble nuclides such as 99 Tc, 135 Cs, 14 C and 129 I, which account for about 1-2% of the activity in spent fuel at 1,000 years, are less certain and may depend on processes such as oxidation of the fuel in the repository air environment. Dissolution rates for several soluble nuclides have been measured from spent fuel specimens using static and semi-static methods. However, such tests do not provide a direct measurement of fuel matrix dissolution rates that may ultimately control soluble-nuclide release rates. Flow-through tests are being developed as a potential supplemental method for determining the matrix component of soluble-nuclide dissolution. Advantages and disadvantages of both semi-static and flow-through methods are discussed. Tests with fuel specimens representing a range of potential fuel states that may occur in the repository, including oxidized fuel, are proposed. Preliminary results from flow-through tests with unirradiated UO 2 suggesting that matrix dissolution rates are very sensitive to water composition are also presented

  4. Laser etching as an alternative

    International Nuclear Information System (INIS)

    Dreyfus, R.W.; Kelly, R.

    1989-01-01

    Atoms and molecules are removed from surfaces by intense laser beams. This fact has been known almost since the discovery of the laser. Within the present overall area of interest, namely understanding ion-beam-induced sputtering, it is equally important both to contrast laser etching to ion sputtering and to understand the underlying physics taking place during laser etching. Beyond some initial broad observations, the specific discussion is limited to, and aimed at, two areas: (i) short wavelength, UV, laser-pulse effects and (ii) energy fluences sufficiently small that only monolayers (and not microns) of material are removed per pulse. 38 refs.; 13 figs.; 5 tabs

  5. Measurement of sulfur dioxide oxidation rates in wintertime orographic clouds

    International Nuclear Information System (INIS)

    Snider, J.R.

    1990-01-01

    SO2-reaction studies in the clouds are examined and summarized to experimentally confirm model predictions and previous field studies regarding dominant SO2-reaction pathways. Controlled amounts of SO2 were released into nonprecipitating orographic clouds, and sulfate yields are compared to oxidant depletions. The sulfate yields were taken from cloud-water samples and liquid-water-concentration measurements, and oxidant-depletion data were generated from continuous gas-phase measurements. Comparisons of Y sub SO4 and D sub H2O2 suggest that H2O2 is the dominant oxidant, and the in-cloud reaction between H2O2 and the bisulfite ion can be expressed by a simple rate that agrees with predictions and laboratory results. The rate measurements are found to be inconsistent with the rate law proposed by Hegg and Hobbs (1982) and with some observational data. The present conclusions are of interest to evaluating the effects of sulfur dioxide emissions on sulfuric acid deposition. 30 refs

  6. Etching of enamel for direct bonding with a thulium fiber laser

    Science.gov (United States)

    Kabaş Sarp, Ayşe S.; Gülsoy, Murat

    2011-03-01

    Background: Laser etching of enamel for direct bonding can decrease the risk of surface enamel loss and demineralization which are the adverse effects of acid etching technique. However, in excess of +5.5°C can cause irreversible pulpal responses. In this study, a 1940- nm Thulium Fiber Laser in CW mode was used for laser etching. Aim: Determination of the suitable Laser parameters of enamel surface etching for direct bonding of ceramic brackets and keeping that intrapulpal temperature changes below the threshold value. Material and Method: Polycrystalline ceramic orthodontic brackets were bonded on bovine teeth by using 2 different kinds of etching techniques: Acid and Laser Etching. In addition to these 3 etched groups, there was also a group which was bonded without etching. Brackets were debonded with a material testing machine. Breaking time and the load at the breaking point were measured. Intrapulpal temperature changes were recorded by a K-type Thermocouple. For all laser groups, intrapulpal temperature rise was below the threshold value of 5.5°C. Results and Conclusion: Acid-etched group ( 11.73 MPa) significantly required more debonding force than 3- second- irradiated ( 5.03 MPa) and non-etched groups ( 3.4 MPa) but the results of acid etched group and 4- second- irradiated group (7.5 MPa) showed no significant difference. Moreover, 4- second irradiated group was over the minimum acceptable value for clinical use. Also, 3- second lasing caused a significant reduction in time according to acid-etch group. As a result, 1940- nm laser irradiation is a promising method for laser etching.

  7. The etching property of the surface of CR-39 and the track core radius of fission fragment

    CERN Document Server

    Mineyama, D; Yamauchi, T; Oda, K; El-Rahman, A

    2002-01-01

    The etch pits of fission fragments in CR-39 detector have been observed carefully using an atomic force microscope (AFM) after extremely short chemical etching in stirred 6N KOH solution kept at 70degC. It was found that there existed a thin layer where the bulk etch rate is relativity from large the etch-pit growth curve for the etching duration between 10 and 1800 seconds. The track core radius of fission fragment was evaluated to be about 6 nm from the extrapolation of the growth curve in a thinner region. (author)

  8. High density plasma via hole etching in SiC

    International Nuclear Information System (INIS)

    Cho, H.; Lee, K.P.; Leerungnawarat, P.; Chu, S.N.G.; Ren, F.; Pearton, S.J.; Zetterling, C.-M.

    2001-01-01

    Throughwafer vias up to 100 μm deep were formed in 4H-SiC substrates by inductively coupled plasma etching with SF 6 /O 2 at a controlled rate of ∼0.6 μm min-1 and use of Al masks. Selectivities of >50 for SiC over Al were achieved. Electrical (capacitance-voltage: current-voltage) and chemical (Auger electron spectroscopy) analysis techniques showed that the etching produced only minor changes in reverse breakdown voltage, Schottky barrier height, and near surface stoichiometry of the SiC and had high selectivity over common frontside metallization. The SiC etch rate was a strong function of the incident ion energy during plasma exposure. This process is attractive for power SiC transistors intended for high current, high temperature applications and also for SiC micromachining

  9. Solvent composition of one-step self-etch adhesives and dentine wettability.

    Science.gov (United States)

    Grégoire, Geneviève; Dabsie, Firas; Dieng-Sarr, Farimata; Akon, Bernadette; Sharrock, Patrick

    2011-01-01

    Our aim was to determine the wettability of dentine by four commercial self-etch adhesives and evaluate their spreading rate on the dentine surface. Any correlation with chemical composition was sought, particularly with the amount of solvent or HEMA present in the adhesive. The adhesives used were AdheSE One, Optibond All.In.One, Adper Easy Bond and XenoV. Chemical compositions were determined by proton nuclear magnetic resonance (NMR) spectroscopy of the adhesives dissolved in dimethylsulfoxide. Apparent contact angles for sessile drops of adhesives were measured on dentine slices as a function of time for up to 180s. The water contact angles were determined for fully polymerised adhesives. All adhesives were water-based with total solvent contents ranging from 27% to 73% for HEMA-free adhesives, and averaging 45% for HEMA containing adhesives. The contents in hydrophobic groups decreased as water contents increased. No differences were found in the adhesive contact angles after 180s even though the spreading rates were different for the products tested. Water contact angles differed significantly but were not correlated with HEMA or solvent presence. Manufacturers use different approaches to stabilise acid co-monomer ingredients in self-etch adhesives. Co-solvents, HEMA, or acrylamides without co-solvents are used to simultaneously etch and infiltrate dentine. A large proportion of water is necessary for decalcification action. Copyright © 2010 Elsevier Ltd. All rights reserved.

  10. Measurement of blowdown flow rates using load cells

    International Nuclear Information System (INIS)

    Dolas, P.K.; Venkat Raj, V.; Ghosh, A.K.; Murty, L.G.K.; Muralidhar Rao, S.

    1980-01-01

    To establish a reliable method for measuring two-phase flow, experiments were planned for measurement of transient single phase flow rates from vessels using load cells. Suitability of lead-zirconate-titanate piezoelectric ceramic discs was examined. Discharge time constant of the disc used was low, leading to large measurement errors. Subsequently, experiments were carried out using strain gauge load cells and these were found satisfactory. The unsteady flow equation has been derived for the system under investigation. The equation has been solved numerically using the fourth order Runge-Kutta method and also by integrating it analytically. The experimental results are compared with the theoretical results and presented in this report. (auth.)

  11. Constrained independent component analysis approach to nonobtrusive pulse rate measurements

    Science.gov (United States)

    Tsouri, Gill R.; Kyal, Survi; Dianat, Sohail; Mestha, Lalit K.

    2012-07-01

    Nonobtrusive pulse rate measurement using a webcam is considered. We demonstrate how state-of-the-art algorithms based on independent component analysis suffer from a sorting problem which hinders their performance, and propose a novel algorithm based on constrained independent component analysis to improve performance. We present how the proposed algorithm extracts a photoplethysmography signal and resolves the sorting problem. In addition, we perform a comparative study between the proposed algorithm and state-of-the-art algorithms over 45 video streams using a finger probe oxymeter for reference measurements. The proposed algorithm provides improved accuracy: the root mean square error is decreased from 20.6 and 9.5 beats per minute (bpm) for existing algorithms to 3.5 bpm for the proposed algorithm. An error of 3.5 bpm is within the inaccuracy expected from the reference measurements. This implies that the proposed algorithm provided performance of equal accuracy to the finger probe oximeter.

  12. Field measurement and interpretation of beta doses and dose rates

    International Nuclear Information System (INIS)

    Selby, J.M.; Swinth, K.L.; Hooker, C.D.; Kenoyer, J.L.

    1983-01-01

    A large number of portable survey instruments employing G.M., ionization chamber, and scintillation detectors used for gamma measurements are also used for monitoring in beta fields by using removable shields to separate the beta and gamma components of the radiation field. The difference does not correspond to an absorbed dose rate for the beta field due to a variety of factors. Among these factors are the dependence on beta energy, source-detector geometries, mixed fields and variable ambient conditions. Attempting to use such measurements directly can lead to errors as high as a factor of 100. Appropriate calibrations and correction factors can be used to reduce the errors in beta measurements to a tolerable level

  13. The influence of the laser spot size and the pulse number on laser-induced backside wet etching

    International Nuclear Information System (INIS)

    Boehme, R.; Zimmer, K.

    2005-01-01

    The laser-induced backside wet etching (LIBWE) of transparent solids at the interface to absorbing liquid is a new promising method for laser microstructuring. The influence of the laser spot size and the applied pulse number to the etch rate were investigated in detail for fused silica and two different liquids. Additional to the significant rise of the etch rate with increasing spot size considerable incubation effects have been observed at low laser fluences and pulse numbers. Based on the bubble formation during LIBWE processing, a relation between the bubble collapse time and the etch rate was ascertained. This relation fits the etch rate dependence on the spot size well. It is assumed that the deposition of decomposition products from the bubble accounts for the spot size influence the etch rate

  14. Measurements of astrophysical reaction rates for radioactive samples

    International Nuclear Information System (INIS)

    Koehler, P.E.; O'Brien, H.A.; Bowman, C.D.

    1987-01-01

    Reaction rates for both big-bang and stellar nucleosynthesis can be obtained from the measurement of (n,p) and (n,γ) cross sections for radioactive nuclei. In the past, large backgrounds associated with the sample activity limited these types of measurements to radioisotopes with very long half lives. The advent of the low-energy, high-intensity neutron source at the Los Alamos Neutron Scattering CEnter (LANSCE) has greatly increased the number of nuclei which can be studied. Results of (n,p) measurements on samples with half lives as short as fifty-three days will be given. The astrophysics to be learned from these data will be discussed. Additional difficulties are encountered when making (n,γ) rather than (n,p) measurements. However, with a properly designed detector, and with the high peak neutron intensities now available, (n,γ) measurements can be made for nuclei with half lives as short as several weeks. Progress on the Los Alamos (n,γ) cross-section measurement program for radioactive samples will be discussed. 25 refs., 3 figs., 1 tab

  15. A new high rate positron lifetime measurement system

    International Nuclear Information System (INIS)

    Bedwell, M.O.; Paulus, T.J.

    1979-01-01

    Positron lifetime measuring system, a technique to perform non-destructive studies on the internal structure of materials, has many components common to those used for nuclear time spectroscopy systems. In each case, a timing coincidence curve is measured for the energy range of interest, and this is accomplished in a typical timing coincidence system. The paper first describes the conventional timing coincidence system, then a new fast timing system is introduced. Comparing to the conventional fast/slow timing system, the fast timing technique offers reduced complexity, lower system cost, and improved high data rate capability. Experimental results show that the FWHM timing resolution ranges from 190 ps for a 1.1 : 1 dynamic range to 337 ps for a 100 : 1 dynamic range of signals with 60 Co. As for the timing resolution as a function of energy, the FWHM resolution for each channel ranges from 124 ps at 1 MeV to 400 ps at 100 keV. Since the excellent timing performance is maintained even at very high input rate, the experimenters can use much more active sources to increase the true coincidence rate and reduce data accumulation time. This method has the added advantage of minimizing long term drift effects since the experiments can be conducted in less time. (Wakatsuki, Y.)

  16. Measurements of waste tank passive ventilation rates using tracer gases

    International Nuclear Information System (INIS)

    Huckaby, J.L.; Olsen, K.B.; Sklarew, D.S.; Evans, J.C.; Remund, K.M.

    1997-09-01

    This report presents the results of ventilation rate studies of eight passively ventilated high-level radioactive waste tanks using tracer gases. Head space ventilation rates were determined for Tanks A-101, AX-102, AX-103, BY-105, C-107, S-102, U-103, and U-105 using sulfur hexafluoride (SF 6 ) and/or helium (He) as tracer gases. Passive ventilation rates are needed for the resolution of several key safety issues. These safety issues are associated with the rates of flammable gas production and ventilation, the rates at which organic salt-nitrate salt mixtures dry out, and the estimation of organic solvent waste surface areas. This tracer gas study involves injecting a tracer gas into the tank headspace and measuring its concentration at different times to establish the rate at which the tracer is removed by ventilation. Tracer gas injection and sample collection were performed by SGN Eurisys Service Corporation and/or Lockheed Martin Hanford Corporation, Characterization Project Operations. Headspace samples were analyzed for He and SF 6 by Pacific Northwest National Laboratory (PNNL). The tracer gas method was first demonstrated on Tank S-102. Tests were conducted on Tank S-102 to verify that the tracer gas was uniformly distributed throughout the tank headspace before baseline samples were collected, and that mixing was sufficiently vigorous to maintain an approximately uniform distribution of tracer gas in the headspace during the course of the study. Headspace samples, collected from a location about 4 in away from the injection point and 15, 30, and 60 minutes after the injection of He and SF 6 , indicated that both tracer gases were rapidly mixed. The samples were found to have the same concentration of tracer gases after 1 hour as after 24 hours, suggesting that mixing of the tracer gas was essentially complete within 1 hour

  17. Advanced Simulation Technology to Design Etching Process on CMOS Devices

    Science.gov (United States)

    Kuboi, Nobuyuki

    2015-09-01

    Prediction and control of plasma-induced damage is needed to mass-produce high performance CMOS devices. In particular, side-wall (SW) etching with low damage is a key process for the next generation of MOSFETs and FinFETs. To predict and control the damage, we have developed a SiN etching simulation technique for CHxFy/Ar/O2 plasma processes using a three-dimensional (3D) voxel model. This model includes new concepts for the gas transportation in the pattern, detailed surface reactions on the SiN reactive layer divided into several thin slabs and C-F polymer layer dependent on the H/N ratio, and use of ``smart voxels''. We successfully predicted the etching properties such as the etch rate, polymer layer thickness, and selectivity for Si, SiO2, and SiN films along with process variations and demonstrated the 3D damage distribution time-dependently during SW etching on MOSFETs and FinFETs. We confirmed that a large amount of Si damage was caused in the source/drain region with the passage of time in spite of the existing SiO2 layer of 15 nm in the over etch step and the Si fin having been directly damaged by a large amount of high energy H during the removal step of the parasitic fin spacer leading to Si fin damage to a depth of 14 to 18 nm. By analyzing the results of these simulations and our previous simulations, we found that it is important to carefully control the dose of high energy H, incident energy of H, polymer layer thickness, and over-etch time considering the effects of the pattern structure, chamber-wall condition, and wafer open area ratio. In collaboration with Masanaga Fukasawa and Tetsuya Tatsumi, Sony Corporation. We thank Mr. T. Shigetoshi and Mr. T. Kinoshita of Sony Corporation for their assistance with the experiments.

  18. Guidelines for etching silicon MEMS structures using fluorine high-density plasmas at cryogenic temperatures

    NARCIS (Netherlands)

    de Boer, Meint J.; Gardeniers, Johannes G.E.; Jansen, Henricus V.; Gilde, M.J.; Roelofs, Gerard; Sasserath, Jay N.; Elwenspoek, Michael Curt

    This paper presents guidelines for the deep reactive ion etching (DRIE) of silicon MEMS structures, employing SF6/O2-based high-density plasmas at cryogenic temperatures. Procedures of how to tune the equipment for optimal results with respect to etch rate and profile control are described. Profile

  19. Neutron dosimetry using electrochemical etching

    International Nuclear Information System (INIS)

    Su, S.J.; Stillwagon, G.B.; Morgan, K.Z.

    1977-01-01

    Registration of α-tracks and fast-neutron-induced recoils tracks by the electrochemical etching technique as applied to sensitive polymer foils (e.g., polycarbonate) provides a simple, sensitive and inexpensive means of fast neutron personnel dosimetry as well as a valuable research tool for microdosimetry. When tracks were amplified by our electrochemical technique and the etching results compared with conventional etching technique a striking difference was noted. The electrochemically etched tracks were of much larger diameter (approx. 100 μm) and gave superior contrast. Two optical devices--the transparency projector and microfiche reader--were adapted to facilitate counting of the tracks appearing on our polycarbonate foils. The projector produced a magnification of 14X for a screen to projector distance of 5.0 meter and read's magnification was 50X. A Poisson distribution was determined for the number of tracks located in a particular area of the foil and experimentally verified by random counting of quarter sections of the microfiche reader screen. Finally, in an effort to determine dose equivalent (rem), a conversion factor is being determined by finding the sensitivity response (tracks/neutron) of recoil particle induced tracks as a function of monoenergetic fast neutrons and comparing results with those obtained by others

  20. Liquid droplet sensing using twisted optical fiber couplers fabricated by hydrofluoric acid flow etching

    Science.gov (United States)

    Son, Gyeongho; Jung, Youngho; Yu, Kyoungsik

    2017-04-01

    We report a directional-coupler-based refractive index sensor and its cost-effective fabrication method using hydrofluoric acid droplet wet-etching and surface-tension-driven liquid flows. The proposed fiber sensor consists of a pair of twisted tapered optical fibers with low excess losses. The fiber cores in the etched microfiber region are exposed to the surrounding medium for efficient interaction with the guided light. We observe that the etching-based low-loss fiber-optic sensors can measure the water droplet volume by detecting the refractive index changes of the surrounding medium around the etched fiber core region.

  1. Scale factor measure method without turntable for angular rate gyroscope

    Science.gov (United States)

    Qi, Fangyi; Han, Xuefei; Yao, Yanqing; Xiong, Yuting; Huang, Yuqiong; Wang, Hua

    2018-03-01

    In this paper, a scale factor test method without turntable is originally designed for the angular rate gyroscope. A test system which consists of test device, data acquisition circuit and data processing software based on Labview platform is designed. Taking advantage of gyroscope's sensitivity of angular rate, a gyroscope with known scale factor, serves as a standard gyroscope. The standard gyroscope is installed on the test device together with a measured gyroscope. By shaking the test device around its edge which is parallel to the input axis of gyroscope, the scale factor of the measured gyroscope can be obtained in real time by the data processing software. This test method is fast. It helps test system miniaturized, easy to carry or move. Measure quarts MEMS gyroscope's scale factor multi-times by this method, the difference is less than 0.2%. Compare with testing by turntable, the scale factor difference is less than 1%. The accuracy and repeatability of the test system seems good.

  2. Process Measurement Deviation Analysis for Flow Rate due to Miscalibration

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Eunsuk; Kim, Byung Rae; Jeong, Seog Hwan; Choi, Ji Hye; Shin, Yong Chul; Yun, Jae Hee [KEPCO Engineering and Construction Co., Deajeon (Korea, Republic of)

    2016-10-15

    An analysis was initiated to identify the root cause, and the exemption of high static line pressure correction to differential pressure (DP) transmitters was one of the major deviation factors. Also the miscalibrated DP transmitter range was identified as another major deviation factor. This paper presents considerations to be incorporated in the process flow measurement instrumentation calibration and the analysis results identified that the DP flow transmitter electrical output decreased by 3%. Thereafter, flow rate indication decreased by 1.9% resulting from the high static line pressure correction exemption and measurement range miscalibration. After re-calibration, the flow rate indication increased by 1.9%, which is consistent with the analysis result. This paper presents the brief calibration procedures for Rosemount DP flow transmitter, and analyzes possible three cases of measurement deviation including error and cause. Generally, the DP transmitter is required to be calibrated with precise process input range according to the calibration procedure provided for specific DP transmitter. Especially, in case of the DP transmitter installed in high static line pressure, it is important to correct the high static line pressure effect to avoid the inherent systematic error for Rosemount DP transmitter. Otherwise, failure to notice the correction may lead to indicating deviation from actual value.

  3. Measurement of gastric emptying rate in humans. Simplified scanning method

    Energy Technology Data Exchange (ETDEWEB)

    Holt, S.; Colliver, J.; Guram, M.; Neal, C.; Verhulst, S.J.; Taylor, T.V. (Univ. of South Carolina School of Medicine, Columbia (USA))

    1990-11-01

    Simultaneous measurements of the gastric emptying rate of the solid and liquid phase of a dual-isotope-labeled test meal were made using a gamma camera and a simple scintillation detector, similar to that used in a hand-held probe. A simple scanning apparatus, similar to that used in a hand-held scintillation probe, was compared with simultaneous measurements made by a gamma camera in 16 healthy males. A dual-labeled test meal was utilized to measure liquid and solid emptying simultaneously. Anterior and posterior scans were taken at intervals up to 120 min using both a gamma camera and the scintillation probe. Good relative agreement between the methods was obtained both for solid-phase (correlation range 0.92-0.99, mean 0.97) and for liquid-phase data (correlation range 0.93-0.99, mean 0.97). For solid emptying data regression line slopes varied from 0.75 to 1.03 (mean 0.84). Liquid emptying data indicated that slopes ranged from 0.71 to 1.06 (mean 0.87). These results suggested that an estimate of the gamma measurement could be obtained by multiplying the scintillation measurement by a factor of 0.84 for the solid phase and 0.87 for the liquid phase. Correlation between repeat studies was 0.97 and 0.96 for solids and liquids, respectively. The application of a hand-held probe technique provides a noninvasive and inexpensive method for accurately assessing solid- and liquid-phase gastric emptying from the human stomach that correlates well with the use of a gamma camera, within the range of gastric emptying rate in the normal individuals in this study.

  4. Measurement of gastric emptying rate in humans. Simplified scanning method

    International Nuclear Information System (INIS)

    Holt, S.; Colliver, J.; Guram, M.; Neal, C.; Verhulst, S.J.; Taylor, T.V.

    1990-01-01

    Simultaneous measurements of the gastric emptying rate of the solid and liquid phase of a dual-isotope-labeled test meal were made using a gamma camera and a simple scintillation detector, similar to that used in a hand-held probe. A simple scanning apparatus, similar to that used in a hand-held scintillation probe, was compared with simultaneous measurements made by a gamma camera in 16 healthy males. A dual-labeled test meal was utilized to measure liquid and solid emptying simultaneously. Anterior and posterior scans were taken at intervals up to 120 min using both a gamma camera and the scintillation probe. Good relative agreement between the methods was obtained both for solid-phase (correlation range 0.92-0.99, mean 0.97) and for liquid-phase data (correlation range 0.93-0.99, mean 0.97). For solid emptying data regression line slopes varied from 0.75 to 1.03 (mean 0.84). Liquid emptying data indicated that slopes ranged from 0.71 to 1.06 (mean 0.87). These results suggested that an estimate of the gamma measurement could be obtained by multiplying the scintillation measurement by a factor of 0.84 for the solid phase and 0.87 for the liquid phase. Correlation between repeat studies was 0.97 and 0.96 for solids and liquids, respectively. The application of a hand-held probe technique provides a noninvasive and inexpensive method for accurately assessing solid- and liquid-phase gastric emptying from the human stomach that correlates well with the use of a gamma camera, within the range of gastric emptying rate in the normal individuals in this study

  5. The stratigraphic filter and bias in measurement of geologic rates

    Science.gov (United States)

    Schumer, Rina; Jerolmack, Douglas; McElroy, Brandon

    2011-01-01

    Erosion and deposition rates estimated from the stratigraphic record frequently exhibit a power-law dependence on measurement interval. This dependence can result from a power-law distribution of stratigraphic hiatuses. By representing the stratigraphic filter as a stochastic process called a reverse ascending ladder, we describe a likely origin of power-law hiatuses, and thus, rate scaling. While power-law hiatuses in certain environments can be a direct result of power-law periods of stasis (no deposition or erosion), they are more generally the result of randomness in surface fluctuations irrespective of mean subsidence or uplift. Autocorrelation in fluctuations can make hiatuses more or less heavy-tailed, but still exhibit power-law characteristics. In addition we show that by passing stratigraphic data backward through the filter, certain statistics of surface kinematics from their formative environments can be inferred.

  6. Bonding effectiveness of self-etch adhesives to dentin after 24 h water storage.

    Science.gov (United States)

    Sarr, Mouhamed; Benoist, Fatou Leye; Bane, Khaly; Aidara, Adjaratou Wakha; Seck, Anta; Toure, Babacar

    2018-01-01

    This study evaluated the immediate bonding effectiveness of five self-etch adhesive systems bonded to dentin. The microtensile bond strength of five self-etch adhesives systems, including one two-step and four one-step self-etch adhesives to dentin, was measured. Human third molars had their superficial dentin surface exposed, after which a standardized smear layer was produced using a medium-grit diamond bur. The selected adhesives were applied according to their respective manufacturer's instructions for μTBS measurement after storage in water at 37°C for 24 h. The μTBS varied from 11.1 to 44.3 MPa; the highest bond strength was obtained with the two-step self-etch adhesive Clearfil SE Bond and the lowest with the one-step self-etch adhesive Adper Prompt L-Pop. Pretesting failures mainly occurring during sectioning with the slow-speed diamond saw were observed only with the one-step self-etch adhesive Adper Prompt L-Pop (4 out of 18). When bonded to dentin, the self-etch adhesives with simplified application procedures (one-step self-etch adhesives) still underperform as compared to the two-step self-etch adhesive Clearfil SE Bond.

  7. The influence of chemical etching time on efficiency of radon detection using CR-39

    International Nuclear Information System (INIS)

    Reway, Adriana P.; Kappke, Jaqueline; Narloch, Danielle C.; Del Claro, Flavia; Paschuk, Sergei A.; Correa, Janine N.

