Effects of temperature variation on MOSFET dosimetry

International Nuclear Information System (INIS)

Cheung Tsang; Butson, Martin J; Yu, Peter K N

2004-01-01

This note investigates temperature effects on dosimetry using a metal oxide semiconductor field effect transistor (MOSFET) for radiotherapy x-ray treatment. This was performed by analysing the dose response and threshold voltage outputs for MOSFET dosimeters as a function of ambient temperature. Results have shown that the clinical semiconductor dosimetry system (CSDS) MOSFET provides stable dose measurements with temperatures varying from 15 deg. C up to 40 deg. C. Thus standard irradiations performed at room temperature can be directly compared to in vivo dose assessments performed at near body temperature without a temperature correction function. The MOSFET dosimeter threshold voltage varies with temperature and this level is dependent on the dose history of the MOSFET dosimeter. However, the variation can be accounted for in the measurement method. For accurate dosimetry, the detector should be placed for approximately 60 s on a patient to allow thermal equilibrium before measurements are taken with the final reading performed whilst still attached to the patient or conversely left for approximately 120 s after removal from the patient if initial readout was measured at room temperature to allow temperature equilibrium to be established. (note)

Effect of neutron irradiation on the breakdown voltage of power MOSFET's

International Nuclear Information System (INIS)

Hasan, S.M.Y.; Kosier, S.L.; Schrimpf, R.D.; Galloway, K.F.

1994-01-01

The effect of neutron irradiation on power metal-oxide-semiconductor field effect transistor (power MOSFET) breakdown voltage has been investigated. Transistors with various breakdown voltage ratings were irradiated in a TRIGA nuclear reactor with cumulative fluence levels up to 5 x 10 14 neutrons/cm 2 (1 MeV equivalent). Noticeable increases in the breakdown voltages are observed in n-type MOSFET's after 10 13 neutrons/cm 2 and in p-type MOSFETs after 10 12 neutrons/cm 2 . An increase in breakdown voltage of as much as 30% is observed after 5 x 10 14 neutrons/cm 2 . The increase in breakdown voltage is attributed to the neutron-irradiation-induced defects which decrease the mean free path and trap majority carriers in the space charge region. The effect of positive trapped oxide charge due to concomitant gamma radiation and the effect of the termination structure on the increase in breakdown voltage are considered. An empirical model is presented to predict the value of the breakdown voltage as a function of neutron fluence

Prognostics of Power MOSFET

Science.gov (United States)

Celaya, Jose Ramon; Saxena, Abhinav; Vashchenko, Vladislay; Saha, Sankalita; Goebel, Kai Frank

2011-01-01

This paper demonstrates how to apply prognostics to power MOSFETs (metal oxide field effect transistor). The methodology uses thermal cycling to age devices and Gaussian process regression to perform prognostics. The approach is validated with experiments on 100V power MOSFETs. The failure mechanism for the stress conditions is determined to be die-attachment degradation. Change in ON-state resistance is used as a precursor of failure due to its dependence on junction temperature. The experimental data is augmented with a finite element analysis simulation that is based on a two-transistor model. The simulation assists in the interpretation of the degradation phenomena and SOA (safe operation area) change.

Potential of carbon nanotube field effect transistors for analogue circuits

KAUST Repository

Hayat, Khizar; Cheema, Hammad; Shamim, Atif

2013-01-01

This Letter presents a detailed comparison of carbon nanotube field effect transistors (CNFETs) and metal oxide semiconductor field effect transistors (MOSFETs) with special focus on carbon nanotube FET's potential for implementing analogue circuits in the mm-wave and sub-terahertz range. The latest CNFET lithographic dimensions place it at-par with complementary metal oxide semiconductor in terms of current handling capability, whereas the forecasted improvement in the lithography enables the CNFETs to handle more than twice the current of MOSFETs. The comparison of RF parameters shows superior performance of CNFETs with a g m , f T and f max of 2.7, 2.6 and 4.5 times higher, respectively. MOSFET- and CNFET-based inverter, three-stage ring oscillator and LC oscillator have been designed and compared as well. The CNFET-based inverters are found to be ten times faster, the ring oscillator demonstrates three times higher oscillation frequency and CNFET-based LC oscillator also shows improved performance than its MOSFET counterpart.

Potential of carbon nanotube field effect transistors for analogue circuits

KAUST Repository

Hayat, Khizar

2013-05-11

This Letter presents a detailed comparison of carbon nanotube field effect transistors (CNFETs) and metal oxide semiconductor field effect transistors (MOSFETs) with special focus on carbon nanotube FET\\'s potential for implementing analogue circuits in the mm-wave and sub-terahertz range. The latest CNFET lithographic dimensions place it at-par with complementary metal oxide semiconductor in terms of current handling capability, whereas the forecasted improvement in the lithography enables the CNFETs to handle more than twice the current of MOSFETs. The comparison of RF parameters shows superior performance of CNFETs with a g m , f T and f max of 2.7, 2.6 and 4.5 times higher, respectively. MOSFET- and CNFET-based inverter, three-stage ring oscillator and LC oscillator have been designed and compared as well. The CNFET-based inverters are found to be ten times faster, the ring oscillator demonstrates three times higher oscillation frequency and CNFET-based LC oscillator also shows improved performance than its MOSFET counterpart.

Prognostics of Power MOSFET

Data.gov (United States)

National Aeronautics and Space Administration — This paper demonstrates how to apply prognostics to power MOSFETs (metal oxide field effect transistor). The methodology uses thermal cycling to age devices and...

A new spin-functional MOSFET based on magnetic tunnel junction technology: pseudo-spin-MOSFET

OpenAIRE

Shuto, Yusuke; Nakane, Ryosho; Wang, Wenhong; Sukegawa, Hiroaki; Yamamoto, Shuu'ichirou; Tanaka, Masaaki; Inomata, Koichiro; Sugahara, Satoshi

2009-01-01

We fabricated and characterized a new spin-functional MOSFET referred to as a pseudo-spin-MOSFET (PS-MOSFET). The PS-MOSFET is a circuit using an ordinary MOSFET and magnetic tunnel junction (MTJ) for reproducing functions of spin-transistors. Device integration techniques for a bottom gate MOSFET using a silicon-on-insulator (SOI) substrate and for an MTJ with a full-Heusler alloy electrode and MgO tunnel barrier were developed. The fabricated PS-MOSFET exhibited high and low transconductanc...

Comparison between the effects of positive noncatastrophic HMB ESD stress in n-channel and p-channel power MOSFET's

Science.gov (United States)

Zupac, Dragan; Kosier, Steven L.; Schrimpf, Ronald D.; Galloway, Kenneth F.; Baum, Keith W.

1991-10-01

The effect of noncatastrophic positive human body model (HBM) electrostatic discharge (ESD) stress on n-channel power MOSFETs is radically different from that on p-channel MOSFETs. In n-channel transistors, the stress causes negative shifts of the current-voltage characteristics indicative of positive charge trapping in the gate oxide. In p-channel transistors, the stress increases the drain-to-source leakage current, probably due to localized avalanche electron injection from the p-doped drain.

MOSFET Electric-Charge Sensor

Science.gov (United States)

Robinson, Paul A., Jr.

1988-01-01

Charged-particle probe compact and consumes little power. Proposed modification enables metal oxide/semiconductor field-effect transistor (MOSFET) to act as detector of static electric charges or energetic charged particles. Thickened gate insulation acts as control structure. During measurements metal gate allowed to "float" to potential of charge accumulated in insulation. Stack of modified MOSFET'S constitutes detector of energetic charged particles. Each gate "floats" to potential induced by charged-particle beam penetrating its layer.

Clinical dosimetry using mosfets

International Nuclear Information System (INIS)

Ramani, Ramaseshan; Russell, Stephen; O'Brien, Peter

1997-01-01

Purpose: The use of metal oxide-silicon field effect transistors (MOSFETs) as clinical dosimeters is demonstrated for a number of patients with targets at different clinical sites. Methods and Materials: Commercially available MOSFETs were characterized for energy response, angular dependency of response, and effect of accumulated dose on sensitivity and some inherent properties of MOSFETs. The doses determined both by thermoluminescence dosimetry (TLD) and MOSFETs in clinical situation were evaluated and compared to expected doses determined by calculation. Results: It was observed that a standard calibration of 0.01 Gy/mV gave MOSFET determined doses which agreed with expected doses to within 5% at the 95% confidence limit for photon beams from 6 to 25 MV and electron beams from 5 to 14 MeV. An energy-dependent variation in response of up to 28% was observed between two orientations of a MOSFET. The MOSFET doses compared very well with the doses estimated by TLDs, and the patients tolerated MOSFETs very well. A standard deviation of 3.9% between expected dose and MOSFET determined dose was observed, while for TLDs the standard deviation was 5.1%. The advantages and disadvantages of using MOSFETs for clinical dosimetry are discussed in detail. Conclusion: It was concluded that MOSFETs can be used as clinical dosimeters and can be a good alternative to TLDs. However, they have limitations under certain clinical situations

JMOSFET: A MOSFET parameter extractor with geometry-dependent terms

Science.gov (United States)

Buehler, M. G.; Moore, B. T.

1985-01-01

The parameters from metal-oxide-silicon field-effect transistors (MOSFETs) that are included on the Combined Release and Radiation Effects Satellite (CRRES) test chips need to be extracted to have a simple but comprehensive method that can be used in wafer acceptance, and to have a method that is sufficiently accurate that it can be used in integrated circuits. A set of MOSFET parameter extraction procedures that are directly linked to the MOSFET model equations and that facilitate the use of simple, direct curve-fitting techniques are developed. In addition, the major physical effects that affect MOSFET operation in the linear and saturation regions of operation for devices fabricated in 1.2 to 3.0 mm CMOS technology are included. The fitting procedures were designed to establish single values for such parameters as threshold voltage and transconductance and to provide for slope matching between the linear and saturation regions of the MOSFET output current-voltage curves. Four different sizes of transistors that cover a rectangular-shaped region of the channel length-width plane are analyzed.

Nanowire field effect transistors principles and applications

CERN Document Server

Jeong, Yoon-Ha

2014-01-01

“Nanowire Field Effect Transistor: Basic Principles and Applications” places an emphasis on the application aspects of nanowire field effect transistors (NWFET). Device physics and electronics are discussed in a compact manner, together with the p-n junction diode and MOSFET, the former as an essential element in NWFET and the latter as a general background of the FET. During this discussion, the photo-diode, solar cell, LED, LD, DRAM, flash EEPROM and sensors are highlighted to pave the way for similar applications of NWFET. Modeling is discussed in close analogy and comparison with MOSFETs. Contributors focus on processing, electrostatic discharge (ESD) and application of NWFET. This includes coverage of solar and memory cells, biological and chemical sensors, displays and atomic scale light emitting diodes. Appropriate for scientists and engineers interested in acquiring a working knowledge of NWFET as well as graduate students specializing in this subject.

Long Channel Carbon Nanotube as an Alternative to Nanoscale Silicon Channels in Scaled MOSFETs

Directory of Open Access Journals (Sweden)

Michael Loong Peng Tan

2013-01-01

Full Text Available Long channel carbon nanotube transistor (CNT can be used to overcome the high electric field effects in nanoscale length silicon channel. When maximum electric field is reduced, the gate of a field-effect transistor (FET is able to gain control of the channel at varying drain bias. The device performance of a zigzag CNTFET with the same unit area as a nanoscale silicon metal-oxide semiconductor field-effect transistor (MOSFET channel is assessed qualitatively. The drain characteristic of CNTFET and MOSFET device models as well as fabricated CNTFET device are explored over a wide range of drain and gate biases. The results obtained show that long channel nanotubes can significantly reduce the drain-induced barrier lowering (DIBL effects in silicon MOSFET while sustaining the same unit area at higher current density.

Silicon junctionless field effect transistors as room temperature terahertz detectors

Energy Technology Data Exchange (ETDEWEB)

Marczewski, J., E-mail: jmarcz@ite.waw.pl; Tomaszewski, D.; Zaborowski, M. [Institute of Electron Technology, al. Lotnikow 32/46, 02-668 Warsaw (Poland); Knap, W. [Institute of High Pressure Physics of the Polish Academy of Sciences, ul. Sokolowska 29/37, 01-142 Warsaw (Poland); Laboratory Charles Coulomb, Montpellier University & CNRS, Place E. Bataillon, Montpellier 34095 (France); Zagrajek, P. [Institute of Optoelectronics, Military University of Technology, ul. gen. S. Kaliskiego 2, 00-908 Warsaw (Poland)

2015-09-14

Terahertz (THz) radiation detection by junctionless metal-oxide-semiconductor field-effect transistors (JL MOSFETs) was studied and compared with THz detection using conventional MOSFETs. It has been shown that in contrast to the behavior of standard transistors, the junctionless devices have a significant responsivity also in the open channel (low resistance) state. The responsivity for a photolithographically defined JL FET was 70 V/W and the noise equivalent power 460 pW/√Hz. Working in the open channel state may be advantageous for THz wireless and imaging applications because of its low thermal noise and possible high operating speed or large bandwidth. It has been proven that the junctionless MOSFETs can also operate in a zero gate bias mode, which enables simplification of the THz array circuitry. Existing models of THz detection by MOSFETs were considered and it has been demonstrated that the process of detection by these junctionless devices cannot be explained within the framework of the commonly accepted models and therefore requires a new theoretical approach.

Low Power and High Sensitivity MOSFET-Based Pressure Sensor

International Nuclear Information System (INIS)

Zhang Zhao-Hua; Ren Tian-Ling; Zhang Yan-Hong; Han Rui-Rui; Liu Li-Tian

2012-01-01

Based on the metal-oxide-semiconductor field effect transistor (MOSFET) stress sensitive phenomenon, a low power MOSFET pressure sensor is proposed. Compared with the traditional piezoresistive pressure sensor, the present pressure sensor displays high performances on sensitivity and power consumption. The sensitivity of the MOSFET sensor is raised by 87%, meanwhile the power consumption is decreased by 20%. (cross-disciplinary physics and related areas of science and technology)

The effect of gate length on SOI-MOSFETS operation | Baedi ...

African Journals Online (AJOL)

The effect of gate length on the operation of silicon-on-insulator (SOI) MOSFET structure with a layer of buried silicon oxide added to isolate the device body has been simulated. Three transistors with gate lengths of 100, 200 and 500 nm were simulated. Simulations showed that with a fixed channel length, when the gate ...

Quantum Transport in Tunnel Field-Effect Transistors for Future Nano-CMOS Applications

OpenAIRE

Vandenberghe, William

2012-01-01

After decades of scientific and technological development to fabricate ever smaller, faster and more energy efficient MOSFETs, reducing MOSFET power consumption is becoming increasingly difficult. As a possible successor to the MOSFET, the tunnel field-effect transistor (TFET) has been proposed. The topic of this thesis is to study the working principle of the TFET and to go beyond the semiclassical models towards a fully quantum mechanical modeling of the TFET which has band-to-band tunnelin...

Reliability Assessment of SiC Power MOSFETs From The End User's Perspective

DEFF Research Database (Denmark)

Karaventzas, Vasilios Dimitris; Nawaz, Muhammad; Iannuzzo, Francesco

2016-01-01

The reliability of commercial Silicon Carbide (SiC) Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) is investigated, and comparative assessment is performed under various test environments. The MOSFETs are tested both regarding the electrical properties of the dies and the packaging...

Power Consumption of a MOSFET

Directory of Open Access Journals (Sweden)

Frederick Selkey

2010-01-01

Full Text Available A MOSFET is defined as metal oxide semiconductor field effect transistor. These electrical components are combined or integrated to form control and logic functions for laptop and desktop computers, power controls in printing devices, motor controls and are used in many other electrical circuits. All electrical devices consume electrical power based on current and voltage. For this paper we calculated the power consumption of a Toshiba 2SK3563 MOSFET during its triode mode by finding the area under the current-voltage characteristic curve.

Radiation-hardened gate-around n-MOSFET structure for radiation-tolerant application-specific integrated circuits

International Nuclear Information System (INIS)

Lee, Min Su; Lee, Hee Chul

2012-01-01

To overcome the total ionizing dose effect on an n-type metal-oxide-semiconductor field-effect transistor (n-MOSFET), we designed a radiation-hardened gate-around n-MOSFET structure and evaluated it through a radiation-exposure experiment. Each test device was fabricated in a commercial 0.35-micron complementary metal-oxide-semiconductor (CMOS) process. The fabricated devices were evaluated under a total dose of 1 Mrad (Si) at a dose rate of 250 krad/h to obtain very high reliability for space electronics. The experimental results showed that the gate-around n-MOSFET structure had very good performance against 1 Mrad (Si) of gamma radiation, while the conventional n-MOSFET experienced a considerable amount of radiation-induced leakage current. Furthermore, a source follower designed with the gate-around transistor worked properly at 1 Mrad (Si) of gamma radiation while a source follower designed with the conventional n-MOSFET lost its functionality.

Investigations of Tunneling for Field Effect Transistors

OpenAIRE

Matheu, Peter

2012-01-01

Over 40 years of scaling dimensions for new and continuing product cycles has introduced new challenges for transistor design. As the end of the technology roadmap for semiconductors approaches, new device structures are being investigated as possible replacements for traditional metal-oxide-semiconductor field effect transistors (MOSFETs). Band-to-band tunneling (BTBT) in semiconductors, often viewed as an adverse effect of short channel lengths in MOSFETs, has been discussed as a promising ...

Dimensional effects and scalability of Meta-Stable Dip (MSD) memory effect for 1T-DRAM SOI MOSFETs

Science.gov (United States)

Hubert, A.; Bawedin, M.; Cristoloveanu, S.; Ernst, T.

2009-12-01

The difficult scaling of bulk Dynamic Random Access Memories (DRAMs) has led to various concepts of capacitor-less single-transistor (1T) architectures based on SOI transistor floating-body effects. Amongst them, the Meta-Stable Dip RAM (MSDRAM), which is a double-gate Fully Depleted SOI transistor, exhibits attractive performances. The Meta-Stable Dip effect results from the reduced junction leakage current and the long carrier generation lifetime in thin silicon film transistors. In this study, various devices with different gate lengths, widths and silicon film thicknesses have been systematically explored, revealing the impact of transistor dimensions on the MSD effect. These experimental results are discussed and validated by two-dimensional numerical simulations. It is found that MSD is maintained for small dimensions even in standard SOI MOSFETs, although specific optimizations are expected to enhance MSDRAM performances.

MCT/MOSFET Switch

Science.gov (United States)

Rippel, Wally E.

1990-01-01

Metal-oxide/semiconductor-controlled thyristor (MCT) and metal-oxide/semiconductor field-effect transistor (MOSFET) connected in switching circuit to obtain better performance. Offers high utilization of silicon, low forward voltage drop during "on" period of operating cycle, fast turnon and turnoff, and large turnoff safe operating area. Includes ability to operate at high temperatures, high static blocking voltage, and ease of drive.