    2015-01-01

    Natural radiation is the principal source of human exposure to ionizing radiation. Radon is noble radioactive gas that emanates from the soil and rocks entering the atmosphere of dwellings where it could be accumulated. The inhalation of 222 Rn represents a significant health risk. Solid-State Nuclear Track Detectors (SSNTD) represents an efficient method for alpha particle detection and measurements of the activity concentration of 222 Rn. The aim of present work was to study the etching time impact on CR-39 efficiency in radon activity measurements. The investigation was performed using 80 CR-39 detectors, which were exposed to a source of radon. After the exposition, alpha particle tracks development was achieved by chemical etching using 6.25M NaOH solution and ethanol (2%) at 70°C. Etching alpha particle tracks were identified and counted manually using the optical microscope with magnification of 100x and glass overlay mask. The etching time ranged from 7 to 14 hours. The results show that there is an increase in the number of visible tracks with increased etching time. The number of traces obtained for 7 hours and 8 hours of revelation was 1430 +/- 90 and 2090 +/- 160, respectively. However, for etching time of 13 and 14 hours was not observed statistical increase in the number of visible tracks. The number of tracks in this situation was 3630 +/- 180 and 3870 +/- 160 to 13 and 14 hours etching. Thus, for assumed etching parameters, the etching optimal time was observed 14 hours. (author)

  8. Accuracy assessment of high-rate GPS measurements for seismology

    Science.gov (United States)

    Elosegui, P.; Davis, J. L.; Ekström, G.

    2007-12-01

    Analysis of GPS measurements with a controlled laboratory system, built to simulate the ground motions caused by tectonic earthquakes and other transient geophysical signals such as glacial earthquakes, enables us to assess the technique of high-rate GPS. The root-mean-square (rms) position error of this system when undergoing realistic simulated seismic motions is 0.05~mm, with maximum position errors of 0.1~mm, thus providing "ground truth" GPS displacements. We have acquired an extensive set of high-rate GPS measurements while inducing seismic motions on a GPS antenna mounted on this system with a temporal spectrum similar to real seismic events. We found that, for a particular 15-min-long test event, the rms error of the 1-Hz GPS position estimates was 2.5~mm, with maximum position errors of 10~mm, and the error spectrum of the GPS estimates was approximately flicker noise. These results may however represent a best-case scenario since they were obtained over a short (~10~m) baseline, thereby greatly mitigating baseline-dependent errors, and when the number and distribution of satellites on the sky was good. For example, we have determined that the rms error can increase by a factor of 2--3 as the GPS constellation changes throughout the day, with an average value of 3.5~mm for eight identical, hourly-spaced, consecutive test events. The rms error also increases with increasing baseline, as one would expect, with an average rms error for a ~1400~km baseline of 9~mm. We will present an assessment of the accuracy of high-rate GPS based on these measurements, discuss the implications of this study for seismology, and describe new applications in glaciology.

  9. Prospects for DNA methods to measure human heritable mutation rates

    International Nuclear Information System (INIS)

    Mendelsohn, M.L.

    1985-01-01

    A workshop cosponsored by ICPEMC and the US Department of Energy was held in Alta, Utah, December 9-13, 1984 to examine the extent to which DNA-oriented methods might provide new approaches to the important but intractable problem of measuring mutation rates in control and exposed human populations. The workshop identified and analyzed six DNA methods for detection of human heritable mutation, including several created at the meeting, and concluded that none of the methods combine sufficient feasibility and efficiency to be recommended for general application. 8 refs

  10. Exploration of suitable dry etch technologies for directed self-assembly

    Science.gov (United States)

    Yamashita, Fumiko; Nishimura, Eiichi; Yatsuda, Koichi; Mochiki, Hiromasa; Bannister, Julie

    2012-03-01

    Directed self-assembly (DSA) has shown the potential to replace traditional resist patterns and provide a lower cost alternative for sub-20-nm patterns. One of the possible roadblocks for DSA implementation is the ability to etch the polymers to produce quality masks for subsequent etch processes. We have studied the effects of RF frequency and etch chemistry for dry developing DSA patterns. The results of the study showed a capacitively-coupled plasma (CCP) reactor with very high frequency (VHF) had superior pattern development after the block co-polymer (BCP) etch. The VHF CCP demonstrated minimal BCP height loss and line edge roughness (LER)/line width roughness (LWR). The advantage of CCP over ICP is the low dissociation so the etch rate of BCP is maintained low enough for process control. Additionally, the advantage of VHF is the low electron energy with a tight ion energy distribution that enables removal of the polymethyl methacrylate (PMMA) with good selectivity to polystyrene (PS) and minimal LER/LWR. Etch chemistries were evaluated on the VHF CCP to determine ability to treat the BCPs to increase etch resistance and feature resolution. The right combination of RF source frequencies and etch chemistry can help overcome the challenges of using DSA patterns to create good etch results.

  11. Self-etching ceramic primer versus hydrofluoric acid etching: Etching efficacy and bonding performance.

    Science.gov (United States)

    El-Damanhoury, Hatem M; Gaintantzopoulou, Maria D

    2018-01-01

    This study assessed the effect of pretreatment of hybrid and glass ceramics using a self-etching primer on the shear bond strength (SBS) and surface topography, in comparison to pretreatment with hydrofluoric acid and silane. 40 rectangular discs from each ceramic material (IPS e.max CAD;EM, Vita Mark II;VM, Vita Enamic;VE), were equally divided (n=10) and assigned to one of four surface pretreatment methods; etching with 4.8% hydrofluoric acid followed by Monobond plus (HFMP), Monobond etch & prime (Ivoclar Vivadent) (MEP), No treatment (NT) as negative control and Monobond plus (Ivoclar Vivadent) with no etching (MP) as positive control. SBS of resin cement (Multilink-N, Ivoclar Vivadent) to ceramic surfaces was tested following a standard protocol. Surface roughness was evaluated using an Atomic force microscope (AFM). Surface topography and elemental analysis were analyzed using SEM/EDX. Data were analyzed with two-way analysis of variance (ANOVA) and post-hoc Bonferroni test at a significance level of α=0.05. Pretreatment with HFMP resulted in higher SBS and increased surface roughness in comparison to MEP and MP. Regardless the method of surface pretreatment, the mean SBS values of EM ceramic was significantly higher (pceramics for resin-luting cementation. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  12. High-Density Plasma-Induced Etch Damage of GaN

    International Nuclear Information System (INIS)

    Baca, A.G.; Han, J.; Lester, L.F.; Pearton, S.J.; Ren, F.; Shul, R.J.; Willison, C.G.; Zhang, L.; Zolper, J.C.

    1999-01-01

    Anisotropic, smooth etching of the group-III nitrides has been reported at relatively high rates in high-density plasma etch systems. However, such etch results are often obtained under high de-bias and/or high plasma flux conditions where plasma induced damage can be significant. Despite the fact that the group-III nitrides have higher bonding energies than more conventional III-V compounds, plasma-induced etch damage is still a concern. Attempts to minimize such damage by reducing the ion energy or increasing the chemical activity in the plasma often result in a loss of etch rate or anisotropy which significantly limits critical dimensions and reduces the utility of the process for device applications requiring vertical etch profiles. It is therefore necessary to develop plasma etch processes which couple anisotropy for critical dimension and sidewall profile control and high etch rates with low-damage for optimum device performance. In this study we report changes in sheet resistance and contact resistance for n- and p-type GaN samples exposed to an Ar inductively coupled plasma (ICP). In general, plasma-induced damage was more sensitive to ion bombardment energies as compared to plasma flux. In addition, p-GaN was typically more sensitive to plasma-induced damage as compared to n-GaN

  13. Device for measuring flow rate in a nuclear reactor core

    International Nuclear Information System (INIS)

    Hamano, Jiro.

    1980-01-01

    Purpose: To always calculate core flow rate automatically and accurately in BWR type nuclear power plants. Constitution: Jet pumps are provided to the recycling pump and to the inside of the pressure vessel of a nuclear reactor. The jet pumps comprise a plurality of calibrated jet pumps for forcively convecting the coolants and a plurality of not calibrated jet pumps in order to cool the heat generated in the reactor core. The difference in the pressures between the upper and the lower portions in both of the jet pumps is measured by difference pressure transducers. Further, a thermo-sensitive element is provided to measure the temperature of recycling water at the inlet of the recycling pump. The output signal from the difference pressure transducer is inputted to a process computer, calculated periodically based on predetermined calculation equations, compensated for the temperature by a recycling water temperature signal and outputted as a core flow rate signal to a recoder. The signal is also used for the power distribution calculation in the process computer and the minimum limit power ratio as the thermal limit value for the fuels is outputted. (Furukawa, Y.)

  14. Lagrangian measurements of sulfur dioxide to sulfate conversion rates

    Energy Technology Data Exchange (ETDEWEB)

    Zak, B D

    1981-12-01

    On the basis of Project MISTT data and proposed homogenous gas phase oxidation mechanisms for sulfur dioxide, it has been suggested that the degree of mixing with background air, the chemical composition of the background air, and the intensity of the sunlight available are key factors determining the rate of sulfur dioxide to sulfate conversion. These hypotheses are examined in light of Lagrangian measrements of conversion rates in power plant plumes made during the Tennessee Plume Study and Project Da Vinci. It is found that the Lagrangian conversion rate measurements are consistent with these hypotheses. It has also been suggested that the concentration of ozone may serve as a workable surrogate for the concentrations of the free radicals involved in the homogeneous gas phase mechanism. The night-time Lagrangian data remind one that the gross difference in mean lifetime of ozone and free radicals can lead to situations in which the ozone concentration is not a good surrogate for the free radical concentrations.

  15. Gamma dosimetry with CR-39 etch track detector

    International Nuclear Information System (INIS)

    Matiullah; Dogar, A.H.; Ahmad, N.; Amin, M.; Kudo, Katsuhisa

    1999-01-01

    To preserve and improve the safety of food for commercial purposes, it is exposed to high gamma-ray doses. The gamma-ray doses used for this purpose range from 0.15 kGy to 50 kGy. At such high doses, the etching characteristics of CR-39 are severely affected. This property, therefore, can be used to develop a CR-39-based gamma dosimeter. In this context, systematic studies were carried out and the bulk etching rate was determined as a function of gamma-ray dose using different methods. (author)

  16. A Reactive-Ion Etch for Patterning Piezoelectric Thin Film

    Science.gov (United States)

    Yang, Eui-Hyeok; Wild, Larry

    2003-01-01

    Reactive-ion etching (RIE) under conditions described below has been found to be a suitable means for patterning piezoelectric thin films made from such materials as PbZr(1-x)Ti(x)O3 or Ba(x)Sr(1.x)TiO3. In the original application for which this particular RIE process was developed, PbZr(1-x)Ti(x)O3 films 0.5 microns thick are to be sandwiched between Pt electrode layers 0.1 microns thick and Ir electrode layers 0.1 microns thick to form piezoelectric capacitor structures. Such structures are typical of piezoelectric actuators in advanced microelectromechanical systems now under development or planned to be developed in the near future. RIE of PbZr(1-x)Ti(x)O3 is usually considered to involve two major subprocesses: an ion-assisted- etching reaction, and a sputtering subprocess that removes reactive byproducts. RIE is favored over other etching techniques because it offers a potential for a high degree of anisotropy, high-resolution pattern definition, and good process control. However, conventional RIE is not ideal for patterning PbZr(1-x)Ti(x)O3 films at a thickness as great as that in the original intended application. In order to realize the potential benefits mentioned above, it is necessary to optimize process conditions . in particular, the composition of the etching gas and the values of such other process parameters as radio-frequency power, gas pressure, gas-flow rate, and duration of the process. Guidelines for determining optimum conditions can be obtained from experimental determination of etch rates as functions of these parameters. Etch-gas mixtures of BCl3 and Cl2, some also including Ar, have been found to offer a high degree of selectivity as needed for patterning of PbZr(1-x)Ti(x)O3 films on top of Ir electrode layers in thin-film capacitor structures. The selectivity is characterized by a ratio of approx.10:1 (rate of etching PbZr(1-x)Ti(x)O3 divided by rate of etching Ir and IrO(x)). At the time of reporting the information for this article

  17. A novel deep reactive ion etched (DRIE) glass micro-model for two-phase flow experiments.

    Science.gov (United States)

    Karadimitriou, N K; Joekar-Niasar, V; Hassanizadeh, S M; Kleingeld, P J; Pyrak-Nolte, L J

    2012-09-21

    In the last few decades, micro-models have become popular experimental tools for two-phase flow studies. In this work, the design and fabrication of an innovative, elongated, glass-etched micro-model with dimensions of 5 × 35 mm(2) and constant depth of 43 microns is described. This is the first time that a micro-model with such depth and dimensions has been etched in glass by using a dry etching technique. The micro-model was visualized by a novel setup that allowed us to monitor and record the distribution of fluids throughout the length of the micro-model continuously. Quasi-static drainage experiments were conducted in order to obtain equilibrium data points that relate capillary pressure to phase saturation. By measuring the flow rate of water through the flow network for known pressure gradients, the intrinsic permeability of the micro-model's flow network was also calculated. The experimental results were used to calibrate a pore-network model and test its validity. Finally, we show that glass-etched micro-models can be valuable tools in single and/or multi-phase flow studies and their applications.

  18. Adiabatic tapered optical fiber fabrication in two step etching

    Science.gov (United States)

    Chenari, Z.; Latifi, H.; Ghamari, S.; Hashemi, R. S.; Doroodmand, F.

    2016-01-01

    A two-step etching method using HF acid and Buffered HF is proposed to fabricate adiabatic biconical optical fiber tapers. Due to the fact that the etching rate in second step is almost 3 times slower than the previous droplet etching method, terminating the fabrication process is controllable enough to achieve a desirable fiber diameter. By monitoring transmitted spectrum, final diameter and adiabaticity of tapers are deduced. Tapers with losses about 0.3 dB in air and 4.2 dB in water are produced. The biconical fiber taper fabricated using this method is used to excite whispering gallery modes (WGMs) on a microsphere surface in an aquatic environment. So that they are suitable to be used in applications like WGM biosensors.

  19. Variability in the measurement of hospital-wide mortality rates.

    Science.gov (United States)

    Shahian, David M; Wolf, Robert E; Iezzoni, Lisa I; Kirle, Leslie; Normand, Sharon-Lise T

    2010-12-23

    Several countries use hospital-wide mortality rates to evaluate the quality of hospital care, although the usefulness of this metric has been questioned. Massachusetts policymakers recently requested an assessment of methods to calculate this aggregate mortality metric for use as a measure of hospital quality. The Massachusetts Division of Health Care Finance and Policy provided four vendors with identical information on 2,528,624 discharges from Massachusetts acute care hospitals from October 1, 2004, through September 30, 2007. Vendors applied their risk-adjustment algorithms and provided predicted probabilities of in-hospital death for each discharge and for hospital-level observed and expected mortality rates. We compared the numbers and characteristics of discharges and hospitals included by each of the four methods. We also compared hospitals' standardized mortality ratios and classification of hospitals with mortality rates that were higher or lower than expected, according to each method. The proportions of discharges that were included by each method ranged from 28% to 95%, and the severity of patients' diagnoses varied widely. Because of their discharge-selection criteria, two methods calculated in-hospital mortality rates (4.0% and 5.9%) that were twice the state average (2.1%). Pairwise associations (Pearson correlation coefficients) of discharge-level predicted mortality probabilities ranged from 0.46 to 0.70. Hospital-performance categorizations varied substantially and were sometimes completely discordant. In 2006, a total of 12 of 28 hospitals that had higher-than-expected hospital-wide mortality when classified by one method had lower-than-expected mortality when classified by one or more of the other methods. Four common methods for calculating hospital-wide mortality produced substantially different results. This may have resulted from a lack of standardized national eligibility and exclusion criteria, different statistical methods, or

  20. Measuring Effective Tax Rates for Oil and Gas in Canada

    Directory of Open Access Journals (Sweden)

    Jack M. Mintz

    2010-03-01

    Full Text Available The purpose of this report is to provide cost of capital formulae for assessing the effects of taxation on the incentive to invest in oil and gas industries in Canada. The analysis is based on the assumption that businesses invest in capital until the after-tax rate of return on capital is equal to the tax-adjusted cost of capital. The cost of capital in absence of taxation is the inflation-adjusted cost of finance. The after-tax rate of return on capital is the annualized profit earned on a project net of the taxes paid by the businesses. For this purpose, we include corporate income, sales and other capital-related taxes as applied to oil and gas investments. For oil and gas taxation, it is necessary to account for royalties in a special way. Royalties are payment made by businesses for the right to extract oil and gas from land owned by the property holder. The land is owned by the province so the royalties are a rental payment for the benefit received from extracting the product from provincial lands. Thus, provincial royalty payments are a cost to oil and gas companies for using public property. However, since the provincial government is responsible for the royalty regime and could use taxes like the corporate income tax to extract revenue, one might think of royalties as part of the overall fiscal regime to raise revenue. In principle, one should subtract the rental benefit received from oil and gas businesses from taxes and royalty payments to assess the overall fiscal impact. This is impossible to do without measuring some explicit rental rate for use of provincial property. Further, royalty payments may distort economic decisions unlike a payment based on the economic rents earned on oil and gas projects. Instead, for comparability across jurisdictions, one might calculate the aggregate tax and royalty effective tax rates (such as between Alberta and Texas.

  1. Performance of a universal adhesive on etched and non-etched surfaces: Do the results match the expectations?

    Energy Technology Data Exchange (ETDEWEB)

    Grégoire, Geneviève, E-mail: genevieve.gregoire@univ-tlse3.fr [Department of Biomaterials, Faculty of Odontology, University Toulouse III, 31062 Toulouse (France); Sharrock, Patrick, E-mail: patrick.sharrock@gmail.com [CNRS UMR 5302, University Toulouse III, Mines-Albi, 81013 Albi (France); Prigent, Yann, E-mail: prigent@chimie.ups-tlse.fr [Institut de Chimie de Toulouse (ICT) – FR 2599, Faculté des Sciences et de l' Ingénierie, University Toulouse III, 31062 Toulouse (France)

    2016-09-01

    A universal adhesive was applied to human dentin in both the etched and rinsed state and the normal non etched state, to compare the resulting properties and detect any significant differences. The study focused on observations of the hybrid layer by scanning electron microscopy and on fluid permeation measurements as a function of time. Spectroscopic characterizations included infrared and differential calorimetric curves of the samples. The results obtained show non-statistically significant fluid permeability between the two sample types. Both the etched and rinsed samples and the non-etched ones showed similar homogeneous hybrid layers that reduced the fluid flow, and corresponded to well spread polymer coatings. The infrared results illustrated the spectra obtained on going from the outside adhesive layer to the inside portion of the dentin-polymer interface and did not reveal any intermediate zone resembling demineralized collagen that would be water saturated and not infiltrated with adhesive. The Differential Scanning Calorimetry (DSC) curves corresponded to the curves obtained with ethanol wet bonding in that free water (melting at 0 °C) was removed by the universal adhesive, and that no collagen melting was observed for the non-etched samples. The Diffusion-Ordered Spectroscopy Nuclear Magnetic Resonance (DOSY NMR) spectrum of the virgin adhesive showed the presence of water and ethanol solvents and indicated that several monomer or prepolymer molecules were present with multiple acrylic functional groups with diffusion coefficients related to molecular weights. Overall, the results show that universal adhesive can be used in the milder self-etch mode and that more aggressive etch and rinse procedure can be reserved for the occasions with sclerotic dentin or enamel regions more difficult to treat.

  2. Performance of a universal adhesive on etched and non-etched surfaces: Do the results match the expectations?

    International Nuclear Information System (INIS)

    Grégoire, Geneviève; Sharrock, Patrick; Prigent, Yann

    2016-01-01

    A universal adhesive was applied to human dentin in both the etched and rinsed state and the normal non etched state, to compare the resulting properties and detect any significant differences. The study focused on observations of the hybrid layer by scanning electron microscopy and on fluid permeation measurements as a function of time. Spectroscopic characterizations included infrared and differential calorimetric curves of the samples. The results obtained show non-statistically significant fluid permeability between the two sample types. Both the etched and rinsed samples and the non-etched ones showed similar homogeneous hybrid layers that reduced the fluid flow, and corresponded to well spread polymer coatings. The infrared results illustrated the spectra obtained on going from the outside adhesive layer to the inside portion of the dentin-polymer interface and did not reveal any intermediate zone resembling demineralized collagen that would be water saturated and not infiltrated with adhesive. The Differential Scanning Calorimetry (DSC) curves corresponded to the curves obtained with ethanol wet bonding in that free water (melting at 0 °C) was removed by the universal adhesive, and that no collagen melting was observed for the non-etched samples. The Diffusion-Ordered Spectroscopy Nuclear Magnetic Resonance (DOSY NMR) spectrum of the virgin adhesive showed the presence of water and ethanol solvents and indicated that several monomer or prepolymer molecules were present with multiple acrylic functional groups with diffusion coefficients related to molecular weights. Overall, the results show that universal adhesive can be used in the milder self-etch mode and that more aggressive etch and rinse procedure can be reserved for the occasions with sclerotic dentin or enamel regions more difficult to treat.

  3. Plasma Etching for Failure Analysis of Integrated Circuit Packages

    NARCIS (Netherlands)

    Tang, J.; Schelen, J.B.J.; Beenakker, C.I.M.

    2011-01-01

    Plastic integrated circuit packages with copper wire bonds are decapsulated by a Microwave Induced Plasma system. Improvements on microwave coupling of the system are achieved by frequency tuning and antenna modification. Plasmas with a mixture of O2 and CF4 showed a high etching rate around 2

  4. Study of surfactant-added TMAH for applications in DRIE and wet etching-based micromachining

    Science.gov (United States)

    Tang, B.; Shikida, M.; Sato, K.; Pal, P.; Amakawa, H.; Hida, H.; Fukuzawa, K.

    2010-06-01

    In this paper, etching anisotropy is evaluated for a number of different crystallographic orientations of silicon in a 0.1 vol% Triton-X-100 added 25 wt% tetramethylammonium hydroxide (TMAH) solution using a silicon hemisphere. The research is primarily aimed at developing advanced applications of wet etching in microelectromechanical systems (MEMS). The etching process is carried out at different temperatures in the range of 61-81 °C. The etching results of silicon hemisphere and different shapes of three-dimensional structures in {1 0 0}- and {1 1 0}-Si surfaces are analyzed. Significantly important anisotropy, different from a traditional etchant (e.g. pure KOH and TMAH), is investigated to extend the applications of the wet etching process in silicon bulk micromachining. The similar etching behavior of exact and vicinal {1 1 0} and {1 1 1} planes in TMAH + Triton is utilized selectively to remove the scalloping from deep reactive-ion etching (DRIE) etched profiles. The direct application of the present research is demonstrated by fabricating a cylindrical lens with highly smooth etched surface finish. The smoothness of a micro-lens at different locations is measured qualitatively by a scanning electron microscope and quantitatively by an atomic force microscope. The present paper provides a simple and effective fabrication method of the silicon micro-lens for optical MEMS applications.

  5. Isolating GaSb membranes grown metamorphically on GaAs substrates using highly selective substrate removal etch processes

    Energy Technology Data Exchange (ETDEWEB)

    Lavrova, Olga [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering. Center for High Technology Materials; Balakrishnan, Ganesh [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering. Center for High Technology Materials

    2017-02-24

    The etch rates of NH4OH:H2O2 and C6H8O7:H2O2 for GaAs and GaSb have been investigated to develop a selective etch for GaAs substrates and to isolate GaSb epilayers grown on GaAs. The NH4OH:H2O2 solution has a greater etch rate differential for the GaSb/GaAs material system than C6H8O7:H2O2 solution. The selectivity of NH4OH:H2O2 for GaAs/GaSb under optimized etch conditions has been observed to be as high as 11471 ± 1691 whereas that of C6H8O7:H2O2 has been measured up to 143 ± 2. The etch contrast has been verified by isolating 2 μm thick GaSb epi-layers that were grown on GaAs substrates. GaSb membranes were tested and characterized with high-resolution X-Ray diffraction (HR-XRD) and atomic force microscopy (AFM).

  6. Improved PECVD Si x N y film as a mask layer for deep wet etching of the silicon

    Science.gov (United States)

    Han, Jianqiang; Yin, Yi Jun; Han, Dong; Dong, LiZhen

    2017-09-01

    Although plasma enhanced chemical vapor deposition (PECVD) silicon nitride (Si x N y ) films have been extensively investigated by many researchers, requirements of film properties vary from device to device. For some applications utilizing Si x N y film as the mask Layer for deep wet etching of the silicon, it is very desirable to obtain a high quality film. In this study, Si x N y films were deposited on silicon substrates by PECVD technique from the mixtures of NH3 and 5% SiH4 diluted in Ar. The deposition temperature and RF power were fixed at 400 °C and 20 W, respectively. By adjusting the SiH4/NH3 flow ratio, Si x N y films of different compositions were deposited on silicon wafers. The stoichiometry, residual stress, etch rate in 1:50 HF, BHF solution and 40% KOH solution of deposited Si x N y films were measured. The experimental results show that the optimum SiH4/NH3 flow ratio at which deposited Si x N y films can perfectly protect the polysilicon resistors on the front side of wafers during KOH etching is between 1.63 and 2.24 under the given temperature and RF power. Polysilicon resistors protected by the Si x N y films can withstand 6 h 40% KOH double-side etching at 80 °C. At the range of SiH4/NH3 flow ratios, the Si/N atom ratio of films ranges from 0.645 to 0.702, which slightly deviate the ideal stoichiometric ratio of LPCVD Si3N4 film. In addition, the silicon nitride films with the best protection effect are not the films of minimum etch rate in KOH solution.

  7. Electronic transport in helium-ion-beam etched encapsulated graphene nanoribbons

    NARCIS (Netherlands)

    Nanda, G.; Hlawacek, Gregor; Goswami, S.; Watanabe, Kenji; Taniguchi, Takashi; Alkemade, P.F.A.

    2017-01-01

    We report the etching of and electronic transport in nanoribbons of graphene sandwiched between atomically flat hexagonal boron nitride (h-BN). The etching of ribbons of varying width was achieved with a focused beam of 30 keV He+ ions. Using in-situ electrical measurements, we

  8. Monitoring of PVD, PECVD and etching plasmas using Fourier components of RF voltage

    International Nuclear Information System (INIS)

    Dvorak, P; Vasina, P; Bursikova, V; Zemlicka, R

    2010-01-01

    Fourier components of discharge voltages were measured in two different reactive plasmas and their response to the creation or destruction of a thin film was studied. In reactive magnetron sputtering the effect of transition from the metallic to the compound mode accompanied by the creation of a compound film on the sputtered target was observed. Further, deposition and etching of a diamond-like carbon film and their effects on amplitudes of Fourier components of the discharge voltage were studied. It was shown that the Fourier components, including higher harmonic frequencies, sensitively react to the presence of a film. Therefore, they can be used as a powerful tool for the monitoring of deposition and etching processes. It was demonstrated that the behaviour of the Fourier components was caused in both experiments by the presence of the film. It was not caused by changes in the chemical composition of the gas phase induced by material etched from the film or decrease in gettering rate. Further, the observed behaviour was not affected by the film conductivity. The behaviour of the Fourier components can be explained by the difference between the coefficients of secondary electron emission of the film and its underlying material.