Effect of interface roughness on the carrier transport in germanium MOSFETs investigated by Monte Carlo method

International Nuclear Information System (INIS)

Gang, Du; Xiao-Yan, Liu; Zhi-Liang, Xia; Jing-Feng, Yang; Ru-Qi, Han

2010-01-01

Interface roughness strongly influences the performance of germanium metal–organic–semiconductor field effect transistors (MOSFETs). In this paper, a 2D full-band Monte Carlo simulator is used to study the impact of interface roughness scattering on electron and hole transport properties in long- and short- channel Ge MOSFETs inversion layers. The carrier effective mobility in the channel of Ge MOSFETs and the in non-equilibrium transport properties are investigated. Results show that both electron and hole mobility are strongly influenced by interface roughness scattering. The output curves for 50 nm channel-length double gate n and p Ge MOSFET show that the drive currents of n- and p-Ge MOSFETs have significant improvement compared with that of Si n- and p-MOSFETs with smooth interface between channel and gate dielectric. The 82% and 96% drive current enhancement are obtained for the n- and p-MOSFETs with the completely smooth interface. However, the enhancement decreases sharply with the increase of interface roughness. With the very rough interface, the drive currents of Ge MOSFETs are even less than that of Si MOSFETs. Moreover, the significant velocity overshoot also has been found in Ge MOSFETs. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Advanced p-MOSFET Ionizing-Radiation Dosimeter

Science.gov (United States)

Buehler, Martin G.; Blaes, Brent R.

1994-01-01

Circuit measures total dose of ionizing radiation in terms of shift in threshold gate voltage of doped-channel metal oxide/semiconductor field-effect transistor (p-MOSFET). Drain current set at temperature-independent point to increase accuracy in determination of radiation dose.

Prognostics Of Power Mosfets Under Thermal Stress Accelerated Aging Using Data-Driven And Model-Based Methodologies

Data.gov (United States)

National Aeronautics and Space Administration — An approach for predicting remaining useful life of power MOSFETs (metal oxide field effect transistor) devices has been developed. Power MOSFETs are semiconductor...

Multi-valued logic circuits using hybrid circuit consisting of three gates single-electron transistors (TG-SETs) and MOSFETs.

Science.gov (United States)

Shin, SeungJun; Yu, YunSeop; Choi, JungBum

2008-10-01

New multi-valued logic (MVL) families using the hybrid circuits consisting of three gates single-electron transistors (TG-SETs) and a metal-oxide-semiconductor field-effect transistor (MOSFET) are proposed. The use of SETs offers periodic literal characteristics due to Coulomb oscillation of SET, which allows a realization of binary logic (BL) circuits as well as multi-valued logic (MVL) circuits. The basic operations of the proposed MVL families are successfully confirmed through SPICE circuit simulation based on the physical device model of a TG-SET. The proposed MVL circuits are found to be much faster, but much larger power consumption than a previously reported MVL, and they have a trade-off between speed and power consumption. As an example to apply the newly developed MVL families, a half-adder is introduced.

High-performance III-V MOSFET with nano-stacked high-k gate dielectric and 3D fin-shaped structure.

Science.gov (United States)

Chen, Szu-Hung; Liao, Wen-Shiang; Yang, Hsin-Chia; Wang, Shea-Jue; Liaw, Yue-Gie; Wang, Hao; Gu, Haoshuang; Wang, Mu-Chun

2012-08-01

A three-dimensional (3D) fin-shaped field-effect transistor structure based on III-V metal-oxide-semiconductor field-effect transistor (MOSFET) fabrication has been demonstrated using a submicron GaAs fin as the high-mobility channel. The fin-shaped channel has a thickness-to-width ratio (TFin/WFin) equal to 1. The nano-stacked high-k Al2O3 dielectric was adopted as a gate insulator in forming a metal-oxide-semiconductor structure to suppress gate leakage. The 3D III-V MOSFET exhibits outstanding gate controllability and shows a high Ion/Ioff ratio > 105 and a low subthreshold swing of 80 mV/decade. Compared to a conventional Schottky gate metal-semiconductor field-effect transistor or planar III-V MOSFETs, the III-V MOSFET in this work exhibits a significant performance improvement and is promising for future development of high-performance n-channel devices based on III-V materials.

Scheme for the fabrication of ultrashort channel metal-oxide-semiconductor field-effect transistors

International Nuclear Information System (INIS)

Appenzeller, J.; Martel, R.; Solomon, P.; Chan, K.; Avouris, Ph.; Knoch, J.; Benedict, J.; Tanner, M.; Thomas, S.; Wang, K. L.

2000-01-01

We present a scheme for the fabrication of ultrashort channel length metal-oxide-semiconductor field-effect transistors (MOSFETs) involving nanolithography and molecular-beam epitaxy. The active channel is undoped and is defined by a combination of nanometer-scale patterning and anisotropic etching of an n ++ layer grown on a silicon on insulator wafer. The method is self-limiting and can produce MOSFET devices with channel lengths of less than 10 nm. Measurements on the first batch of n-MOSFET devices fabricated with this approach show very good output characteristics and good control of short-channel effects. (c) 2000 American Institute of Physics

Evaluation of performance of metal oxide-silicon semiconductor field effect transistor (MOSFET) dosimeter

International Nuclear Information System (INIS)

Nagashima, Hiroyuki; Sano, Naoki; Nakamura, Osamu

2001-01-01

The JARP level dosimeter is the most suitable for absorbed dose determination in radiotherapy because of its high accuracy. However, in measuring the dose of an extremely small field, a dosimeter with a smaller active region is required. The active region of the MOSFET dosimeter is very small, having a volume of just 0.02 mm 3 . In this study, we evaluated the performance of MOSFET dosimeters with two different sensitivities and examined the usefulness of the MOSFET dosimeter in stereotactic radiosurgery. Using the high-sensitivity MOSFET dosimeter, we were able to reduce the experimental error of absorbed dose (≤±1.8%), and, by correcting the sensitivity, we could use it as a field dosimeter. By turning detectors inside out, we could reduce directional dependence (≤±1.8%). Correction was necessary in the TMR determination because peak depth shifts according to the material of the detector. In the determination of the dose distribution in the penumbra, the resolution of the MOSFET detectors was equal to that of the diamond detector. In the determination of OPF for the extremely small field, better results were obtained with MOSFET than with other small detectors. The high-sensitivity MOSFET dosimeter could properly evaluate the dose of an extremely small field and will be useful in dosimetry of the maximum dose of the field center in stereotactic radiosurgery. (author)

Radiation effects on junction field-effect transistors (JFETS), MOSFETs, and bipolar transistors, as related to SSC circuit design

International Nuclear Information System (INIS)

Kennedy, E.J.; Alley, G.T.; Britton, C.L. Jr.; Skubic, P.L.; Gray, B.; Wu, A.

1990-01-01

Some results of radiation effects on selected junction field-effect transistors, MOS field-effect transistors, and bipolar junction transistors are presented. The evaluations include dc parameters, as well as capacitive variations and noise evaluations. The tests are made at the low current and voltage levels (in particular, at currents ≤1 mA) that are essential for the low-power regimes required by SSC circuitry. Detailed noise data are presented both before and after 5-Mrad (gamma) total-dose exposure. SPICE radiation models for three high-frequency bipolar processes are compared for a typical charge-sensitive preamplifier

Driver Circuit For High-Power MOSFET's

Science.gov (United States)

Letzer, Kevin A.

1991-01-01

Driver circuit generates rapid-voltage-transition pulses needed to switch high-power metal oxide/semiconductor field-effect transistor (MOSFET) modules rapidly between full "on" and full "off". Rapid switching reduces time of overlap between appreciable current through and appreciable voltage across such modules, thereby increasing power efficiency.

Analysis of the effect of interface state charges on threshold voltage and transconductance of 6H-SiC N-channel MOSFET

International Nuclear Information System (INIS)

Tang Xiaoyan; Zhang Yimen; Zhang Yuming

2002-01-01

The effect of interface state charges on the threshold voltage and transconductance of 6H-SiC N-channel metal-oxide semiconductor field-effect transistor (MOSFET) is analyzed based on the non-uniformly distributed interface state density in the band gap and incomplete impurity ionization in silicon carbide. The results show that the nonuniform distribution of interface state density cause not only the increment of the threshold voltage but also the degradation of the transconductance of MOSFET so that it is one of the important factors to influence the characteristics of SiC MOSFET

Electric field and temperature effects in irradiated MOSFETs

Energy Technology Data Exchange (ETDEWEB)

Silveira, M. A. G., E-mail: marcilei@fei.edu.br; Santos, R. B. B.; Leite, F. G.; Araújo, N. E.; Cirne, K. H.; Melo, M. A. A.; Rallo, A. [Centro Universitário da FEI, São Bernardo do Campo, S.P. (Brazil); Aguiar, Vitor A. P.; Aguirre, F.; Macchione, E. L. A.; Added, N.; Medina, N. H. [Instituto de Física da USP, São Paulo, S.P. (Brazil)

2016-07-07

Electronic devices exposed to ionizing radiation exhibit degradation on their electrical characteristics, which may compromise the functionality of the device. Understanding the physical phenomena responsible for radiation damage, which may be specific to a particular technology, it is of extreme importance to develop methods for testing and recovering the devices. The aim of this work is to check the influence of thermal annealing processes and electric field applied during irradiation of Metal Oxide Semiconductor Field Effect Transistors (MOSFET) in total ionizing dose experiments analyzing the changes in the electrical parameters in these devices.

Performance analysis of SOI MOSFET with rectangular recessed channel

Science.gov (United States)

Singh, M.; Mishra, S.; Mohanty, S. S.; Mishra, G. P.

2016-03-01

In this paper a two dimensional (2D) rectangular recessed channel-silicon on insulator metal oxide semiconductor field effect transistor (RRC-SOI MOSFET), using the concept of groove between source and drain regions, which is one of the channel engineering technique to suppress the short channel effect (SCE). This suppression is mainly due to corner potential barrier of the groove and the simulation is carried out by using ATLAS 2D device simulator. To have further improvement of SCE in RRC-SOI MOSFET, three more devices are designed by using dual material gate (DMG) and gate dielectric technique, which results in formation of devices i.e. DMRRC-SOI,MLSMRRC-SOI, MLDMRRC-SOI MOSFET. The effect of different structures of RRC-SOI on AC and RF parameters are investigated and the importance of these devices over RRC MOSFET regarding short channel effect is analyzed.

Monte carlo study of MOSFET packaging, optimised for improved energy response: single MOSFET filtration.

Science.gov (United States)

Othman, M A R; Cutajar, D L; Hardcastle, N; Guatelli, S; Rosenfeld, A B

2010-09-01

Monte Carlo simulations of the energy response of a conventionally packaged single metal-oxide field effect transistors (MOSFET) detector were performed with the goal of improving MOSFET energy dependence for personal accident or military dosimetry. The MOSFET detector packaging was optimised. Two different 'drop-in' design packages for a single MOSFET detector were modelled and optimised using the GEANT4 Monte Carlo toolkit. Absorbed photon dose simulations of the MOSFET dosemeter placed in free-air response, corresponding to the absorbed doses at depths of 0.07 mm (D(w)(0.07)) and 10 mm (D(w)(10)) in a water equivalent phantom of size 30 x 30 x 30 cm(3) for photon energies of 0.015-2 MeV were performed. Energy dependence was reduced to within + or - 60 % for photon energies 0.06-2 MeV for both D(w)(0.07) and D(w)(10). Variations in the response for photon energies of 15-60 keV were 200 and 330 % for D(w)(0.07) and D(w)(10), respectively. The obtained energy dependence was reduced compared with that for conventionally packaged MOSFET detectors, which usually exhibit a 500-700 % over-response when used in free-air geometry.

Dosimetric characteristics of a MOSFET dosimeter for clinical electron beams.

Science.gov (United States)

Manigandan, D; Bharanidharan, G; Aruna, P; Devan, K; Elangovan, D; Patil, Vikram; Tamilarasan, R; Vasanthan, S; Ganesan, S

2009-09-01

The fundamental dosimetric characteristics of commercially available metal oxide semiconductor field effect transistor (MOSFET) detectors were studied for clinical electron beam irradiations. MOSFET showed excellent linearity against doses measured using an ion chamber in the dose range of 20-630cGy. MOSFET reproducibility is better at high doses compared to low doses. The output factors measured with the MOSFET were within +/-3% when compared with those measured with a parallel plate chamber. From 4 to 12MeV, MOSFETs showed a large angular dependence in the tilt directions and less in the axial directions. MOSFETs do not show any dose-rate dependence between 100 and 600MU/min. However, MOSFETs have shown under-response when the dose per pulse of the beam is decreased. No measurable effect in MOSFET response was observed in the temperature range of 23-40 degrees C. The energy dependence of a MOSFET dosimeter was within +/-3.0% for 6-18MeV electron beams and 5.5% for 4MeV ones. This study shows that MOSFET detectors are suitable for dosimetry of electron beams in the energy range of 4-18MeV.

Simulation of dual-gate SOI MOSFET with different dielectric layers

Science.gov (United States)

Yadav, Jyoti; Chaudhary, R.; Mukhiya, R.; Sharma, R.; Khanna, V. K.

2016-04-01

The paper presents the process design and simulation of silicon-on-insulator (SOI)-based dual-gate metal oxide field-effect transistor (DG-MOSFET) stacked with different dielectric layers on the top of gate oxide. A detailed 2D process simulation of SOI-MOSFETs and its electrical characterization has been done using SILVACO® TCAD tool. A variation in transconductance was observed with different dielectric layers, AlN-gate MOSFET having the highest tranconductance value as compared to other three dielectric layers (SiO2, Si3N4 and Al2O3).

Electrical characterization of Ω-gated uniaxial tensile strained Si nanowire-array metal-oxide-semiconductor field effect transistors with - and channel orientations

International Nuclear Information System (INIS)

Habicht, Stefan; Feste, Sebastian; Zhao, Qing-Tai; Buca, Dan; Mantl, Siegfried

2012-01-01

Nanowire-array metal-oxide-semiconductor field effect transistors (MOSFETs) were fabricated along and crystal directions on (001) un-/strained silicon-on-insulator substrates. Lateral strain relaxation through patterning was employed to transform biaxial tensile strain into uniaxial tensile strain along the nanowire. Devices feature ideal subthreshold swings and maximum on-current/off-current ratios of 10 11 for n and p-type transistors on both substrates. Electron and hole mobilities were extracted by split C–V method. For p-MOSFETs an increased mobility is observed for channel direction devices compared to devices. The n-MOSFETs showed a 45% increased electron mobility compared to devices. The comparison of strained and unstrained n-MOSFETs along and clearly demonstrates improved electron mobilities for strained channels of both channel orientations.

CMOS-compatible batch processing of monolayer MoS2 MOSFETs

Science.gov (United States)

Xiong, Kuanchen; Kim, Hyun; Marstell, Roderick J.; Göritz, Alexander; Wipf, Christian; Li, Lei; Park, Ji-Hoon; Luo, Xi; Wietstruck, Matthias; Madjar, Asher; Strandwitz, Nicholas C.; Kaynak, Mehmet; Lee, Young Hee; Hwang, James C. M.

2018-04-01

Thousands of high-performance 2D metal-oxide-semiconductor field effect transistors (MOSFETs) were fabricated on wafer-scale chemical vapor deposited MoS2 with fully-CMOS-compatible processes such as photolithography and aluminum metallurgy. The yield was greater than 50% in terms of effective gate control with less-than-10 V threshold voltage, even for MOSFETs having deep-submicron gate length. The large number of fabricated MOSFETs allowed statistics to be gathered and the main yield limiter to be attributed to the weak adhesion between the transferred MoS2 and the substrate. With cut-off frequencies approaching the gigahertz range, the performances of the MOSFETs were comparable to that of state-of-the-art MoS2 MOSFETs, whether the MoS2 was grown by a thin-film process or exfoliated from a bulk crystal.

Progress in MOSFET double-layer metalization

Science.gov (United States)

Gassaway, J. D.; Trotter, J. D.; Wade, T. E.

1980-01-01

Report describes one-year research effort in VLSL fabrication. Four activities are described: theoretical study of two-dimensional diffusion in SOS (silicon-on-sapphire); setup of sputtering system, furnaces, and photolithography equipment; experiments on double layer metal; and investigation of two-dimensional modeling of MOSFET's (metal-oxide-semiconductor field-effect transistors).

Demonstration of hetero-gate-dielectric tunneling field-effect transistors (HG TFETs).

Science.gov (United States)

Choi, Woo Young; Lee, Hyun Kook

2016-01-01

The steady scaling-down of semiconductor device for improving performance has been the most important issue among researchers. Recently, as low-power consumption becomes one of the most important requirements, there have been many researches about novel devices for low-power consumption. Though scaling supply voltage is the most effective way for low-power consumption, performance degradation is occurred for metal-oxide-semiconductor field-effect transistors (MOSFETs) when supply voltage is reduced because subthreshold swing (SS) of MOSFETs cannot be lower than 60 mV/dec. Thus, in this thesis, hetero-gate-dielectric tunneling field-effect transistors (HG TFETs) are investigated as one of the most promising alternatives to MOSFETs. By replacing source-side gate insulator with a high- k material, HG TFETs show higher on-current, suppressed ambipolar current and lower SS than conventional TFETs. Device design optimization through simulation was performed and fabrication based on simulation demonstrated that performance of HG TFETs were better than that of conventional TFETs. Especially, enlargement of gate insulator thickness while etching gate insulator at the source side was improved by introducing HF vapor etch process. In addition, the proposed HG TFETs showed higher performance than our previous results by changing structure of sidewall spacer by high- k etching process.

Power MOSFET Thermal Instability Operation Characterization Support

Science.gov (United States)

Shue, John L.; Leidecker, Henning

2010-01-01

Metal-oxide semiconductor field-effect transistors (MOSFETs) are used extensively in flight hardware and ground support equipment. In the quest for faster switching times and lower "on resistance," the MOSFETs designed from 1998 to the present have achieved most of their intended goals. In the quest for lower on resistance and higher switching speeds, the designs now being produced allow the charge-carrier dominated region (once small and outside of the area of concern) to become important and inside the safe operating area (SOA). The charge-carrier dominated region allows more current to flow as the temperature increases. The higher temperatures produce more current resulting in the beginning of thermal runaway. Thermal runaway is a problem affecting a wide range of modern MOSFETs from more than one manufacturer. This report contains information on MOSFET failures, their causes and test results and information dissemination.

Modeling transient radiation effects in power MOSFETS

International Nuclear Information System (INIS)

Hoffman, J.R.; Hall, W.E.; Dunn, D.E.

1987-01-01

Using standard device specifications and simple assumptions, the transient radiation response of VDMOS MOSFETs can be modeled in a standard circuit analysis program. The device model consists of a body diode, a parasitic bipolar transistor, and elements to simulate high-current reduced breakdown. The attached photocurrent model emulates response to any pulse shape and accounts for bias-dependent depletion regions. The model can be optimized to best fit available test data

Lightning Pin Injection Testing on MOSFETS

Science.gov (United States)

Ely, Jay J.; Nguyen, Truong X.; Szatkowski, George N.; Koppen, Sandra V.; Mielnik, John J.; Vaughan, Roger K.; Wysocki, Philip F.; Celaya, Jose R.; Saha, Sankalita

2009-01-01

Lightning transients were pin-injected into metal-oxide-semiconductor field-effect transistors (MOSFETs) to induce fault modes. This report documents the test process and results, and provides a basis for subsequent lightning tests. MOSFETs may be present in DC-DC power supplies and electromechanical actuator circuits that may be used on board aircraft. Results show that unprotected MOSFET Gates are susceptible to failure, even when installed in systems in well-shielded and partial-shielded locations. MOSFET Drains and Sources are significantly less susceptible. Device impedance decreased (current increased) after every failure. Such a failure mode may lead to cascading failures, as the damaged MOSFET may allow excessive current to flow through other circuitry. Preliminary assessments on a MOSFET subjected to 20-stroke pin-injection testing demonstrate that Breakdown Voltage, Leakage Current and Threshold Voltage characteristics show damage, while the device continues to meet manufacturer performance specifications. The purpose of this research is to develop validated tools, technologies, and techniques for automated detection, diagnosis and prognosis that enable mitigation of adverse events during flight, such as from lightning transients; and to understand the interplay between lightning-induced surges and aging (i.e. humidity, vibration thermal stress, etc.) on component degradation.