  9. Effect of electroless etching parameters on the growth and reflection properties of silicon nanowires

    International Nuclear Information System (INIS)

    Ozdemir, Baris; Unalan, Husnu Emrah; Kulakci, Mustafa; Turan, Rasit

    2011-01-01

    Vertically aligned silicon nanowire (Si NW) arrays have been fabricated over large areas using an electroless etching (EE) method, which involves etching of silicon wafers in a silver nitrate and hydrofluoric acid based solution. A detailed parametric study determining the relationship between nanowire morphology and time, temperature, solution concentration and starting wafer characteristics (doping type, resistivity, crystallographic orientation) is presented. The as-fabricated Si NW arrays were analyzed by field emission scanning electron microscope (FE-SEM) and a linear dependency of nanowire length to both temperature and time was obtained and the change in the growth rate of Si NWs at increased etching durations was shown. Furthermore, the effects of EE parameters on the optical reflectivity of the Si NWs were investigated in this study. Reflectivity measurements show that the 42.8% reflectivity of the starting silicon wafer drops to 1.3%, recorded for 10 μm long Si NW arrays. The remarkable decrease in optical reflectivity indicates that Si NWs have a great potential to be utilized in radial or coaxial p-n heterojunction solar cells that could provide orthogonal photon absorption and enhanced carrier collection.

  10. Effect of electroless etching parameters on the growth and reflection properties of silicon nanowires.

    Science.gov (United States)

    Ozdemir, Baris; Kulakci, Mustafa; Turan, Rasit; Unalan, Husnu Emrah

    2011-04-15

    Vertically aligned silicon nanowire (Si NW) arrays have been fabricated over large areas using an electroless etching (EE) method, which involves etching of silicon wafers in a silver nitrate and hydrofluoric acid based solution. A detailed parametric study determining the relationship between nanowire morphology and time, temperature, solution concentration and starting wafer characteristics (doping type, resistivity, crystallographic orientation) is presented. The as-fabricated Si NW arrays were analyzed by field emission scanning electron microscope (FE-SEM) and a linear dependency of nanowire length to both temperature and time was obtained and the change in the growth rate of Si NWs at increased etching durations was shown. Furthermore, the effects of EE parameters on the optical reflectivity of the Si NWs were investigated in this study. Reflectivity measurements show that the 42.8% reflectivity of the starting silicon wafer drops to 1.3%, recorded for 10 µm long Si NW arrays. The remarkable decrease in optical reflectivity indicates that Si NWs have a great potential to be utilized in radial or coaxial p-n heterojunction solar cells that could provide orthogonal photon absorption and enhanced carrier collection.

  11. Effect of electroless etching parameters on the growth and reflection properties of silicon nanowires

    Science.gov (United States)

    Ozdemir, Baris; Kulakci, Mustafa; Turan, Rasit; Emrah Unalan, Husnu

    2011-04-01

    Vertically aligned silicon nanowire (Si NW) arrays have been fabricated over large areas using an electroless etching (EE) method, which involves etching of silicon wafers in a silver nitrate and hydrofluoric acid based solution. A detailed parametric study determining the relationship between nanowire morphology and time, temperature, solution concentration and starting wafer characteristics (doping type, resistivity, crystallographic orientation) is presented. The as-fabricated Si NW arrays were analyzed by field emission scanning electron microscope (FE-SEM) and a linear dependency of nanowire length to both temperature and time was obtained and the change in the growth rate of Si NWs at increased etching durations was shown. Furthermore, the effects of EE parameters on the optical reflectivity of the Si NWs were investigated in this study. Reflectivity measurements show that the 42.8% reflectivity of the starting silicon wafer drops to 1.3%, recorded for 10 µm long Si NW arrays. The remarkable decrease in optical reflectivity indicates that Si NWs have a great potential to be utilized in radial or coaxial p-n heterojunction solar cells that could provide orthogonal photon absorption and enhanced carrier collection.

  12. Vadose Zone Infiltration Rates from Sr isotope Measurements

    Science.gov (United States)

    Maher, K.; Maher, K.; DePaolo, D. J.; DePaolo, D. J.; Conrad, M.

    2001-12-01

    Predicting infiltration rates and recharge through the vadose zone in arid regions is difficult and hence developing methods for the measurement of infiltration rates is important. We have been investigating the use of Sr isotope measurements for determining infiltration at the 200 Area plateau on the Hanford reservation in central Washington. In this context, infiltration affects the transport of contaminants to the water table as well as recharge of the groundwater system. Using Sr isotopes for this purpose requires drill core and water samples from the vadose zone, although leaches of the cores can substitute for water samples. Complementary information, including some constraints on regional recharge, can also be obtained using water samples from groundwater monitoring wells. The VZ method is based on the fact that the Sr isotope ratio of soil water just below the surface is often set by dissolution of aeolian material including carbonate, and this ratio is different from the average value in the deeper underlying vadose zone rock matrix. As water infiltrates, the Sr isotopic composition of the water changes toward the rock values as a result of Sr released from the rocks by weathering reactions. The rate of change with depth of the Sr isotope ratio of the vadose zone water is a function ultimately of q/R; the ratio of the infiltration flux (q) to the bulk rock weathering rate (R). Where it is possible to evaluate R, q can be estimated. As data accumulate it may be possible to improve the calibration of the method. At Hanford the vadose zone rock material is mostly unconsolidated sand, silt, and gravel of broadly granitic composition, which constitute the Hanford and Ringold formations. Annual precipitation is about 160 mm/yr. Drilling and coring of a ca. 70m hole to the water table in 1999 as part of the Hanford groundwater monitoring program, in a relatively undisturbed area of the site, allowed us to generate a unique Sr isotope data set. The Sr isotope

  13. Enhancement of laser induced damage threshold of fused silica by acid etching combined with UV laser conditioning

    International Nuclear Information System (INIS)

    Chen Meng; Xiang Xia; Jiang Yong; Zu Xiaotao; Yuan Xiaodong; Zheng Wanguo; Wang Haijun; Li Xibin; Lu Haibing; Jiang Xiaodong; Wang Chengcheng

    2010-01-01

    Acid etching combined with UV laser conditioning is developed to enhance the laser induced damage threshold (LIDT) of fused silica. Firstly, the fused silica is etched for 1 ∼ 100 min with a buffered 1% HF solution. After acid etching, its transmittance, surface roughness and LIDT are measured. The results reveal that the fused silica has the highest LIDT and transmittance after etching for 10 min. Then UV laser (355 nm) conditioning is adopted to process the 10-min-etched fused silica. When the laser fluence is below 60% of fused silica's zero probability damage threshold, the LIDT increases gradually with the increase of laser conditioning fluence. However, the LIDT rapidly decreases to be lower than the threshold of the 10-min-etched fused silica when the conditioning fluence is up to 80% of the threshold. Proper acid etching and laser conditioning parameters will effectively enhance the laser damage resistance of fused silica. (authors)

  14. Methods of etching a substrate

    Energy Technology Data Exchange (ETDEWEB)

    Cosmo, J J; Gambino, R J; Harper, J M.E.

    1979-05-16

    The invention relates to a method of etching a substrate. The substrate is located opposite a target electrode in a vacuum chamber, and the surface of the target electrode is bombarded with energetic particles of atomic dimensions. The target electrode is an intermetallic composition (compound, alloy or finely divided homogeneous mixture) of two metals A and B such that upon bombardment the electrode emits negative ions of metal B which have sufficient energy to produce etching of the substrate. Many target materials are exemplified. Typically the metal A has an electronegativity XA and metal B has an electronegativity XB such that Xb - Xa is greater than about 2.55 electron volts, with the exception of combinations of metals having a fractional ionicity Q less than about 0.314. The source of the energetic particles may be an ionised gas in the vacuum chamber. The apparatus and its mode of operation are described in detail.

  15. Methods of etching a substrate

    International Nuclear Information System (INIS)

    Cosmo, J.J.; Gambino, R.J.; Harper, J.M.E.

    1979-01-01

    The invention relates to a method of etching a substrate. The substrate is located opposite a target electrode in a vacuum chamber, and the surface of the target electrode is bombarded with energetic particles of atomic dimensions. The target electrode is an intermetallic composition (compound, alloy or finely divided homogeneous mixture) of two metals A and B such that upon bombardment the electrode emits negative ions of metal B which have sufficient energy to produce etching of the substrate. Many target materials are exemplified. Typically the metal A has an electronegativity XA and metal B has an electronegativity XB such that Xb - Xa is greater than about 2.55 electron volts, with the exception of combinations of metals having a fractional ionicity Q less than about 0.314. The source of the energetic particles may be an ionised gas in the vacuum chamber. The apparatus and its mode of operation are described in detail. (U.K.)

  16. Hybrid mask for deep etching

    KAUST Repository

    Ghoneim, Mohamed T.

    2017-08-10

    Deep reactive ion etching is essential for creating high aspect ratio micro-structures for microelectromechanical systems, sensors and actuators, and emerging flexible electronics. A novel hybrid dual soft/hard mask bilayer may be deposited during semiconductor manufacturing for deep reactive etches. Such a manufacturing process may include depositing a first mask material on a substrate; depositing a second mask material on the first mask material; depositing a third mask material on the second mask material; patterning the third mask material with a pattern corresponding to one or more trenches for transfer to the substrate; transferring the pattern from the third mask material to the second mask material; transferring the pattern from the second mask material to the first mask material; and/or transferring the pattern from the first mask material to the substrate.

  17. Radiation dosemeters and ambient dose rate measuring systems

    International Nuclear Information System (INIS)

    Maushart, R.

    1985-01-01

    The manufacturers have got the feeling that the PTB only reluctantly accepts complex dosimetric systems or systems with modern digital and microprocessor technology. Especially the fact that the PTB demands a restriction to a defined system configuration which must not be changed after design approval is felt to be a severe handicap. The rigid frame of design qualification forces manufacturers to adopt a two-tier development line, at least for ambient dose rate measuring systems, and frequently it is not necessarily the 'nature' system, i.e. equipment with modern technology, that is sent in to the PTB for testing. The way of solving the problem could be that PTB more readily accepts less familiar technologies, for instance by more frequently approving equipment at least preliminarily or for a restricted period of time, in order to collect experience. Another way could be to grant licence for system components, especially detectors. (orig./HP) [de

  18. Improving Pyroelectric Energy Harvesting Using a Sandblast Etching Technique

    Directory of Open Access Journals (Sweden)

    An-Shen Siao

    2013-09-01

    Full Text Available Large amounts of low-grade heat are emitted by various industries and exhausted into the environment. This heat energy can be used as a free source for pyroelectric power generation. A three-dimensional pattern helps to improve the temperature variation rates in pyroelectric elements by means of lateral temperature gradients induced on the sidewalls of the responsive elements. A novel method using sandblast etching is successfully applied in fabricating the complex pattern of a vortex-like electrode. Both experiment and simulation show that the proposed design of the vortex-like electrode improved the electrical output of the pyroelectric cells and enhanced the efficiency of pyroelectric harvesting converters. A three-dimensional finite element model is generated by commercial software for solving the transient temperature fields and exploring the temperature variation rate in the PZT pyroelectric cells with various designs. The vortex-like type has a larger temperature variation rate than the fully covered type, by about 53.9%.The measured electrical output of the vortex-like electrode exhibits an obvious increase in the generated charge and the measured current, as compared to the fully covered electrode, by of about 47.1% and 53.1%, respectively.

  19. Characterization of deep wet etching of fused silica glass for single cell and optical sensor deposition

    International Nuclear Information System (INIS)

    Zhu, Haixin; Holl, Mark; Ray, Tathagata; Bhushan, Shivani; Meldrum, Deirdre R

    2009-01-01

    The development of a high-throughput single-cell metabolic rate monitoring system relies on the use of transparent substrate material for a single cell-trapping platform. The high optical transparency, high chemical resistance, improved surface quality and compatibility with the silicon micromachining process of fused silica make it very attractive and desirable for this application. In this paper, we report the results from the development and characterization of a hydrofluoric acid (HF) based deep wet-etch process on fused silica. The pin holes and notching defects of various single-coated masking layers during the etching are characterized and the most suitable masking materials are identified for different etch depths. The dependence of the average etch rate and surface roughness on the etch depth, impurity concentration and HF composition are also examined. The resulting undercut from the deep HF etch using various masking materials is also investigated. The developed and characterized process techniques have been successfully implemented in the fabrication of micro-well arrays for single cell trapping and sensor deposition. Up to 60 µm deep micro-wells have been etched in a fused silica substrate with over 90% process yield and repeatability. To our knowledge, such etch depth has never been achieved in a fused silica substrate by using a non-diluted HF etchant and a single-coated masking layer at room temperature

  20. Nitride-based Schottky diodes and HFETs fabricated by photo-enhanced chemical wet etching

    International Nuclear Information System (INIS)

    Su, Y.K.; Chang, S.J.; Kuan, T.M.; Ko, C.H.; Webb, J.B.; Lan, W.H.; Cherng, Y.T.; Chen, S.C.

    2004-01-01

    Photo-enhanced chemical (PEC) wet etching technology was used to etch GaN and AlGaN epitaxial layers. It was found that the maximum etch rates were 510, 1960, 300, and 0 nm/mm for GaN, Al 0.175 Ga 0.825 N, Al 0.23 Ga 0.77 N, and Al 0.4 Ga 0.6 N, respectively. It was also found that we could achieve a high Al 0.175 Ga 0.825 N to GaN etch rate ratio of 12.6. Nitride-based Schottky diodes and heterostructure field effect transistors (HFETs) were also fabricated by PEC wet etching. It was found that we could achieve a saturated I D larger than 850 mA/mm and a maximum g m about 163 mS/mm from PEC wet etched HFET with a 0.5 μm gate length. Compared with dry etched devices, the leakage currents observed from the PEC wet etched devices were also found to be smaller

  1. Standard test method for measurement of fatigue crack growth rates

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2015-01-01

    1.1 This test method covers the determination of fatigue crack growth rates from near-threshold to Kmax controlled instability. Results are expressed in terms of the crack-tip stress-intensity factor range (ΔK), defined by the theory of linear elasticity. 1.2 Several different test procedures are provided, the optimum test procedure being primarily dependent on the magnitude of the fatigue crack growth rate to be measured. 1.3 Materials that can be tested by this test method are not limited by thickness or by strength so long as specimens are of sufficient thickness to preclude buckling and of sufficient planar size to remain predominantly elastic during testing. 1.4 A range of specimen sizes with proportional planar dimensions is provided, but size is variable to be adjusted for yield strength and applied force. Specimen thickness may be varied independent of planar size. 1.5 The details of the various specimens and test configurations are shown in Annex A1-Annex A3. Specimen configurations other than t...

  2. Measuring hand hygiene compliance rates at hospital entrances.

    Science.gov (United States)

    Vaidotas, Marina; Yokota, Paula Kiyomi Onaga; Marra, Alexandre R; Camargo, Thiago Zinsly Sampaio; Victor, Elivane da Silva; Gysi, Deisy Morselli; Leal, Flavio; Santos, Oscar Fernando Pavão dos; Edmond, Michael B

    2015-07-01

    Despite the importance of hand hygiene in the health care setting, there are no studies evaluating hand hygiene compliance at hospital entrances. The study was prospectively performed over a 33-week period from March 30, 2014-November 15, 2014, to evaluate hand hygiene compliance in 2 hospital reception areas. We compared electronic handwash counters with the application of radiofrequency identification (GOJO SMARTLINK) (electronic observer) that counts each activation of alcohol gel dispensers to direct observation (human observer) via remote review of video surveillance. We found low hand hygiene compliance rates of 2.2% (99/4,412) and 1.7% (140/8,277), respectively, at reception areas A and D, detected by direct observation. Using the electronic observer, we measured rates of 17% (15,624/91,724) and 7.1% (51,605/730,357) at reception areas A and D, respectively. For the overall time period of simultaneous electronic and human observation, the human observer captured 1% of the hand hygiene episodes detected by the electronic observer. Our study showed very low hand hygiene compliance in hospital reception areas, and we found an electronic hand hygiene system to be a useful method to monitor hand hygiene compliance. Copyright © 2015 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  3. Thermal history-based etching

    Science.gov (United States)

    Simpson, John T.

    2017-11-28

    A method for adjusting an etchability of a first borosilicate glass by heating the first borosilicate glass; combining the first borosilicate glass with a second borosilicate glass to form a composite; and etching the composite with an etchant. A material having a protrusive phase and a recessive phase, where the protrusive phase protrudes from the recessive phase to form a plurality of nanoscale surface features, and where the protrusive phase and the recessive phase have the same composition.

  4. Study of Thermal Electrical Modified Etching for Glass and Its Application in Structure Etching

    Directory of Open Access Journals (Sweden)

    Zhan Zhan

    2017-02-01

    Full Text Available In this work, an accelerating etching method for glass named thermal electrical modified etching (TEM etching is investigated. Based on the identification of the effect in anodic bonding, a novel method for glass structure micromachining is proposed using TEM etching. To validate the method, TEM-etched glasses are prepared and their morphology is tested, revealing the feasibility of the new method for micro/nano structure micromachining. Furthermore, two kinds of edge effect in the TEM and etching processes are analyzed. Additionally, a parameter study of TEM etching involving transferred charge, applied pressure, and etching roughness is conducted to evaluate this method. The study shows that TEM etching is a promising manufacture method for glass with low process temperature, three-dimensional self-control ability, and low equipment requirement.

  5. Femtosecond laser etching of dental enamel for bracket bonding.

    Science.gov (United States)

    Kabas, Ayse Sena; Ersoy, Tansu; Gülsoy, Murat; Akturk, Selcuk

    2013-09-01

    The aim is to investigate femtosecond laser ablation as an alternative method for enamel etching used before bonding orthodontic brackets. A focused laser beam is scanned over enamel within the area of bonding in a saw tooth pattern with a varying number of lines. After patterning, ceramic brackets are bonded and bonding quality of the proposed technique is measured by a universal testing machine. The results are compared to the conventional acid etching method. Results show that bonding strength is a function of laser average power and the density of the ablated lines. Intrapulpal temperature changes are also recorded and observed minimal effects are observed. Enamel surface of the samples is investigated microscopically and no signs of damage or cracking are observed. In conclusion, femtosecond laser exposure on enamel surface yields controllable patterns that provide efficient bonding strength with less removal of dental tissue than conventional acid-etching technique.

  6. Two-year Randomized Clinical Trial of Self-etching Adhesives and Selective Enamel Etching.

    Science.gov (United States)

    Pena, C E; Rodrigues, J A; Ely, C; Giannini, M; Reis, A F

    2016-01-01

    The aim of this randomized, controlled prospective clinical trial was to evaluate the clinical effectiveness of restoring noncarious cervical lesions with two self-etching adhesive systems applied with or without selective enamel etching. A one-step self-etching adhesive (Xeno V(+)) and a two-step self-etching system (Clearfil SE Bond) were used. The effectiveness of phosphoric acid selective etching of enamel margins was also evaluated. Fifty-six cavities were restored with each adhesive system and divided into two subgroups (n=28; etch and non-etch). All 112 cavities were restored with the nanohybrid composite Esthet.X HD. The clinical effectiveness of restorations was recorded in terms of retention, marginal integrity, marginal staining, caries recurrence, and postoperative sensitivity after 3, 6, 12, 18, and 24 months (modified United States Public Health Service). The Friedman test detected significant differences only after 18 months for marginal staining in the groups Clearfil SE non-etch (p=0.009) and Xeno V(+) etch (p=0.004). One restoration was lost during the trial (Xeno V(+) etch; p>0.05). Although an increase in marginal staining was recorded for groups Clearfil SE non-etch and Xeno V(+) etch, the clinical effectiveness of restorations was considered acceptable for the single-step and two-step self-etching systems with or without selective enamel etching in this 24-month clinical trial.

  7. Layer-by-layer thinning of MoSe_2 by soft and reactive plasma etching

    International Nuclear Information System (INIS)

    Sha, Yunfei; Xiao, Shaoqing; Zhang, Xiumei; Qin, Fang; Gu, Xiaofeng

    2017-01-01

    Highlights: • Soft plasma etching technique using SF_6 + N_2 as precursors for layer-by-layer thinning of MoSe_2 was adopted in this work. • Optical microscopy, Raman, photoluminescence and atomic force microscopy measurements were used to confirm the thickness change. • Layer-dependent vibrational and photoluminescence spectra of the etched MoSe_2 were also demonstrated. • Equal numbers of MoSe_2 layers can be removed uniformly without affecting the underlying SiO_2 substrate and the remaining MoSe_2 layers. - Abstract: Two-dimensional (2D) transition metal dichalcogenides (TMDs) like molybdenum diselenide (MoSe_2) have recently gained considerable interest since their properties are complementary to those of graphene. Unlike gapless graphene, the band structure of MoSe_2 can be changed from the indirect band gap to the direct band gap when MoSe_2 changed from bulk material to monolayer. This transition from multilayer to monolayer requires atomic-layer-precision thining of thick MoSe_2 layers without damaging the remaining layers. Here, we present atomic-layer-precision thinning of MoSe_2 nanaosheets down to monolayer by using SF_6 + N_2 plasmas, which has been demonstrated to be soft, selective and high-throughput. Optical microscopy, atomic force microscopy, Raman and photoluminescence spectra suggest that equal numbers of MoSe_2 layers can be removed uniformly regardless of their initial thickness, without affecting the underlying SiO_2 substrate and the remaining MoSe_2 layers. By adjusting the etching rates we can achieve complete MoSe_2 removal and any disired number of MoSe_2 layers including monolayer. This soft plasma etching method is highly reliable and compatible with the semiconductor manufacturing processes, thereby holding great promise for various 2D materials and TMD-based devices.

  8. Cortisol production rates measured by liquid chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Esteban, N.V.; Yergey, A.L.

    1990-01-01

    Cortisol production rates (FPRs) in physiologic and pathologic states in humans have been investigated over the past 30 years. However, there has been conflicting evidence concerning the validity of the currently accepted value of FPRs in humans (12 to 15 mg/m2/d) as determined by radiotracer methodology. The present study reviews previous methods proposed for the measurement of FPRs in humans and discusses the applications of the first method for the direct determination of 24-hour plasma FPRs during continuous administration of a stable isotope, using a thermospray high-pressure liquid chromatography-mass spectrometry technique. The technique is fast, sensitive, and, unlike gas chromatography-mass spectrometry methods, does not require derivatization, allowing on-line detection and quantification of plasma cortisol after a simple extraction procedure. The results of determination of plasma FPRs by stable tracer/mass spectrometry are directly in units of mass/time and, unlike radiotracer methods, are independent of any determination of volume of distribution or cortisol concentration. Our methodology offers distinct advantages over radiotracer techniques in simplicity and reliability since only single measurements of isotope ratios are required. The technique was validated in adrenalectomized patients. Circadian variations in daily FRPs were observed in normal volunteers, and, to date, results suggest a lower FRP in normal children and adults than previously believed. 88 references

  9. Differential measurement of low level HTO and HT leak rates

    International Nuclear Information System (INIS)

    Sheehan, W.E.; Muldoon, K.M.

    1976-08-01

    Leak rates of 5 x 10 -17 cm 3 /sec and greater can be measured by a very simple technique that will also differentiate tritium oxide (HTO) from tritium gas (HT). Because of the much greater health hazard of tritium oxide (200 to 1), the determination of chemical form is significant. The method involves flushing a gas collection chamber, containing the item being measured, with dry air. The flushed air is passed through an ethylene glycol bubbler which removes only the HTO. The outlet of the ethylene glycol bubbler is connected to a heated (400 0 C) palladium sponge catalyst which converts the HT to HTO and then to a second ethylene glycol bubbler for collection of the oxidized tritium gas. Liquid scintillation (p-dioxane base) counting solution is added directly to the bubblers and counted for tritium in a Liquid Scintillation Spectrometer. Advantages, method validation, operational experience, and data obtained by this technique are discussed. The sensitivity of the method is dependent on the time allowed between bubbler changes, the liquid scintillation spectrometer counting efficiency, background, and counting times employed

  10. Prediction of plasma-induced damage distribution during silicon nitride etching using advanced three-dimensional voxel model

    Energy Technology Data Exchange (ETDEWEB)

    Kuboi, Nobuyuki, E-mail: Nobuyuki.Kuboi@jp.sony.com; Tatsumi, Tetsuya; Kinoshita, Takashi; Shigetoshi, Takushi; Fukasawa, Masanaga; Komachi, Jun; Ansai, Hisahiro [Device and Material Research Group, RDS Platform, Sony Corporation, 4-14-1 Asahi-cho, Atsugi, Kanagawa 243-0014 (Japan)

    2015-11-15

    The authors modeled SiN film etching with hydrofluorocarbon (CH{sub x}F{sub y}/Ar/O{sub 2}) plasma considering physical (ion bombardment) and chemical reactions in detail, including the reactivity of radicals (C, F, O, N, and H), the area ratio of Si dangling bonds, the outflux of N and H, the dependence of the H/N ratio on the polymer layer, and generation of by-products (HCN, C{sub 2}N{sub 2}, NH, HF, OH, and CH, in addition to CO, CF{sub 2}, SiF{sub 2}, and SiF{sub 4}) as ion assistance process parameters for the first time. The model was consistent with the measured C-F polymer layer thickness, etch rate, and selectivity dependence on process variation for SiN, SiO{sub 2}, and Si film etching. To analyze the three-dimensional (3D) damage distribution affected by the etched profile, the authors developed an advanced 3D voxel model that can predict the time-evolution of the etched profile and damage distribution. The model includes some new concepts for gas transportation in the pattern using a fluid model and the property of voxels called “smart voxels,” which contain details of the history of the etching situation. Using this 3D model, the authors demonstrated metal–oxide–semiconductor field-effect transistor SiN side-wall etching that consisted of the main-etch step with CF{sub 4}/Ar/O{sub 2} plasma and an over-etch step with CH{sub 3}F/Ar/O{sub 2} plasma under the assumption of a realistic process and pattern size. A large amount of Si damage induced by irradiated hydrogen occurred in the source/drain region, a Si recess depth of 5 nm was generated, and the dislocated Si was distributed in a 10 nm deeper region than the Si recess, which was consistent with experimental data for a capacitively coupled plasma. An especially large amount of Si damage was also found at the bottom edge region of the metal–oxide–semiconductor field-effect transistors. Furthermore, our simulation results for bulk fin-type field-effect transistor side-wall etching

  11. The etching behaviour of silicon carbide compacts

    International Nuclear Information System (INIS)

    Jepps, N.W.; Page, T.F.

    1981-01-01

    A series of microstructural investigations has been undertaken in order to explore the reliability of particular etches in revealing microstructural detail in silicon carbide compacts. A series of specimens has been etched and examined following complete prior microstructural characterization by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffractometry techniques. In particular, the sensitivity of both a molten salt (KOH/KNO 3 ) etch and a commonly-used oxidizing electrolytic 'colour' etch to crystal purity, crystallographic orientation and polytypic structure has been established. The molten salt etch was found to be sensitive to grain boundaries and stacking disorder while the electrolytic etch was found to be primarily sensitive to local purity and crystallographic orientation. Neither etch appeared intrinsically polytype sensitive. Specifically, for the 'colour' etch, the p- or n-type character of impure regions appears critical in controlling etching behaviour; p-type impurities inhibiting, and n-type impurities enhancing, oxidation. The need to interpret etching behaviour in a manner consistent with the results obtained by a variety of other microstructural techniques will be emphasized. (author)

  12. Effect of Cl2- and HBr-based inductively coupled plasma etching on InP surface composition analyzed using in situ x-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Bouchoule, S.; Vallier, L.; Patriarche, G.; Chevolleau, T.; Cardinaud, C.

    2012-01-01

    A Cl 2 -HBr-O 2 /Ar inductively coupled plasma (ICP) etching process has been adapted for the processing of InP-based heterostructures in a 300-mm diameter CMOS etching tool. Smooth and anisotropic InP etching is obtained at moderate etch rate (∼600 nm/min). Ex situ x-ray energy dispersive analysis of the etched sidewalls shows that the etching anisotropy is obtained through a SiO x passivation mechanism. The stoichiometry of the etched surface is analyzed in situ using angle-resolved x-ray photoelectron spectroscopy. It is observed that Cl 2 -based ICP etching results in a significantly P-rich surface. The phosphorous layer identified on the top surface is estimated to be ∼1-1.3-nm thick. On the other hand InP etching in HBr/Ar plasma results in a more stoichiometric surface. In contrast to the etched sidewalls, the etched surface is free from oxides with negligible traces of silicon. Exposure to ambient air of the samples submitted to Cl 2 -based chemistry results in the complete oxidation of the P-rich top layer. It is concluded that a post-etch treatment or a pure HBr plasma step may be necessary after Cl 2 -based ICP etching for the recovery of the InP material.

  13. Etching characteristic and mechanism of BST thin films using inductively coupled Cl2/Ar plasma with additive CF4 gas

    International Nuclear Information System (INIS)

    Kim, Gwan-Ha; Kim, Kyoung-Tae; Kim, Dong-Pyo; Kim, Chang-Il

    2004-01-01

    BST thin films were etched with inductively coupled CF 4 /(Cl 2 +Ar) plasmas. The maximum etch rate of the BST thin films was 53.6 nm/min for a 10% CF 4 to the Cl 2 /Ar gas mixture at RF power of 700 W, DC bias of -150 V, and chamber pressure of 2 Pa. Small addition of CF 4 to the Cl 2 /Ar mixture increased chemical effect. Consequently, the increased chemical effect caused the increase in the etch rate of the BST thin films. To clarify the etching mechanism, the surface reaction of the BST thin films was investigated by X-ray photoelectron spectroscopy

  14. Study of Gallium Arsenide Etching in a DC Discharge in Low-Pressure HCl-Containing Mixtures

    Science.gov (United States)

    Dunaev, A. V.; Murin, D. B.

    2018-04-01

    Halogen-containing plasmas are often used to form topological structures on semiconductor surfaces; therefore, spectral monitoring of the etching process is an important diagnostic tool in modern electronics. In this work, the emission spectra of gas discharges in mixtures of hydrogen chloride with argon, chlorine, and hydrogen in the presence of a semiconducting gallium arsenide plate were studied. Spectral lines and bands of the GaAs etching products appropriate for monitoring the etching rate were determined. It is shown that the emission intensity of the etching products is proportional to the GaAs etching rate in plasmas of HCl mixtures with Ar and Cl2, which makes it possible to monitor the etching process in real time by means of spectral methods.

  15. Influence of external magnetic field on the etching of a steel ball in an aqueous solution of nitric acid

    International Nuclear Information System (INIS)

    Yu, Ilchenko M.; Yu, Gorobets O.; Bondar, I.A.; Gaponov, A.M.

    2010-01-01

    The effect of change of shape of a steel ball was revealed as a result of its etching in an aqueous solution of nitric acid under influence of an external magnetic field. The elongation of a ferromagnetic ball was observed along the direction of an external magnetic field while etching took place uniformly in all the directions without magnetic field application. The steel ball etching in a magnetic field is characterized by formation of three cylindrically symmetric regions with different etching rates and surface structures, divided from each other by clear borders (namely, the pole, equator and transition regions are formed). The non-monotone dependences of etching rate, surface structure of a sample and sample shape after etching on an external magnetic field are observed.

  16. Effects of a power and photon energy of incident light on near-field etching properties

    Science.gov (United States)

    Yatsui, T.; Saito, H.; Nishioka, K.; Leuschel, B.; Soppera, O.; Nobusada, K.

    2017-12-01

    We developed a near-field etching technique for realizing an ultra-flat surfaces of various materials and structures. To elucidate the near-field etching properties, we have investigated the effects of power and the photon energy of the incident light. First, we established theoretically that an optical near-field with photon energy lower than the absorption edge of the molecules can induce molecular vibrations. We used nanodiamonds to study the power dependence of the near-field etching properties. From the topological changes of the nanodiamonds, we confirmed the linear-dependence of the etching volume with the incident power. Furthermore, we studied the photon energy dependence using TiO2 nanostriped structures, which revealed that a lower photon energy results in a lower etching rate.

  17. Interest rate risk measurement in Brazilian sovereign markets

    Directory of Open Access Journals (Sweden)

    Caio Ibsen Rodrigues de Almeida

    2004-06-01

    Full Text Available Fixed income emerging markets are an interesting investment alternative. Measuring market risks is mandatory in order to avoid unexpected huge losses. The most used market risk measure is the Value at Risk, based on the profit-loss probability distribution of the portfolio under consideration. Estimating this probability distribution requires the prior estimation of the probability distribution of term structures of interest rates. An interesting possibility is to estimate term structures using a decomposition of the spread function into a linear combination of Legendre polynomials. Numerical examples from the Brazilian sovereign fixed income international market illustrate the practical use of the methodology.Os mercados emergentes de renda fixa são alternativas interessantes para investimentos. Devido ao elevado nível de incerteza existente em tais mercados, a mensuração dos riscos de mercado de uma carteira de investimentos é fundamental para que se evite um nível elevado de perdas. Uma das medidas de risco de mercado mais utilizadas é o Value at Risk, baseado na distribuição de probabilidades de perdas-ganhos da carteira sob análise. A estimação desta distribuição requer, no entanto, a estimação prévia da distribuição de pro-babilidades das variações da estrutura a termo da taxa de juros. Uma possibilidade interessante para a estimação de tal distribuição é efetuar uma decomposição da função de spread da estrutura a termo em uma combinação linear de Polinômios de Legendre. Exemplos numéricos do mercado internacional de títulos soberanos brasileiros são apresentados para ilustrar o uso prático desta nova metodologia.

  18. Measurements of the potential ozone production rate in a forest

    Science.gov (United States)

    Crilley, L.; Sklaveniti, S.; Kramer, L.; Bloss, W.; Flynn, J. H., III; Alvarez, S. L.; Erickson, M.; Dusanter, S.; Locoge, N.; Stevens, P. S.; Millet, D. B.; Alwe, H. D.

    2017-12-01

    Biogenic volatile organic compounds (BVOC) are a significant source of organic compounds globally and alongside NOx play a key role in the formation of ozone in the troposphere. Understanding how changes in NOx concentrations feed through to altered ozone production in BVOC dominated environments will aid our understanding of future atmospheric composition, notably as developing nations transition from NOx dominated to NOx limited chemistry as a result of mitigation strategies. Here we empirically investigate this ambient ozone formation potential. We report deployment of a custom built instrument to measure in near real time the potential for in situ chemical ozone production, using an artificial light source. Our results are thus indicative of the ozone formation potential for a sampled ambient air mixture, including full VOC complexity, i.e. independent of characterization of individual organic compounds. Ground level measurements were performed as part of the PROPHET-AMOS 2016 field campaign, at a site located within a Northern Michigan forest that has typically low NOx abundance, but high isoprene and terpenoid loadings. As the ambient NOx concentrations were low during the campaign, experiments were performed in which NO was artificially added to the sampled ambient air mixture, to quantify changes in the potential ozone production rate as a function of NOx, and hence the ozone forming characteristics of the ambient air. Preliminarily results from these experiments are presented, and indicate that while ozone production increases with added NO, significant variation was observed for a given NO addition, reflecting differences in the ambient VOC chemical reactivity and ozone formation tendency.

  19. Etching of UO2 in NF3 RF Plasma Glow Discharge

    Energy Technology Data Exchange (ETDEWEB)

    Veilleux, John M. [Univ. of California, Berkeley, CA (United States)

    1999-08-01

    A series of room temperature, low pressure (10.8 to 40 Pa), low power (25 to 210 W) RF plasma glow discharge experiments with UO2 were conducted to demonstrate that plasma treatment is a viable method for decontaminating UO2 from stainless steel substrates. Experiments were conducted using NF3 gas to decontaminate depleted uranium dioxide from stainless-steel substrates. Depleted UO2 samples each containing 129.4 Bq were prepared from 100 microliter solutions of uranyl nitrate hexahydrate solution. The amorphous UO2 in the samples had a relatively low density of 4.8 gm/cm3. Counting of the depleted UO2 on the substrate following plasma immersion was performed using liquid scintillation counting with alpha/beta discrimination due to the presence of confounding beta emitting daughter products, 234Th and 234Pa. The alpha emission peak from each sample was integrated using a gaussian and first order polynomial fit to improve quantification. The uncertainties in the experimental measurement of the etched material were estimated at about ± 2%. Results demonstrated that UO2 can be completely removed from stainless-steel substrates after several minutes processing at under 200 W. At 180 W and 32.7 Pa gas pressure, over 99% of all UO2 in the samples was removed in just 17 minutes. The initial etch rate in the experiments ranged from 0.2 to 7.4 μm/min. Etching increased with the plasma absorbed power and feed gas pressure in the range of 10.8 to 40 Pa. A different pressure effect on UO2 etching was also noted below 50 W in which etching increased up to a maximum pressure, ~23 Pa, then decreased with further increases in pressure.

  20. Effects of hard mask etch on final topography of advanced phase shift masks

    Science.gov (United States)

    Hortenbach, Olga; Rolff, Haiko; Lajn, Alexander; Baessler, Martin

    2017-07-01

    Continuous shrinking of the semiconductor device dimensions demands steady improvements of the lithographic resolution on wafer level. These requirements challenge the photomask industry to further improve the mask quality in all relevant printing characteristics. In this paper topography of the Phase Shift Masks (PSM) was investigated. Effects of hard mask etch on phase shift uniformity and mask absorber profile were studied. Design of experiments method (DoE) was used for the process optimization, whereas gas composition, bias power of the hard mask main etch and bias power of the over-etch were varied. In addition, influence of the over-etch time was examined at the end of the experiment. Absorber depth uniformity, sidewall angle (SWA), reactive ion etch lag (RIE lag) and through pitch (TP) dependence were analyzed. Measurements were performed by means of Atomic-force microscopy (AFM) using critical dimension (CD) mode with a boot-shaped tip. Scanning electron microscope (SEM) cross-section images were prepared to verify the profile quality. Finally CD analysis was performed to confirm the optimal etch conditions. Significant dependence of the absorber SWA on hard mask (HM) etch conditions was observed revealing an improvement potential for the mask absorber profile. It was found that hard mask etch can leave a depth footprint in the absorber layer. Thus, the etch depth uniformity of hard mask etch is crucial for achieving a uniform phase shift over the active mask area. The optimized hard mask etch process results in significantly improved mask topography without deterioration of tight CD specifications.

  1. Suitability of N2 plasma for the RIE etching of thin Ag layers

    International Nuclear Information System (INIS)

    Hrkut, P.; Matay, L.; Kostic, I.; Bencurova, A.; Konecnikova, A.; Nemec, P.; Andok, R.; Hacsik, S.

    2013-01-01

    Silver layers of 48 nm thickness were evaporated using EB PVD on Si wafers. The masking resist layers were spin-coated and patterned by the EBDW lithography on the ZBA 21 (20 keV) (Carl-Zeiss, Jena; currently Vistec, Ltd.) variable shaped e-beam pattern generator in II SAS. In order to check the etching process in N 2 , we covered a part of the samples containing Ag with a layer of various resists. The samples were dried on a hot-plate and RIE etched in SCM 600 (1 Pa; 20 sccm; 500 W). After 8 minutes the non-masked Ag layer was completely etched away, what testified suitability of N 2 as an etching gas. Also the etch time of 4 minutes showed to be sufficient for etching through the Ag layer. In order to optimize the etching process it was necessary to estimate the etch-rate (E.R.) of suitable resist layers and of the silver layer. The (authors)

  2. Formation of Mach angle profiles during wet etching of silica and silicon nitride materials

    Energy Technology Data Exchange (ETDEWEB)

    Ghulinyan, M., E-mail: ghulinyan@fbk.eu [Centre for Materials and Microsystems, Fondazione Bruno Kessler, I-38123 Povo (Italy); Bernard, M.; Bartali, R. [Centre for Materials and Microsystems, Fondazione Bruno Kessler, I-38123 Povo (Italy); Deptartment of Physics, University of Trento, I-38123 Povo (Italy); Pucker, G. [Centre for Materials and Microsystems, Fondazione Bruno Kessler, I-38123 Povo (Italy)

    2015-12-30

    Highlights: • Photoresist adhesion induces the formation of complex etch profiles in dielectrics. • Hydrofluoric acid etching of silica glass and silicon nitride materials was studied. • The phenomenon has been modeled in analogy with sonic boom propagation. • The material etch rate and resist adhesion/erosion define the final profile. - Abstract: In integrated circuit technology peeling of masking photoresist films is a major drawback during the long-timed wet etching of materials. It causes an undesired film underetching, which is often accompanied by a formation of complex etch profiles. Here we report on a detailed study of wedge-shaped profile formation in a series of silicon oxide, silicon oxynitride and silicon nitride materials during wet etching in a buffered hydrofluoric acid (BHF) solution. The shape of etched profiles reflects the time-dependent adhesion properties of the photoresist to a particular material and can be perfectly circular, purely linear or a combination of both, separated by a knee feature. Starting from a formal analogy between the sonic boom propagation and the wet underetching process, we model the wedge formation mechanism analytically. This model predicts the final form of the profile as a function of time and fits the experimental data perfectly. We discuss how this knowledge can be extended to the design and the realization of optical components such as highly efficient etch-less vertical tapers for passive silicon photonics.

  3. EFFECT OF AN ADDITIONAL HYDROPHILIC VERSUS HYDROPHOBIC COAT ON THE QUALITY OF DENTINAL SEALING PROVIDED BY TWO-STEP ETCH-AND-RINSE ADHESIVES

    Science.gov (United States)

    Silva, Safira Marques de Andrade; Carrilho, Marcela Rocha de Oliveira; Marquezini, Luiz; Garcia, Fernanda Cristina Pimentel; Manso, Adriana Pigozzo; Alves, Marcelo Corrêa; de Carvalho, Ricardo Marins

    2009-01-01

    Objective: To test the hypothesis that the quality of the dentinal sealing provided by two-step etch-and-rinse adhesives cannot be altered by the addition of an extra layer of the respective adhesive or the application of a more hydrophobic, non-solvated resin. Material and Methods: full-crown preparations were acid-etched with phosphoric acid for 15 s and bonded with Adper Single Bond (3M ESPE), Excite DSC (Ivoclar/Vivadent) or Prime & Bond NT (Dentsply). The adhesives were used according to the manufacturers' instructions (control groups) or after application to dentin they were a) covered with an extra coat of each respective system or b) coated with a non-solvated bonding agent (Adper Scotchbond Multi-Purpose Adhesive, 3M ESPE). Fluid flow rate was measured before and after dentin surfaces were acid-etched and bonded with adhesives. Results: None of the adhesives or experimental treatments was capable to block completely the fluid transudation across the treated dentin. Application of an extra coat of the adhesive did not reduce the fluid flow rate of adhesive-bonded dentin (p>0.05). Conversely, the application of a more hydrophobic non-solvated resin resulted in significant reductions in the fluid flow rate (padhesives. Conclusions: The quality of the dentinal sealing provided by etch-and-rinse adhesives can be significantly improved by the application of a more hydrophobic, non-solvated bonding agent. PMID:19466248

  4. Selective photochemical dry etching of compound semiconductors

    International Nuclear Information System (INIS)

    Ashby, C.I.H.

    1988-01-01

    When laser-driven etching of a semiconductor requires direct participation of photogenerated carriers, the etching quantum yield will be sensitive to the electronic properties of a specific semiconductor material. The band-gap energy of the semiconductor determines the minimum photon energy needed for carrier-driven etching since sub-gap photons do not generate free carriers. However, only those free carriers that reach the reacting surface contribute to etching and the ultimate carrier flux to the surface is controlled by more subtle electronic properties than the lowest-energy band gap. For example, the initial depth of carrier generation and the probability of carrier recombination between the point of generation and the surface profoundly influence the etching quantum yield. Appropriate manipulation of process parameters can provide additional reaction control based on such secondary electronic properties. Applications to selective dry etching of GaAs and related materials are discussed

  5. Effect of gamma irradiation on the etching properties of Lexan and Makrofol-DE polycarbonate plastics

    International Nuclear Information System (INIS)

    Ashok Kumar; Jain, R.K.; Praveen Yadav; Chakraborty, R.N.; Singh, B.K.; Nayak, B.K.

    2013-01-01

    It is observed that for Lexan and Makrofol-DE polycarbonate plastic detectors the mean diameters of fission fragments from a 252 Cf source increases as a result of gamma-ray exposure. We have studied the bulk etching rate and track etching rate before and after gamma-ray irradiation on Lexan and Makrofol-DE polycarbonate plastics. The mechanism of Lexan and Makrofol-DE polycarbonate plastic detectors can be understood with the help of this exposures. It is also noted that degree of ordering of Lexan and Makrofol-DE polycarbonate is dependent on the gamma ray dose due to degradation and cross-linking processes. The results show that bulk and track etch rate increases with gamma dose while activation energy associated with bulk and track etch rates at a particular temperature and sensitivity decreases with gamma dose. (author)

  6. Individual laboratory-measured discount rates predict field behavior.

    Science.gov (United States)

    Chabris, Christopher F; Laibson, David; Morris, Carrie L; Schuldt, Jonathon P; Taubinsky, Dmitry

    2008-12-01

    We estimate discount rates of 555 subjects using a laboratory task and find that these individual discount rates predict inter-individual variation in field behaviors (e.g., exercise, BMI, smoking). The correlation between the discount rate and each field behavior is small: none exceeds 0.28 and many are near 0. However, the discount rate has at least as much predictive power as any variable in our dataset (e.g., sex, age, education). The correlation between the discount rate and field behavior rises when field behaviors are aggregated: these correlations range from 0.09-0.38. We present a model that explains why specific intertemporal choice behaviors are only weakly correlated with discount rates, even though discount rates robustly predict aggregates of intertemporal decisions.

  7. A method to control the fabrication of etched optical fiber probes with nanometric tips

    International Nuclear Information System (INIS)

    Tao, Miaomiao; Gu, Ning; Huang, Lan; Jin, Yonglong

    2010-01-01

    Optical fiber probes with small size tips have attracted much interest in the areas of biosensor and near-field scanning optical microscopy. Chemical etching is a common useful method to fabricate such probes. But it is difficult to study or determine the etching time and control the shape of the fiber during the etching. In this work, a new method combining a fiber optic spectrometer with static chemical etching has been developed to fabricate optical fiber probe nanotips, where the fiber optic spectrometer is used to measure the optical signal during the etching. By calculating and analyzing the testing data, the relationship between the apex angle and the optical signal can be obtained. Accordingly, the process of fabricating optical fibers based on the optical signal can be controlled

  8. Dry etching technologies for reflective multilayer

    Science.gov (United States)

    Iino, Yoshinori; Karyu, Makoto; Ita, Hirotsugu; Kase, Yoshihisa; Yoshimori, Tomoaki; Muto, Makoto; Nonaka, Mikio; Iwami, Munenori

    2012-11-01

    We have developed a highly integrated methodology for patterning Extreme Ultraviolet (EUV) mask, which has been highlighted for the lithography technique at the 14nm half-pitch generation and beyond. The EUV mask is characterized as a reflective-type mask which is completely different compared with conventional transparent-type of photo mask. And it requires not only patterning of absorber layer without damaging the underlying multi reflective layers (40 Si/Mo layers) but also etching multi reflective layers. In this case, the dry etch process has generally faced technical challenges such as the difficulties in CD control, etch damage to quartz substrate and low selectivity to the mask resist. Shibaura Mechatronics ARESTM mask etch system and its optimized etch process has already achieved the maximal etch performance at patterning two-layered absorber. And in this study, our process technologies of multi reflective layers will be evaluated by means of optimal combination of process gases and our optimized plasma produced by certain source power and bias power. When our ARES™ is used for multilayer etching, the user can choose to etch the absorber layer at the same time or etch only the multilayer.

  9. Silicon germanium mask for deep silicon etching

    KAUST Repository

    Serry, Mohamed

    2014-07-29

    Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

  10. Silicon germanium mask for deep silicon etching

    KAUST Repository

    Serry, Mohamed; Rubin, Andrew; Refaat, Mohamed; Sedky, Sherif; Abdo, Mohammad

    2014-01-01

    Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

  11. Micromorphological characterization of adhesive interface of sound dentin and total-etch and self-etch adhesives.

    Science.gov (United States)

    Drobac, Milan; Stojanac, Igor; Ramić, Bojana; Premović, Milica; Petrović, Ljubomir

    2015-01-01

    The ultimate goal in restorative dentistry has always been to achieve strong and permanent bond between the dental tissues and filling materials. It is not easy to achieve this task because the bonding process is different for enamel and dentin-dentin is more humid and more organic than enamel. It is moisture and organic nature of dentin that make this hard tissue very complex to achieve adhesive bond. One of the first and most widely used tools for examining the adhesive bond between hard dental tissues and composite restorative materials is scanning electron microscopy. The aim of this study was scanning electron microscopy analyzes the interfacial micro morphology of total-etch and self-etch adhesives. Micro morphological characteristics of interface between total-etch adhesive (Prime & Bond NT) in combination with the corresponding composite (Ceram X Mono) were compared with those of self-etching adhesive (AdheSE One) in, combination with the corresponding composite (Tetric EvoCeram). The specimens were observed under 1000 x magnification of scanning electron microscopy (JEOL, JSM-6460 Low Vacuum). Measurement of the thickness of the hybrid layer of the examined com posite systems was performed with the software of the device used (NIH Image Analyser). Micromorphological analysis of interface showed that the hybrid layer in sound dentin was well formed, its average thickness being 2.68 microm, with a large number of resin tags and a large amount of lateral branches for specimens with a composite system Prime & Bond NT-Ceram X Mono. However, the specimens' with composite systems Adhese One-Tetric EvoCeram did not show the presence of hybrid layer and the resin tags were poorly represented. The results of this study suggest that total-etch adhesives bond better with sound dentin than self-etch adhesive.

  12. Etching.

    Science.gov (United States)

    1980-09-01

    4 - 0 2- G xC 0 .- 04.410Zt .0 f.-C 13-a U Z W:; LU OU SS 0 L = 0 . 6c C! tun a.- I- -. 4 *CZ=U K 0 2N 0 (3 A LWE’-0 Z W Z4 £C 0.C ?A C. V;, 4US CI US...z Q. cm -2 C’S *-D WX 4 an 0 N 4 W 0(A1 -O 0-C -C ZaW U. aNi x 400 C O CD0 0 00Ix - WA - C 0 0 C A. J -4 * 0-4 w~ aT L C M 0n N U- X ZOWO 2 %-0 IM

  13. Self-etch and etch-and-rinse adhesive systems in clinical dentistry.

    Science.gov (United States)

    Ozer, Fusun; Blatz, Markus B

    2013-01-01

    Current adhesive systems follow either an "etch-and-rinse" or "self-etch" approach, which differ in how they interact with natural tooth structures. Etch-and-rinse systems comprise phosphoric acid to pretreat the dental hard tissues before rinsing and subsequent application of an adhesive. Self-etch adhesives contain acidic monomers, which etch and prime the tooth simultaneously. Etch-and-rinse adhesives are offered as two- or three-step systems, depending on whether primer and bonding are separate or combined in a single bottle. Similarly, self-etch adhesives are available as one- or two-step systems. Both etch-and-rinse and self-etch systems form a hybrid layer as a result of resins impregnating the porous enamel or dentin. Despite current trends toward fewer and simpler clinical application steps, one-step dentin bonding systems exhibit bonding agent lower bond strengths and seem less predictable than multi-step etch-and-rinse and self-etch systems. The varying evidence available today suggests that the choice between etch-and-rinse and self-etch systems is often a matter of personal preference. In general, however, phosphoric acid creates a more pronounced and retentive etching pattern in enamel. Therefore, etch-and-rinse bonding systems are often preferred for indirect restorations and when large areas of enamel are still present. Conversely, self-etch adhesives provide superior and more predictable bond strength to dentin and are, consequently, recommended for direct composite resin restorations, especially when predominantly supported by dentin.

  14. Measurement of glomerular filtration rate in the conscious rat.

    Science.gov (United States)

    Pestel, Sabine; Krzykalla, Volker; Weckesser, Gerhard

    2007-01-01

    Glomerular filtration rate (GFR) is an important parameter for studying drug-induced impairments on renal function in rats. The GFR is calculated from the concentration of creatinine and blood urea nitrogen (BUN) in serum and in urine, respectively. Following current protocols serum and urine samples must be taken from the same animal. Thus, in order to determine time-dependent effects it is necessary to use for each time point one separated group of animals. We developed a statistical test which allows analyzing the GFR from two different groups of animals: one used for repeated serum and the other one used for repeated urine analysis. Serum and urine samples were taken from two different sets of rats which were otherwise treated identically, i.e. drug doses, routes of administration (per os or per inhalation) and tap water loading. For each dose group GFR mean, standard deviation and statistical analysis to identify differences between the dose groups were determined. After determination of the optimal time points for measurements, the effect on GFR of the three reference compounds, furosemide, hydrochlorothiazide and formoterol, was calculated. The results showed that the diuretic drugs furosemide and hydrochlorothiazide decreased the GFR and the antidiuretic drug formoterol increased the GFR, as counter regulation on urine loss or urine retention, respectively. A mathematical model and the corresponding algorithm were developed, which can be used to calculate the GFR, and to test for differences between groups from two separated sets of rats, one used for urine, and the other one for serum analysis. This new method has the potential to reduce the number of animals needed and to improve the quality of data generated from various groups of animals in renal function studies.