Simulation of 50-nm Gate Graphene Nanoribbon Transistors

Directory of Open Access Journals (Sweden)

Cedric Nanmeni Bondja

2016-01-01

Full Text Available An approach to simulate the steady-state and small-signal behavior of GNR MOSFETs (graphene nanoribbon metal-semiconductor-oxide field-effect transistor is presented. GNR material parameters and a method to account for the density of states of one-dimensional systems like GNRs are implemented in a commercial device simulator. This modified tool is used to calculate the current-voltage characteristics as well the cutoff frequency fT and the maximum frequency of oscillation fmax of GNR MOSFETs. Exemplarily, we consider 50-nm gate GNR MOSFETs with N = 7 armchair GNR channels and examine two transistor configurations. The first configuration is a simplified MOSFET structure with a single GNR channel as usually studied by other groups. Furthermore, and for the first time in the literature, we study in detail a transistor structure with multiple parallel GNR channels and interribbon gates. It is shown that the calculated fT of GNR MOSFETs is significantly lower than that of GFETs (FET with gapless large-area graphene channel with comparable gate length due to the mobility degradation in GNRs. On the other hand, GNR MOSFETs show much higher fmax compared to experimental GFETs due the semiconducting nature of the GNR channels and the resulting better saturation of the drain current. Finally, it is shown that the gate control in FETs with multiple parallel GNR channels is improved while the cutoff frequency is degraded compared to single-channel GNR MOSFETs due to parasitic capacitances of the interribbon gates.

Performance analysis of SOI MOSFET with rectangular recessed channel

International Nuclear Information System (INIS)

Singh, M; Mishra, G P; Mishra, S; Mohanty, S S

2016-01-01

In this paper a two dimensional (2D) rectangular recessed channel–silicon on insulator metal oxide semiconductor field effect transistor (RRC-SOI MOSFET), using the concept of groove between source and drain regions, which is one of the channel engineering technique to suppress the short channel effect (SCE). This suppression is mainly due to corner potential barrier of the groove and the simulation is carried out by using ATLAS 2D device simulator. To have further improvement of SCE in RRC-SOI MOSFET, three more devices are designed by using dual material gate (DMG) and gate dielectric technique, which results in formation of devices i.e. DMRRC-SOI,MLSMRRC-SOI, MLDMRRC-SOI MOSFET. The effect of different structures of RRC-SOI on AC and RF parameters are investigated and the importance of these devices over RRC MOSFET regarding short channel effect is analyzed. (paper)

Effective dose estimation for pediatric upper gastrointestinal examinations using an anthropomorphic phantom set and metal oxide semiconductor field-effect transistor (MOSFET) technology.

Science.gov (United States)

Emigh, Brent; Gordon, Christopher L; Connolly, Bairbre L; Falkiner, Michelle; Thomas, Karen E

2013-09-01

There is a need for updated radiation dose estimates in pediatric fluoroscopy given the routine use of new dose-saving technologies and increased radiation safety awareness in pediatric imaging. To estimate effective doses for standardized pediatric upper gastrointestinal (UGI) examinations at our institute using direct dose measurement, as well as provide dose-area product (DAP) to effective dose conversion factors to be used for the estimation of UGI effective doses for boys and girls up to 10 years of age at other centers. Metal oxide semiconductor field-effect transistor (MOSFET) dosimeters were placed within four anthropomorphic phantoms representing children ≤10 years of age and exposed to mock UGI examinations using exposures much greater than used clinically to minimize measurement error. Measured effective dose was calculated using ICRP 103 weights and scaled to our institution's standardized clinical UGI (3.6-min fluoroscopy, four spot exposures and four examination beam projections) as determined from patient logs. Results were compared to Monte Carlo simulations and related to fluoroscope-displayed DAP. Measured effective doses for standardized pediatric UGI examinations in our institute ranged from 0.35 to 0.79 mSv in girls and were 3-8% lower for boys. Simulation-derived and measured effective doses were in agreement (percentage differences  0.18). DAP-to-effective dose conversion factors ranged from 6.5 ×10(-4) mSv per Gy-cm(2) to 4.3 × 10(-3) mSv per Gy-cm(2) for girls and were similarly lower for boys. Using modern fluoroscopy equipment, the effective dose associated with the UGI examination in children ≤10 years at our institute is MOSFETs, which were shown to agree with Monte Carlo simulated doses.

Aspect Ratio Model for Radiation-Tolerant Dummy Gate-Assisted n-MOSFET Layout.

Science.gov (United States)

Lee, Min Su; Lee, Hee Chul

2014-01-01

In order to acquire radiation-tolerant characteristics in integrated circuits, a dummy gate-assisted n-type metal oxide semiconductor field effect transistor (DGA n-MOSFET) layout was adopted. The DGA n-MOSFET has a different channel shape compared with the standard n-MOSFET. The standard n-MOSFET has a rectangular channel shape, whereas the DGA n-MOSFET has an extended rectangular shape at the edge of the source and drain, which affects its aspect ratio. In order to increase its practical use, a new aspect ratio model is proposed for the DGA n-MOSFET and this model is evaluated through three-dimensional simulations and measurements of the fabricated devices. The proposed aspect ratio model for the DGA n-MOSFET exhibits good agreement with the simulation and measurement results.

Simulating single-event burnout of n-channel power MOSFET's

International Nuclear Information System (INIS)

Johnson, G.H.; Hohl, J.H.; Schrimpf, R.D.; Galloway, K.F.

1993-01-01

Heavy ions are ubiquitous in a space environment. Single-event burnout of power MOSFET's is a sudden catastrophic failure mechanism that is initiated by the passage of a heavy ion through the device structure. The passage of the heavy ion generates a current filament that locally turns on a parasitic n-p-n transistor inherent to the power MOSFET. Subsequent high currents and high voltage in the device induce second breakdown of the parasitic bipolar transistor and hence meltdown of the device. This paper presents a model that can be used for simulating the burnout mechanism in order to gain insight into the significant device parameters that most influence the single-event burnout susceptibility of n-channel power MOSFET's

Evolution of the MOS transistor - From conception to VLSI

International Nuclear Information System (INIS)

Sah, C.T.

1988-01-01

Historical developments of the metal-oxide-semiconductor field-effect-transistor (MOSFET) during the last sixty years are reviewed, from the 1928 patent disclosures of the field-effect conductivity modulation concept and the semiconductor triodes structures proposed by Lilienfeld to the 1947 Shockley-originated efforts which led to the laboratory demonstration of the modern silicon MOSFET thirty years later in 1960. A survey is then made of the milestones of the past thirty years leading to the latest submicron silicon logic CMOS (Complementary MOS) and BICMOS (Bipolar-Junction-Transistor CMOS combined) arrays and the three-dimensional and ferroelectric extensions of Dennard's one-transistor dynamic random access memory (DRAM) cell. Status of the submicron lithographic technologies (deep ultra-violet light, X-ray, electron-beam) are summarized. Future trends of memory cell density and logic gate speed are projected. Comparisons of the switching speed of the silicon MOSFET with that of silicon bipolar and GaAs field-effect transistors are reviewed. Use of high-temperature superconducting wires and GaAs-on-Si monolithic semiconductor optical clocks to break the interconnect-wiring delay barrier is discussed. Further needs in basic research and mathematical modeling on the failure mechanisms in submicron silicon transistors at high electric fields (hot electron effects) and in interconnection conductors at high current densities and low as well as high electric fields (electromigration) are indicated

A novel charge pump drive circuit for power MOSFETs

International Nuclear Information System (INIS)

Wang Songlin; Zhou Bo; Wang Hui; Guo Wangrui; Ye Qiang

2010-01-01

Novel improved power metal oxide semiconductor field effect transistor (MOSFET) drive circuits are introduced. An anti-deadlock block is used in the P-channel power MOSFET drive circuit to avoid deadlocks and improve the transient response. An additional charging path is added to the N-channel power MOSFET drive circuit to enhance its drive capability and improve the transient response. The entire circuit is designed in a 0.6 μm BCD process and simulated with Cadence Spectre. Compared with traditional power MOSFET drive circuits, the simulation results show that improved P-channel power MOSFET drive circuit makes the rise time reduced from 60 to 14 ns, the fall time reduced from 240 to 30 ns, and its power dissipation reduced from 2 to 1 mW, while the improved N-channel power MOSFET drive circuit makes the rise time reduced from 360 to 27 ns and its power dissipation reduced from 1.1 to 0.8 mW. (semiconductor integrated circuits)

Technology computer aided design simulation for VLSI MOSFET

CERN Document Server

Sarkar, Chandan Kumar

2013-01-01

Responding to recent developments and a growing VLSI circuit manufacturing market, Technology Computer Aided Design: Simulation for VLSI MOSFET examines advanced MOSFET processes and devices through TCAD numerical simulations. The book provides a balanced summary of TCAD and MOSFET basic concepts, equations, physics, and new technologies related to TCAD and MOSFET. A firm grasp of these concepts allows for the design of better models, thus streamlining the design process, saving time and money. This book places emphasis on the importance of modeling and simulations of VLSI MOS transistors and

Model of hot-carrier induced degradation in ultra-deep sub-micrometer nMOSFET

International Nuclear Information System (INIS)

Lei Xiao-Yi; Liu Hong-Xia; Zhang Yue; Ma Xiao-Hua; Hao Yue

2014-01-01

The degradation produced by hot carrier (HC) in ultra-deep sub-micron n-channel metal oxide semiconductor field effect transistor (nMOSFET) has been analyzed in this paper. The generation of negatively charged interface states is the predominant mechanism for the ultra-deep sub-micron nMOSFET. According to our lifetime model of p-channel MOFET (pMOFET) that was reported in a previous publication, a lifetime prediction model for nMOSFET is presented and the parameters in the model are extracted. For the first time, the lifetime models of nMOFET and pMOSFET are unified. In addition, the model can precisely predict the lifetime of the ultra-deep sub-micron nMOSFET and pMOSFET. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Analyzing Single-Event Gate Ruptures In Power MOSFET's

Science.gov (United States)

Zoutendyk, John A.

1993-01-01

Susceptibilities of power metal-oxide/semiconductor field-effect transistors (MOSFET's) to single-event gate ruptures analyzed by exposing devices to beams of energetic bromine ions while applying appropriate bias voltages to source, gate, and drain terminals and measuring current flowing into or out of each terminal.

High performance multi-finger MOSFET on SOI for RF amplifiers

Science.gov (United States)

Adhikari, M. Singh; Singh, Y.

2017-10-01

In this paper, we propose structural modifications in the conventional planar metal-oxide-semiconductor field-effect transistor (MOSFET) on silicon-on-insulator by utilizing trenches in the epitaxial layer. The proposed multi-finger MOSFET (MF-MOSFET) has dual vertical-gates placed in separate trenches to form multiple channels in the p-base which carry the drain current in parallel. The proposed device uses TaN as gate electrode and SiO2 as gate dielectric. Simultaneous conduction of multiple channels enhances the drain current (ID) and provides higher transconductance (gm) leading to significant improvement in cut-off frequency (ft). Two-dimensional simulations are performed to evaluate and compare the performance of the MF-MOSFET with the conventional MOSFET. At a gate length of 60 nm, the proposed device provides 4 times higher ID, 3 times improvement in gm and 1.25 times increase in ft with better control over the short channel effects as compared with the conventional device.

Comment on "Performance of a spin based insulated gate field effect transistor" [cond-mat/0603260] [cond-mat/0603260

OpenAIRE

Bandyopadhyay, S.; Cahay, M.

2006-01-01

In a recent e-print [cond-mat/0603260] Hall and Flatte claim that a particular spin based field effect transistor (SPINFET), which they have analyzed, will have a lower threshold voltage, lower switching energy and lower leakage current than a comparable metal oxide semiconductor field effect transistor (MOSFET). Here, we show that all three claims of HF are invalid.

Effect of 1MeV electron beam on transistors and circuits

International Nuclear Information System (INIS)

Lee, Tae Hoon

1998-02-01

It has been known that semiconductor devices operating in a radiation environment exhibited significant alterations of their electrical responses. Since an electron beam bombardment produces lattice damage in Si and charged defects in SiO 2 , several electrical parameters of transistors exhibit significant changes. Those parameters are the current gain of BJT (Bipolar Junction Transistor) and the threshold voltage of MOSFET (Metal Oxide Semiconductor Field Effect Transistor). The degradation of transistors brings about that of circuits. This paper presents the results of experiments and simulations performed to study the effects of 1MeV electron beam irradiation on selected silicon transistors and circuits. For BJTs, the current gains of npn (2N3904) and pnp (2N3906) linearly decreased as the irradiation dose increased, and from this result, the damage constants, Ks were obtained as 13.65 for 2N3904 and 22.52 for 2N3906 in MGy, indicating a more stable operation in the electron radiation environment for pnp than that for npn. The decrease of current gain was due to that of minority-carrier lifetime in the base region. For MOSFETs (CD4007s), the threshold voltages of NMOS and PMOS shifted to the lower values, which was resulted from the accumulation of charge in SiO 2 . The charges could be categorized into fixed oxide charge and interfacial trap charge. From experimental results, the amounts of the induced charges could be quantitatively estimated. These degradations of transistors brought about the decrease in the voltage gain of CE (Common Emitter) amplifier and the shifts in the inverting voltage of inverter. Additionally, PSpice simulations of these circuits were carried out by modeling of irradiated transistors. The comparison of simulation with experiment showed the relatively good agreement of simulation for the degradation of circuits after irradiation

Measurement and comparison of skin dose using OneDose MOSFET and Mobile MOSFET for patients with acute lymphoblastic leukemia.

Science.gov (United States)

Mattar, Essam H; Hammad, Lina F; Al-Mohammed, Huda I

2011-07-01

Total body irradiation is a protocol used to treat acute lymphoblastic leukemia in patients prior to bone marrow transplant. It is involved in the treatment of the whole body using a large radiation field with extended source-skin distance. Therefore measuring and monitoring the skin dose during the treatment is important. Two kinds of metal oxide semiconductor field effect transistor (OneDose MOSFET and mobile MOSEFT) dosimeter are used during the treatment delivery to measure the skin dose to specific points and compare it with the target prescribed dose. The objective of this study was to compare the variation of skin dose in patients with acute lymphatic leukemia (ALL) treated with total body irradiation (TBI) using OneDose MOSFET detectors and Mobile MOSFET, and then compare both results with the target prescribed dose. The measurements involved 32 patient's (16 males, 16 females), aged between 14-30 years, with an average age of 22.41 years. One-Dose MOSFET and Mobile MOSFET dosimetry were performed at 10 different anatomical sites on every patient. The results showed there was no variation between skin dose measured with OneDose MOSFET and Mobile MOSFET in all patients. Furthermore, the results showed for every anatomical site selected there was no significant difference in the dose delivered using either OneDose MOSFET detector or Mobile MOSFET as compared to the prescribed dose. The study concludes that One-Dose MOSFET detectors and Mobile MOSFET both give a direct read-out immediately after the treatment; therefore both detectors are suitable options when measuring skin dose for total body irradiation treatment.

Engineering Nanowire n-MOSFETs at L_{g}<8 nm

Science.gov (United States)

Mehrotra, Saumitra R.; Kim, SungGeun; Kubis, Tillmann; Povolotskyi, Michael; Lundstrom, Mark S.; Klimeck, Gerhard

2013-07-01

As metal-oxide-semiconductor field-effect transistors (MOSFET) channel lengths (Lg) are scaled to lengths shorter than Lg<8 nm source-drain tunneling starts to become a major performance limiting factor. In this scenario a heavier transport mass can be used to limit source-drain (S-D) tunneling. Taking InAs and Si as examples, it is shown that different heavier transport masses can be engineered using strain and crystal orientation engineering. Full-band extended device atomistic quantum transport simulations are performed for nanowire MOSFETs at Lg<8 nm in both ballistic and incoherent scattering regimes. In conclusion, a heavier transport mass can indeed be advantageous in improving ON state currents in ultra scaled nanowire MOSFETs.

MOSFET analog memory circuit achieves long duration signal storage

Science.gov (United States)

1966-01-01

Memory circuit maintains the signal voltage at the output of an analog signal amplifier when the input signal is interrupted or removed. The circuit uses MOSFET /Metal Oxide Semiconductor Field Effect Transistor/ devices as voltage-controlled switches, triggered by an external voltage-sensing device.

Comparative study on skin dose measurement using MOSFET and TLD for pediatric patients with acute lymphatic leukemia.

Science.gov (United States)

Al-Mohammed, Huda I; Mahyoub, Fareed H; Moftah, Belal A

2010-07-01

The object of this study was to compare the difference of skin dose measured in patients with acute lymphatic leukemia (ALL) treated with total body irradiation (TBI) using metal oxide semiconductor field-effect transistors (mobile MOSFET dose verification system (TN-RD-70-W) and thermoluminescent dosimeters (TLD-100 chips, Harshaw/ Bicron, OH, USA). Because TLD has been the most-commonly used technique in the skin dose measurement of TBI, the aim of the present study is to prove the benefit of using the mobile MOSFET (metal oxide semiconductor field effect transistor) dosimeter, for entrance dose measurements during the total body irradiation (TBI) over thermoluminescent dosimeters (TLD). The measurements involved 10 pediatric patients ages between 3 and 14 years. Thermoluminescent dosimeters and MOSFET dosimetry were performed at 9 different anatomic sites on each patient. The present results show there is a variation between skin dose measured with MOSFET and TLD in all patients, and for every anatomic site selected, there is no significant difference in the dose delivered using MOSFET as compared to the prescribed dose. However, there is a significant difference for every anatomic site using TLD compared with either the prescribed dose or MOSFET. The results indicate that the dosimeter measurements using the MOSFET gave precise measurements of prescribed dose. However, TLD measurement showed significant increased skin dose of cGy as compared to either prescribed dose or MOSFET group. MOSFET dosimeters provide superior dose accuracy for skin dose measurement in TBI as compared with TLD.

Dosimetric evaluation of a MOSFET detector for clinical application in photon therapy.

Science.gov (United States)

Kohno, Ryosuke; Hirano, Eriko; Nishio, Teiji; Miyagishi, Tomoko; Goka, Tomonori; Kawashima, Mitsuhiko; Ogino, Takashi

2008-01-01

Dosimetric characteristics of a metal oxide-silicon semiconductor field effect transistor (MOSFET) detector are studied with megavoltage photon beams for patient dose verification. The major advantages of this detector are its size, which makes it a point dosimeter, and its ease of use. In order to use the MOSFET detector for dose verification of intensity-modulated radiation therapy (IMRT) and in-vivo dosimetry for radiation therapy, we need to evaluate the dosimetric properties of the MOSFET detector. Therefore, we investigated the reproducibility, dose-rate effect, accumulated-dose effect, angular dependence, and accuracy in tissue-maximum ratio measurements. Then, as it takes about 20 min in actual IMRT for the patient, we evaluated fading effect of MOSFET response. When the MOSFETs were read-out 20 min after irradiation, we observed a fading effect of 0.9% with 0.9% standard error of the mean. Further, we applied the MOSFET to the measurement of small field total scatter factor. The MOSFET for dose measurements of small field sizes was better than the reference pinpoint chamber with vertical direction. In conclusion, we assessed the accuracy, reliability, and usefulness of the MOSFET detector in clinical applications such as pinpoint absolute dosimetry for small fields.