  15. Measuring real exchange rate misalignment in Croatia: cointegration approach

    Directory of Open Access Journals (Sweden)

    Irena Palić

    2014-12-01

    Full Text Available The purpose of the paper is to analyze misalignment of the real exchange rate in Croatia. The misalignment analysis is conducted using the permanent equilibrium exchange rate approach. The equilibrium real exchange rate is computed using the cointegration approach whereby the real exchange rate and its fundamentals, namely terms of trade, net foreign assets and the ratio of prices of tradables to non-tradables are included in cointegration analysis. The Hodrick and Prescott filter is used to obtain permanent values of the equilibrium real exchange rate. The real exchange rate misalignment is computed as the deviation of the RER from its permanent equilibrium level. Four overvaluation periods and three undervaluation periods are recorded in Croatia in the observed period. Overvaluation periods are more often and of longer duration than undervaluation periods. However, the real exchange rate does not deviate largely from its estimated equilibrium value in the observed period, and it is neither overvalued nor undervalued constantly, but the periods alternate. Considering the results of the analysis, together with the empirical characteristics of Croatian economy, namely the high foreign currency indebtedness, highly euroized economy and underdeveloped export oriented sector, the depreciation of the real exchange rate is not recommended to economic policy makers and the current Croatian exchange rate policy is appropriate.

  16. Development of an instrument for direct ozone production rate measurements: measurement reliability and current limitations

    Science.gov (United States)

    Sklaveniti, Sofia; Locoge, Nadine; Stevens, Philip S.; Wood, Ezra; Kundu, Shuvashish; Dusanter, Sébastien

    2018-02-01

    Ground-level ozone (O3) is an important pollutant that affects both global climate change and regional air quality, with the latter linked to detrimental effects on both human health and ecosystems. Ozone is not directly emitted in the atmosphere but is formed from chemical reactions involving volatile organic compounds (VOCs), nitrogen oxides (NOx = NO + NO2) and sunlight. The photochemical nature of ozone makes the implementation of reduction strategies challenging and a good understanding of its formation chemistry is fundamental in order to develop efficient strategies of ozone reduction from mitigation measures of primary VOCs and NOx emissions. An instrument for direct measurements of ozone production rates (OPRs) was developed and deployed in the field as part of the IRRONIC (Indiana Radical, Reactivity and Ozone Production Intercomparison) field campaign. The OPR instrument is based on the principle of the previously published MOPS instrument (Measurement of Ozone Production Sensor) but using a different sampling design made of quartz flow tubes and a different Ox (O3 and NO2) conversion-detection scheme composed of an O3-to-NO2 conversion unit and a cavity attenuated phase shift spectroscopy (CAPS) NO2 monitor. Tests performed in the laboratory and in the field, together with model simulations of the radical chemistry occurring inside the flow tubes, were used to assess (i) the reliability of the measurement principle and (ii) potential biases associated with OPR measurements. This publication reports the first field measurements made using this instrument to illustrate its performance. The results showed that a photo-enhanced loss of ozone inside the sampling flow tubes disturbs the measurements. This issue needs to be solved to be able to perform accurate ambient measurements of ozone production rates with the instrument described in this study. However, an attempt was made to investigate the OPR sensitivity to NOx by adding NO inside the instrument

  17. Measuring protein breakdown rate in individual proteins in vivo

    DEFF Research Database (Denmark)

    Holm, Lars; Kjaer, Michael

    2010-01-01

    To outline different approaches of how protein breakdown can be quantified and to present a new approach to determine the fractional breakdown rate of individual slow turnover proteins in vivo.......To outline different approaches of how protein breakdown can be quantified and to present a new approach to determine the fractional breakdown rate of individual slow turnover proteins in vivo....

  18. Estimation of the rate of volcanism on Venus from reaction rate measurements

    Science.gov (United States)

    Fegley, Bruce, Jr.; Prinn, Ronald G.

    1989-01-01

    Laboratory rate data for the reaction between SO2 and calcite to form anhydrite are presented. If this reaction rate represents the SO2 reaction rate on Venus, then all SO2 in the Venusian atmosphere will disappear in 1.9 Myr unless volcanism replenishes the lost SO2. The required volcanism rate, which depends on the sulfur content of the erupted material, is in the range 0.4-11 cu km of magma erupted per year. The Venus surface composition at the Venera 13, 14, and Vega 2 landing sites implies a volcanism rate of about 1 cu km/yr. This geochemically estimated rate can be used to determine if either (or neither) of two discordant geophysically estimated rates is correct. It also suggests that Venus may be less volcanically active than the earth.

  19. Reaction rate constants of H-abstraction by OH from large ketones: Measurements and site-specific rate rules

    KAUST Repository

    Badra, Jihad; Elwardani, Ahmed Elsaid; Farooq, Aamir

    2014-01-01

    -pentanone, and 4-methl-2-pentanone. Rate constants are measured under pseudo-first-order kinetics at temperatures ranging from 866 K to 1375 K and pressures near 1.5 atm. The reported high-temperature rate constant measurements are the first direct

  20. Analysis of InP-based single photon avalanche diodes based on a single recess-etching process

    Science.gov (United States)

    Lee, Kiwon

    2018-04-01

    Effects of the different etching techniques have been investigated by analyzing electrical and optical characteristics of two-types of single-diffused single photon avalanche diodes (SPADs). The fabricated two-types of SPADs have no diffusion depth variation by using a single diffusion process at the same time. The dry-etched SPADs show higher temperature dependence of a breakdown voltage, larger dark-count-rate (DCR), and lower photon-detection-efficiency (PDE) than those of the wet-etched SPADs due to plasma-induced damage of dry-etching process. The results show that the dry etching damages can more significantly affect the performance of the SPADs based on a single recess-etching process.

  1. Characterization of the CH4/H2/Ar high density plasma etching process for ZnSe

    Science.gov (United States)

    Eddy, C. R.; Leonhardt, D.; Shamamian, V. A.; Butler, J. E.

    2001-05-01

    High density plasma etching of zinc selenide using CH4/H2/Ar plasma chemistries is investigated. Mass spectrometry, using through-the-platen sampling, is used to identify and monitor etch products evolving from the surface during etching. The identifiable primary etch products are Zn, Se, ZnH2, SeH2, Zn(CH3)2, and Se(CH3)2. Their concentrations are monitored as ion and neutral fluxes (both in intensity and composition), ion energy, and substrate temperature are varied. General insights about the surface chemistry mechanisms of the etch process are given from these observations. Regions of process parameter space best suited for moderate rate, anisotropic, and low damage etching of ZnSe are proposed.

  2. Etch characteristics of (Pb,Sr)TiO3 thin films using CF4/Ar inductively coupled plasma

    International Nuclear Information System (INIS)

    Kim, Gwan-Ha; Kim, Kyoung-Tae; Kim, Dong-Pyo; Kim, Chang-Il

    2003-01-01

    The investigations of the (Pb,Sr)TiO 3 (PST) etching characteristics in CF 4 /Ar plasma were carried out using the inductively coupled plasma system. Experiments showed that an increase of the Ar mixing ratio under constant pressure and input power conditions leads to increasing etch rate of PST, which reaches a maximum of 740 A/min when the Ar is 80% of the gas mixture. To understand the etching mechanism, the surface state of the etched PST samples was investigated using x-ray photoelectron spectroscopy. It was found that Pb and Ti atoms were removed mainly by the ion-assisted etching mechanism. At the same time, Sr forms extremely low volatile fluorides and therefore can be removed only by physical (sputter) etching

  3. Consideration of correlativity between litho and etching shape

    Science.gov (United States)

    Matsuoka, Ryoichi; Mito, Hiroaki; Shinoda, Shinichi; Toyoda, Yasutaka

    2012-03-01

    We developed an effective method for evaluating the correlation of shape of Litho and Etching pattern. The purpose of this method, makes the relations of the shape after that is the etching pattern an index in wafer same as a pattern shape on wafer made by a lithography process. Therefore, this method measures the characteristic of the shape of the wafer pattern by the lithography process and can predict the hotspot pattern shape by the etching process. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used wafer CD-SEM. Currently, as semiconductor manufacture moves towards even smaller feature size, this necessitates more aggressive optical proximity correction (OPC) to drive the super-resolution technology (RET). In other words, there is a trade-off between highly precise RET and lithography management, and this has a big impact on the semiconductor market that centers on the semiconductor business. 2-dimensional shape of wafer quantification is important as optimal solution over these problems. Although 1-dimensional shape measurement has been performed by the conventional technique, 2-dimensional shape management is needed in the mass production line under the influence of RET. We developed the technique of analyzing distribution of shape edge performance as the shape management technique. In this study, we conducted experiments for correlation method of the pattern (Measurement Based Contouring) as two-dimensional litho and etch evaluation technique. That is, observation of the identical position of a litho and etch was considered. It is possible to analyze variability of the edge of the same position with high precision.

  4. Rotation Rate of Saturn's Magnetosphere using CAPS Plasma Measurements

    Science.gov (United States)

    Sittler, E.; Cooper, J.; Simpson, D.; Paterson, W.

    2012-01-01

    We present the present status of an investigation of the rotation rate of Saturn 's magnetosphere using a 3D velocity moment technique being developed at Goddard which is similar to the 2D version used by Sittler et al. (2005) [1] for SOI and similar to that used by Thomsen et al. (2010). This technique allows one to nearly cover the full energy range of the CAPS IMS from 1 V less than or equal to E/Q less than 50 kV. Since our technique maps the observations into a local inertial frame, it does work during roll manoeuvres. We have made comparisons with Wilson et al. (2008) [2] (2005-358 and 2005-284) who performs a bi-Maxwellian fit to the ion singles data and our results are nearly identical. We will also make comparisons with results by Thomsen et al. (2010) [3]. Our analysis uses ion composition data to weight the non-compositional data, referred to as singles data, to separate H+, H2+ and water group ions (W+) from each other. The ion data set is especially valuable for measuring flow velocities for protons, which are more difficult to derive using singles data within the inner magnetosphere, where the signal is dominated by heavy ions (i.e., proton peak merges with W+ peak as low energy shoulder). Our technique uses a flux function, which is zero in the proper plasma flow frame, to estimate fluid parameter uncertainties. The comparisons investigate the experimental errors and potential for systematic errors in the analyses, including ours. The rolls provide the best data set when it comes to getting 4PI coverage of the plasma but are more susceptible to time aliasing effects. Since our analysis is a velocity moments technique it will work within the inner magnetosphere where pickup ions are important and velocity distributions are non-Maxwellian. So, we will present results inside Enceladus' L shell and determine if mass loading is important. In the future we plan to make comparisons with magnetic field observations, use Saturn ionosphere conductivities as

  5. RATES OF PHOTOSPHERIC MAGNETIC FLUX CANCELLATION MEASURED WITH HINODE

    International Nuclear Information System (INIS)

    Park, Soyoung; Chae, Jongchul; Litvinenko, Yuri E.

    2009-01-01

    Photospheric magnetic flux cancellation on the Sun is generally believed to be caused by magnetic reconnection occurring in the low solar atmosphere. Individual canceling magnetic features are observationally characterized by the rate of flux cancellation. The specific cancellation rate, defined as the rate of flux cancellation divided by the interface length, gives an accurate estimate of the electric field in the reconnecting current sheet. We have determined the specific cancellation rate using the magnetograms taken by the Solar Optical Telescope (SOT) aboard the Hinode satellite. The specific rates determined with SOT turned out to be systematically higher than those based on the data taken by the Michelson Doppler Imager (MDI) aboard the Solar and Heliospheric Observatory. The median value of the specific cancellation rate was found to be 8 x 10 6 G cm s -1 -a value four times that obtained from the MDI data. This big difference is mainly due to a higher angular resolution and better sensitivity of the SOT, resulting in magnetic fluxes up to five times larger than those obtained from the MDI. The higher rates of flux cancellation correspond to either faster inflows or stronger magnetic fields of the reconnection inflow region, which may have important consequences for the physics of photospheric magnetic reconnection.

  6. Growth and etching characteristics of (001) β-Ga2O3 by plasma-assisted molecular beam epitaxy

    Science.gov (United States)

    Oshima, Yuichi; Ahmadi, Elaheh; Kaun, Stephen; Wu, Feng; Speck, James S.

    2018-01-01

    We investigated the homoepitaxial growth and etching characteristics of (001) β-Ga2O3 by plasma-assisted molecular beam epitaxy. The growth rate of β-Ga2O3 increased with increasing Ga-flux, reaching a clear plateau of 56 nm h-1, and then decreased at higher Ga-flux. The growth rate decreased from 56 to 42 nm h-1 when the substrate temperature was increased from 750 °C to 800 °C. The growth rate was negative (net etching) when only Ga-flux was supplied. The etching rate proportionally increased with increasing the Ga-flux, reaching 84 nm h-1. The etching was enhanced at higher temperatures. It was found that Ga-etching of (001) β-Ga2O3 substrates prior to the homoepitaxial growth markedly improved the surface roughness of the film.

  7. Measuring Item Fill-Rate Performance in a Finite Horizon

    OpenAIRE

    Douglas J. Thomas

    2005-01-01

    The standard treatment of fill rate relies on stationary and serially independent demand over an infinite horizon. Even if demand is stationary, managers are held accountable for performance over a finite horizon. In a finite horizon, the fill rate is a random variable. Studying the distribution is relevant because a vendor may be subject to financial penalty if she fails to achieve her target fill rate over a specified finite period. It is known that for a zero lead time, base-stock model, t...

  8. Fabrication of Light Extraction Efficiency of Organic Light-Emitting Diodes with 3D Aspherical Microlens by Using Dry Etching Process

    Directory of Open Access Journals (Sweden)

    Y. C. Chen

    2013-01-01

    Full Text Available organic light-emitting diode (OLED can enable a greater artificial contrast ratio and viewing angle compared to liquid crystal display (LCD because OLED pixels directly emit light. There is a shortcoming that the internal quantum efficiency can reach values close to 100%, but about 80% light disperses because of the difference among the refractive indices of the substrate, anode, indium tin oxide (ITO film, and air. In this paper, three dimensions aspherical microlens arrays (3D A-MLAs with substrate modifications are developed to simulate the optical luminous field by using FRED software. This study modified parameters of 3D A-MLAs such as the diameter, fill-factor, aspect ratio, dry etching parameters, and electroforming rates of microlens to improve the extraction efficiency of the OLED. In dry etching, not only the aspect ratio with better extraction rate can be obtained by reactive ion etching (RIE dry etching, but also an undercutting phenomenon can be avoided. The dimensions of 3D A-MLAs can be accurately controlled in the electroforming process used to make a nickel-cobalt (Ni-Co metal mold to achieve the designed dimensions. According to the measured results, the average luminance efficacy of the OLEDs with 3D A-MLAs can be enhanced.

  9. Blood flow rate measurements with indicator techniques revisited

    DEFF Research Database (Denmark)

    Sejrsen, Per; Bülow, Jens

    2009-01-01

    In view of the emerging role, disturbances in regional blood flow rate seem to play in the pathogenesis of the metabolic syndrome; we review the concepts of the classical indicator dilution and washout techniques used for determinations of regional blood flow rate. Prerequisites, assumptions......, necessary precautions for the application of these experimental techniques are emphasized. Special attention has been carried out to elucidate the consequence of a choice of indicators having a large distribution volume in the tissues....

  10. Magnetically enhanced triode etching of large area silicon membranes in a molecular bromine plasma

    International Nuclear Information System (INIS)

    Wolfe, J.C.; Sen, S.; Pendharkar, S.V.; Mauger, P.; Shimkunas, A.R.

    1992-01-01

    The optimization of a process for etching 125 mm silicon membranes formed on 150 mm wafers and bonded to Pyrex rings is discussed. A magnetically enhanced triode etching system was designed to provide an intense, remote plasma surrounding the membrane while, at the same time, suppressing the discharge over the membrane itself. For the optimized molecular bromine process, the silicon etch rate is 40 nm/min and the selectivity relative to SiO 2 is 160:1. 14 refs., 6 figs

  11. A Nanoscale Plasma Etching Process for Pole Tip Recession of Perpendicular Recording Magnetic Head

    OpenAIRE

    LIU, Shoubin; HE, Dayao

    2017-01-01

    The pole tip of perpendicular recording head is constructed in a stacked structure with materials of NiCoFe, NiFe, Al2O3 and AlTiC. The surfaces of different materials are set at different heights below the air-bearing surface of slider. This paper presented a plasma dry etching process for Pole Tip Recession (PTR) based on an ion beam etching system. Ar and O2 mixed plasma at small incident angles have a high removal rate to the nonmagnetic material. It was utilised to etch the reference sur...

  12. Surface characterization after subaperture reactive ion beam etching

    Energy Technology Data Exchange (ETDEWEB)

    Miessler, Andre; Arnold, Thomas; Rauschenbach, Bernd [Leibniz-Institut fuer Oberflaechenmodifizierung (IOM), Leipzig (Germany)

    2010-07-01

    In usual ion beam etching processes using inert gas (Ar, Xe, Kr..) the material removal is determined by physical sputtering effects on the surface. The admixture of suitable gases (CF{sub 4}+O{sub 2}) into the glow discharge of the ion beam source leads to the generation of reactive particles, which are accelerated towards the substrate where they enhance the sputtering process by formation of volatile chemical reaction products. During the last two decades research in Reactive Ion Beam Etching (RIBE) has been done using a broad beam ion source which allows the treatment of smaller samples (diameter sample < diameter beam). Our goal was to apply a sub-aperture Kaufman-type ion source in combination with an applicative movement of the sample with respect to the source, which enables us to etch areas larger than the typical lateral dimensions of the ion beam. Concerning this matter, the etching behavior in the beam periphery plays a decisive role and has to be investigated. We use interferometry to characterize the final surface topography and XPS measurements to analyze the chemical composition of the samples after RIBE.

  13. Micro-structuring of thick NdFeB films using high-power plasma etching for magnetic MEMS application

    International Nuclear Information System (INIS)

    Jiang, Yonggang; Fujita, Takayuki; Higuchi, Kohei; Maenaka, Kazusuke; Masaoka, Shingo; Uehara, Minoru

    2011-01-01

    This paper describes the micro-patterning of thick NdFeB magnetic films using a high-power plasma etching method. The effects of RF bias power and gas composition on the selectivity and etching rate are experimentally studied. A maximum etching rate of 60 nm min −1 is achieved with an inductively coupled plasma power of 500 W and a RF bias power of 200 W. A maximum selectivity of 0.26 between hard baked AZP4903 photoresist and NdFeB magnetic films is achieved when volumetric Cl 2 concentration is 2.5%. NdFeB micro-magnets as thick as 4.2 µm are achieved by using AZP4903 photoresist. Magnetic film as thick as 10 µm can be patterned by using SU-8 photoresist with a thickness of 100 µm as the mask. The magnetic property of patterned microstructures is characterized using a vibrating sample magnetometer and the magnetic field distribution is measured using a Hall effect sensor IC. The characterization results indicate that the patterned magnetic microstructures have a high magnetic remanance of 1.0 T, which is comparable to that of the non-patterned NdFeB films.

  14. Fluorocarbon based atomic layer etching of Si_3N_4 and etching selectivity of SiO_2 over Si_3N_4

    International Nuclear Information System (INIS)

    Li, Chen; Metzler, Dominik; Oehrlein, Gottlieb S.; Lai, Chiukin Steven; Hudson, Eric A.

    2016-01-01

    , precursor chemistry has a weak impact on etching selectivity. Surface chemistry analysis shows that surface fluorination and FC reduction take place during a single ALE cycle for FC depleted conditions. A fluorine rich carbon layer was observed on the Si_3N_4 surface after ALE processes for which FC accumulation takes place. The angle resolved-XPS thickness calculations confirmed the results of the ellipsometry measurements in all cases.

  15. Modeling the characteristic etch morphologies along specific crystallographic orientations by anisotropic chemical etching

    Science.gov (United States)

    Li, Kun-Dar; Miao, Jin-Ru

    2018-02-01

    To improve the advanced manufacturing technology for functional materials, a sophisticated control of chemical etching process is highly demanded, especially in the fields of environment and energy related applications. In this study, a phase-field-based model is utilized to investigate the etch morphologies influenced by the crystallographic characters during anisotropic chemical etching. Three types of etching modes are inspected theoretically, including the isotropic, and preferred oriented etchings. Owing to the specific etching behavior along the crystallographic directions, different characteristic surface structures are presented in the simulations, such as the pimple-like, pyramidal hillock and ridge-like morphologies. In addition, the processing parameters affecting the surface morphological formation and evolution are also examined systematically. According to the numerical results, the growth mechanism of surface morphology in a chemical etching is revealed distinctly. While the etching dynamics plays a dominant role on the surface formation, the characteristic surface morphologies corresponding to the preferred etching direction become more apparent. As the atomic diffusion turned into a determinative factor, a smoothened surface would appear, even under the anisotropic etching conditions. These simulation results provide fundamental information to enhance the development and application of anisotropic chemical etching techniques.

  16. Modeling the characteristic etch morphologies along specific crystallographic orientations by anisotropic chemical etching

    Directory of Open Access Journals (Sweden)

    Kun-Dar Li

    2018-02-01

    Full Text Available To improve the advanced manufacturing technology for functional materials, a sophisticated control of chemical etching process is highly demanded, especially in the fields of environment and energy related applications. In this study, a phase-field-based model is utilized to investigate the etch morphologies influenced by the crystallographic characters during anisotropic chemical etching. Three types of etching modes are inspected theoretically, including the isotropic, and preferred oriented etchings. Owing to the specific etching behavior along the crystallographic directions, different characteristic surface structures are presented in the simulations, such as the pimple-like, pyramidal hillock and ridge-like morphologies. In addition, the processing parameters affecting the surface morphological formation and evolution are also examined systematically. According to the numerical results, the growth mechanism of surface morphology in a chemical etching is revealed distinctly. While the etching dynamics plays a dominant role on the surface formation, the characteristic surface morphologies corresponding to the preferred etching direction become more apparent. As the atomic diffusion turned into a determinative factor, a smoothened surface would appear, even under the anisotropic etching conditions. These simulation results provide fundamental information to enhance the development and application of anisotropic chemical etching techniques.

  17. Etching Behavior of Aluminum Alloy Extrusions

    Science.gov (United States)

    Zhu, Hanliang

    2014-11-01

    The etching treatment is an important process step in influencing the surface quality of anodized aluminum alloy extrusions. The aim of etching is to produce a homogeneously matte surface. However, in the etching process, further surface imperfections can be generated on the extrusion surface due to uneven materials loss from different microstructural components. These surface imperfections formed prior to anodizing can significantly influence the surface quality of the final anodized extrusion products. In this article, various factors that influence the materials loss during alkaline etching of aluminum alloy extrusions are investigated. The influencing variables considered include etching process parameters, Fe-rich particles, Mg-Si precipitates, and extrusion profiles. This study provides a basis for improving the surface quality in industrial extrusion products by optimizing various process parameters.

  18. Obtaining porous silicon suitable for sensor technology using MacEtch nonelectrolytic etching

    Directory of Open Access Journals (Sweden)

    Iatsunskyi I. R.

    2013-12-01

    Full Text Available The author suggests to use the etching method MacEtch (metal-assisted chemical etching for production of micro- and nanostructures of porous silicon. The paper presents research results on the morphology structures obtained at different parameters of deposition and etching processes. The research has shown that, depending on the parameters of deposition of silver particles and silicon wafers etching, the obtained surface morphology may be different. There may be both individual crater-like pores and developed porous or macroporous surface. These results indicate that the MacEtch etching is a promising method for obtaining micro-porous silicon nanostructures suitable for effective use in gas sensors and biological object sensors.

  19. Carrier-lifetime-controlled selective etching process for semiconductors using photochemical etching

    International Nuclear Information System (INIS)

    Ashby, C.I.H.; Myers, D.R.

    1992-01-01

    This patent describes a process for selectively photochemically etching a semiconductor material. It comprises introducing at least one impurity into at least one selected region of a semiconductor material to be etched to increase a local impurity concentration in the at least one selected region relative to an impurity concentration in regions of the semiconductor material adjacent thereto, for reducing minority carrier lifetimes within the at least one selected region relative to the adjacent regions for thereby providing a photochemical etch-inhibiting mask at the at least one selected region; and etching the semiconductor material by subjecting the surface of the semiconductor material to a carrier-driven photochemical etching reaction for selectively etching the regions of the semiconductor material adjacent the at least one selected region having the increase impurity concentration; wherein the step of introducing at least one impurity is performed so as not to produce damage to the at least one selected region before any etching is performed

  20. External scintigraphy in measuring rate of gastric emptying in beagles

    Energy Technology Data Exchange (ETDEWEB)

    Theodorakis, M.C.

    1980-07-01

    The application of external scintigraphy and preparation of a new radiopharmaceutical agent for the investigation of the rate and pattern of gastric emptying in beagles and for the visualization of segments of the intestines have been described. 99mTc-labeled triethylenetetramine-polystyrene resin was mixed in a test meal and was administered to the animal. The gastric emptying rate of the beagle was evaluated by serially recording the gastric radioactivity by means of a scintillation camera. The experimental data indicate that the pattern of gastric emptying of beagles during the first 60 min was monoexponential and the gastric emptying half time was 1.3 h. The usefulness of external scintigraphy as a noninvasive method for determining the gastric emptying rates and for visualizing segments of GI tract in animals has been demonstrated.

  1. Dynamical analysis of electrochemical wall shear rate measurements

    NARCIS (Netherlands)

    Steenhoven, van A.A.; Beucken, van den F.J.H.M.

    1991-01-01

    The performance of a circular electrochemical wall shear rate probe under unsteady flow conditions is analysed through a combined ezxperimental, numerical and analytical approach. The experiments are performed with a ferri- and ferrocyanide redox couple and compared to finite element analysis of the

  2. Measuring Vocational Preferences: Ranking versus Categorical Rating Procedures.

    Science.gov (United States)

    Carifio, James

    1978-01-01

    Describes a study to compare the relative validities of ranking v categorical rating procedures for obtaining student vocational preference data in exploratory program assignment situations. Students indicated their vocational program preferences from career clusters, and the frequency of wrong assignments made by each method was analyzed. (MF)

  3. Measurement of oxygen consumption rate of osteoblasts from ...

    African Journals Online (AJOL)

    The cells were evaluated through live/dead assay, hematoxylin-eosin (HE) and alkaline phosphatase (ALP) staining. Moreover, Von-Kossa staining and Alizarin Red S staining were carried out for mineralized nodule formation. Following this, the oxygen consumption rates of osteoblasts in the earlier mentioned different ...

  4. Continuous measurement of heart rate variability following carbon ...

    African Journals Online (AJOL)

    Background: Previous studies of autonomic nervous system activity through analysis of heart rate variability (HRV) have demonstrated increased sympathetic activity during positive-pressure pneumoperitoneum. We employed an online, continuous method for rapid HRV analysis (MemCalc™, Tarawa, Suwa Trust, Tokyo, ...

  5. Continuous measurement of heart rate variability following carbon ...

    African Journals Online (AJOL)

    2010-07-16

    Jul 16, 2010 ... Power spectral analysis of the electrocardiographic R-R interval [heart rate variability: (HRV)] is a well known, non- invasive method for assessing autonomic nervous activity.1. Studies using HRV analysis during positive-pressure pneumoperitoneum (PPP) have demonstrated increased sympathetic ...

  6. Neutron detector for fusion reaction-rate measurements

    International Nuclear Information System (INIS)

    Lerche, R.A.; Phillion, D.W.; Tietbohl, G.L.

    1993-01-01

    We have developed a fast, sensitive neutron detector for recording the fusion reaction-rate history of inertial-confinement fusion (ICF) experiments. The detector is based on the fast rise-time of a commercial plastic scintillator (BC-422) and has a response 7 neutrons

  7. Characterization of plasma etching damage on p-type GaN using Schottky diodes

    International Nuclear Information System (INIS)

    Kato, M.; Mikamo, K.; Ichimura, M.; Kanechika, M.; Ishiguro, O.; Kachi, T.

    2008-01-01

    The plasma etching damage in p-type GaN has been characterized. From current-voltage and capacitance-voltage characteristics of Schottky diodes, it was revealed that inductively coupled plasma (ICP) etching causes an increase in series resistance of the Schottky diodes and compensation of acceptors in p-type GaN. We investigated deep levels near the valence band of p-type GaN using current deep level transient spectroscopy (DLTS), and no deep level originating from the ICP etching damage was observed. On the other hand, by capacitance DLTS measurements for n-type GaN, we observed an increase in concentration of a donor-type defect with an activation energy of 0.25 eV after the ICP etching. The origin of this defect would be due to nitrogen vacancies. We also observed this defect by photocapacitance measurements for ICP-etched p-type GaN. For both n- and p-type GaN, we found that the low bias power ICP etching is effective to reduce the concentration of this defect introduced by the high bias power ICP etching

  8. Effects of the Addictives on Etching Characteristics of Aluminum Foil

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.K.; Jang, J.M.; Chi, C.S. [Kookmin University, Seoul (Korea); Shin, D.C. [Sungnam Polytechnic, Sungnam (Korea); Lee, J.H.; Oh, H.J. [Hanseo University, Seosan (Korea)

    2001-01-01

    The effects of additives in the HCI etching solution on etching behaviors of aluminium foil as dielectric film for electrolytic capacitors were investigated. The etch pits formed in 1M hydrochloric acid containing ethylene glycol as an additive contain more fine and homogeneous etch tunnels compared to thoese in 1 M hydrochloric acid only, which led to the increase in the effective internal surface area of aluminum foil. After anodizing of aluminum foil etched in etching solutions, the LCR meter results have shown that the capacitance of dielectric film etched in hydrochloric acid with ethylene glycol was increased remarkably compared to that etched in hydrochloric acid only. (author). 21 refs., 10 figs.

  9. Direct Measurement of the Supernova Rate in Starburst Galaxies

    Science.gov (United States)

    Bregman, Jesse D.; Temi, Pasquale; Rank, David; DeVincenzi, Donald L. (Technical Monitor)

    1999-01-01

    Supernovae play a key role in the dynamics, structure, and chemical evolution of galaxies. The massive stars that end their lives as supernovae live for short times. Many are still associated with dusty star formation regions when they explode, making them difficult to observe at visible wavelengths. In active star forming regions (galactic nuclei and starburst regions), dust extintion is especially severe. Thus, determining the supernova rate in the active star forming regions of galaxies, where the supernova rate can be one or two orders of magnitude higher than the average, has proven to be difficult. From observations of SN1987A, we know that the [NiII] 6.63 micron emission line was the strongest line in the infrared spectrum for a period of a year and a half after the explosion. Since dust extintion is much less at 6.63 pm than at visible wavelengths (A(sub 6.63)/A(sub V) = 0.025), the NiII line can be used as a sensitive probe for the detection of recent supernovae. We have observed a sample of starburst galaxies at 6.63 micron using ISOCAM to search for the NiII emission line characteristic of recent supernovae. We did not detect any NiII line emission brighter than a 5sigma limit of 5 mJy. We can set upper limits to the supernova rate in our sample, scaled to the rate in M82, of less than 0.3 per year at the 90% confidence level using Bayesian methods. Assuming that a supernova would have a NiII with the same luminosity as observed in SN1987A, we find less than 0.09 and 0.15 per year at the 50% and 67% confidence levels. These rates are somewhat less if a more normal type II supernovae has a NiII line luminosity greater than the line in SN1987A.

  10. Sputter etching of polymer fibres

    International Nuclear Information System (INIS)

    Carter, G.; Hill, A.E.; Nobes, M.J.; Jeffries, R.; Simmens, S.C.

    1979-01-01

    Fibres of polyamide, polyester and an aromatic polyamide (Kevlar) have been subjected to Ar + ion bombardment erosion in an ion accelerator or an rf discharge system. In the case of the former two polymers, cones are observed to develop upon the fibre surface and these are associated with etch protection resulting from the presence of particles of titanium dioxide pigment. This effect is absent in the third, unpigmented, fibre. In all cases ripple structures with a habit transverse to the fibre axes and of wavelength of approximately 1000 Angstrom are gradually developed during ion bombardment. It is suggested that this morphology results from an underlying periodicity of the fibre structure either inherent in the fibre structure or induced by the irradiation. (author)

  11. A Novel performance measure for picture rate conversion methods.

    NARCIS (Netherlands)

    Heinrich, A.; Haan, de G.; Cordes, C.N.

    2008-01-01

    Motion compensated interpolation (MCI) is crucial for motion portrayal improvement of modern displays, and film judder elimination. As MCI complexity grows, subjective optimization becomes cumbersome and elaborate. We present an objective metric that matches perception better than earlier measures

  12. Vacuum effect on the etch induction time and registration sensitivity of polymer track detectors

    International Nuclear Information System (INIS)

    Csige, I.; Hunyadi, I.; Somogyi, G.

    1988-01-01

    The effect of a vacuum on etch induction time and track etch rate ratio of some polymer track detectors was studied systematically with alpha particles of different energies. It was found that the etch induction time increases, and the track etch rate ratio decreases, drastically when the detectors were irradiated in a vacuum and also kept in a vacuum for a few hours before and for a few minutes after the irradiation. These times proved to be characteristic for the outgassing of oxygen from the sheets and the stabilization of latent tracks, respectively. The role of oxygen in latent track formation is discussed. We have found that the vacuum effect is most significant near the surface. Its diminution with depth depends on the time of outgassing in accordance with the time variation of the dissolved oxygen concentration profile inside the sheets. (author)

  13. Vacuum effect on the etch induction time and registration sensitivity of polymer track detectors

    Energy Technology Data Exchange (ETDEWEB)

    Csige, I.; Hunyadi, I.; Somogyi, G. (Magyar Tudomanyos Akademia, Debrecen (Hungary). Atommag Kutato Intezete); Fujii, M. (Institute of Space and Astronautical Science, Sagamihara (Japan))

    1988-01-01

    The effect of a vacuum on etch induction time and track etch rate ratio of some polymer track detectors was studied systematically with alpha particles of different energies. It was found that the etch induction time increases, and the track etch rate ratio decreases, drastically when the detectors were irradiated in a vacuum and also kept in a vacuum for a few hours before and for a few minutes after the irradiation. These times proved to be characteristic for the outgassing of oxygen from the sheets and the stabilization of latent tracks, respectively. The role of oxygen in latent track formation is discussed. We have found that the vacuum effect is most significant near the surface. Its diminution with depth depends on the time of outgassing in accordance with the time variation of the dissolved oxygen concentration profile inside the sheets. (author).

  14. The use of CH3OH additive to NaOH for etching alpha particle tracks in a CR-39 plastic nuclear track detector

    International Nuclear Information System (INIS)

    Ashry, A.H.; Abdalla, A.M.; Rammah, Y.S.; Eisa, M.; Ashraf, O.

    2014-01-01

    Fast detection of alpha particles in CR-39 detectors was investigated using a new chemical etchant. 252 Cf and 241 Am sources were used for irradiating samples of CR-39 SSNTDs with fission fragments and alpha particles in air at normal temperature and pressure. A series of experimental chemical etching are carried out using new etching solution (8 ml of 10N NaOH+1 ml CH 3 OH) at 60 °C to detect alpha particle in short time in CR-39 detectors. Suitable analyzing software has been used to analyze experimental data. From fission and alpha track diameters, the value of bulk etching rate is equal to 2.73 μm/h. Both the sensitivity and etching efficiency were found to vary with the amount of methanol in the etching solution. Pure NaOH was used as a control to compare with the result from etching in NaOH with different concentrations of CH 3 OH. The etching efficiency is determined and compared with conventional aqueous solution of 6.25N NaOH at 70 °C for etching time equals 5 h. In this study, the obtained etching efficiency shows a considerable agreement with the previous work. - Highlights: • The value of bulk etching rate is equal to 2.73 μm/h. • Fast detection of alpha particles in CR-39 detectors. • Samples of CR-39 have been irradiated with fission fragments. • Etching efficiency was determined

  15. The memory characteristics of submicron feature-size PZT capacitors with PtOx top electrode by using dry-etching

    International Nuclear Information System (INIS)

    Huang, C.-K.; Wang, C.-C.; Wu, T.-B.

    2007-01-01

    Dry etching and its effect on the characteristics of submicron feature-size PbZr 1-x Ti x O 3 (PZT) capacitors with PtO x top electrode were investigated. The photoresist (PR)-masked PtO x films were etched by an Ar/(20%)Cl 2 /O 2 helicon wave plasma. A fence-free pattern with a significantly high etch rate and sidewall slope was obtained by the addition of O 2 into the etching gas mixture, due to the chemical instability of PtO x and the formation of a PtO 2 passivation layer to suppress redeposition of the etch by-products on the etched surface. The patterned PtO x electrode can be further used as a hard mask for etching the PZT film, subsequently, with the gas mixture of Ar, CF 4 and O 2 . A high etching rate of PZT and a good etching selectivity to PtO x can be obtained at 30% O 2 addition into the Ar/(50%)CF 4 plasma. The etched capacitors have a steep, 72 0 , sidewall angle with a clean surface. Moreover, the addition of O 2 into the etching gas can well preserve the properties and the fatigue endurance of PtO x /PZT capacitors

  16. Localized etching of polymer films using an atmospheric pressure air microplasma jet

    International Nuclear Information System (INIS)

    Guo, Honglei; Liu, Jingquan; Yang, Bin; Chen, Xiang; Yang, Chunsheng

    2015-01-01

    A direct-write process device based on the atmospheric pressure air microplasma jet (AμPJ) has been developed for the localized etching of polymer films. The plasma was generated by the air discharge ejected out through a tip-nozzle (inner diameter of 100 μm), forming the microplasma jet. The AμPJ was capable of reacting with the polymer surface since it contains a high concentration of oxygen reactive species and thus resulted in the selective removal of polymer films. The experimental results demonstrated that the AμPJ could fabricate different microstructures on a parylene-C film without using any masks or causing any heat damage. The etch rate of parylene-C reached 5.1 μm min −1 and microstructures of different depth and width could also be realized by controlling two process parameters, namely, the etching time and the distance between the nozzle and the substrate. In addition, combining XPS analysis and oxygen-induced chemical etching principles, the potential etching mechanism of parylene-C by the AμPJ was investigated. Aside from the etching of parylene-C, micro-holes on the photoresist and polyimide film were successfully created by the AμPJ. In summary, maskless pattern etching of polymer films could be achieved using this AμPJ. (paper)

  17. Evaluation of Stress Parameters Based on Heart Rate Variability Measurements

    OpenAIRE

    Uysal, Fatma; Tokmakçı, Mahmut

    2018-01-01

    In this study, heart rate variabilitymeasurements and analysis was carried with help of the ECG recordings to showhow autonom nervous system activity changes. So as to evaluate the parametersrelated to stress of the study, the situation of relaxation, Stroop color/wordtest, mental test and auditory stimulus that would stress someone out wereapplied to six volunteer participants in a laboratory environment. Being takentotally seven minutes ECG recording and made analysis in time and frequencyd...

  18. Measurement of Sediment Deposition Rates using an Optical Backscatter Sensor

    Science.gov (United States)

    Ridd, P.; Day, G.; Thomas, S.; Harradence, J.; Fox, D.; Bunt, J.; Renagi, O.; Jago, C.

    2001-02-01

    An optical method for measuring siltation of sediment has been developed using an optical fibre backscatter (OBS) nephelometer. Sediment settling upon the optical fibre sensor causes an increase in the backscatter reading which can be related to the settled sediment surface density (SSSD) as measured in units of mg cm -2. Calibration and laboratory tests indicate that the resolution of measurements of SSSD is 0·01 mg cm -2and an accuracy of 5% in still water. In moving water it is more difficult to determine the accuracy of the method because other methods with suitable resolution are unavailable. However, indirect methods using measurements of changing suspended sediment concentration in a ring flume, indicate that the OBS method under-predicts deposition. The series of siltation from three field sites are presented. This sensor offers considerable advances over other methods of measuring settling because time series of settling may be taken and thus settling events may be related to other hydrodynamic parameters such as wave climate and currents.

  19. Plasma treatment of porous GaAs surface formed by electrochemical etching method: Characterization and properties

    International Nuclear Information System (INIS)

    Saloum, S.; Naddaf, M.

    2010-01-01

    Porous GaAs samples were formed by electrochemical anodic etching of Zn doped p-type GaAs (100) wafers at different etching parameters (time, mode of applied voltage or current and electrolyte). The effect of etching parameters and plasma surface treatment on the optical properties of the prepared sample has been investigated by using room temperature photoluminescence (PL), Raman spectroscopy and reflectance spectroscopic measurements in the range (400-800 nm). The surface morphological changes were studied by using atomic force microscope. (author)

  20. Track-Etched Magnetic Micropores for Immunomagnetic Isolation of Pathogens

    Science.gov (United States)

    Muluneh, Melaku; Shang, Wu

    2014-01-01

    A microfluidic chip is developed to selectively isolate magnetically tagged cells from heterogeneous suspensions, the track-etched magnetic micropore (TEMPO) filter. The TEMPO consists of an ion track-etched polycarbonate membrane coated with soft magnetic film (Ni20Fe80). In the presence of an applied field, provided by a small external magnet, the filter becomes magnetized and strong magnetic traps are created along the edges of the micropores. In contrast to conventional microfluidics, fluid flows vertically through the porous membrane allowing large flow rates while keeping the capture rate high and the chip compact. By utilizing track-etching instead of conventional semiconductor fabrication, TEMPOs can be fabricated with microscale pores over large areas A > 1 cm2 at little cost ( 500 at a flow rate of Φ = 5 mL h−1. Furthermore, the large density of micropores (ρ = 106 cm−2) allows the TEMPO to sort E. coli from unprocessed environmental and clinical samples, as the blockage of a few pores does not significantly change the behavior of the device. PMID:24535921

  1. Etching of fission tracks in silicate glasses by means of deionized water

    International Nuclear Information System (INIS)

    Dran, J.C.; Petit, J.C.

    1985-09-01

    Fission tracks have been revealed in silicate glasses with deionized water. Their sharp conical shape implies a marked enhancement of the dissolution rate along their core and consequently a cone angle and an etching efficiency (close to 100%) much higher than previously reported for glasses. We show that etching of fission tracks in natural environments has generally very limited geochemical implications except in specific cases such as that found in the Oklo uranium ores

  2. ANALYSIS OF MEASURES FOR INCREASING THE RATING OF UNIVERSITY IN INTERNATIONAL RATING SYSTEM

    Directory of Open Access Journals (Sweden)

    В.П. Харченко

    2011-02-01

    Full Text Available The principles of forming the world's most popular international Internet-ranking of universities are considered. The principles of forming the international rating of electronic resources known as Webometrics, which results are defined by summing four values based on quantity of unique external links to the site page and by the quantity of “valuable” files placed on website are represented.  Мost Internet ratings make slope on the  Web activity of the university and its researchers, therefore the participation of entire staff at university is required

  3. Using a smartphone to measure heart rate changes during relived happiness and anger

    NARCIS (Netherlands)

    Lakens, D.

    2013-01-01

    This study demonstrates the feasibility of measuring heart rate differences associated with emotional states such as anger and happiness with a smartphone. Novice experimenters measured higher heart rates during relived anger and happiness (replicating findings in the literature) outside a

  4. Biomass burning fuel consumption rates: a field measurement database

    CSIR Research Space (South Africa)

    Van Leeuwen, TT

    2014-01-01

    Full Text Available residue (n = 4, FC = 6.5), chaparral (n = 2, FC = 32), tropical peatland (n = 4, FC = 314), boreal peatland (n = 2, FC = 42), and tundra (n = 1, FC = 40). Within biomes the regional variability in the number of measurements was sometimes large, with e...

  5. Device for measuring the dose rate of pulsed neutrons

    International Nuclear Information System (INIS)

    Klett, A.

    2009-01-01

    The author presents a new apparatus, developed in collaboration by Berthold Technologies and the German company DESY, allowing neutron pulsed fields to be measured. It is based on the activation by high energy neutrons of carbon 12 present in the sensor materials, and on the decay of short life radionuclides produced by this activation. The detection principle and system are briefly presented

  6. The influence of chemical etching time on efficiency of radon detection using CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Reway, Adriana P.; Kappke, Jaqueline; Narloch, Danielle C., E-mail: adrireway@hotmail.com, E-mail: jaquelinekappke@gmail.com, E-mail: daninarloch@hotmail.com [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Departamento Academico de Fisica; Del Claro, Flavia; Paschuk, Sergei A., E-mail: flaviadelclaro@gmail.com, E-mail: spaschuk@gmail.com [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Programa de Pos-Graduaca em Engenharia Eletrica e Informatica Industrial; Correa, Janine N., E-mail: janine_nicolosi@hotmail.com [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Departamento Academico de Construcao Civil

    2015-07-01

    Natural radiation is the principal source of human exposure to ionizing radiation. Radon is noble radioactive gas that emanates from the soil and rocks entering the atmosphere of dwellings where it could be accumulated. The inhalation of {sup 222}Rn represents a significant health risk. Solid-State Nuclear Track Detectors (SSNTD) represents an efficient method for alpha particle detection and measurements of the activity concentration of {sup 222}Rn. The aim of present work was to study the etching time impact on CR-39 efficiency in radon activity measurements. The investigation was performed using 80 CR-39 detectors, which were exposed to a source of radon. After the exposition, alpha particle tracks development was achieved by chemical etching using 6.25M NaOH solution and ethanol (2%) at 70°C. Etching alpha particle tracks were identified and counted manually using the optical microscope with magnification of 100x and glass overlay mask. The etching time ranged from 7 to 14 hours. The results show that there is an increase in the number of visible tracks with increased etching time. The number of traces obtained for 7 hours and 8 hours of revelation was 1430 +/- 90 and 2090 +/- 160, respectively. However, for etching time of 13 and 14 hours was not observed statistical increase in the number of visible tracks. The number of tracks in this situation was 3630 +/- 180 and 3870 +/- 160 to 13 and 14 hours etching. Thus, for assumed etching parameters, the etching optimal time was observed 14 hours. (author)

  7. Etch Defect Characterization and Reduction in Hard-Mask-Based Al Interconnect Etching

    International Nuclear Information System (INIS)

    Lee, H.J.; Hung, C.L.; Leng, C.H.; Lian, N.T.; Young, L.W.

    2009-01-01

    This paper identifies the defect adders, for example, post hard-mask etch residue, post metal etch residue, and blocked etch metal island and investigates the removal characteristics of these defects within the oxide-masked Al etching process sequence. Post hard-mask etch residue containing C atom is related to the hardening of photoresist after the conventional post-RIE ashing at 275 degree C. An in situ O 2 -based plasma ashing on RIE etcher was developed to prevent the photoresist hardening from the high-ashing temperature; followed wet stripping could successfully eliminate such hardened polymeric residue. Post metal etch residue was caused from the attack of the Al sidewall by Cl atoms, and too much CHF 3 addition in the Al main etch step passivated the surface of Al resulting in poor capability to remove the Al-containing residue. The lower addition of CHF 3 in the Al main etch step would benefit from the residue removal. One possibility of blocked etch metal island creating was due to the micro masking formed on the opening of Ti N during the hard-mask patterning. We report that an additional Ti N surface pretreatment with the Ar/CHF 3 /N 2 plasmas could reduce the impact of the micro masking residues on blocked metal etch.

  8. Optimization of time on CF{sub 4}/O{sub 2} etchant for inductive couple plasma reactive ion etching of TiO{sub 2} thin film

    Energy Technology Data Exchange (ETDEWEB)

    Adzhri, R., E-mail: adzhri@gmail.com; Fathil, M. F. M.; Ruslinda, A. R.; Gopinath, Subash C. B.; Voon, C. H.; Foo, K. L.; Nuzaihan, M. N. M.; Azman, A. H.; Zaki, M. [Institute of Nano Electronic Engineering (INEE), Universiti Malaysia Perlis (UniMAP), Perlis (Malaysia); Arshad, M. K. Md., E-mail: mohd.khairuddin@unimap.edu.my; Hashim, U.; Ayub, R. M. [Institute of Nano Electronic Engineering (INEE), Universiti Malaysia Perlis (UniMAP), Perlis (Malaysia); School of Microelectronic Engineering, Universiti Malaysia Perlis (UniMAP), Perlis (Malaysia)

    2016-07-06

    In this work, we investigate the optimum etching of titanium dioxide (TiO{sub 2}) using inductive couple plasma reactive ion etching (ICP-RIE) on our fabricated devices. By using a combination of CF{sub 4}/O{sub 2} gases as plasma etchant with ratio of 3:1, three samples of TiO{sub 2} thin film were etched with different time duration of 10 s, 15 s and 20 s. The ion bombardment of CF{sub 4} gases with plasma enhancement by O{sub 2} gas able to break the oxide bond of TiO{sub 2} and allow anisotropic etch profile with maximum etch rate of 18.6 nm/s. The sample was characterized by using optical profilometer to determine the depth of etched area and scanning electron microscopy (SEM) for etch profile characterization.

  9. Optimization of time on CF_4/O_2 etchant for inductive couple plasma reactive ion etching of TiO_2 thin film

    International Nuclear Information System (INIS)

    Adzhri, R.; Fathil, M. F. M.; Ruslinda, A. R.; Gopinath, Subash C. B.; Voon, C. H.; Foo, K. L.; Nuzaihan, M. N. M.; Azman, A. H.; Zaki, M.; Arshad, M. K. Md.; Hashim, U.; Ayub, R. M.

    2016-01-01

    In this work, we investigate the optimum etching of titanium dioxide (TiO_2) using inductive couple plasma reactive ion etching (ICP-RIE) on our fabricated devices. By using a combination of CF_4/O_2 gases as plasma etchant with ratio of 3:1, three samples of TiO_2 thin film were etched with different time duration of 10 s, 15 s and 20 s. The ion bombardment of CF_4 gases with plasma enhancement by O_2 gas able to break the oxide bond of TiO_2 and allow anisotropic etch profile with maximum etch rate of 18.6 nm/s. The sample was characterized by using optical profilometer to determine the depth of etched area and scanning electron microscopy (SEM) for etch profile characterization.

  10. Torque and Axial Loading Physics for Measuring Atmospheric Icing Load and Icing Rate

    OpenAIRE

    Mughal, Umair Najeeb; Virk, Muhammad Shakeel

    2015-01-01

    Measuring icing load and icing rate are important parameters for an atmospheric icing sensor. A new icing sensor has recently been designed and developed at Narvik University College for measuring atmospheric icing rate, icing load and icing type. Unlike the existing atmospheric icing sensors commercially available in market, which uses the axial loading for measuring icing load and icing rate, this new sensory system measures icing load and icing rate using the torque loading physics. The pe...

  11. Outcome Rating Scale and Session Rating Scale in Psychological Practice: Clinical Utility of Ultra-Brief Measures

    Science.gov (United States)

    Campbell, Alistair; Hemsley, Samantha

    2009-01-01

    The validity and reliability of the Outcome Rating Scale (ORS) and the Session Rating Scale (SRS) were evaluated against existing longer measures, including the Outcome Questionnaire-45, Working Alliance Inventory, Depression Anxiety Stress Scale-21, Quality of Life Scale, Rosenberg Self-Esteem Scale and General Self-efficacy Scale. The measures…

  12. Minimizing Isolate Catalyst Motion in Metal-Assisted Chemical Etching for Deep Trenching of Silicon Nanohole Array.

    Science.gov (United States)

    Kong, Lingyu; Zhao, Yunshan; Dasgupta, Binayak; Ren, Yi; Hippalgaonkar, Kedar; Li, Xiuling; Chim, Wai Kin; Chiam, Sing Yang

    2017-06-21

    The instability of isolate catalysts during metal-assisted chemical etching is a major hindrance to achieve high aspect ratio structures in the vertical and directional etching of silicon (Si). In this work, we discussed and showed how isolate catalyst motion can be influenced and controlled by the semiconductor doping type and the oxidant concentration ratio. We propose that the triggering event in deviating isolate catalyst motion is brought about by unequal etch rates across the isolate catalyst. This triggering event is indirectly affected by the oxidant concentration ratio through the etching rates. While the triggering events are stochastic, the doping concentration of silicon offers a good control in minimizing isolate catalyst motion. The doping concentration affects the porosity at the etching front, and this directly affects the van der Waals (vdWs) forces between the metal catalyst and Si during etching. A reduction in the vdWs forces resulted in a lower bending torque that can prevent the straying of the isolate catalyst from its directional etching, in the event of unequal etch rates. The key understandings in isolate catalyst motion derived from this work allowed us to demonstrate the fabrication of large area and uniformly ordered sub-500 nm nanoholes array with an unprecedented high aspect ratio of ∼12.

  13. Consequences of atomic layer etching on wafer scale uniformity in inductively coupled plasmas

    Science.gov (United States)

    Huard, Chad M.; Lanham, Steven J.; Kushner, Mark J.