Effective dose estimation for pediatric upper gastrointestinal examinations using an anthropomorphic phantom set and metal oxide semiconductor field-effect transistor (MOSFET) technology

International Nuclear Information System (INIS)

Emigh, Brent; Gordon, Christopher L.; Falkiner, Michelle; Thomas, Karen E.; Connolly, Bairbre L.

2013-01-01

There is a need for updated radiation dose estimates in pediatric fluoroscopy given the routine use of new dose-saving technologies and increased radiation safety awareness in pediatric imaging. To estimate effective doses for standardized pediatric upper gastrointestinal (UGI) examinations at our institute using direct dose measurement, as well as provide dose-area product (DAP) to effective dose conversion factors to be used for the estimation of UGI effective doses for boys and girls up to 10 years of age at other centers. Metal oxide semiconductor field-effect transistor (MOSFET) dosimeters were placed within four anthropomorphic phantoms representing children ≤10 years of age and exposed to mock UGI examinations using exposures much greater than used clinically to minimize measurement error. Measured effective dose was calculated using ICRP 103 weights and scaled to our institution's standardized clinical UGI (3.6-min fluoroscopy, four spot exposures and four examination beam projections) as determined from patient logs. Results were compared to Monte Carlo simulations and related to fluoroscope-displayed DAP. Measured effective doses for standardized pediatric UGI examinations in our institute ranged from 0.35 to 0.79 mSv in girls and were 3-8% lower for boys. Simulation-derived and measured effective doses were in agreement (percentage differences 0.18). DAP-to-effective dose conversion factors ranged from 6.5 x 10 -4 mSv per Gy-cm 2 to 4.3 x 10 -3 mSv per Gy-cm 2 for girls and were similarly lower for boys. Using modern fluoroscopy equipment, the effective dose associated with the UGI examination in children ≤10 years at our institute is < 1 mSv. Estimations of effective dose associated with pediatric UGI examinations can be made for children up to the age of 10 using the DAP-normalized conversion factors provided in this study. These estimates can be further refined to reflect individual hospital examination protocols through the use of direct organ

Experimental evaluation of a MOSFET dosimeter for proton dose measurements

International Nuclear Information System (INIS)

Kohno, Ryosuke; Nishio, Teiji; Miyagishi, Tomoko; Hirano, Eriko; Hotta, Kenji; Kawashima, Mitsuhiko; Ogino, Takashi

2006-01-01

The metal oxide semiconductor field-effect transistor (MOSFET) dosimeter has been widely studied for use as a dosimeter for patient dose verification. The major advantage of this detector is its size, which acts as a point dosimeter, and also its ease of use. The commercially available TN502RD MOSFET dosimeter manufactured by Thomson and Nielsen has never been used for proton dosimetry. Therefore we used the MOSFET dosimeter for the first time in proton dose measurements. In this study, the MOSFET dosimeter was irradiated with 190 MeV therapeutic proton beams. We experimentally evaluated dose reproducibility, linearity, fading effect, beam intensity dependence and angular dependence for the proton beam. Furthermore, the Bragg curve and spread-out Bragg peak were also measured and the linear-energy transfer (LET) dependence of the MOSFET response was investigated. Many characteristics of the MOSFET response for proton beams were the same as those for photon beams reported in previous papers. However, the angular MOSFET responses at 45, 90, 135, 225, 270 and 315 degrees for proton beams were over-responses of about 15%, and moreover the MOSFET response depended strongly on the LET of the proton beam. This study showed that the angular dependence and LET dependence of the MOSFET response must be considered very carefully for quantitative proton dose evaluations

On theory of single-molecule transistor

International Nuclear Information System (INIS)

Tran Tien Phuc

2009-01-01

The results of the study on single-molecule transistor are mainly investigated in this paper. The structure of constructed single-molecule transistor is similar to a conventional MOSFET. The conductive channel of the transistors is a single-molecule of halogenated benzene derivatives. The chemical simulation software CAChe was used to design and implement for the essential parameter of the molecules utilized as the conductive channel. The GUI of Matlab has been built to design its graphical interface, calculate and plot the output I-V characteristic curves for the transistor. The influence of temperature, length and width of the conductive channel, and gate voltage is considered. As a result, the simulated curves are similar to the traditional MOSFET's. The operating temperature range of the transistors is wider compared with silicon semiconductors. The supply voltage for transistors is only about 1 V. The size of transistors in this research is several nanometers.

Dc-To-Dc Converter Uses Reverse Conduction Of MOSFET's

Science.gov (United States)

Gruber, Robert P.; Gott, Robert W.

1991-01-01

In modified high-power, phase-controlled, full-bridge, pulse-width-modulated dc-to-dc converters, switching devices power metal oxide/semiconductor field-effect transistors (MOSFET's). Decreases dissipation of power during switching by eliminating approximately 0.7-V forward voltage drop in anti-parallel diodes. Energy-conversion efficiency increased.

Homostructured ZnO-based metal-oxide-semiconductor field-effect transistors deposited at low temperature by vapor cooling condensation system

Energy Technology Data Exchange (ETDEWEB)

Lin, Tzu-Shun [Institute of Nanotechnology and Microsystems Engineering, National Cheng Kung University, 701 Tainan, Taiwan, ROC (China); Lee, Ching-Ting, E-mail: ctlee@ee.ncku.edu.tw [Institute of Nanotechnology and Microsystems Engineering, National Cheng Kung University, 701 Tainan, Taiwan, ROC (China); Institute of Microelectronics, Department of Electrical Engineering, Advanced Optoelectronic Technology Center, National Cheng Kung University, 701 Tainan, Taiwan, ROC (China)

2015-11-01

Highlights: • The vapor cooling condensation system was designed and used to deposit homostructured ZnO-based metal-oxide-semiconductor field-effect transistors. • The resulting homostructured ZnO-based MOSFETs operated at a reverse voltage of −6 V had a very low gate leakage current of 24 nA. • The associated I{sub DSS} and the g{sub m(max)} were 5.64 mA/mm and 1.31 mS/mm, respectively. - Abstract: The vapor cooling condensation system was designed and used to deposit homostructured ZnO-based metal-oxide-semiconductor field-effect transistors (MOSFETs) on sapphire substrates. Owing to the high quality of the deposited, various ZnO films and interfaces, the resulting MOSFETs manifested attractive characteristics, such as the low gate leakage current of 24 nA, the low average interface state density of 2.92 × 10{sup 11} cm{sup −2} eV{sup −1}, and the complete pinch-off performance. The saturation drain–source current, the maximum transconductance, and the gate voltage swing of the resulting homostructured ZnO-based MOSFETs were 5.64 mA/mm, 1.31 mS/mm, and 3.2 V, respectively.

Hydrogen-terminated diamond vertical-type metal oxide semiconductor field-effect transistors with a trench gate

Energy Technology Data Exchange (ETDEWEB)

Inaba, Masafumi, E-mail: inaba-ma@ruri.waseda.jp; Muta, Tsubasa; Kobayashi, Mikinori; Saito, Toshiki; Shibata, Masanobu; Matsumura, Daisuke; Kudo, Takuya; Hiraiwa, Atsushi [Graduate School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan); Kawarada, Hiroshi [Graduate School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan); Kagami Memorial Laboratory for Materials Science and Technology, Waseda University, 2-8-26 Nishiwaseda, Shinjuku, Tokyo 169-0051 (Japan)

2016-07-18

The hydrogen-terminated diamond surface (C-H diamond) has a two-dimensional hole gas (2DHG) layer independent of the crystal orientation. A 2DHG layer is ubiquitously formed on the C-H diamond surface covered by atomic-layer-deposited-Al{sub 2}O{sub 3}. Using Al{sub 2}O{sub 3} as a gate oxide, C-H diamond metal oxide semiconductor field-effect transistors (MOSFETs) operate in a trench gate structure where the diamond side-wall acts as a channel. MOSFETs with a side-wall channel exhibit equivalent performance to the lateral C-H diamond MOSFET without a side-wall channel. Here, a vertical-type MOSFET with a drain on the bottom is demonstrated in diamond with channel current modulation by the gate and pinch off.

Single photon sources in 4H-SiC metal-oxide-semiconductor field-effect transistors

Science.gov (United States)

Abe, Y.; Umeda, T.; Okamoto, M.; Kosugi, R.; Harada, S.; Haruyama, M.; Kada, W.; Hanaizumi, O.; Onoda, S.; Ohshima, T.

2018-01-01

We present single photon sources (SPSs) embedded in 4H-SiC metal-oxide-semiconductor field-effect transistors (MOSFETs). They are formed in the SiC/SiO2 interface regions of wet-oxidation C-face 4H-SiC MOSFETs and were not found in other C-face and Si-face MOSFETs. Their bright room-temperature photoluminescence (PL) was observed in the range from 550 to 750 nm and revealed variable multi-peak structures as well as variable peak shifts. We characterized a wide variety of their PL spectra as the inevitable variation of local atomic structures at the interface. Their polarization dependence indicates that they are formed at the SiC side of the interface. We also demonstrate that it is possible to switch on/off the SPSs by a bias voltage of the MOSFET.

A two-dimensional analytical subthreshold behavior model for junctionless dual-material cylindrical surrounding-gate MOSFETs

International Nuclear Information System (INIS)

Li Cong; Zhuang Yi-Qi; Zhang Li; Jin Gang

2014-01-01

A two-dimensional analytical subthreshold behavior model for junctionless dual-material cylindrical surrounding-gate (JLDMCSG) metal-oxide-semiconductor field-effect transistors (MOSFETs) is proposed. It is derived by solving the two-dimensional Poisson's equation in two continuous cylindrical regions with any simplifying assumption. Using this analytical model, the subthreshold characteristics of JLDMCSG MOSFETs are investigated in terms of channel electrostatic potential, horizontal electric field, and subthreshold current. Compared to junctionless single-material cylindrical surrounding-gate MOSFETs, JLDMCSG MOSFETs can effectively suppress short-channel effects and simultaneously improve carrier transport efficiency. It is found that the subthreshold current of JLDMCSG MOSFETs can be significantly reduced by adopting both a thin oxide and thin silicon channel. The accuracy of the analytical model is verified by its good agreement with the three-dimensional numerical simulator ISE TCAD

Synchrotron X-ray irradiation effects on the device characteristics and the resistance to hot-carrier damage of MOSFETs with 4 nm thick gate oxides

International Nuclear Information System (INIS)

Tanaka, Yuusuke; Tanabe, Akira; Suzuki, Katsumi

1998-01-01

The effects of synchrotron x-ray irradiation on the device characteristics and hot-carrier resistance of n- and p-channel metal oxide semiconductor field effect transistors (MOSFETs) with 4 nm thick gate oxides are investigated. In p-channel MOSFETs, device characteristics were significantly affected by the x-ray irradiation but completely recovered after annealing, while the device characteristics in n-channel MOSFETs were not noticeably affected by the irradiation. This difference appears to be due to a difference in interface-state generation. In p-channel MOSFETs, defects caused by boron-ion penetration through the gate oxides may be sensitive to x-ray irradiation, causing the generation of many interface states. These interface states are completely eliminated after annealing in hydrogen gas. The effects of irradiation on the resistance to hot-carrier degradation in annealed 4 nm thick gate-oxide MOSFETs were negligible even at an x-ray dose of 6,000 mJ/cm 2

The effects of ionizing radiation on commercial power MOSFETs operated at cryogenic temperatures

International Nuclear Information System (INIS)

Johnson, G.H.; Kemp, W.T.; Ackermann, M.R.; Pugh, R.D.; Schrimpf, R.D.; Galloway, K.F.

1994-01-01

This is the first report of commercial n- and p-channel power MOSFETs exposed to ionizing radiation while operating in a cryogenic environment. The transistors were exposed to low energy x-rays while placed in a liquid nitrogen-cooled dewar. Results demonstrate significant performance and survivability advantages for space-borne power MOSFETs operated at cryogenic temperatures. The key advantages for low-temperature operation of power MOSFET's in an ionizing radiation environment are: (1) steeper subthreshold current slope before and after irradiation; (2) lower off-state leakage currents before and after irradiation; and (3) larger prerad threshold voltage for n-channel devices. The first two points are also beneficial for devices that are not irradiated, but the advantages are more significant in radiation environments. The third point is only an advantage for commercial devices operated in radiation environments. Results also demonstrate that commercial off-the-shelf power MOSFETs can be used for low-temperature operations in a limited total dose environment (i.e., many space applications)

Energy dependence corrections to MOSFET dosimetric sensitivity

International Nuclear Information System (INIS)

Cheung, T.; Yu, P.K.N.; Butson, M.J.; Illawarra Cancer Care Centre, Crown St, Wollongong

2009-01-01

Metal Oxide Semiconductor Field Effect Transistors (MOSFET's) are dosimeters which are now frequently utilized in radiotherapy treatment applications. An improved MOSFET, clinical semiconductor dosimetry system (CSDS) which utilizes improved packaging for the MOSFET device has been studied for energy dependence of sensitivity to x-ray radiation measurement. Energy dependence from 50 kVp to 10 MV x-rays has been studied and found to vary by up to a factor of 3.2 with 75 kVp producing the highest sensitivity response. The detectors average life span in high sensitivity mode is energy related and ranges from approximately 100 Gy for 75 kVp x-rays to approximately 300 Gy at 6MV x-ray energy. The MOSFET detector has also been studied for sensitivity variations with integrated dose history. It was found to become less sensitive to radiation with age and the magnitude of this effect is dependant on radiation energy with lower energies producing a larger sensitivity reduction with integrated dose. The reduction in sensitivity is however approximated reproducibly by a slightly non linear, second order polynomial function allowing corrections to be made to reading to account for this effect to provide more accurate dose assessments both in phantom and in-vivo.

Energy dependence corrections to MOSFET dosimetric sensitivity.

Science.gov (United States)

Cheung, T; Butson, M J; Yu, P K N

2009-03-01

Metal Oxide Semiconductor Field Effect Transistors (MOSFET's) are dosimeters which are now frequently utilized in radiotherapy treatment applications. An improved MOSFET, clinical semiconductor dosimetry system (CSDS) which utilizes improved packaging for the MOSFET device has been studied for energy dependence of sensitivity to x-ray radiation measurement. Energy dependence from 50 kVp to 10 MV x-rays has been studied and found to vary by up to a factor of 3.2 with 75 kVp producing the highest sensitivity response. The detectors average life span in high sensitivity mode is energy related and ranges from approximately 100 Gy for 75 kVp x-rays to approximately 300 Gy at 6 MV x-ray energy. The MOSFET detector has also been studied for sensitivity variations with integrated dose history. It was found to become less sensitive to radiation with age and the magnitude of this effect is dependant on radiation energy with lower energies producing a larger sensitivity reduction with integrated dose. The reduction in sensitivity is however approximated reproducibly by a slightly non linear, second order polynomial function allowing corrections to be made to readings to account for this effect to provide more accurate dose assessments both in phantom and in-vivo.

Modeling and simulation of 4H-SiC field effect transistor

Science.gov (United States)

Pedryc, A.; Martychowiec, A.; Kociubiński, A.

2017-08-01

This paper presents the technological issue of silicon carbide MOSFET design. Through the use of simulations of silicon carbide transistor, the influence of the different the technological parameters are described and discussed. MOSFET transistor was performed in Silvaco TCAD using technology elaborated at Lublin University of Technology. The most important parameters related to ion implantation, which was used in p-i-n photodiode technology. The electrical simulations were performed, transfer and output characteristics for different values of technological parameters were generated - influence of gate oxide thickness on threshold voltage and influence of channel length modulation were checked. The results of simulations as well as transfer and output characteristics allowed to select optimal parameters between expected device working and available technology - gate oxide thickness and transistor channel length were established. This work was in fact carried out to increase our understanding of the device characteristics so as to allow the design of new SiC circuits which could meet the stressful requirements of ultraviolet detector systems.

Loss analysis and optimum design of a highly efficient and compact CMOS DC–DC converter with novel transistor layout using 60 nm multipillar-type vertical body channel MOSFET

Science.gov (United States)

Itoh, Kazuki; Endoh, Tetsuo

2018-04-01

In this paper, we present a novel transistor layout of multi pillar-type vertical body-channel (BC) MOSFET for cascode power switches for improving the efficiency and compactness of CMOS DC–DC converters. The proposed layout features a stacked and multifingered layout to suppress the loss due to parasitic components such as diffusion resistance and contact resistance. In addition, the loss of each MOSFET, which configures cascode power switches, is analyzed, and it is revealed that the total optimum gate width and loss with the high-side (HS) n-type MOSFET topology are 27 and 16% smaller than those with the HS p-type MOSFET topology, respectively. Moreover, a circuit simulation of 2.0 to 0.8 V, 100 MHz CMOS DC–DC converters with the proposed layout is carried out by using experimentally extracted models of BSIM4 60 nm vertical BC MOSFETs. The peak efficiency of the HS n-type MOSFET converter with the proposed layout is 90.1%, which is 6.0% higher than that with the conventional layout.

Response Of A MOSFET To A Cosmic Ray

Science.gov (United States)

Benumof, Reuben; Zoutendyk, John A.

1988-01-01

Theoretical paper discusses response of enhancement-mode metal oxide/semiconductor field-effect transistor to cosmic-ray ion that passes perpendicularly through gate-oxide layers. Even if ion causes no permanent damage, temporary increase of electrical conductivity along track of ion large enough and long enough to cause change in logic state in logic circuit containing MOSFET.

A Novel Fully Depleted Air AlN Silicon-on-Insulator Metal-Oxide-Semiconductor Field Effect Transistor

International Nuclear Information System (INIS)

Yuan, Yang; Yong, Gao; Peng-Liang, Gong

2008-01-01

A novel fully depleted air AlN silicon-on-insulator (SOI) metal-oxide-semiconductor field effect transistor (MOS-FET) is presented, which can eliminate the self-heating effect and solve the problem that the off-state current of SOI MOSFETs increases and the threshold voltage characteristics become worse when employing a high thermal conductivity material as a buried layer. The simulation results reveal that the lattice temperature in normal SOI devices is 75 K higher than the atmosphere temperature, while the lattice temperature is just 4K higher than the atmosphere temperature resulting in less severe self-heating effect in air AlN SOI MOSFETs and AlN SOI MOSFETs. The on-state current of air AlN SOI MOSFETs is similar to the AlN SOI structure, and improves 12.3% more than that of normal SOI MOSFETs. The off-state current of AlN SOI is 6.7 times of normal SOI MOSFETs, while the counterpart of air AlN SOI MOSFETs is lower than that of SOI MOSFETs by two orders of magnitude. The threshold voltage change of air AlN SOI MOSFETs with different drain voltage is much less than that of AlN SOI devices, when the drain voltage is biased at 0.8 V, this difference is 28mV, so the threshold voltage change induced by employing high thermal conductivity material is cured. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Radiation hardness of β-Ga2O3 metal-oxide-semiconductor field-effect transistors against gamma-ray irradiation

Science.gov (United States)

Wong, Man Hoi; Takeyama, Akinori; Makino, Takahiro; Ohshima, Takeshi; Sasaki, Kohei; Kuramata, Akito; Yamakoshi, Shigenobu; Higashiwaki, Masataka

2018-01-01

The effects of ionizing radiation on β-Ga2O3 metal-oxide-semiconductor field-effect transistors (MOSFETs) were investigated. A gamma-ray tolerance as high as 1.6 MGy(SiO2) was demonstrated for the bulk Ga2O3 channel by virtue of weak radiation effects on the MOSFETs' output current and threshold voltage. The MOSFETs remained functional with insignificant hysteresis in their transfer characteristics after exposure to the maximum cumulative dose. Despite the intrinsic radiation hardness of Ga2O3, radiation-induced gate leakage and drain current dispersion ascribed respectively to dielectric damage and interface charge trapping were found to limit the overall radiation hardness of these devices.