    2018-04-01

    Atomic layer etching (ALE) typically divides the etching process into two self-limited reactions. One reaction passivates a single layer of material while the second preferentially removes the passivated layer. As such, under ideal conditions the wafer scale uniformity of ALE should be independent of the uniformity of the reactant fluxes onto the wafers, provided all surface reactions are saturated. The passivation and etch steps should individually asymptotically saturate after a characteristic fluence of reactants has been delivered to each site. In this paper, results from a computational investigation are discussed regarding the uniformity of ALE of Si in Cl2 containing inductively coupled plasmas when the reactant fluxes are both non-uniform and non-ideal. In the parameter space investigated for inductively coupled plasmas, the local etch rate for continuous processing was proportional to the ion flux. When operated with saturated conditions (that is, both ALE steps are allowed to self-terminate), the ALE process is less sensitive to non-uniformities in the incoming ion flux than continuous etching. Operating ALE in a sub-saturation regime resulted in less uniform etching. It was also found that ALE processing with saturated steps requires a larger total ion fluence than continuous etching to achieve the same etch depth. This condition may result in increased resist erosion and/or damage to stopping layers using ALE. While these results demonstrate that ALE provides increased etch depth uniformity, they do not show an improved critical dimension uniformity in all cases. These possible limitations to ALE processing, as well as increased processing time, will be part of the process optimization that includes the benefits of atomic resolution and improved uniformity.

  14. Electrochemical etching of a niobium foil in methanolic HF for electrolytic capacitor

    International Nuclear Information System (INIS)

    Kim, Kyungmin; Park, Jiyoung; Cha, Gihoon; Yoo, Jeong Eun; Choi, Jinsub

    2013-01-01

    Electrochemical etching of niobium foil in order to enlarge the surface area for the application in electrolytic capacitor was carried out in a methanolic electrolyte. We found that the pit density and depth are not linearly proportional to concentration of HF and applied potential: there is the optimal concentration of HF at each applied potential. The optimal etching condition was obtained at 50 V in 0.99 vol.% HF, which exhibited the capacitance of 350 μF cm −2 . Pit density and depth of pits on electrochemical etched Nb foil under different conditions were counted from SEM images and electrochemical impedance spectroscopy (EIS) of the etched Nb foils was carried out for the capacitance measurement. Equivalent circuit model showing less than 5% error was suggested for applying to the etched niobium foil. - Highlights: • Surface enlargement of Nb foil can be achieved by electrochemical etching in methanolic HF. • Electrolytic capacitor of etched niobium foil exhibits a capacitance of 350 μF cm −2 . • The method provides a way of developing commercially viable process

  15. On the long standing question of nuclear track etch induction time: Surface-cap model

    International Nuclear Information System (INIS)

    Rana, Mukhtar Ahmed

    2008-01-01

    Using a systematic set of experiments, nuclear track etch induction time measurements in a widely used CR-39 detector were completed for accessible track-forming particles (fission fragments, 5.2 MeV alpha particles and 5.9 MeV antiprotons). Results of the present work are compared with appropriately selected published results. The possibility of the use of etch induction time for charged particle identification is evaluated. Analysis of experimental results along with the use of well-established theoretical concepts yielded a model about delay in the start of chemical etching of nuclear tracks. The suggested model proposes the formation of a surface-cap (top segment) in each nuclear track consisting of chemically modified material with almost same or even higher resistance to chemical etching compared with bulk material of the track detector. Existing track formation models are reviewed very briefly, which provide one of the two bases of the proposed model. The other basis of the model is the general behavior of hot or energised material having a connection with an environment containing a number of species like ordinary air. Another reason for the delay in the start of etching is suggested as the absence of localization of etching atoms/molecules, which is present during etching at depth along the latent track

  16. High-density plasma-induced etch damage of wafer-bonded AlGaInP/mirror/Si light-emitting diodes

    CERN Document Server

    Wuu, D S; Huang, S H; Chung, C R

    2002-01-01

    Dry etch of wafer-bonded AlGaInP/mirror/Si light-emitting diodes (LEDs) with planar electrodes was performed by high-density plasma using an inductively coupled plasma (ICP) etcher. The etching characteristics were investigated by varying process parameters such as Cl sub 2 /N sub 2 gas combination, chamber pressure, ICP power and substrate-bias power. The corresponding plasma properties (ion flux and dc bias), in situ measured by a Langmuir probe, show a strong relationship to the etch results. With a moderate etch rate of 1.3 mu m/min, a near vertical and smooth sidewall profile can be achieved under a Cl sub 2 /(Cl sub 2 +N sub 2) gas mixture of 0.5, ICP power of 800 W, substrate-bias power of 100 W, and chamber pressure of 0.67 Pa. Quantitative analysis of the plasma-induced damage was attempted to provide a means to study the mechanism of leakage current and brightness with various dc bias voltages (-110 to -328 V) and plasma duration (3-5 min) on the wafer-bonded LEDs. It is found that the reverse leaka...

  17. Etching patterns on the micro‐ and nanoscale

    DEFF Research Database (Denmark)

    Michael-Lindhard, Jonas; Herstrøm, Berit; Stöhr, Frederik

    2014-01-01

    ‐ray beam down to a spot size of some 100 nm, the sidewalls of the cavities etched down to 300 μm into a silicon wafer must be perfectly straight and normal to the surface and have minimum roughness.The range of possible applications of the silicon etches is greatly extended if combined with electroplating...... and polymer injection molding. High precision patterns of, for instance microfluidic devices, are etched intosilicon which is then electroplated with nickel that will serve as a stamp in the polymer injection molding tool where thousands of devices may be replicated. In addition to silicon and its derived...

  18. Dry etching of ferroelectric Bi4-xEuxTi3O12 (BET) thin films

    International Nuclear Information System (INIS)

    Lim, Kyu-Tae; Kim, Kyoung-Tae; Kim, Dong-Pyo; Kim, Chang-Il

    2004-01-01

    Bi 4-x Eu x Ti 3 O 12 (BET) thin films were etched by using a inductively coupled Cl 2 /Ar plasma. We obtained a maximum etch rate of 69 nm/min at a gas mixing ratio of Cl 2 (20 %)/Ar (80 %). This result suggests that an effective method for BET etching is chemically assisted physical etching. With increasing coil RF power, the plasma density increases so that the increased reactive free radicals and ions enhance the etch rates of BET, Pt, and SiO 2 . As the dc-bias voltage is increased, the increased ion energy leads to an increased etch rate of BET films. From X-ray photoelectron spectroscopy, the intensities of the Bi-O, the Eu-O, and the Ti-O peaks change with increasing Cl 2 concentration. For a pure Ar plasma, the peak associated with the oxygen-metal (O-M: TiO 2 , Bi 2 O 3 , Eu 2 O 3 ) bond seems to disappear while the pure oxygen peak does not appear. After the BET thin films is etched by using a Cl 2 /Ar plasma, the peak associated with the O-M bond increases slowly, but more quickly than the peak associated with pure oxygen atoms, due to a decrease in the Ar-ion bombardment. These results seem to indicate that Bi and Eu react little with Cl atoms and are removed predominantly by argon-ion bombardment. Also, Ti reacts little with Cl radicals and is mainly removed by chemically assisted physical etching.

  19. Effect of certain production parameters and post-production treatments on the etching characteristics of CR-39 sheets

    Energy Technology Data Exchange (ETDEWEB)

    Somogyi, G.; Toth-Szilagyi, M.; Hunyadi, I.; Hafez, A.-F.

    1986-01-01

    There is a permanent need in producing track recording detectors of well defined behaviour from CR-39 monomer. Therefore, more studies on the role of production parameters determining the stability of main etching characteristics (bulk etch rate, Vsub(B);etch rate ratio, Vsub(T)/Vsub(B);opaqueness after longer etching periods) are highly required. In our studies we have examined different commercial CR-39 sheets (Homalite, Pershore, MA-ND) to compare their registration sensitivity to selected alpha and proton energies. In addition, we have investigated the main etching parameters of CR-39 sheets manufactured under different casting conditions varying the concentration of initiator and certain additives. Finally, the effect of some post-production treatments, annealing and storage in vacuum, on the Vsub(B) and Vsub(T)/Vsub(B) values is studied.

  20. Room temperature inductively coupled plasma etching of InAs/InSb in BCl 3/Cl 2/Ar

    KAUST Repository

    Sun, Jian

    2012-10-01

    Inductively coupled plasma (ICP) etching of InAs and InSb at room temperature has been investigated using BCl 3/Cl 2/Ar plasma. Specifically, the etch rate and post-etching surface morphology were investigated as functions of the gas composition, ICP power, process pressure, and RF chuck power. An optimized process has been developed, yielding anisotropic etching and very smooth surfaces with roughnesses of 0.25 nm for InAs, and 0.57 nm for InSb, which is comparable with the surface of epi-ready polished wafers. The process provides moderate etching rates of 820 /min for InAs and 2800 /min for InSb, and the micro-masking effect is largely avoided. © 2012 Elsevier B.V. All rights reserved.

  1. Alternative Measured-Service Rate Structures for Local Telephone Service,

    Science.gov (United States)

    1980-06-01

    contracts or grants . Views expressed in a Papet are the author’s own, and are not necessarily shared by Rand or its research sponsors. The Rand Corporation...by National Science Foundation, grant DAR 77-16286 to The Rand Corporation. Measuring costs depend strongly on the technology of the telephone network...a Budget Constraint. The Case of the Two-Part Tariff," Review of Economic Studies, July 1974, Vol. 41, pp. 337-345. -28- Oi, W. Y., "A Disneyland

  2. Grafting of acrylic acid on etched latent tracks induced by swift heavy ions on polypropylene films

    International Nuclear Information System (INIS)

    Mazzei, R.; Fernandez, A.; Garcia Bermudez, G.; Torres, A.; Gutierrez, M.C.; Magni, M.; Celma, G.; Tadey, D.

    2008-01-01

    In order to continue with a systematic study that include different polymers and monomers, the residual active sites produced by heavy ion beams, that remain after the etching process, were used to start the grafting process. To produce tracks, foils of polypropylene (PP) were irradiated with 208 Pb of 25.62 MeV/n. Then, these were etched and grafted with acrylic acid (AA) monomers. Experimental curves of grafting yield as a function of grafting time with the etching time as a parameter were measured. Also, the grating yield as a function of the fluence and etching time was obtained. In addition, the permeation of solutions, with different pH, through PP grafted foils was measured

  3. Magnetoelectrolysis of Co nanowire arrays grown in a track-etched polycarbonate membrane

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Barriga, J. [Instituto de Magnetismo Aplicado (UCM-RENFE-CSIC), P.O. Box 155, 28230, Las Rozas, Madrid (Spain)]. E-mail: sbarriga@bessy.de; Lucas, M. [Technische Universitaet Berlin, Institut fuer Theoretische Physik, Hardenbergstr. 36, D-10623 Berlin (Germany); Rivero, G. [Instituto de Magnetismo Aplicado (UCM-RENFE-CSIC), P.O. Box 155, 28230, Las Rozas, Madrid (Spain); Marin, P. [Instituto de Magnetismo Aplicado (UCM-RENFE-CSIC), P.O. Box 155, 28230, Las Rozas, Madrid (Spain); Hernando, A. [Instituto de Magnetismo Aplicado (UCM-RENFE-CSIC), P.O. Box 155, 28230, Las Rozas, Madrid (Spain)

    2007-05-15

    Arrays of Cobalt nanowires with a controlled length of 6{mu}m have been fabricated by electrochemical deposition into the pores of track-etched polycarbonate membranes with a nominal pore diameter of 30nm. The magnetic properties of Co-deposited nanowires and the effects of a magnetic field applied during electrodeposition of the arrays have been studied. An enhancement of the mass deposition rate due to the presence of a 50Oe magnetic field along the nanowire axis has been observed by measuring the experimental development of the current in the electrochemical cell during the fabrication process. X-ray diffraction measurements reveal a different polycrystalline degree for each deposition configuration, indicating that the crystalline structure of the deposited material has been substantially modified. Magnetic measurements show a clear dependence of the anisotropy directions on the orientation of the magnetic field applied during the electrodeposition.

  4. Magnetoelectrolysis of Co nanowire arrays grown in a track-etched polycarbonate membrane

    International Nuclear Information System (INIS)

    Sanchez-Barriga, J.; Lucas, M.; Rivero, G.; Marin, P.; Hernando, A.

    2007-01-01

    Arrays of Cobalt nanowires with a controlled length of 6μm have been fabricated by electrochemical deposition into the pores of track-etched polycarbonate membranes with a nominal pore diameter of 30nm. The magnetic properties of Co-deposited nanowires and the effects of a magnetic field applied during electrodeposition of the arrays have been studied. An enhancement of the mass deposition rate due to the presence of a 50Oe magnetic field along the nanowire axis has been observed by measuring the experimental development of the current in the electrochemical cell during the fabrication process. X-ray diffraction measurements reveal a different polycrystalline degree for each deposition configuration, indicating that the crystalline structure of the deposited material has been substantially modified. Magnetic measurements show a clear dependence of the anisotropy directions on the orientation of the magnetic field applied during the electrodeposition

  5. Excimer laser beam profile recording based on electrochemical etched polycarbonate

    International Nuclear Information System (INIS)

    Parvin, P.; Jaleh, B.; Zangeneh, H.R.; Zamanipour, Z.; Davoud-Abadi, Gh.R.

    2008-01-01

    There is no polymeric detector used to register the beam profile of UV lasers. Here, a method is proposed for the measurement of intensive UV beam pattern of the excimer lasers based on the photoablated polycarbonate detector after coherent UV exposure and the subsequent electrochemical etching. UV laser induced defects in the form of self-microstructuring on polycarbonate are developed to replicate the spatial intensity distribution as a beam profiler

  6. Excimer laser beam profile recording based on electrochemical etched polycarbonate

    Energy Technology Data Exchange (ETDEWEB)

    Parvin, P. [Physics Department, Amirkabir University of Technology, P.O. Box 15875-4413, Hafez Ave, Tehran (Iran, Islamic Republic of); Laser Research Center, AEOI, P.O. Box 1165-8486, Tehran (Iran, Islamic Republic of)], E-mail: parvin@aut.ac.ir; Jaleh, B. [Physics Department, Bu-Ali Sina University, Postal Code 65174, Hamedan (Iran, Islamic Republic of); Zangeneh, H.R. [Physics Department, Amirkabir University of Technology, P.O. Box 15875-4413, Hafez Ave, Tehran (Iran, Islamic Republic of); Zamanipour, Z. [Laser Research Center, AEOI, P.O. Box 1165-8486, Tehran (Iran, Islamic Republic of); Davoud-Abadi, Gh.R. [Physics Department, Amirkabir University of Technology, P.O. Box 15875-4413, Hafez Ave, Tehran (Iran, Islamic Republic of)

    2008-08-15

    There is no polymeric detector used to register the beam profile of UV lasers. Here, a method is proposed for the measurement of intensive UV beam pattern of the excimer lasers based on the photoablated polycarbonate detector after coherent UV exposure and the subsequent electrochemical etching. UV laser induced defects in the form of self-microstructuring on polycarbonate are developed to replicate the spatial intensity distribution as a beam profiler.

  7. Chemical etching and polishing of InP

    International Nuclear Information System (INIS)

    Kurth, E.; Reif, A.; Gottschalch, V.; Finster, J.; Butter, E.

    1988-01-01

    This paper describes possibilities of several chemical preparations for the selective cleaning of InP surfaces. The investigations of the surface states after the chemical treatment were carried out by means of XPS measurements. A pre-etching with (NH 4 ) 2 S 2 O 8 :H 2 SO 4 :H 2 O and a polishing with 1% bromine in methanol produce optically smooth (100)-and (111) P surfaces free of oxides. (author)

  8. Prevention of sidewall redeposition of etched byproducts in the dry Au etch process

    International Nuclear Information System (INIS)

    Aydemir, A; Akin, T

    2012-01-01

    In this paper we present a new technique of etching thin Au film in a dual frequency inductively coupled plasma (ICP) system on Si substrate to prevent the redeposition of etched Au particles over the sidewall of the masking material known as veils. First, the effect of the lithography step was investigated. Then the effects of etch chemistry and the process parameters on the redeposition of etched Au particles on the sidewall of the masking material were investigated. The redeposition effect was examined by depositing a thin Ti film over the masking material acting as a hard mask. The results showed that depositing a thin Ti film over the masking material prevents the formation of veils after etching Au in plasma environments for submicron size structures. Based on the results of this study, we propose a new technique that completely eliminates formation of veils after etching Au in plasma environments for submicron size structures. (paper)

  9. Thermal and epithermal neutron fluence rate gradient measurements by PADC detectors in LINAC radiotherapy treatments-field

    Energy Technology Data Exchange (ETDEWEB)

    Barrera, M. T., E-mail: mariate9590@gmail.com; Barros, H.; Pino, F.; Sajo-Bohus, L. [Universidad Simón Bolívar, Nuclear Physics Laboratory, Sartenejas, Caracas (Venezuela, Bolivarian Republic of); Dávila, J. [Física Médica C. A. and Universidad Central de Venezuela, Caracas (Venezuela, Bolivarian Republic of)

    2015-07-23

    LINAC VARIAN 2100 is where energetic electrons produce Bremsstrahlung radiation, with energies above the nucleon binding energy (E≈5.5MeV). This radiation induce (γ,n) and (e,e’n) reactions mainly in the natural tungsten target material (its total photoneutron cross section is about 4000 mb in a energy range from 9-17 MeV). These reactions may occur also in other components of the system (e.g. multi leaf collimator). During radiation treatment the human body may receive an additional dose inside and outside the treated volume produced by the mentioned nuclear reactions. We measured the neutron density at the treatment table using nuclear track detectors (PADC-NTD). These covered by a boron-converter are employed, including a cadmium filter, to determine the ratio between two groups of neutron energy, i.e. thermal and epithermal. The PADC-NTD detectors were exposed to the radiation field at the iso-center during regular operation of the accelerator. Neutron are determined indirectly by the converting reaction {sup 10}B(n,α){sup 7}Li the emerging charged particle leave their kinetic energy in the PADC forming a latent nuclear track, enlarged by chemical etching (6N, NaOH, 70°C). Track density provides information on the neutron density through calibration coefficient (∼1.6 10{sup 4} neutrons /track) obtained by a californium source. We report the estimation of the thermal and epithermal neutron field and its gradient for photoneutrons produced in radiotherapy treatments with 18 MV linear accelerators. It was obsered that photoneutron production have higher rate at the iso-center.

  10. Dry Etching of Copper Phthalocyanine Thin Films: Effects on Morphology and Surface Stoichiometry

    Directory of Open Access Journals (Sweden)

    Michael J. Brett

    2012-08-01

    Full Text Available We investigate the evolution of copper phthalocyanine thin films as they are etched with argon plasma. Significant morphological changes occur as a result of the ion bombardment; a planar surface quickly becomes an array of nanopillars which are less than 20 nm in diameter. The changes in morphology are independent of plasma power, which controls the etch rate only. Analysis by X-ray photoelectron spectroscopy shows that surface concentrations of copper and oxygen increase with etch time, while carbon and nitrogen are depleted. Despite these changes in surface stoichiometry, we observe no effect on the work function. The absorbance and X-ray diffraction spectra show no changes other than the peaks diminishing with etch time. These findings have important implications for organic photovoltaic devices which seek nanopillar thin films of metal phthalocyanine materials as an optimal structure.

  11. Application of a cellular automaton for the evolution of etched nuclear tracks

    International Nuclear Information System (INIS)

    Cruz-Trujillo, Leonardo de la; Hernández-Hernández, C.; Vázquez-López, C.; Zendejas-Leal, B.E.; Golzarri, I.; Espinosa, G.

    2013-01-01

    In the present work, it is demonstrated the first application of cellular automata to the growing of etched nuclear tracks. The simplest case in which conical etched tracks are gradually formed is presented, as well as a general case of time varying etching rate V t . It is demonstrated that the cellular automata elements consist in an image pattern of the latent nuclear track input cells, 16 rules for updating states, the Moore neighborhood and an algorithm of four states. - Highlights: ► We model the evolution of an etched nuclear track using cellular automata (ca). ► A cellular automaton of a conical track has 4 states and 16 transition rules. ► The ca of general tracks require a not regular mesh and the L(t) and V b parameters

  12. Thermal stability of dyed tracks and electrochemical etching sensitivity of some polymeric detectors

    International Nuclear Information System (INIS)

    Monnin, M.; Gourcy, J.; Somogyi, G.; Dajko, D.

    1980-01-01

    Recent results on the mechanism of the formation of tracks obtained by the dyed tracks technique are given and the thermal annealing of the detectors is used to demonstrate their ability to retain tracks under more severe conditions than by the etching technique. Electrochemical etching of polycarbonate and polyethylene terephthalate detectors is investigated both from the background and sensitivity points of view. The polyethylene terephthalate detector is shown to be well suited for low neutron flux measurements. (author)

  13. Hydroxyapatite Effect on Photopolymerization of Self-etching Adhesives with Different Aggressiveness

    Science.gov (United States)

    Zhang, Ying; Wang, Yong

    2012-01-01

    Objective To understand the correlation of the acidic monomer/hydroxyapatite (HAp) reaction with the photopolymerization behavior of self-etching adhesives with different aggressiveness. Methods Two commercial self-etching adhesives the strong Adper Prompt L-Pop (APLP, pH~0.8) and the mild Adper Easy Bond (AEB, pH~2.5) were used. HAp powders were incorporated into both adhesives to acquire solutions with concentrations of 0, 1, 3, 5, 7 wt%. The attenuated total reflectance Fourier transform infrared (ATR/FT-IR) technique was employed to collect the in-situ spectra during light-curing, from which the degree of conversion (DC) and polymerization rate (PR) were calculated. The pH of each tested solution was also measured. Results Without HAp incorporation, the DC and PR of the strong APLP (7.8% and 0.12%/s, respectively) were much lower than those of the mild AEB (85.5% and 5.7%/s, respectively). The DC and PR of APLP displayed an apparent increasing trend with the HAp content. For example, the DC increased from 7.8% to 58.4% and the PR increased from 0.12 to 3.8%/s when the HAp content increased from 0 to 7 wt%. In contrast, the DC and PR of AEB were much less affected by the HAp content. The observations were correlated well with the spectral and pH changes, which indicated that APLP underwent a higher extent of chemical reaction with HAp than AEB. Conclusions The results disclosed the important role of the acidic monomer/HAp chemical reaction in improving the photopolymerization of the strong (low-pH) self-etching adhesives such as APLP. The phenomenon of polymerization improvement strongly depended on the adhesive aggressiveness. PMID:22445789

  14. A spatial track formation model and its use for calculating etch-pit parameters of light nuclei

    International Nuclear Information System (INIS)

    Somogyi, G.; Scherzer, R.; Grabisch, K.; Enge, W.

    1976-01-01

    A generalized geometrical model of etch-pit formation in three dimensions is presented for nuclear particles entering isotropic solids at arbitrary angles of incidence. With this model one can calculate the relations between any particle parameter /Z = charge, M = mass, R = range, theta = angle of incidence/ and etching or track parameter /h = removed detector layer, L = track length, d = track diameter, etch-pit profile and contour/ for track etching rates varying monotonically along the trajectory of particles. Using a computer algorithm, calculations have been performed to study identification problems of nuclei of Z = 1-8 registered in a stack of polycarbonate sheets. For these calculations the etching rate ratio vs residual range curves were parametrized with a form of V -1 (R) = 1-Σasub(i) exp (- bsub(i)R) which does not involve the existence of a threshold for track registration. Particular attention was paid to the study of the evolution of etch-pit sizes for relatively high values of h. For this case, data are presented for the charge and isotope resolving power of the identification methods based on the relations L(R) of d(R). Calculations were also made to show the effect of the relative /parallel and opposite/ orientations between the directions of track etching and particle speed on etch-pit evolution. These studies offered new identification methods based on the determination of the curves L(parallel) vs L(opposite) and d(parallel) vs d(opposite), respectively. (orig.) [de

  15. Transport through track etched polymeric blend membrane

    Indian Academy of Sciences (India)

    Unknown

    Department of Physics, University of Rajasthan, Jaipur 302 004, India. MS received 10 June 2005 ... Both the track and bulk etching takes place in the irradiated membrane. ... using rotating flywheel attachment, the details having been given ...

  16. Semiconductor structure and recess formation etch technique

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Bin; Sun, Min; Palacios, Tomas Apostol

    2017-02-14

    A semiconductor structure has a first layer that includes a first semiconductor material and a second layer that includes a second semiconductor material. The first semiconductor material is selectively etchable over the second semiconductor material using a first etching process. The first layer is disposed over the second layer. A recess is disposed at least in the first layer. Also described is a method of forming a semiconductor structure that includes a recess. The method includes etching a region in a first layer using a first etching process. The first layer includes a first semiconductor material. The first etching process stops at a second layer beneath the first layer. The second layer includes a second semiconductor material.

  17. Directional Etching of Silicon by Silver Nanostructures

    Science.gov (United States)

    Sharma, Pradeep; Wang, Yuh-Lin

    2011-02-01

    We report directional etching of nanostructures (nanochannels and nanotrenches) into the Si(100) substrates in aqueous HF and H2O2 solution by lithographically defined Ag patterns (nanoparticles, nanorods, and nanorings). The Effect of Ag/Si interface oxide on the directional etching has been studied by etching Ag/SiOx/Si samples of known interface oxide thickness. Based on high resolution transmission electron microscopy (HRTEM) imaging and TEM-energy dispersive X-ray (EDX) spectra of the Ag/Si interfaces, we propose that maintenance of the sub-nanometer oxide at the Ag/Si interfaces and Ag-Si interaction are the key factors which regulate the directional etching of Si.

  18. Anisotropic etching of polycrystalline silicon with a hot Cl2 molecular beam

    International Nuclear Information System (INIS)

    Suzuki, K.; Hiraoka, S.; Nishimatsu, S.

    1988-01-01

    A hot Cl 2 molecular (Cl/sup */ 2 ) beam was successfully applied to achieve highly anisotropic, highly selective, and almost damage-free etching of polycrystalline Si. The anisotropy, the ratio of etch rates in vertical and horizontal directions, was larger than 25. The selectivity, the ratio of polycrystalline Si and SiO 2 etch rates, was larger than 1000. The Cl/sup */ 2 beam was produced by free jet expansion of a Cl 2 gas heated in a graphite furnace. The furnace temperature was 830 0 C. The substrate temperature was 180 0 C. The average total energy (0.38 eV) of a Cl/sup */ 2 molecule impinging on a substrate surface is much lower than the critical energy (approximately 10 eV) to displace the atoms of the etched material and to cause surface damage. This is the essential reason why this highly selective and almost damage-free etching has been achieved. The highly anisotropic etching mechanism is explained by a model taking into account the directional incidence of Cl/sup */ 2 molecules to the surface, and the deactivation process of the Cl/sup */ 2 molecules on a cold surface

  19. Cryogenic flow rate measurement with a laser Doppler velocimetry standard

    Science.gov (United States)

    Maury, R.; Strzelecki, A.; Auclercq, C.; Lehot, Y.; Loubat, S.; Chevalier, J.; Ben Rayana, F.