Superficial x-ray in-vivo dosimetry with MOSFET detectors

International Nuclear Information System (INIS)

Cheung, T.; Yu, P.K.N.; Butson, M.J.; Cancer Services, Wollongong, NSW

2004-01-01

Full text: This note investigates in-vivo dosimetry using a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) for radiotherapy treatment at superficial and orthovoltage x-ray energies. This was performed within one fraction of the patient's treatment. Standard measurements along with energy response of the detector are given. Results showed that the MOSFET measurements in-vivo agreed with calculated results on average within ± 5.6% over all superficial and orthovoltage energies. These variations were slightly larger than TLD results with variations between measured and calculated results being ± 5.0% for the same patient measurements. The MOSFET device provides adequate in-vivo dosimetry for superficial and orthovoltage energy treatments with the accuracy of the measurements seeming to be relatively on par with TLD in our case. The MOSFET does have the advantage of returning a relatively immediate dosimetric result after irradiation. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

TID and Displacement Damage Effects in Vertical and Lateral Power MOSFETs for Integrated DC-DC Converters

CERN Document Server

Faccio, F; Michelis, S; Faccio, Federico; Fuentes, C; Allongue, B; Sorge, R; Orlandi, S

2010-01-01

TID and displacement damage effects are studied for vertical and lateral power MOSFETs in five different technologies in view of the development of radiation-tolerant fully integrated DC-DC converters. Investigation is pushed to the very high level of radiation expected for an upgrade to the LHC experiments. TID induces threshold voltage shifts and, in n-channel transistors, source-drain leakage currents. Wide variability in the magnitude of these effects is observed. Displacement damage increases the on-resistance of both vertical and lateral high-voltage transistors. In the latter case, degradation at high particle fluence might lead to a distortion of the output characteristics curve. HBD techniques to limit or eliminate the radiation-induced leakage currents are successfully applied to these high-voltage transistors, but have to be used carefully to avoid consequences on the breakdown voltage.

A simulation study of 6H-SiC Schottky barrier source/drain MOSFET

International Nuclear Information System (INIS)

Wang Yuan; Zhang Yimen; Zhang Yuming; Tang Xiaoyan

2003-01-01

A novel SiC metal-oxide-semiconductor field-effect transistor (SiC SBSD-MOSFET) with Schottky barrier contacts for source and drain is presented in this paper. This kind of device gives a fabrication advantage of avoiding the steps of ion implantation and annealing at high temperatures of the conventional SiC MOSFET. Also it has no problems of crystal damage caused by ion implantation and low activation rate of implanted atoms. The operational mechanism of this device is analyzed and its characteristics are comparable to the conventional SiC MOSFET from the simulation with MEDICI. The effects of different metal workfunctions, oxide thickness, and gate length on the device performance are discussed

Evaluation of SEGR threshold in power MOSFETs

International Nuclear Information System (INIS)

Allenspach, M.; Brews, J.R.; Mouret, I.; Schrimpf, R.D.; Galloway, K.F.

1994-01-01

Bias values, determined experimentally to result in single-event gate rupture (SEGR) in power metal oxide semiconductor field effect transistors (MOSFETs), are used in 2-D device simulations, incorporating the experimental geometry. The simulations indicate that very short time oxide field transients occur for ion strikes when V DS ≠ 0V. These transients can affect SEGR through hole trapping and redistribution in the oxide

Radiation effects on JFETS, MOSFETS, and bipolar transistors, as related to SSC circuit design

Energy Technology Data Exchange (ETDEWEB)

Kennedy, E J; Gray, B; Wu, A [Dept. of Electrical and Computer Engineering, Univ. of Tennessee, Knoxville, TN (United States); Alley, G T; Britton, Jr, C L [Oak Ridge National Lab., TN (United States); Skubic, P L [Univ. of Oklahoma, Dept. of Physics and Astronomy, Norman, OK (United States)

1991-10-01

Some results of radiation effects on selected junction field-effect transistors, MOS field-effect transistors, and bipolar junction transistors are presented. The evaluations include dc parameters, as well as capacitive variations and noise evaluations. The tests are made at the low current and voltage levels (in particular at currents {<=} 1 mA) that are essential for the low-power regimes required by SSC circuitry. Detailed noise data are presented both before and after 5-Mrad (gamma) total-dose exposure. SPICE radiation models for three high-frequency bipolar processes are compared for a typical charge-sensitive preamplifier. (orig.).

GaN MOSFET with Boron Trichloride-Based Dry Recess Process

International Nuclear Information System (INIS)

Jiang, Y; Wang, Q P; Tamai, K; Ao, J P; Ohno, Y; Miyashita, T; Motoyama, S; Wang, D J

2013-01-01

The dry recessed-gate GaN metal-oxide-semiconductor field-effect transistors (MOSFETs) on AlGaN/GaN heterostructure using boron trichloride (BCl 3 ) as etching gas were fabricated and characterized. Etching with different etching power was conducted. Devices with silicon tetrachloride (SiCl 4 ) etching gas were also prepared for comparison. Field-effect mobility and interface state density were extracted from current-voltage (I-V) characteristics. GaN MOSFETs on AlGaN/GaN heterostructure with BCl 3 based dry recess achieved a high maximum electron mobility of 141.5 cm 2 V −1 s −1 and a low interface state density.

Characterization of responses and comparison of calibration factor for commercial MOSFET detectors.

Science.gov (United States)

Bharanidharan, Ganesan; Manigandan, Durai; Devan, Krishnamurthy; Subramani, Vellaiyan; Gopishankar, Natanasabapathi; Ganesh, Tharmar; Joshi, Rakeshchander; Rath, Gourakishore; Velmurugan, Jagadeesan; Aruna, Prakasarao; Ganesan, Singaravelu

2005-01-01

A commercial metal oxide silicon field effect transistor (MOSFET) dosimeter of model TN502-RD has been characterized for its linearity, reproducibility, field size dependency, dose rate dependency, and angular dependency for Cobalt-60 (60Co), 6-MV, and 15-MV beam energies. The performance of the MOSFET clearly shows that it is highly reproducible, independent of field size and dose rate. Furthermore, MOSFET has a very high degree of linearity, with r-value>0.9 for all 3 energies. The calibration factor for 2 similar MOSFET detectors of model TN502-RD were also estimated and compared for all 3 energies. The calibration factor between the 2 similar MOSFET detectors shows a variation of about 1.8% for 60Co and 15 MV, and for 6 MV it shows variation of about 2.5%, indicating that calibration should be done whenever a new MOSFET is used. However, the detector shows considerable angular dependency of about 8.8% variation. This may be due to the variation in radiation sensitivity between flat and bubble sides of the MOSFET, and indicates that positional care must be taken while using MOSFET for stereotactic radiosurgery and stereotactic radiotherapy dosimetric applications.

Modeling of anisotropic two-dimensional materials monolayer HfS{sub 2} and phosphorene metal-oxide semiconductor field effect transistors

Energy Technology Data Exchange (ETDEWEB)

Chang, Jiwon [SEMATECH, 257 Fuller Rd #2200, Albany, New York 12203 (United States)

2015-06-07

Ballistic transport characteristics of metal-oxide semiconductor field effect transistors (MOSFETs) based on anisotropic two-dimensional materials monolayer HfS{sub 2} and phosphorene are explored through quantum transport simulations. We focus on the effects of the channel crystal orientation and the channel length scaling on device performances. Especially, the role of degenerate conduction band (CB) valleys in monolayer HfS{sub 2} is comprehensively analyzed. Benchmarking monolayer HfS{sub 2} with phosphorene MOSFETs, we predict that the effect of channel orientation on device performances is much weaker in monolayer HfS{sub 2} than in phosphorene due to the degenerate CB valleys of monolayer HfS{sub 2}. Our simulations also reveal that at 10 nm channel length scale, phosphorene MOSFETs outperform monolayer HfS{sub 2} MOSFETs in terms of the on-state current. However, it is observed that monolayer HfS{sub 2} MOSFETs may offer comparable, but a little bit degraded, device performances as compared with phosphorene MOSFETs at 5 nm channel length.

Characterization of MOSFET dosimeters for low-dose measurements in maxillofacial anthropomorphic phantoms

NARCIS (Netherlands)

Koivisto, J.H.; Wolff, J.E.; Kiljunen, T.; Schulze, D.; Kortesniemi, M.

2015-01-01

The aims of this study were to characterize reinforced metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters to assess the measurement uncertainty, single exposure low-dose limit with acceptable accuracy, and the number of exposures required to attain the corresponding limit of the

SiC Power MOSFET with Improved Gate Dielectric

Energy Technology Data Exchange (ETDEWEB)

Sbrockey, Nick M. [Structured Materials Industries, Inc., Piscataway, NJ (United States); Tompa, Gary S. [Structured Materials Industries, Inc., Piscataway, NJ (United States); Spencer, Michael G. [Structured Materials Industries, Inc., Piscataway, NJ (United States); Chandrashekhar, Chandra M.V. S. [Structured Materials Industries, Inc., Piscataway, NJ (United States)

2010-08-23

In this STTR program, Structured Materials Industries (SMI), and Cornell University are developing novel gate oxide technology, as a critical enabler for silicon carbide (SiC) devices. SiC is a wide bandgap semiconductor material, with many unique properties. SiC devices are ideally suited for high-power, highvoltage, high-frequency, high-temperature and radiation resistant applications. The DOE has expressed interest in developing SiC devices for use in extreme environments, in high energy physics applications and in power generation. The development of transistors based on the Metal Oxide Semiconductor Field Effect Transistor (MOSFET) structure will be critical to these applications.

Characterization of commercial MOSFETS electron dosimetry

International Nuclear Information System (INIS)

Carvajal, M. A.; Simancas, F.; Guirado, D.; Banqueri, J.; Vilches, M.; Lallena, A. M.; Palma, A. J.

2011-01-01

In recent years there have been commercial dosimetry devices based on transistors Metal-Oxide-Semiconductor (MOSFET) having a number of advantages over traditional systems for dosimetry in medical applications. These include the portability of the sensor element and a reading process quick and relatively simple dose, linearity, and so on. The use of electron beams is important in modern radiotherapy include its use in intra-operative radiotherapy (RIO). This paper presents an initial characterization of different business models MOSFET, not specific for radiation detection, to demonstrate their potential as sensors for electron beam dosimetry. (Author)

Molecular-beam-deposited yttrium-oxide dielectrics in aluminum-gated metal - oxide - semiconductor field-effect transistors: Effective electron mobility

International Nuclear Information System (INIS)

Ragnarsson, L.-A degree.; Guha, S.; Copel, M.; Cartier, E.; Bojarczuk, N. A.; Karasinski, J.

2001-01-01

We report on high effective mobilities in yttrium-oxide-based n-channel metal - oxide - semiconductor field-effect transistors (MOSFETs) with aluminum gates. The yttrium oxide was grown in ultrahigh vacuum using a reactive atomic-beam-deposition system. Medium-energy ion-scattering studies indicate an oxide with an approximate composition of Y 2 O 3 on top of a thin layer of interfacial SiO 2 . The thickness of this interfacial oxide as well as the effective mobility are found to be dependent on the postgrowth anneal conditions. Optimum conditions result in mobilities approaching that of SiO 2 -based MOSFETs at higher fields with peak mobilities at approximately 210 cm 2 /Vs. [copyright] 2001 American Institute of Physics

Hot carrier degradation and a new lifetime prediction model in ultra-deep sub-micron pMOSFET

International Nuclear Information System (INIS)

Lei Xiao-Yi; Liu Hong-Xia; Zhang Kai; Zhang Yue; Zheng Xue-Feng; Ma Xiao-Hua; Hao Yue

2013-01-01

The hot carrier effect (HCE) of an ultra-deep sub-micron p-channel metal—oxide semiconductor field-effect transistor (pMOSFET) is investigated in this paper. Experiments indicate that the generation of positively charged interface states is the predominant mechanism in the case of the ultra-deep sub-micron pMOSFET. The relation of the pMOSFET hot carrier degradation to stress time (t), channel width (W), channel length (L), and stress voltage (V d ) is then discussed. Based on the relation, a lifetime prediction model is proposed, which can predict the lifetime of the ultra-deep sub-micron pMOSFET accurately and reflect the influence of the factors on hot carrier degradation directly. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Analyses of the radiation-caused characteristics change in SOI MOSFETs using field shield isolation

International Nuclear Information System (INIS)

Hirano, Yuuichi; Maeda, Shigeru; Fernandez, Warren; Iwamatsu, Toshiaki; Yamaguchi, Yasuo; Maegawa, Shigeto; Nishimura, Tadashi

1999-01-01

Reliability against radiation ia an important issue in silicon on insulator metal oxide semiconductor field effect transistors (SOI MOSFETs) used in satellites and nuclear power plants and so forth which are severely exposed to radiation. Radiation-caused characteristic change related to the isolation-edge in an irradiated environment was analyzed on SOI MOSFETs. Moreover short channel effects for an irradiated environment were investigated by simulations. It was revealed that the leakage current which was observed in local oxidation of silicon (LOCOS) isolated SOI MOSFETs was successfully suppressed by using field shield isolation. Simulated potential indicated that the potential rise at the LOCOS edge can not be seen in the case of field shield isolation edge which does not have physical isolation. Also it was found that the threshold voltage shift caused by radiation in short channel regime is severer than that in long regime channel. In transistors with a channel length of 0.18μm, a potential rise of the body region by radiation-induced trapped holes can be seen in comparison with that of 1.0μm. As a result, we must consider these effects for designing deep submicron devices used in an irradiated environment. (author)

Band-to-band tunneling in a carbon nanotube metal-oxide-semiconductor field-effect transistor is dominated by phonon-assisted tunneling.

Science.gov (United States)

Koswatta, Siyuranga O; Lundstrom, Mark S; Nikonov, Dmitri E

2007-05-01

Band-to-band tunneling (BTBT) devices have recently gained a lot of interest due to their potential for reducing power dissipation in integrated circuits. We have performed extensive simulations for the BTBT operation of carbon nanotube metal-oxide-semiconductor field-effect transistors (CNT-MOSFETs) using the nonequilibrium Green's function formalism for both ballistic and dissipative quantum transport. In comparison with recently reported experimental data (J. Am. Chem. Soc. 2006, 128, 3518-3519), we have obtained strong evidence that BTBT in CNT-MOSFETs is dominated by optical phonon assisted inelastic transport, which can have important implications on the transistor characteristics. It is shown that, under large biasing conditions, two-phonon scattering may also become important.

Comparative Study of Si and SiC MOSFETs for High Voltage Class D Audio Amplifiers

DEFF Research Database (Denmark)

Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

2014-01-01

Silicon (Si) Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) are traditional utilised in class D audio amplifiers. It has been proposed to replace the traditional inefficient electrodynamic transducer with the electrostatic transducer. This imposes new high voltage requirements...... on the MOSFETs of class D amplifiers, and significantly reduces the selection of suitable MOSFETs. As a consequence it is investigated, if Silicon-Carbide (SiC) MOSFETs could represent a valid alternative. The theory of pulse timing errors are revisited for the application of high voltage and capactive loaded...... class D amplifiers. It is shown, that SiC MOSFETs can compete with Si MSOFETs in terms of THD. Validation is done using simulations and a 500 V amplifier driving a 100 nF load. THD+N below 0.3 % is reported...

Verification of angular dependence in MOSFET detector

International Nuclear Information System (INIS)

Souza, Clayton H.; Shorto, Julian M.B.; Siqueira, Paulo T.D.; Nunes, Maíra G.; Silva Junior, Iremar A.; Yoriyaz, Hélio

2017-01-01

In vivo dosimetry is an essential tool for quality assurance programs, being a procedure commonly performed with thermoluminescent dosimeters (TLDs) or diodes. However, a type of dosimeter that has increasing popularity in recent years is the metal-oxide-semiconductor field effect transistor (MOSFET) detector. MOSFET dosimeters fulfill all the necessary characteristics to realize in vivo dosimetry since it has a small size, good precision and feasibility of measurement, as well as easy handling. Nevertheless, its true differential is to allow reading of the dose in real time, enabling immediate intervention in the correction of physical parameters deviations and anticipation of small anatomical changes in a patient during treatment. In order for MOSFET dosimeter to be better accepted in clinical routine, information reporting performance should be available frequently. For this reason, this work proposes to verify reproducibility and angular dependence of a standard sensitivity MOSFET dosimeter (TN-502RD-H) for Cs-137 and Co-60 sources. Experimental data were satisfactory and MOSFET dosimeter presented a reproducibility of 3.3% and 2.7% (1 SD) for Cs-137 and Co-60 sources, respectively. In addition, an angular dependence of up to 6.1% and 16.3% for both radioactive sources, respectively. It is conclusive that MOSFET dosimeter TN-502RD-H has satisfactory reproducibility and a considerable angular dependence, mainly for the Co-60 source. This means that although precise measurements, special attention must be taken for applications in certain anatomical regions in a patient. (author)

Verification of angular dependence in MOSFET detector

Energy Technology Data Exchange (ETDEWEB)

Souza, Clayton H.; Shorto, Julian M.B.; Siqueira, Paulo T.D.; Nunes, Maíra G.; Silva Junior, Iremar A.; Yoriyaz, Hélio, E-mail: chsouza@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2017-07-01

In vivo dosimetry is an essential tool for quality assurance programs, being a procedure commonly performed with thermoluminescent dosimeters (TLDs) or diodes. However, a type of dosimeter that has increasing popularity in recent years is the metal-oxide-semiconductor field effect transistor (MOSFET) detector. MOSFET dosimeters fulfill all the necessary characteristics to realize in vivo dosimetry since it has a small size, good precision and feasibility of measurement, as well as easy handling. Nevertheless, its true differential is to allow reading of the dose in real time, enabling immediate intervention in the correction of physical parameters deviations and anticipation of small anatomical changes in a patient during treatment. In order for MOSFET dosimeter to be better accepted in clinical routine, information reporting performance should be available frequently. For this reason, this work proposes to verify reproducibility and angular dependence of a standard sensitivity MOSFET dosimeter (TN-502RD-H) for Cs-137 and Co-60 sources. Experimental data were satisfactory and MOSFET dosimeter presented a reproducibility of 3.3% and 2.7% (1 SD) for Cs-137 and Co-60 sources, respectively. In addition, an angular dependence of up to 6.1% and 16.3% for both radioactive sources, respectively. It is conclusive that MOSFET dosimeter TN-502RD-H has satisfactory reproducibility and a considerable angular dependence, mainly for the Co-60 source. This means that although precise measurements, special attention must be taken for applications in certain anatomical regions in a patient. (author)

Measurement of Gamma Knife registered helmet factors using MOSFETs

International Nuclear Information System (INIS)

Kurjewicz, Laryssa; Berndt, Anita

2007-01-01

The relative dose rate for the different Gamma Knife registered helmets (4, 8, 14, and 18 mm) is characterized by their respective helmet factors. Since the plateau of the dose profile for the 4 mm helmet is at most 1 mm wide, detector choices are limited. Traditionally helmet factors have been measured using 1x1x1 mm 3 thermoluminescent dosimeters (TLDs). However, these are time-consuming, cumbersome measurements. This article investigates the use of metal-oxide-semiconductor field effect transistors (MOSFETs) (active area of 0.2x0.2 mm 2 ) as a more accurate and convenient dosimeter. Their suitability for these measurements was confirmed by basic characterization measurements. Helmet factors were measured using both MOSFETs and the established TLD approach. A custom MOSFET cassette was designed in analogy to the Elekta TLD cassette (Elekta Instruments AB) for use with the Elekta dosimetry sphere. Although both dosimeters provided values within 3% of the manufacturer's suggestion, MOSFETs provided superior accuracy and precision, in a fraction of the time required for the TLD measurements. Thus, MOSFETs proved to be a reasonable alternative to TLDs for performing helmet factor measurements

Skin dose measurements using MOSFET and TLD for head and neck patients treated with tomotherapy

International Nuclear Information System (INIS)

Kinhikar, Rajesh A.; Murthy, Vedang; Goel, Vineeta; Tambe, Chandrashekar M.; Dhote, Dipak S.; Deshpande, Deepak D.