    2018-03-01

    A very promising alternative to the state-of-the-art static volume measurements for liquefied natural gas (LNG) custody transfer processes is the dynamic principle of flow metering. As the Designated Institute (DI) of the LNE (‘Laboratoire National de métrologie et d’Essais’, being the French National Metrology Institute) for high-pressure gas flow metering, Cesame-Exadebit is involved in various research and development programs. Within the framework of the first (2010-2013) and second (2014-2017) EURAMET Joint Research Project (JRP), named ‘Metrological support for LNG custody transfer and transport fuel applications’, Cesame-Exadebit explored a novel cryogenic flow metering technology using laser Doppler velocimetry (LDV) as an alternative to ultrasonic and Coriolis flow metering. Cesame-Exadebit is trying to develop this technique as a primary standard for cryogenic flow meters. Currently, cryogenic flow meters are calibrated at ambient temperatures with water. Results are then extrapolated to be in the Reynolds number range of real applications. The LDV standard offers a unique capability to perform online calibration of cryogenic flow meters in real conditions (temperature, pressure, piping and real flow disturbances). The primary reference has been tested on an industrial process in a LNG terminal during truck refuelling. The reference can calibrate Coriolis flow meters being used daily with all the real environmental constraints, and its utilisation is transparent for LNG terminal operators. The standard is traceable to Standard International units and the combined extended uncertainties have been determined and estimated to be lower than 0.6% (an ongoing improvement to reducing the correlation function uncertainty, which has a major impact in the uncertainty estimation).

  20. Plasma/Neutral-Beam Etching Apparatus

    Science.gov (United States)

    Langer, William; Cohen, Samuel; Cuthbertson, John; Manos, Dennis; Motley, Robert

    1989-01-01

    Energies of neutral particles controllable. Apparatus developed to produce intense beams of reactant atoms for simulating low-Earth-orbit oxygen erosion, for studying beam-gas collisions, and for etching semiconductor substrates. Neutral beam formed by neutralization and reflection of accelerated plasma on metal plate. Plasma ejected from coaxial plasma gun toward neutralizing plate, where turned into beam of atoms or molecules and aimed at substrate to be etched.

  1. Influence of Etching Mode on Enamel Bond Durability of Universal Adhesive Systems.

    Science.gov (United States)

    Suzuki, T; Takamizawa, T; Barkmeier, W W; Tsujimoto, A; Endo, H; Erickson, R L; Latta, M A; Miyazaki, M

    2016-01-01

    The purpose of this study was to determine the enamel bond durability of three universal adhesives in different etching modes through fatigue testing. The three universal adhesives used were Scotchbond Universal, Prime&Bond Elect universal dental adhesive, and All-Bond Universal light-cured dental adhesive. A single-step self-etch adhesive, Clearfil S 3 Bond Plus was used as a control. The shear bond strength (SBS) and shear fatigue strength (SFS) to human enamel were evaluated in total-etch mode and self-etch mode. A stainless steel metal ring with an internal diameter of 2.4 mm was used to bond the resin composite to the flat-ground (4000-grit) tooth surfaces for determination of both SBS and SFS. For each enamel surface treatment, 15 specimens were prepared for SBS and 30 specimens for SFS. The staircase method for fatigue testing was then used to determine the SFS of the resin composite bonded to the enamel using 10-Hz frequencies for 50,000 cycles or until failure occurred. Scanning electron microscopy was used to observe representative debonded specimen surfaces and the resin-enamel interfaces. A two-way analysis of variance and the Tukey post hoc test were used for analysis of the SBS data, whereas a modified t-test with Bonferroni correction was used for the SFS data. All adhesives in total-etch mode showed significantly higher SBS and SFS values than those in self-etch mode. Although All-Bond Universal in self-etch mode showed a significantly lower SBS value than the other adhesives, there was no significant difference in SFS values among the adhesives in this mode. All adhesives showed higher SFS:SBS ratios in total-etch mode than in self-etch mode. With regard to the adhesive systems used in this study, universal adhesives showed higher enamel bond strengths in total-etch mode. Although the influence of different etching modes on the enamel-bonding performance of universal adhesives was found to be dependent on the adhesive material, total-etch mode

  2. A passive monitor for radon using electrochemical track etch detector

    International Nuclear Information System (INIS)

    Massera, G.E.; Hassib, G.M.; Piesch, E.

    1980-01-01

    A passive, inexpensive monitor for radon detection and dosimetry is described in detail. It consists of a Makrofoil track etch detector inside a diffusion chamber which is sealed by a fibreglass filter through which radon may diffuse while radon daughters and aerosols are retained on the surface of the filter. The α-particle tracks are revealed by etching the Makrofoil in KOH. The lower detection limit of the radon dosimeter is equivalent to a mean dose in the lung of 130 mrem. After an exposure period of 3 months, a mean radon concentration of 0.3 pCi/l can be detected. The instrument is intended for use in a study to measure the long-term radon exposure in buildings in West Germany. (UK)

  3. Silicon germanium as a novel mask for silicon deep reactive ion etching

    KAUST Repository

    Serry, Mohamed Y.

    2013-10-01

    This paper reports on the use of p-type polycrystalline silicon germanium (poly-Si1-xGex) thin films as a new masking material for the cryogenic deep reactive ion etching (DRIE) of silicon. We investigated the etching behavior of various poly-Si1-xGex:B (0Etching selectivity for silicon, silicon oxide, and photoresist was determined at different etching temperatures, ICP and RF powers, and SF6 to O2 ratios. The study demonstrates that the etching selectivity of the SiGe mask for silicon depends strongly on three factors: Ge content; boron concentration; and etching temperature. Compared to conventional SiO2 and SiN masks, the proposed SiGe masking material exhibited several advantages, including high etching selectivity to silicon (>1:800). Furthermore, the SiGe mask was etched in SF6/O2 plasma at temperatures ≥ - 80°C and at rates exceeding 8 μm/min (i.e., more than 37 times faster than SiO2 or SiN masks). Because of the chemical and thermodynamic stability of the SiGe film as well as the electronic properties of the mask, it was possible to deposit the proposed film at CMOS backend compatible temperatures. The paper also confirms that the mask can easily be dry-removed after the process with high etching-rate by controlling the ICP and RF power and the SF6 to O2 ratios, and without affecting the underlying silicon substrate. Using low ICP and RF power, elevated temperatures (i.e., > - 80°C), and an adjusted O2:SF6 ratio (i.e., ~6%), we were able to etch away the SiGe mask without adversely affecting the final profile. Ultimately, we were able to develop deep silicon- trenches with high aspect ratio etching straight profiles. © 1992-2012 IEEE.

  4. Thinning of N-face GaN (0001) samples by inductively coupled plasma etching and chemomechanical polishing

    International Nuclear Information System (INIS)

    Rizzi, F.; Gu, E.; Dawson, M. D.; Watson, I. M.; Martin, R. W.; Kang, X. N.; Zhang, G. Y.

    2007-01-01

    The processing of N-polar GaN (0001) samples has been studied, motivated by applications in which extensive back side thinning of freestanding GaN (FS-GaN) substrates is required. Experiments were conducted on FS-GaN from two commercial sources, in addition to epitaxial GaN with the N-face exposed by a laser lift-off process. The different types of samples produced equivalent results. Surface morphologies were examined over relatively large areas, using scanning electron microscopy and stylus profiling. The main focus of this study was on inductively coupled plasma (ICP) etch processes, employing Cl 2 /Ar or Cl 2 /BCl 3 Ar gas mixtures. Application of a standard etch recipe, optimized for feature etching of Ga-polar GaN (0001) surfaces, caused severe roughening of N-polar samples and confirmed the necessity for specific optimization of etch conditions for N-face material. A series of recipes with a reduced physical (sputter-based) contribution to etching allowed average surface roughness values to be consistently reduced to below 3 nm. Maximum N-face etch rates of 370-390 nm/min have been obtained in recipes examined to date. These are typically faster than etch rates obtained on Ga-face samples under the same conditions and adequate for the process flows of interest. Mechanistic aspects of the ICP etch process and possible factors contributing to residual surface roughness are discussed. This study also included work on chemomechanical polishing (CMP). The optimized CMP process had stock removal rates of ∼500 nm/h on the GaN N face. This was much slower than the ICP etching but showed the important capability of recovering smooth surfaces on samples roughened in previous processing. In one example, a surface roughened by nonoptimized ICP etching was smoothed to give an average surface roughness of ∼2 nm

  5. The discussion on a new measure method of radon chamber leak rate

    International Nuclear Information System (INIS)

    Zhang Junkui; Tang Bing

    2010-01-01

    Radon chamber is the third standard radon source. The leak rate is the key parameter for the radon chamber to naturally and safely operate. One way, that measure the leak rate is introduced. The experience result is that the way is simple and veracious to measure the leak rate. (authors)

  6. Measurement of mean rotation and strain-rate tensors by using stereoscopic PIV

    DEFF Research Database (Denmark)

    Özcan, Oktay; Meyer, Knud Erik; Larsen, Poul Scheel

    2005-01-01

    A technique is described for measuring the mean velocity gradient (rate-of-displacement) tensor by using a conventional stereoscopic particle image velocimetry (SPIV) system. Planar measurement of the mean vorticity vector, rate-of-rotation and rate-of-strain tensors and the production of turbule...

  7. Plasma treatment of porous GaAs surface formed by electrochemical etching method: Characterization and properties

    International Nuclear Information System (INIS)

    Naddaf, M.; Saloum, S.

    2008-12-01

    Porous GaAs samples were formed by electrochemical anodic etching of Zn doped p-type GaAs (100) wafers at different etching parameters (time, mode of applied voltage or current and electrolyte). The effect of etching parameters and plasma surface treatment on the optical properties of the prepared sample has been investigated by using room temperature photoluminescence (PL), Raman spectroscopy and reflectance spectroscopic measurements in the range (400-800 nm). The surface morphological changes were studied by using atomic force microscope. It has been found that etching parameters can be controlled to produce a considerably low optical reflectivity porous GaAs layer, attractive for use in solar cells. In addition, it has been observed that the deposition of plasma polymerized HMDSO thin film on porous GaAs surface can be utilized to produce a surface with novel optical properties interesting for solar cells and optoelectronic devices. (author)

  8. Reactive ion beam etching for microcavity surface emitting laser fabrication: technology and damage characterization

    International Nuclear Information System (INIS)

    Matsutani, A.; Tadokoro, T.; Koyama, F.; Iga, K.

    1993-01-01

    Reactive ion beam etching (RIBE) is an effective dry etching technique for the fabrication of micro-sized surface emitting (SE) lasers and optoelectronic devices. In this chapter, some etching characteristics for GaAs, InP and GaInAsP with a Cl 2 gas using an RIBE system are discussed. Micro-sized circular mesas including GaInAsP/InP multilayers with vertical sidewalls were fabricated. RIBE-induced damage in InP substrates was estimated by C-V and PL measurement. In addition, the removal of the induced damage by the second RIBE with different conditions for the InP wafer was proposed. The sidewall damage is characterized by photoluminescence emitted from the etched sidewall of a GaInAsP/InP DH wafer. (orig.)

  9. Dry etching of MgCaO gate dielectric and passivation layers on GaN

    International Nuclear Information System (INIS)

    Hlad, M.; Voss, L.; Gila, B.P.; Abernathy, C.R.; Pearton, S.J.; Ren, F.

    2006-01-01

    MgCaO films grown by rf plasma-assisted molecular beam epitaxy and capped with Sc 2 O 3 are promising candidates as surface passivation layers and gate dielectrics on GaN-based high electron mobility transistors (HEMTs) and metal-oxide semiconductor HEMTs (MOS-HEMTs), respectively. Two different plasma chemistries were examined for etching these thin films on GaN. Inductively coupled plasmas of CH 4 /H 2 /Ar produced etch rates only in the range 20-70 A/min, comparable to the Ar sputter rates under the same conditions. Similarly slow MgCaO etch rates (∼100 A/min) were obtained with Cl 2 /Ar discharges under the same conditions, but GaN showed rates almost an order of magnitude higher. The MgCaO removal rates are limited by the low volatilities of the respective etch products. The CH 4 /H 2 /Ar plasma chemistry produced a selectivity of around 2 for etching the MgCaO with respect to GaN

  10. Reaction rate constants of H-abstraction by OH from large ketones: measurements and site-specific rate rules.

    Science.gov (United States)

    Badra, Jihad; Elwardany, Ahmed E; Farooq, Aamir

    2014-06-28

    Reaction rate constants of the reaction of four large ketones with hydroxyl (OH) are investigated behind reflected shock waves using OH laser absorption. The studied ketones are isomers of hexanone and include 2-hexanone, 3-hexanone, 3-methyl-2-pentanone, and 4-methl-2-pentanone. Rate constants are measured under pseudo-first-order kinetics at temperatures ranging from 866 K to 1375 K and pressures near 1.5 atm. The reported high-temperature rate constant measurements are the first direct measurements for these ketones under combustion-relevant conditions. The effects of the position of the carbonyl group (C=O) and methyl (CH3) branching on the overall rate constant with OH are examined. Using previously published data, rate constant expressions covering, low-to-high temperatures, are developed for acetone, 2-butanone, 3-pentanone, and the hexanone isomers studied here. These Arrhenius expressions are used to devise rate rules for H-abstraction from various sites. Specifically, the current scheme is applied with good success to H-abstraction by OH from a series of n-ketones. Finally, general expressions for primary and secondary site-specific H-abstraction by OH from ketones are proposed as follows (the subscript numbers indicate the number of carbon atoms bonded to the next-nearest-neighbor carbon atom, the subscript CO indicates that the abstraction is from a site next to the carbonyl group (C=O), and the prime is used to differentiate different neighboring environments of a methylene group):

  11. Effect of surface etching on condensing heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Seok, Sung Chul; Park, Jae Won; Jung, Jiyeon; Choi, Chonggun; Choi, Gyu Hong; Hwang, Seung Sik; Chung, Tae Yong; Shin, Donghoon [Kookmin University, Seoul (Korea, Republic of); Kim, Jin Jun [Hoseo University, Asan (Korea, Republic of)

    2016-02-15

    This study conducted experiments on humid air condensation during heat transfer in an air preheating exchanger attached to a home condensing boiler to improve thermal efficiency. An etchant composed of sulfuric acid and sodium nitrate was used to create roughness on the heat exchanger surface made from STS430J1L. A counter flow heat exchanger was fabricated to test the performance of heat transfer. Results showed that the overall heat transfer coefficients of all specimens treated with etchant improved with respect to the original specimens (not treated with etchant), and the overall heat transfer coefficient of the 60 s etching specimen increased by up to 15%. However, the increasing rate of the heat transfer coefficient was disproportional to the etching time. When the etching time specifically increased above 60 s, the heat transfer coefficient decreased. This effect was assumed to be caused by surface characteristics such as contact angle. Furthermore, a smaller contact angle or higher hydrophilicity leads to higher heat transfer coefficient.

  12. Modification of track membranes structure by gas discharge etching method

    International Nuclear Information System (INIS)

    Dmitriev, S.N.; Kravets, L.I.

    1996-01-01

    An investigation of the properties of polyethyleneterephthalate track membranes (PET TM) treated with the plasma RF-discharge in air has been performed. The influence of the plasma treatment conditions on the basic properties of the membranes, namely pore size and pore shape, porosity and mechanical strength has been studied. It was arranged that the effect of air plasma on the PET TM results to etching a membrane's surface layer. The membranes' pore size and the form in this case change. It is shown that it is possible to change the structure of track membranes directly by the gas discharge etching method. Depending on the choice of discharge parameters, it is possible to make etching either in a part of the channel or along the whole length of the pore channels. In both cases the membranes with an asymmetric pore shape are formed which possess higher porosity and flow rate. The use of the membranes of such a type allows one to increase drastically the efficiency of the filtration processes. 12 refs., 5 figs., 1 tab

  13. Selective etching of n-type silicon in pn junction structure in hydrofluoric acid and its application in silicon nanowire fabrication

    International Nuclear Information System (INIS)

    Wang Huiquan; Jin Zhonghe; Zheng Yangming; Ma Huilian; Wang Yuelin; Li Tie

    2008-01-01

    Boron is selectively implanted on the surface of an n-type silicon wafer to form a p-type area surrounded by an n-type area. The wafer is then put into a buffered oxide etch solution. It is found that the n-type area can be selectively etched without illumination, with an etching rate lower than 1 nm min -1 , while the p-type area can be selectively etched under illumination with a much higher etching rate. The possible mechanism of the etching phenomenon is discussed. A simple fabrication process of silicon nanowires is proposed according to the above phenomenon. In this process only traditional micro-electromechanical system technology is used. Dimensions of the fabricated nanowire can be controlled well. A 50 nm wide and 50 nm thick silicon nanowire has been formed using this method

  14. Laboratory simulation of meteoritic noble gases. 2. Sorption of xenon on carbon: etching and heating experiments

    Energy Technology Data Exchange (ETDEWEB)

    Zadnik, M.G.; Wacker, J.F.; Lewis, R.S. (Chicago Univ., IL (USA). Enrico Fermi Inst.)

    1985-04-01

    Sixteen amorphous carbon (lampblack) samples that had been exposed to Xe/sup 127/ and pumped for > 9 hrs to remove the most labile gas were examined by etching with HNO/sub 3/, for comparison with the release pattern of meteoritic xenon. Samples originally exposed at 100 to 200 deg C lost 90% of their Xe very readily, when the surface had been etched to a mean depth of only approx. 0.2 A. This suggests that the Xe is adsorbed mainly at rare sites that are unusually reactive to HNO/sub 3/. The adsorbed Xe survived several months' storage in vacuum, but on exposure to air, part of it was lost within a few hours, while the remainder persisted without measurable exchange. Samples exposed at 800 to 1000 deg C had a similar adsorbed component, as well as a second, tightly bound component extending to a mean depth of up to 30 A; this component had apparently diffused into the carbon during exposure. The (microscopic) diffusion coefficient for graphitic crystallites is 5 x 10/sup -20/ cm/sup 2//sec at 1000 deg C. PVDC carbon lost its adsorbed Xe at about the same rate as lampblack on exposure to air or HNO/sub 3/, though it differs from lampblack in being non-graphitizable and more porous. It had only a small diffused component, however. The results are discussed.

  15. Electrical, optical and etching properties of Zn-Sn-O thin films deposited by combinatorial sputtering

    International Nuclear Information System (INIS)

    Kim, J. S.; Park, J. K.; Baik, Y. J.; Kim, W. M.; Jeong, J.; Seong, T. Y.

    2012-01-01

    Zn-Sn-O (ZTO) films are known to be able to form an amorphous phase, which provides a smooth surface morphology as well as etched side wall, when deposited by using the conventional sputtering technique and, therefore, to have a potential to be applied as transparent thin film transistors. In this study, ZTO thin films were prepared by using combined sputtering of ZnO and SnO 2 targets, and the dependences of their electrical and optical properties on the composition and the deposition parameters were examined. The Sn content in the films was varied in the range of 35 ∼ 85 at .%. The deposition was carried out at room temperature, 150 and 300 .deg. C, and the oxygen content in sputtering gas was varied from 0 to 1 vol.%. Sn-rich films had better electrical properties, but showed large oxygen deficiency when deposited at low oxygen partial pressures. ZTO films with Sn contents lower than 55 at.% had good optical transmission, but the electrical properties were poor due to very low carrier concentrations. A high Hall mobility of larger than 10 cm 2 /Vs could be obtained in the carrier density range 10 17 ∼ 10 20 cm -3 , and the etching rate was measurable for films with Sn content up to 70 at.% when using a dilute HCl solution, indicating a good possibility of utilizing ZTO films for device applications.

  16. Heart Rate Monitoring in Team Sports—A Conceptual Framework for Contextualizing Heart Rate Measures for Training and Recovery Prescription

    Directory of Open Access Journals (Sweden)

    Christoph Schneider

    2018-05-01

    Full Text Available A comprehensive monitoring of fitness, fatigue, and performance is crucial for understanding an athlete's individual responses to training to optimize the scheduling of training and recovery strategies. Resting and exercise-related heart rate measures have received growing interest in recent decades and are considered potentially useful within multivariate response monitoring, as they provide non-invasive and time-efficient insights into the status of the autonomic nervous system (ANS and aerobic fitness. In team sports, the practical implementation of athlete monitoring systems poses a particular challenge due to the complex and multidimensional structure of game demands and player and team performance, as well as logistic reasons, such as the typically large number of players and busy training and competition schedules. In this regard, exercise-related heart rate measures are likely the most applicable markers, as they can be routinely assessed during warm-ups using short (3–5 min submaximal exercise protocols for an entire squad with common chest strap-based team monitoring devices. However, a comprehensive and meaningful monitoring of the training process requires the accurate separation of various types of responses, such as strain, recovery, and adaptation, which may all affect heart rate measures. Therefore, additional information on the training context (such as the training phase, training load, and intensity distribution combined with multivariate analysis, which includes markers of (perceived wellness and fatigue, should be considered when interpreting changes in heart rate indices. The aim of this article is to outline current limitations of heart rate monitoring, discuss methodological considerations of univariate and multivariate approaches, illustrate the influence of different analytical concepts on assessing meaningful changes in heart rate responses, and provide case examples for contextualizing heart rate measures using

  17. Heart Rate Monitoring in Team Sports-A Conceptual Framework for Contextualizing Heart Rate Measures for Training and Recovery Prescription.

    Science.gov (United States)

    Schneider, Christoph; Hanakam, Florian; Wiewelhove, Thimo; Döweling, Alexander; Kellmann, Michael; Meyer, Tim; Pfeiffer, Mark; Ferrauti, Alexander

    2018-01-01

    A comprehensive monitoring of fitness, fatigue, and performance is crucial for understanding an athlete's individual responses to training to optimize the scheduling of training and recovery strategies. Resting and exercise-related heart rate measures have received growing interest in recent decades and are considered potentially useful within multivariate response monitoring, as they provide non-invasive and time-efficient insights into the status of the autonomic nervous system (ANS) and aerobic fitness. In team sports, the practical implementation of athlete monitoring systems poses a particular challenge due to the complex and multidimensional structure of game demands and player and team performance, as well as logistic reasons, such as the typically large number of players and busy training and competition schedules. In this regard, exercise-related heart rate measures are likely the most applicable markers, as they can be routinely assessed during warm-ups using short (3-5 min) submaximal exercise protocols for an entire squad with common chest strap-based team monitoring devices. However, a comprehensive and meaningful monitoring of the training process requires the accurate separation of various types of responses, such as strain, recovery, and adaptation, which may all affect heart rate measures. Therefore, additional information on the training context (such as the training phase, training load, and intensity distribution) combined with multivariate analysis, which includes markers of (perceived) wellness and fatigue, should be considered when interpreting changes in heart rate indices. The aim of this article is to outline current limitations of heart rate monitoring, discuss methodological considerations of univariate and multivariate approaches, illustrate the influence of different analytical concepts on assessing meaningful changes in heart rate responses, and provide case examples for contextualizing heart rate measures using simple heuristics. To

  18. Oxygen consumption rate v. rate of energy utilization of fishes: a comparison and brief history of the two measurements.

    Science.gov (United States)

    Nelson, J A

    2016-01-01

    Accounting for energy use by fishes has been taking place for over 200 years. The original, and continuing gold standard for measuring energy use in terrestrial animals, is to account for the waste heat produced by all reactions of metabolism, a process referred to as direct calorimetry. Direct calorimetry is not easy or convenient in terrestrial animals and is extremely difficult in aquatic animals. Thus, the original and most subsequent measurements of metabolic activity in fishes have been measured via indirect calorimetry. Indirect calorimetry takes advantage of the fact that oxygen is consumed and carbon dioxide is produced during the catabolic conversion of foodstuffs or energy reserves to useful ATP energy. As measuring [CO2 ] in water is more challenging than measuring [O2 ], most indirect calorimetric studies on fishes have used the rate of O2 consumption. To relate measurements of O2 consumption back to actual energy usage requires knowledge of the substrate being oxidized. Many contemporary studies of O2 consumption by fishes do not attempt to relate this measurement back to actual energy usage. Thus, the rate of oxygen consumption (M˙O2 ) has become a measurement in its own right that is not necessarily synonymous with metabolic rate. Because all extant fishes are obligate aerobes (many fishes engage in substantial net anaerobiosis, but all require oxygen to complete their life cycle), this discrepancy does not appear to be of great concern to the fish biology community, and reports of fish oxygen consumption, without being related to energy, have proliferated. Unfortunately, under some circumstances, these measures can be quite different from one another. A review of the methodological history of the two measurements and a look towards the future are included. © 2016 The Fisheries Society of the British Isles.

  19. Micro-texturing into DLC/diamond coated molds and dies via high density oxygen plasma etching

    Directory of Open Access Journals (Sweden)

    Yunata Ersyzario Edo

    2015-01-01

    Full Text Available Diamond-Like Carbon (DLC and Chemical Vapor Deposition (CVD-diamond films have been widely utilized not only as a hard protective coating for molds and dies but also as a functional substrate for bio-MEMS/NEMS. Micro-texturing into these hard coated molds and dies provides a productive tool to duplicate the original mother micro-patterns onto various work materials and to construct any tailored micro-textures for sensors and actuators. In the present paper, the high density oxygen plasma etching method is utilized to make micro-line and micro-groove patterns onto the DLC and diamond coatings. Our developing oxygen plasma etching system is introduced together with characterization on the plasma state during etching. In this quantitative plasma diagnosis, both the population of activated species and the electron and ion densities are identified through the emissive light spectroscopy and the Langmuir probe method. In addition, the on-line monitoring of the plasmas helps to describe the etching process. DLC coated WC (Co specimen is first employed to describe the etching mechanism by the present method. Chemical Vapor Deposition (CVD diamond coated WC (Co is also employed to demonstrate the reliable capacity of the present high density oxygen plasma etching. This oxygen plasma etching performance is discussed by comparison of the etching rates.

  20. Nanoparticle and nanosphere mask for etching of ITO nanostructures and their reflection properties

    International Nuclear Information System (INIS)

    Xu, Cigang; Deng, Ligang; Holder, Adam; Bailey, Louise R.; Proudfoot, Gary; Thomas, Owain; Gunn, Robert; Cooke, Mike; Leendertz, Caspar; Bergmann, Joachim

    2015-01-01

    Au nanoparticles and polystyrene nanospheres were used as mask for plasma etching of indium tin oxide (ITO) layer. By reactive ion etching (RIE) processes, the morphology of polystyrene nanospheres can be tuned through chemical or physical etching, and Au nanoparticle mask can result in ITO nanostructures with larger aspect ratio than nanosphere mask. During inductively coupled plasma (ICP) processes, Au nanoparticle mask was not affected by the thermal effect of plasma, whereas temperature of the substrate was essential to protect nanospheres from the damaging effect of plasma. Physical bombardment in the plasma can also modify the nanospheres. It was observed that under the same process conditions, the ratio of CH 4 and H 2 in the process gas can affect the etching rate of ITO without completely etching the nanospheres. The morphology of ITO nanostructures also depends on process conditions. The resulting ITO nanostructures show lower reflection in a spectral range of 400-1000 nm than c-Si and conventional antireflection layer of SiN x film. ITO nanostructures obtained after etching (scale bar = 200 nm). (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)