2009-01-01

The purpose of this work was to estimate skin dose for the patients treated with tomotherapy using metal oxide semiconductor field-effect transistors (MOSFETs) and thermoluminescent dosimeters (TLDs). In vivo measurements were performed for two head and neck patients treated with tomotherapy and compared to TLD measurements. The measurements were subsequently carried out for five days to estimate the inter-fraction deviations in MOSFET measurements. The variation between skin dose measured with MOSFET and TLD for first patient was 2.2%. Similarly, the variation of 2.3% was observed between skin dose measured with MOSFET and TLD for second patient. The tomotherapy treatment planning system overestimated the skin dose as much as by 10-12% when compared to both MOSFET and TLD. However, the MOSFET measured patient skin doses also had good reproducibility, with inter-fraction deviations ranging from 1% to 1.4%. MOSFETs may be used as a viable dosimeter for measuring skin dose in areas where the treatment planning system may not be accurate.

Skin dose measurements using MOSFET and TLD for head and neck patients treated with tomotherapy.

Science.gov (United States)

Kinhikar, Rajesh A; Murthy, Vedang; Goel, Vineeta; Tambe, Chandrashekar M; Dhote, Dipak S; Deshpande, Deepak D

2009-09-01

The purpose of this work was to estimate skin dose for the patients treated with tomotherapy using metal oxide semiconductor field-effect transistors (MOSFETs) and thermoluminescent dosimeters (TLDs). In vivo measurements were performed for two head and neck patients treated with tomotherapy and compared to TLD measurements. The measurements were subsequently carried out for five days to estimate the inter-fraction deviations in MOSFET measurements. The variation between skin dose measured with MOSFET and TLD for first patient was 2.2%. Similarly, the variation of 2.3% was observed between skin dose measured with MOSFET and TLD for second patient. The tomotherapy treatment planning system overestimated the skin dose as much as by 10-12% when compared to both MOSFET and TLD. However, the MOSFET measured patient skin doses also had good reproducibility, with inter-fraction deviations ranging from 1% to 1.4%. MOSFETs may be used as a viable dosimeter for measuring skin dose in areas where the treatment planning system may not be accurate.

MOSFET dosimetry in-vivo at superficial and orthovoltage x-ray energies

International Nuclear Information System (INIS)

Cheung, T.; Yu, P.K.N.; Butson, M.J.; Illawarra Cancer Care Centre, Wollongong, NSW

2003-01-01

This note investigates in-vivo dosimetry using a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) for radiotherapy treatment at superficial and orthovoltage x-ray energies. This was performed within one fraction of the patients treatment. Standard measurements along with energy response of the detector are given. Results showed that the MOSFET measurements in-vivo agreed with calculated results on average within ± 5.6% over all superficial and orthovoltage energies. These variations were slightly larger than TLD results with variations between measured and calculated results being ± 5.0% for the same patient measurements. The MOSFET device provides adequate in-vivo dosimetry for superficial and orthovoltage energy treatments with the accuracy of the measurements seeming to be relatively on par with TLD in our case. The MOSFET does have the advantage of returning a relatively immediate dosimetric result after irradiation. Copyright (2003) Australasian College of Physical Scientists and Engineers in Medicine

A novel nanoscale SOI MOSFET by embedding undoped region for improving self-heating effect

Science.gov (United States)

Ghaffari, Majid; Orouji, Ali A.

2018-06-01

Because of the low thermal conductivity of the SiO2 (oxide), the Buried Oxide (BOX) layer in a Silicon-On-Insulator Metal-Oxide Semiconductor Field-Effect Transistor (SOI MOSFET) prevents heat dissipation in the silicon layer and causes increase in the device lattice temperature. In this paper, a new technique is proposed for reducing Self-Heating Effects (SHEs). The key idea in the proposed structure is using a Silicon undoped Region (SR) in the nanoscale SOI MOSFET under the drain and channel regions in order to decrease the SHE. The novel transistor is named Silicon undoped Region SOI-MOSFET (SR-SOI). Due to the embedded silicon undoped region in the suitable place, the proposed structure has decreased the device lattice temperature. The location and dimensions of the proposed region have been carefully optimized to achieve the best results. This work has explored enhancement such as decreased maximum lattice temperature, increased electron mobility, increased drain current, lower DC drain conductance and higher DC transconductance and also decreased bandgap energy variations. Also, for modeling of the structure in the SPICE tools, the main characterizations have been extracted such as thermal resistance (RTH), thermal capacitance (CTH), and SHE characteristic frequency (fTH). All parameters are extracted in relation with the AC operation indicate excellent performance of the SR-SOI device. The results show that proposed region is a suitable alternative to oxide as a part of the buried oxide layer in SOI structures and has better performance in high temperature. Using two-dimensional (2-D) and two-carrier device simulation is done comparison of the SR-SOI structure with a Conventional SOI (C-SOI). As a result, the SR-SOI device can be regarded as a useful substitution for the C-SOI device in nanoscale integrated circuits as a reliable device.

Spin injection, transport, and read/write operation in spin-based MOSFET

International Nuclear Information System (INIS)

Saito, Yoshiaki; Marukame, Takao; Inokuchi, Tomoaki; Ishikawa, Mizue; Sugiyama, Hideyuki; Tanamoto, Tetsufumi

2011-01-01

We proposed a novel spin-based MOSFET 'Spin-Transfer-torque-Switching MOSFET (STS-MOSFET)' that offers non-volatile memory and transistor functions with complementary metal-oxide-semiconductor (CMOS) compatibility, high endurance and fast write time using STS. The STS-MOSFETs with Heusler alloy (Co 2 Fe 1 Al 0.5 Si 0.5 ) were prepared and reconfigurability of a novel spintronics-based MOSFET, STS-MOSFET, was successfully realized for the transport properties owing to reduction of the contact resistance in ferromagnetic metal/thin insulator tunnel barrier/Si junctions. The device showed magnetocurrent (MC) and write characteristics with the endurance of over 10 5 cycles. It was also clarified that the read characteristic can be improved in terms of MC ratio, however, is deteriorated in terms of the mobility by choosing connection configurations of the source and the drain in the STS-MOSFETs.

Single Event Effects (SEE) for Power Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs)

Science.gov (United States)

Lauenstein, Jean-Marie

2011-01-01

Single-event gate rupture (SEGR) continues to be a key failure mode in power MOSFETs. (1) SEGR is complex, making rate prediction difficult SEGR mechanism has two main components: (1) Oxide damage-- Reduces field required for rupture (2) Epilayer response -- Creates transient high field across the oxide.

Numerical study of self-heating effects of small-size MOSFETs fabricated on silicon-on-aluminum nitride substrate

International Nuclear Information System (INIS)

Ding Yanfang; Zhu Ziqiang; Zhu Ming; Lin Chenglu

2006-01-01

Compared with bulk-silicon technology, silicon-on-insulator (SOI) technology possesses many advantages but it is inevitable that the buried silicon dioxide layer also thermally insulates the metal-oxide-silicon field-effect transistors (MOSFETs) from the bulk due to the low thermal conductivity. One of the alternative insulator to replace the buried oxide layer is aluminum nitride (MN), which has a thermal conductivity that is about 200 times higher than that of SiO 2 (320 W·m -1 ·K -1 versus 1.4 W·m -1 ·K -l ). To investigate the self-heating effects of small-size MOSFETs fabricated on silicon-on-aluminum nitride (SOAN) substrate, a two-dimensional numerical analysis is performed by using a device simulator called MEDICI run on a Solaris workstation to simulate the electrical characteristics and temperature distribution by comparing with those of bulk and standard SOI MOSFETs. Our study suggests that AIN is a suitable alternative to silicon dioxide as a buried dielectric in SOI and expands the applications of SOI to high temperature conditions. (authors)

Scaling the Serialization of MOSFETs by Magnetically Coupling Their Gate Electrodes

DEFF Research Database (Denmark)

Dimopoulos, Emmanouil; Munk-Nielsen, Stig

2013-01-01

More than twenty years of thorough research on the serialization of power semiconductor switches, like the Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) or the Insulated Gate Bipolar Transistor (IGBT), have resulted into several different stacking concepts; all aiming towards...... the establishment of a high-efficient, high-voltage, fast-switching device. Among the prevailing stacking approaches lies the gate balancing core technique, which, in its initial form, demonstrated very good performance in strings of high-power IGBT modules, by magnetically coupling their gate electrodes. Recently...

Dopant distributions in n-MOSFET structure observed by atom probe tomography

International Nuclear Information System (INIS)

Inoue, K.; Yano, F.; Nishida, A.; Takamizawa, H.; Tsunomura, T.; Nagai, Y.; Hasegawa, M.

2009-01-01

The dopant distributions in an n-type metal-oxide-semiconductor field effect transistor (MOSFET) structure were analyzed by atom probe tomography. The dopant distributions of As, P, and B atoms in a MOSFET structure (gate, gate oxide, channel, source/drain extension, and halo) were obtained. P atoms were segregated at the interface between the poly-Si gate and the gate oxide, and on the grain boundaries of the poly-Si gate, which had an elongated grain structure along the gate height direction. The concentration of B atoms was enriched near the edge of the source/drain extension where the As atoms were implanted.

Dopant distributions in n-MOSFET structure observed by atom probe tomography.

Science.gov (United States)

Inoue, K; Yano, F; Nishida, A; Takamizawa, H; Tsunomura, T; Nagai, Y; Hasegawa, M

2009-11-01

The dopant distributions in an n-type metal-oxide-semiconductor field effect transistor (MOSFET) structure were analyzed by atom probe tomography. The dopant distributions of As, P, and B atoms in a MOSFET structure (gate, gate oxide, channel, source/drain extension, and halo) were obtained. P atoms were segregated at the interface between the poly-Si gate and the gate oxide, and on the grain boundaries of the poly-Si gate, which had an elongated grain structure along the gate height direction. The concentration of B atoms was enriched near the edge of the source/drain extension where the As atoms were implanted.

Effects of electron-hole generation, transport and trapping in MOSFETs due to γ-ray exposure

International Nuclear Information System (INIS)

Soliman, F.A.S.; Al-Kabbani, A.S.S.

1995-01-01

Ionizing radiation has been found to seriously change the electrical properties of solid-state devices, leading to possible systems failure. The ionizing radiation effects on different n-and p-channel MOSFETs have been studied, where the failure mechanism is found to be mainly due to changes in oxide properties and surface effects which occur in the gate oxide and, or, field/oxide regions. As a result, the threshold voltage of the n-channel transistor was shifted from 1.10 to 2.65 V, while the channel mobility for both the n- and p-channel transistors decreases from 4500 and 3100 to 2000 and 1000 m 2 /V·, respectively. Besides, the transconductance drops from 610, 500 and 380 down to 51, 35 and 150 mS for the MFE 201 (n-channel), 3N128 (n-channel) and 3N163 (p-channel) transistors, respectively. Also, the net effect of charge trapping can also be seen as a random, stochastical process represented by global noise parameters. Finally, the gain and noise parameters have been investigated as a function of γ-dose. (Author)

MOSFET detectors in quality assurance of tomotherapy treatments.

Science.gov (United States)

Cherpak, Amanda; Studinski, Ryan C N; Cygler, Joanna E

2008-02-01

The purpose of this work was to characterize metal oxide semiconductor field-effect transistors (MOSFETs) in a 6 MV conventional linac and investigate their use for quality assurance of radiotherapy treatments with a tomotherapy Hi-Art unit. High sensitivity and standard sensitivity MOSFETs were first calibrated and then tested for reproducibility, field size dependence, and accuracy of measuring surface dose in a 6 MV beam as well as in a tomotherapy Hi-Art unit. In vivo measurements were performed on both a RANDO phantom and several head and neck cancer patients treated with tomotherapy and compared to TLD measurements and treatment plan doses to evaluate the performance of MOSFETs in a high gradient radiation field. The average calibration factor found was 0.345+/-2.5%cGy/mV for the high sensitivity MOSFETs tested and 0.901+/-2.4%cGy/mV for the standard sensitivity MOSFETs. MOSFET measured surface doses had an average agreement with ion chamber measurements of 1.55% for the high sensitivity MOSFET and 5.23% for the standard sensitivity MOSFET when averaged over all trials and field sizes tested. No significant dependence on field size was found for the standard sensitivity MOSFETs, however a maximum difference of 5.34% was found for the high sensitivity MOSFET calibration factors in the field sizes tested. Measurements made with MOSFETS on head and neck patients treated on a tomotherapy Hi-Art unit had an average agreement of (3.26+/-0.03)% with TLD measurements, however the average of the absolute difference between the MOSFET measurements and the treatment plan skin doses was (12.2+/-7.5)%. The MOSFET measured patient skin doses also had good reproducibility, with inter-fraction deviations ranging from 1.4% to 6.6%. Similar results were found from trials using a RANDO phantom. The MOSFETs performed well when used in the tomotherapy Hi-Art unit and did not increase the overall treatment set-up time when used for patient measurements. It was found that MOSFETs

A novel planar vertical double-diffused metal-oxide-semiconductor field-effect transistor with inhomogeneous floating islands

Institute of Scientific and Technical Information of China (English)

Ren Min; Li Ze-Hong; Liu Xiao-Long; Xie Jia-Xiong; Deng Guang-Min; Zhang Bo

2011-01-01

A novel planar vertical double-diffused metal-oxide-semiconductor (VDMOS) structure with an ultra-low specific on-resistance (Ron,sp),whose distinctive feature is the use of inhomogeneous floating p-islands in the n-drift region,is proposed.The theoretical limit of its Ron,sp is deduced,the influence of structure parameters on the breakdown voltage (BV) and Ron,sp are investigated,and the optimized results with BV of 83 V and Ron,sp of 54 mΩ.mm2 are obtained.Simulations show that the inhomogencous-floating-islands metal-oxide-semiconductor field-effect transistor (MOSFET)has a superior “Ron,sp/BV” trade-off to the conventional VDMOS (a 38％ reduction of Ron,sp with the same BV) and the homogeneous-floating-islands MOSFET (a 10％ reduction of Ron,sp with the same BV).The inhomogeneous-floatingislands MOSFET also has a much better body-diode characteristic than the superjunction MOSFET.Its reverse recovery peak current,reverse recovery time and reverse recovery charge are about 50,80 and 40％ of those of the superjunction MOSFET,respectively.

Commissioning and characteristics of MOSFET dosimeter

International Nuclear Information System (INIS)

Gopiraj, A.; Billimagga, Ramesh S.; Rekha, M.; Ramasubramaniam, V.

2007-01-01

The verification of the dose delivered to a patient is an important part of the quality assurance in radiotherapy. Thermoluminescent dosimeters (TLDs) and semiconductor diodes were mostly used for this purpose. Recently Metal Oxide Semiconductor field effect transistors (MOSFET) have been proposed for the application in radiotherapy. Each type of detector has its own advantages and disadvantages. The TLD size is very small and therefore can be used both for measurement and dose delivered to a patient and for measurements of dose distribution in a humanoid phantom. The main disadvantages of the TLDs are the time required by the preparation procedure and the limited accuracy which depends on the experience of the user. Additionally, TLDs do not allow an immediate readout. The main disadvantages of semiconductor diodes are the necessity of using a cable which can disturb normal clinical work especially when in vivo measurements are carried out, and the necessity of applying of many correction factors to achieve high accuracy. We procured MOSFET system from Thomson and Nielsen Electronic Ltd. The reproducibility as a function of dose and linearity and calibration factor of the MOSFET detectors were measured. The effects of energy, field size and accumulated dose on the response of the detectors were investigated

Kink effect in ultrathin FDSOI MOSFETs

Science.gov (United States)

Park, H. J.; Bawedin, M.; Choi, H. G.; Cristoloveanu, S.

2018-05-01

Systematic experiments demonstrate the presence of the kink effect even in FDSOI MOSFETs. The back-gate bias controls the kink effect via the formation of a back accumulation channel. The kink is more or less pronounced according to the film thickness and channel length. However, in ultrathin (MOSFETs.

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

International Nuclear Information System (INIS)

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

1999-01-01

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

Radiation dose response of N channel MOSFET submitted to filtered X-ray photon beam

Science.gov (United States)

Gonçalves Filho, Luiz C.; Monte, David S.; Barros, Fabio R.; Santos, Luiz A. P.

2018-01-01

MOSFET can operate as a radiation detector mainly in high-energy photon beams, which are normally used in cancer treatments. In general, such an electronic device can work as a dosimeter from threshold voltage shift measurements. The purpose of this article is to show a new way for measuring the dose-response of MOSFETs when they are under X-ray beams generated from 100kV potential range, which is normally used in diagnostic radiology. Basically, the method consists of measuring the MOSFET drain current as a function of the radiation dose. For this the type of device, it has to be biased with a high value resistor aiming to see a substantial change in the drain current after it has been irradiated with an amount of radiation dose. Two types of N channel device were used in the experiment: a signal transistor and a power transistor. The delivered dose to the device was varied and the electrical curves were plotted. Also, a sensitivity analysis of the power MOSFET response was made, by varying the tube potential of about 20%. The results show that both types of devices have responses very similar, the shift in the electrical curve is proportional to the radiation dose. Unlike the power MOSFET, the signal transistor does not provide a linear function between the dose rate and its drain current. We also have observed that the variation in the tube potential of the X-ray equipment produces a very similar dose-response.

Large current MOSFET on photonic silicon-on-insulator wafers and its monolithic integration with a thermo-optic 2 × 2 Mach-Zehnder switch.

Science.gov (United States)

Cong, G W; Matsukawa, T; Chiba, T; Tadokoro, H; Yanagihara, M; Ohno, M; Kawashima, H; Kuwatsuka, H; Igarashi, Y; Masahara, M; Ishikawa, H

2013-03-25

n-channel body-tied partially depleted metal-oxide-semiconductor field-effect transistors (MOSFETs) were fabricated for large current applications on a silicon-on-insulator wafer with photonics-oriented specifications. The MOSFET can drive an electrical current as large as 20 mA. We monolithically integrated this MOSFET with a 2 × 2 Mach-Zehnder interferometer optical switch having thermo-optic phase shifters. The static and dynamic performances of the integrated device are experimentally evaluated.

A Wide-Range Tunable Level-Keeper Using Vertical Metal-Oxide-Semiconductor Field-Effect Transistors for Current-Reuse Systems

Science.gov (United States)

Tanoi, Satoru; Endoh, Tetsuo

2012-04-01

A wide-range tunable level-keeper using vertical metal-oxide-semiconductor field-effect transistors (MOSFETs) is proposed for current-reuse analog systems. The design keys for widening tunable range of the operation are a two-path feed-back and a vertical MOSFET with back-bias-effect free. The proposed circuit with the vertical MOSFETs shows the 1.23-V tunable-range of the input level with the 2.4-V internal-supply voltage (VDD) in the simulation. This tunable-range of the proposed circuit is 4.7 times wider than that of the conventional. The achieved current efficiency of the proposed level-keeper is 66% at the 1.2-V output with the 2.4-V VDD. This efficiency of the proposed circuit is twice higher than that of the traditional voltage down converter.

Band-to-band tunneling field effect transistor for low power logic and memory applications: Design, fabrication and characterization

Science.gov (United States)

Mookerjea, Saurabh A.

Over the past decade the microprocessor clock frequency has hit a plateau. The main reason for this has been the inability to follow constant electric field scaling, which requires the transistor supply voltage to be scaled down as the transistor dimensions are reduced. Scaling the supply voltage down reduces the dynamic power quadratically but increases the static leakage power exponentially due to non-scalability of threshold voltage of the transistor, which is required to maintain the same ON state performance. This limitation in supply voltage scaling is directly related to MOSFET's (Metal Oxide Semiconductor Field Effect Transistor) sub-threshold slope (SS) limitation of 60 mV/dec at room temperature. Thus novel device design/materials are required that would allow the transistor to switch with sub-threshold slopes steeper than 60 mV/dec at room temperature, thus facilitating supply voltage scaling. Recently, a new class of devices known as super-steep slope (SSswitching behavior of TFET is studied through mixed-mode numerical simulations. The significance of correct benchmarking methodology to estimate the effective drive current and capacitance in TFET is highlighted and compared with MOSFET. This is followed by the fabrication details of homo-junction TFET. Analysis of the electrical characteristics of homo-junction TFET gives key insight into its device operation and identifies the critical factors that impact its performance. In order to boost the ON current, the design and fabrication of hetero-junction TFET is also presented.

MOSFET and MOS capacitor responses to ionizing radiation

Science.gov (United States)

Benedetto, J. M.; Boesch, H. E., Jr.

1984-01-01

The ionizing radiation responses of metal oxide semiconductor (MOS) field-effect transistors (FETs) and MOS capacitors are compared. It is shown that the radiation-induced threshold voltage shift correlates closely with the shift in the MOS capacitor inversion voltage. The radiation-induced interface-state density of the MOSFETs and MOS capacitors was determined by several techniques. It is shown that the presence of 'slow' states can interfere with the interface-state measurements.

In vivo proton dosimetry using a MOSFET detector in an anthropomorphic phantom with tissue inhomogeneity.

Science.gov (United States)

Kohno, Ryosuke; Hotta, Kenji; Matsubara, Kana; Nishioka, Shie; Matsuura, Taeko; Kawashima, Mitsuhiko

2012-03-08

When in vivo proton dosimetry is performed with a metal-oxide semiconductor field-effect transistor (MOSFET) detector, the response of the detector depends strongly on the linear energy transfer. The present study reports a practical method to correct the MOSFET response for linear energy transfer dependence by using a simplified Monte Carlo dose calculation method (SMC). A depth-output curve for a mono-energetic proton beam in polyethylene was measured with the MOSFET detector. This curve was used to calculate MOSFET output distributions with the SMC (SMC(MOSFET)). The SMC(MOSFET) output value at an arbitrary point was compared with the value obtained by the conventional SMC(PPIC), which calculates proton dose distributions by using the depth-dose curve determined by a parallel-plate ionization chamber (PPIC). The ratio of the two values was used to calculate the correction factor of the MOSFET response at an arbitrary point. The dose obtained by the MOSFET detector was determined from the product of the correction factor and the MOSFET raw dose. When in vivo proton dosimetry was performed with the MOSFET detector in an anthropomorphic phantom, the corrected MOSFET doses agreed with the SMC(PPIC) results within the measurement error. To our knowledge, this is the first report of successful in vivo proton dosimetry with a MOSFET detector.

Proton dose distribution measurements using a MOSFET detector with a simple dose-weighted correction method for LET effects.

Science.gov (United States)

Kohno, Ryosuke; Hotta, Kenji; Matsuura, Taeko; Matsubara, Kana; Nishioka, Shie; Nishio, Teiji; Kawashima, Mitsuhiko; Ogino, Takashi

2011-04-04

We experimentally evaluated the proton beam dose reproducibility, sensitivity, angular dependence and depth-dose relationships for a new Metal Oxide Semiconductor Field Effect Transistor (MOSFET) detector. The detector was fabricated with a thinner oxide layer and was operated at high-bias voltages. In order to accurately measure dose distributions, we developed a practical method for correcting the MOSFET response to proton beams. The detector was tested by examining lateral dose profiles formed by protons passing through an L-shaped bolus. The dose reproducibility, angular dependence and depth-dose response were evaluated using a 190 MeV proton beam. Depth-output curves produced using the MOSFET detectors were compared with results obtained using an ionization chamber (IC). Since accurate measurements of proton dose distribution require correction for LET effects, we developed a simple dose-weighted correction method. The correction factors were determined as a function of proton penetration depth, or residual range. The residual proton range at each measurement point was calculated using the pencil beam algorithm. Lateral measurements in a phantom were obtained for pristine and SOBP beams. The reproducibility of the MOSFET detector was within 2%, and the angular dependence was less than 9%. The detector exhibited a good response at the Bragg peak (0.74 relative to the IC detector). For dose distributions resulting from protons passing through an L-shaped bolus, the corrected MOSFET dose agreed well with the IC results. Absolute proton dosimetry can be performed using MOSFET detectors to a precision of about 3% (1 sigma). A thinner oxide layer thickness improved the LET in proton dosimetry. By employing correction methods for LET dependence, it is possible to measure absolute proton dose using MOSFET detectors.

Proton dose distribution measurements using a MOSFET detector with a simple dose‐weighted correction method for LET effects

Science.gov (United States)

Hotta, Kenji; Matsuura, Taeko; Matsubara, Kana; Nishioka, Shie; Nishio, Teiji; Kawashima, Mitsuhiko; Ogino, Takashi

2011-01-01

We experimentally evaluated the proton beam dose reproducibility, sensitivity, angular dependence and depth‐dose relationships for a new Metal Oxide Semiconductor Field Effect Transistor (MOSFET) detector. The detector was fabricated with a thinner oxide layer and was operated at high‐bias voltages. In order to accurately measure dose distributions, we developed a practical method for correcting the MOSFET response to proton beams. The detector was tested by examining lateral dose profiles formed by protons passing through an L‐shaped bolus. The dose reproducibility, angular dependence and depth‐dose response were evaluated using a 190 MeV proton beam. Depth‐output curves produced using the MOSFET detectors were compared with results obtained using an ionization chamber (IC). Since accurate measurements of proton dose distribution require correction for LET effects, we developed a simple dose‐weighted correction method. The correction factors were determined as a function of proton penetration depth, or residual range. The residual proton range at each measurement point was calculated using the pencil beam algorithm. Lateral measurements in a phantom were obtained for pristine and SOBP beams. The reproducibility of the MOSFET detector was within 2%, and the angular dependence was less than 9%. The detector exhibited a good response at the Bragg peak (0.74 relative to the IC detector). For dose distributions resulting from protons passing through an L‐shaped bolus, the corrected MOSFET dose agreed well with the IC results. Absolute proton dosimetry can be performed using MOSFET detectors to a precision of about 3% (1 sigma). A thinner oxide layer thickness improved the LET in proton dosimetry. By employing correction methods for LET dependence, it is possible to measure absolute proton dose using MOSFET detectors. PACS number: 87.56.‐v

Characterization of vertical strain silicon MOSFET incorporating dielectric pocket (SDP-VMOSFET)

Energy Technology Data Exchange (ETDEWEB)

Napiah, Z. A. F. M., E-mail: zulatfyi@utem.edu.my, E-mail: nazirah6969@gmail.com, E-mail: azlishah@utem.edu.my, E-mail: idzdihar@utem.edu.my, E-mail: faiz.arith@utem.edu.my, E-mail: yashidar@yahoo.com, E-mail: sitinabilahtaib@gmail.com; Makhtar, N., E-mail: zulatfyi@utem.edu.my, E-mail: nazirah6969@gmail.com, E-mail: azlishah@utem.edu.my, E-mail: idzdihar@utem.edu.my, E-mail: faiz.arith@utem.edu.my, E-mail: yashidar@yahoo.com, E-mail: sitinabilahtaib@gmail.com; Othman, M. A., E-mail: zulatfyi@utem.edu.my, E-mail: nazirah6969@gmail.com, E-mail: azlishah@utem.edu.my, E-mail: idzdihar@utem.edu.my, E-mail: faiz.arith@utem.edu.my, E-mail: yashidar@yahoo.com, E-mail: sitinabilahtaib@gmail.com; Idris, M. I., E-mail: zulatfyi@utem.edu.my, E-mail: nazirah6969@gmail.com, E-mail: azlishah@utem.edu.my, E-mail: idzdihar@utem.edu.my, E-mail: faiz.arith@utem.edu.my, E-mail: yashidar@yahoo.com, E-mail: sitinabilahtaib@gmail.com; Arith, F., E-mail: zulatfyi@utem.edu.my, E-mail: nazirah6969@gmail.com, E-mail: azlishah@utem.edu.my, E-mail: idzdihar@utem.edu.my, E-mail: faiz.arith@utem.edu.my, E-mail: yashidar@yahoo.com, E-mail: sitinabilahtaib@gmail.com; Yasin, N. Y. M., E-mail: zulatfyi@utem.edu.my, E-mail: nazirah6969@gmail.com, E-mail: azlishah@utem.edu.my, E-mail: idzdihar@utem.edu.my, E-mail: faiz.arith@utem.edu.my, E-mail: yashidar@yahoo.com, E-mail: sitinabilahtaib@gmail.com; Taib, S. N., E-mail: zulatfyi@utem.edu.my, E-mail: nazirah6969@gmail.com, E-mail: azlishah@utem.edu.my, E-mail: idzdihar@utem.edu.my, E-mail: faiz.arith@utem.edu.my, E-mail: yashidar@yahoo.com, E-mail: sitinabilahtaib@gmail.com [Centre for Telecommunication Research and Innovation (CeTRI), Faculty of Electronic and Computer Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka (Malaysia)

2014-02-24

The vertical Metal-Oxide-Semiconductor Field-Effect-Transistor (MOSFET) leads to a double channel width that can increase the packaging density. The strained silicon MOSFET was introduced to modify the carrier transport properties of silicon in order to enhance transport of both electrons and holes within strained layer. Dielectric pocket was act to control encroachment of the drain doping into the channel and reduce short channel effects (SCE). SDP-VMOSFET which was a combination of those advantages was proposed to overcome the SCE in term of leakage current, threshold voltage roll-off also Drain Induce Barrier Lowering (DIBL). As a result, SDP-VMOSFET produces a better threshold voltage and DIBL compared to related structures. Meanwhile, it gives slightly increased for leakage current compared to Vertical MOSFET Incorporating Dielectric Pocket. The characteristics of the SDP-VMOSFET are analyzed in order to optimize the performance of the device and leading to the next generation of IC technology.

Characterization of vertical strain silicon MOSFET incorporating dielectric pocket (SDP-VMOSFET)

International Nuclear Information System (INIS)

Napiah, Z. A. F. M.; Makhtar, N.; Othman, M. A.; Idris, M. I.; Arith, F.; Yasin, N. Y. M.; Taib, S. N.

2014-01-01

The vertical Metal-Oxide-Semiconductor Field-Effect-Transistor (MOSFET) leads to a double channel width that can increase the packaging density. The strained silicon MOSFET was introduced to modify the carrier transport properties of silicon in order to enhance transport of both electrons and holes within strained layer. Dielectric pocket was act to control encroachment of the drain doping into the channel and reduce short channel effects (SCE). SDP-VMOSFET which was a combination of those advantages was proposed to overcome the SCE in term of leakage current, threshold voltage roll-off also Drain Induce Barrier Lowering (DIBL). As a result, SDP-VMOSFET produces a better threshold voltage and DIBL compared to related structures. Meanwhile, it gives slightly increased for leakage current compared to Vertical MOSFET Incorporating Dielectric Pocket. The characteristics of the SDP-VMOSFET are analyzed in order to optimize the performance of the device and leading to the next generation of IC technology

Static Characteristics of the Ferroelectric Transistor Inverter

Science.gov (United States)

Mitchell, Cody; Laws, crystal; MacLeond, Todd C.; Ho, Fat D.

2010-01-01

The inverter is one of the most fundamental building blocks of digital logic, and it can be used as the foundation for understanding more complex logic gates and circuits. This paper presents the characteristics of an inverter circuit using a ferroelectric field-effect transistor. The voltage transfer characteristics are analyzed with respect to varying parameters such as supply voltage, input voltage, and load resistance. The effects of the ferroelectric layer between the gate and semiconductor are examined, and comparisons are made between the inverters using ferroelectric transistors and those using traditional MOSFETs.

Field isolation for GaN MOSFETs on AlGaN/GaN heterostructure with boron ion implantation

International Nuclear Information System (INIS)

Jiang, Y; Wang, Q P; Wang, D J; Tamai, K; Li, L A; Ao, J-P; Ohno, Y; Shinkai, S; Miyashita, T; Motoyama, S-I

2014-01-01

We report the investigation of boron ion implantation as a device field isolation process for GaN metal-oxide-semiconductor field-effect transistors (MOSFETs) on AlGaN/GaN heterostructure. In the mesa isolation region of a bar-type MOSFET, a parasitic MOS-channel existed and widened the designed channel width, which would result in an overestimated mobility compared with a ring-type MOSFET. After boron ions implantation in the isolation region, the overestimation of field-effect mobility of bar-type MOSFETs was eliminated. The sub-threshold characteristics and on-state drain current of the bar-type MOSFETs coincide with the ring-type devices. Long-channel ring-type MOSFETs, with and without ion implantation, were fabricated on the recess region to evaluate the sub-threshold characteristics. The MOSFETs with boron ions implanted into the recess region showed a low drain current up to the gate bias of 10V. The result indicated that boron ion implantation prevented the formation of parasitic MOS-channel in the isolation region and achieved field isolation. The current–voltage characteristics of MOSFETs with the normal recess condition demonstrated no degradation of device performance after boron ions implanted into the isolation region. Boron ion implantation by further optimization can be a field isolation method for GaN MOSFETs. (paper)

The Complete Semiconductor Transistor and Its Incomplete Forms

International Nuclear Information System (INIS)

Jie Binbin; Sah, C.-T.

2009-01-01

This paper describes the definition of the complete transistor. For semiconductor devices, the complete transistor is always bipolar, namely, its electrical characteristics contain both electron and hole currents controlled by their spatial charge distributions. Partially complete or incomplete transistors, via coined names or/and designed physical geometries, included the 1949 Shockley p/n junction transistor (later called Bipolar Junction Transistor, BJT), the 1952 Shockley unipolar 'field-effect' transistor (FET, later called the p/n Junction Gate FET or JGFET), as well as the field-effect transistors introduced by later investigators. Similarities between the surface-channel MOS-gate FET (MOSFET) and the volume-channel BJT are illustrated. The bipolar currents, identified by us in a recent nanometer FET with 2-MOS-gates on thin and nearly pure silicon base, led us to the recognition of the physical makeup and electrical current and charge compositions of a complete transistor and its extension to other three or more terminal signal processing devices, and also the importance of the terminal contacts.

Direct and pulsed current annealing of p-MOSFET based dosimeter: the "MOSkin".

Science.gov (United States)

Alshaikh, Sami; Carolan, Martin; Petasecca, Marco; Lerch, Michael; Metcalfe, Peter; Rosenfeld, Anatoly

2014-06-01

Contemporary radiation therapy (RT) is complicated and requires sophisticated real-time quality assurance (QA). While 3D real-time dosimetry is most preferable in RT, it is currently not fully realised. A small, easy to use and inexpensive point dosimeter with real-time and in vivo capabilities is an option for routine QA. Such a dosimeter is essential for skin, in vivo or interface dosimetry in phantoms for treatment plan verification. The metal-oxide-semiconductor-field-effect-transistor (MOSFET) detector is one of the best choices for these purposes, however, the MOSFETs sensitivity and its signal stability degrade after essential irradiation which limits its lifespan. The accumulation of positive charge on the gate oxide and the creation of interface traps near the silicon-silicon dioxide layer is the primary physical phenomena responsible for this degradation. The aim of this study is to investigate MOSFET dosimeter recovery using two proposed annealing techniques: direct current (DC) and pulsed current (PC), both based on hot charged carrier injection into the gate oxide of the p-MOSFET dosimeter. The investigated MOSFETs were reused multiple times using an irradiation-annealing cycle. The effect of the current-annealing parameters was investigated for the dosimetric characteristics of the recovered MOSFET dosimeters such as linearity, sensitivity and initial threshold voltage. Both annealing techniques demonstrated excellent results in terms of maintaining a stable response, linearity and sensitivity of the MOSFET dosimeter. However, PC annealing is more preferable than DC annealing as it offers better dose response linearity of the reused MOSFET and has a very short annealing time.

Switching Characteristics of Ferroelectric Transistor Inverters

Science.gov (United States)

Laws, Crystal; Mitchell, Coey; MacLeod, Todd C.; Ho, Fat D.

2010-01-01

This paper presents the switching characteristics of an inverter circuit using a ferroelectric field effect transistor, FeFET. The propagation delay time characteristics, phl and plh are presented along with the output voltage rise and fall times, rise and fall. The propagation delay is the time-delay between the V50% transitions of the input and output voltages. The rise and fall times are the times required for the output voltages to transition between the voltage levels V10% and V90%. Comparisons are made between the MOSFET inverter and the ferroelectric transistor inverter.

Strained silicon/silicon germanium heterojunction n-channel metal oxide semiconductor field effect transistors

International Nuclear Information System (INIS)

Olsen, Sarah H.

2002-01-01

Investigations into the performance of strained silicon/silicon-germanium (Si/SiGe) n-channel metal-oxide-semiconductor field effect transistors (MOSFETs) have been carried out. Theoretical predictions suggest that use of a strained Si/SiGe material system with advanced material properties compared with conventional silicon allows enhanced MOSFET device performance. This study has therefore investigated the practical feasibility of obtaining superior electrical performance using a Si/SiGe material system. The MOSFET devices consisted of a strained Si surface channel and were fabricated on relaxed SiGe material using a reduced thermal budget process in order to preserve the strain. Two batches of strained Si/SiGe devices fabricated on material grown by differing methods have been analysed and both showed good transistor action. A correlation of electrical and physical device data established that the electrical device behaviour was closely related to the SiGe material quality, which differed depending on growth technique. The cross-wafer variation in the electrical performance of the strained Si/SiGe devices was found to be a function of material quality, thus the viability of Si/SiGe MOSFET technology for commercial applications has been addressed. Of particular importance was the finding that large-scale 'cross-hatching' roughness associated with relaxed SiGe alloys led to degradation in the small-scale roughness at the gate oxide interface, which affects electrical device performance. The fabrication of strained Si MOSFET devices on high quality SiGe material thus enabled significant performance gains to be realised compared with conventional Si control devices. In contrast, the performance of devices fabricated on material with severe cross-hatching roughness was found to be diminished by the nanoscale oxide interface roughness. The effect of device processing on SiGe material with differing as-grown roughness has been carried out and compared with the reactions

A novel planar vertical double-diffused metal-oxide-semiconductor field-effect transistor with inhomogeneous floating islands

International Nuclear Information System (INIS)

Ren Min; Li Ze-Hong; Liu Xiao-Long; Xie Jia-Xiong; Deng Guang-Min; Zhang Bo

2011-01-01

A novel planar vertical double-diffused metal-oxide-semiconductor (VDMOS) structure with an ultra-low specific on-resistance (R on,sp ), whose distinctive feature is the use of inhomogeneous floating p-islands in the n-drift region, is proposed. The theoretical limit of its R on,sp is deduced, the influence of structure parameters on the breakdown voltage (BV) and R on,sp are investigated, and the optimized results with BV of 83 V and R on,sp of 54 mΩ·mm 2 are obtained. Simulations show that the inhomogeneous-floating-islands metal-oxide-semiconductor field-effect transistor (MOSFET) has a superior 'R on,sp /BV' trade-off to the conventional VDMOS (a 38% reduction of R on,sp with the same BV) and the homogeneous-floating-islands MOSFET (a 10% reduction of R on,sp with the same BV). The inhomogeneous-floating-islands MOSFET also has a much better body-diode characteristic than the superjunction MOSFET. Its reverse recovery peak current, reverse recovery time and reverse recovery charge are about 50, 80 and 40% of those of the superjunction MOSFET, respectively. (interdisciplinary physics and related areas of science and technology)

A 2D simulation study and characterization of a novel vertical SOI MOSFET with a smart source/body tie

International Nuclear Information System (INIS)

Lin, Jyi-Tsong; Lee, Tai-Yi; Lin, Kao-Cheng

2008-01-01

A novel vertical silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistor (MOSFET) with a smart source/body contact, SSBVMOS, is presented here for the first time. 2D simulations reveal that the SSBVMOS reduces self-heating effects, with the lattice temperature reduced by 14% and the hole temperature reduced by 25%. The SSBVMOS also eliminates the floating body effect, something that other SOI vertical MOSFETs are unable to accomplish, regardless of the thickness of the thin film. The SSBVMOS is further found to have a better drain-induced barrier lowering and subthreshold swing than either a conventional vertical MOSFET or an SOI vertical MOSFET. Moreover, these results are achieved using typical pillar heights and buried oxide thicknesses. Should future technological advances allow for lower pillars or thinner buried oxides, the SSBVMOS performance would further increase

Review on analog/radio frequency performance of advanced silicon MOSFETs

Science.gov (United States)

Passi, Vikram; Raskin, Jean-Pierre

2017-12-01

Aggressive gate-length downscaling of the metal-oxide-semiconductor field-effect transistor (MOSFET) has been the main stimulus for the growth of the integrated circuit industry. This downscaling, which has proved beneficial to digital circuits, is primarily the result of the need for improved circuit performance and cost reduction and has resulted in tremendous reduction of the carrier transit time across the channel, thereby resulting in very high cut-off frequencies. It is only in recent decades that complementary metal-oxide-semiconductor (CMOS) field-effect transistor (FET) has been considered as the radio frequency (RF) technology of choice. In this review, the status of the digital, analog and RF figures of merit (FoM) of silicon-based FETs is presented. State-of-the-art devices with very good performance showing low values of drain-induced barrier lowering, sub-threshold swing, high values of gate transconductance, Early voltage, cut-off frequencies, and low minimum noise figure, and good low-frequency noise characteristic values are reported. The dependence of these FoM on the device gate length is also shown, helping the readers to understand the trends and challenges faced by shorter CMOS nodes. Device performance boosters including silicon-on-insulator substrates, multiple-gate architectures, strain engineering, ultra-thin body and buried-oxide and also III-V and 2D materials are discussed, highlighting the transistor characteristics that are influenced by these boosters. A brief comparison of the two main contenders in continuing Moore’s law, ultra-thin body buried-oxide and fin field-effect transistors are also presented. The authors would like to mention that despite extensive research carried out in the semiconductor industry, silicon-based MOSFET will continue to be the driving force in the foreseeable future.

Large current modulation and tunneling magnetoresistance change by a side-gate electric field in a GaMnAs-based vertical spin metal-oxide-semiconductor field-effect transistor.

Science.gov (United States)

Kanaki, Toshiki; Yamasaki, Hiroki; Koyama, Tomohiro; Chiba, Daichi; Ohya, Shinobu; Tanaka, Masaaki

2018-05-08

A vertical spin metal-oxide-semiconductor field-effect transistor (spin MOSFET) is a promising low-power device for the post scaling era. Here, using a ferromagnetic-semiconductor GaMnAs-based vertical spin MOSFET with a GaAs channel layer, we demonstrate a large drain-source current I DS modulation by a gate-source voltage V GS with a modulation ratio up to 130%, which is the largest value that has ever been reported for vertical spin field-effect transistors thus far. We find that the electric field effect on indirect tunneling via defect states in the GaAs channel layer is responsible for the large I DS modulation. This device shows a tunneling magnetoresistance (TMR) ratio up to ~7%, which is larger than that of the planar-type spin MOSFETs, indicating that I DS can be controlled by the magnetization configuration. Furthermore, we find that the TMR ratio can be modulated by V GS . This result mainly originates from the electric field modulation of the magnetic anisotropy of the GaMnAs ferromagnetic electrodes as well as the potential modulation of the nonmagnetic semiconductor GaAs channel layer. Our findings provide important progress towards high-performance vertical spin MOSFETs.

Robust mode space approach for atomistic modeling of realistically large nanowire transistors

Science.gov (United States)

Huang, Jun Z.; Ilatikhameneh, Hesameddin; Povolotskyi, Michael; Klimeck, Gerhard

2018-01-01

Nanoelectronic transistors have reached 3D length scales in which the number of atoms is countable. Truly atomistic device representations are needed to capture the essential functionalities of the devices. Atomistic quantum transport simulations of realistically extended devices are, however, computationally very demanding. The widely used mode space (MS) approach can significantly reduce the numerical cost, but a good MS basis is usually very hard to obtain for atomistic full-band models. In this work, a robust and parallel algorithm is developed to optimize the MS basis for atomistic nanowires. This enables engineering-level, reliable tight binding non-equilibrium Green's function simulation of nanowire metal-oxide-semiconductor field-effect transistor (MOSFET) with a realistic cross section of 10 nm × 10 nm using a small computer cluster. This approach is applied to compare the performance of InGaAs and Si nanowire n-type MOSFETs (nMOSFETs) with various channel lengths and cross sections. Simulation results with full-band accuracy indicate that InGaAs nanowire nMOSFETs have no drive current advantage over their Si counterparts for cross sections up to about 10 nm × 10 nm.

Anomalous radiation effects in fully depleted SOI MOSFETs fabricated on SIMOX

Science.gov (United States)

Li, Ying; Niu, Guofu; Cressler, J. D.; Patel, J.; Marshall, C. J.; Marshall, P. W.; Kim, H. S.; Reed, R. A.; Palmer, M. J.

2001-12-01

We investigate the proton tolerance of fully depleted silicon-on-insulator (SOI) MOSFETs with H-gate and regular-gate structural configurations. For the front-gate characteristics, the H-gate does not show the edge leakage observed in the regular-gate transistor. An anomalous kink in the back-gate linear I/sub D/-V/sub GS/ characteristics of the fully depleted SOI nFETs has been observed at high radiation doses. This kink is attributed to charged traps generated in the bandgap at the buried oxide/silicon film interface during irradiation. Extensive two-dimensional simulations with MEDICI were used to understand the physical origin of this kink. We also report unusual self-annealing effects in the devices when they are cooled to liquid nitrogen temperature.

Inexpensive and fast pathogenic bacteria screening using field-effect transistors.

Science.gov (United States)

Formisano, Nello; Bhalla, Nikhil; Heeran, Mel; Reyes Martinez, Juana; Sarkar, Amrita; Laabei, Maisem; Jolly, Pawan; Bowen, Chris R; Taylor, John T; Flitsch, Sabine; Estrela, Pedro

2016-11-15

While pathogenic bacteria contribute to a large number of globally important diseases and infections, current clinical diagnosis is based on processes that often involve culturing which can be time-consuming. Therefore, innovative, simple, rapid and low-cost solutions to effectively reduce the burden of bacterial infections are urgently needed. Here we demonstrate a label-free sensor for fast bacterial detection based on metal-oxide-semiconductor field-effect transistors (MOSFETs). The electric charge of bacteria binding to the glycosylated gates of a MOSFET enables quantification in a straightforward manner. We show that the limit of quantitation is 1.9×10(5) CFU/mL with this simple device, which is more than 10,000-times lower than is achieved with electrochemical impedance spectroscopy (EIS) and matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-ToF) on the same modified surfaces. Moreover, the measurements are extremely fast and the sensor can be mass produced at trivial cost as a tool for initial screening of pathogens. Copyright © 2016 Elsevier B.V. All rights reserved.

Volumetric measurement of human red blood cells by MOSFET-based microfluidic gate.

Science.gov (United States)

Guo, Jinhong; Ai, Ye; Cheng, Yuanbing; Li, Chang Ming; Kang, Yuejun; Wang, Zhiming

2015-08-01

In this paper, we present a MOSFET-based (metal oxide semiconductor field-effect transistor) microfluidic gate to characterize the translocation of red blood cells (RBCs) through a gate. In the microfluidic system, the bias voltage modulated by the particles or biological cells is connected to the gate of MOSFET. The particles or cells can be detected by monitoring the MOSFET drain current instead of DC/AC-gating method across the electronic gate. Polystyrene particles with various standard sizes are utilized to calibrate the proposed device. Furthermore, RBCs from both adults and newborn blood sample are used to characterize the performance of the device in distinguishing the two types of RBCs. As compared to conventional DC/AC current modulation method, the proposed device demonstrates a higher sensitivity and is capable of being a promising platform for bioassay analysis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Highly Responsive Silicon Nanowire/Amplifier MOSFET Hybrid Biosensor

Science.gov (United States)

2015-07-21

Hybrid Biosensor Jieun Lee1,2, Jaeman Jang1, Bongsik Choi1, Jinsu Yoon1, Jee-Yeon Kim3, Yang-Kyu Choi3, Dong Myong Kim1, Dae Hwan Kim1 & Sung-Jin Choi1...This study demonstrates a hybrid biosensor comprised of a silicon nanowire (SiNW) integrated with an amplifier MOSFET to improve the current response...of field-effect-transistor (FET)-based biosensors . The hybrid biosensor is fabricated using conventional CMOS technology, which has the potential

SPICE modelling of the transient response of irradiated MOSFETs; Modelisation de la reponse transitoire de MOSFETs irradies avec SPICE

Energy Technology Data Exchange (ETDEWEB)

Pouget, V.; Lapuyade, H.; Lewis, D.; Deval, Y.; Fouillat, P. [Bordeaux-1 Univ., IXL, 33 - Talence (France); Sarger, L. [Bordeaux-1 Univ., CPMOH, 33 - Talence (France)

1999-07-01

A new SPICE model of irradiated MOSFET taking into account the real response of the 4 electrodes is proposed. The component that has been simulated is an NMOS transistor issued from the AMS BiCMOS 0.8 {mu}m technology. A comparison between SPICE-generated transients and PISCES device simulation demonstrates the accuracy benefits when used in complex electronic architectures. This model could be used when designing electronic circuits able to sustain hardening due to SEE (single event effect), it will be an efficient complement to the physical simulations.

The effect of interface trapped charges in DMG-S-SOI MOSFET: a perspective study

International Nuclear Information System (INIS)

Mohapatra, S K; Pradhan, K P; Sahu, P K; Pati, G S; Kumar, M R

2014-01-01

In this paper, the existing two-dimensional (2D) threshold voltage model for a dual material gate fully depleted strained silicon on insulator (DMG-FD-S-SOI) metal-oxide-semiconductor field effect transistor (MOSFET) is modified by considering the interface trapped charge effects. The interface trapped charge is a common phenomenon, and this charge cannot be neglected in nanoscale devices. For finding out the surface potential, parabolic approximation has been utilized and the virtual cathode potential method is used to formulate the threshold voltage. The developed threshold voltage model incorporates both positive as well as negative interface charges. Finally, validity of the presented model is verified with 2D device simulator Sentaurus™. (paper)

The effect of interface trapped charges in DMG-S-SOI MOSFET: a perspective study

Science.gov (United States)

Mohapatra, S. K.; Pradhan, K. P.; Sahu, P. K.; Pati, G. S.; Kumar, M. R.

2014-12-01

In this paper, the existing two-dimensional (2D) threshold voltage model for a dual material gate fully depleted strained silicon on insulator (DMG-FD-S-SOI) metal-oxide-semiconductor field effect transistor (MOSFET) is modified by considering the interface trapped charge effects. The interface trapped charge is a common phenomenon, and this charge cannot be neglected in nanoscale devices. For finding out the surface potential, parabolic approximation has been utilized and the virtual cathode potential method is used to formulate the threshold voltage. The developed threshold voltage model incorporates both positive as well as negative interface charges. Finally, validity of the presented model is verified with 2D device simulator Sentaurus™.

A new metallic oxide semiconductor field effect transistor detector for use of in vivo dosimetry

International Nuclear Information System (INIS)

Qi Zhenyu; Deng Xiaowu; Huang Shaomin; Kang Dehua; Anatoly Rosenfeld

2006-01-01

Objective: To investigate the application of a recently developed metallic oxide semiconductor field effect transistor (MOSFET) detector for use in vivo dosimetry. Methods: The MOSFET detector was calibrated for X-ray beams of 8 MV and 15 MV, as well as electron beams with energy of 6,8,12 and 18 MeV. The dose linearity of the MOSFET detector was investigated for the doses ranging from 0 up to 50 Gy using 8 MV X-ray beams. Angular effect was evaluated as well in a cylindrical PMMA phantom by changing the beam entrance angle every 15 degree clockwise. The MOSFET detector was then used for a breast cancer patient in vivo dose measurement, after the treatment plan was verified in a water phantom using a NE-2571 ion chamber, in vivo measurements were performed in the first and last treatment, and once per week during the whole treatment. The measured doses were then compared with planning dose to evaluate the accuracy of each treatment. Results: The MOSFET detector represented a good energy response for X-ray beams of 8 MV and 15 MV, and for electron beams with energy of 6 MeV up to 18 MeV. With the 6 V bias, Dose linearity error of the MOSFET detector was within 3.0% up to approximately 50 Gy, which can be significantly reduced to 1% when the detector was calibrated before and after each measurement. The MOSFET response varied within 1.5% for angles from 270 degree to 90 degree. However, maximum error of 10.0% was recorded comparing MOSFET response between forward and backward direction. In vivo measurement for a breast cancer patient using 3DCRT showed that, the average dose deviation between measurement and calculation was 2.8%, and the maximum error was less then 5.0%. Conclusions: The new MOSFET detector, with its advantages of being in size, easy use, good energy response and dose linearity, can be used for in vivo dose measurement. (authors)

Dynamic avalanche behavior of power MOSFETs and IGBTs under unclamped inductive switching conditions

International Nuclear Information System (INIS)

Lu Jiang; Tian Xiaoli; Lu Shuojin; Zhou Hongyu; Zhu Yangjun; Han Zhengsheng

2013-01-01

The ability of high-voltage power MOSFETs and IGBTs to withstand avalanche events under unclamped inductive switching (UIS) conditions is measured. This measurement is to investigate and compare the dynamic avalanche failure behavior of the power MOSFETs and the IGBT, which occur at different current conditions. The UIS measurement results at different current conditions show that the main failure reason of the power MOSFETs is related to the parasitic bipolar transistor, which leads to the deterioration of the avalanche reliability of power MOSFETs. However, the results of the IGBT show two different failure behaviors. At high current mode, the failure behavior is similar to the power MOSFETs situation. But at low current mode, the main failure mechanism is related to the parasitic thyristor activity during the occurrence of the avalanche process and which is in good agreement with the experiment result. (semiconductor devices)

Error correcting circuit design with carbon nanotube field effect transistors

Science.gov (United States)

Liu, Xiaoqiang; Cai, Li; Yang, Xiaokuo; Liu, Baojun; Liu, Zhongyong

2018-03-01

In this work, a parallel error correcting circuit based on (7, 4) Hamming code is designed and implemented with carbon nanotube field effect transistors, and its function is validated by simulation in HSpice with the Stanford model. A grouping method which is able to correct multiple bit errors in 16-bit and 32-bit application is proposed, and its error correction capability is analyzed. Performance of circuits implemented with CNTFETs and traditional MOSFETs respectively is also compared, and the former shows a 34.4% decrement of layout area and a 56.9% decrement of power consumption.

Bias temperature instability in tunnel field-effect transistors

Science.gov (United States)

Mizubayashi, Wataru; Mori, Takahiro; Fukuda, Koichi; Ishikawa, Yuki; Morita, Yukinori; Migita, Shinji; Ota, Hiroyuki; Liu, Yongxun; O'uchi, Shinichi; Tsukada, Junichi; Yamauchi, Hiromi; Matsukawa, Takashi; Masahara, Meishoku; Endo, Kazuhiko

2017-04-01

We systematically investigated the bias temperature instability (BTI) of tunnel field-effect transistors (TFETs). The positive BTI and negative BTI mechanisms in TFETs are the same as those in metal-oxide-semiconductor FETs (MOSFETs). In TFETs, although traps are generated in high-k gate dielectrics by the bias stress and/or the interface state is degraded at the interfacial layer/channel interface, the threshold voltage (V th) shift due to BTI degradation is caused by the traps and/or the degradation of the interface state locating the band-to-band tunneling (BTBT) region near the source/gate edge. The BTI lifetime in n- and p-type TFETs is improved by applying a drain bias corresponding to the operation conditions.

Investigation of the use of MOSFET for clinical IMRT dosimetric verification

International Nuclear Information System (INIS)

Chuang, Cynthia F.; Verhey, Lynn J.; Xia Ping

2002-01-01

With advanced conformal radiotherapy using intensity modulated beams, it is important to have radiation dose verification measurements prior to treatment. Metal oxide semiconductor field effect transistors (MOSFET) have the advantage of a faster and simpler reading procedure compared to thermoluminescent dosimeters (TLD), and with the commercial MOSFET system, multiple detectors can be used simultaneously. In addition, the small size of the detector could be advantageous, especially for point dose measurements in small homogeneous dose regions. To evaluate the feasibility of MOSFET for routine IMRT dosimetry, a comprehensive set of experiments has been conducted, to investigate the stability, linearity, energy, and angular dependence. For a period of two weeks, under a standard measurement setup, the measured dose standard deviation using the MOSFETs was ±0.015 Gy with the mean dose being 1.00 Gy. For a measured dose range of 0.3 Gy to 4.2 Gy, the MOSFETs present a linear response, with a linearity coefficient of 0.998. Under a 10x10 cm 2 square field, the dose variations measured by the MOSFETs for every 10 degrees from 0 to 180 degrees is ±2.5%. The percent depth dose (PDD) measurements were used to verify the energy dependence. The measured PDD using the MOSFETs from 0.5 cm to 34 cm depth agreed to within ±3% when compared to that of the ionization chamber. For IMRT dose verification, two special phantoms were designed. One is a solid water slab with 81 possible MOSFET placement holes, and another is a cylindrical phantom with 48 placement holes. For each IMRT phantom verification, an ionization chamber and 3 to 5 MOSFETs were used to measure multiple point doses at different locations. Preliminary results show that the agreement between dose measured by MOSFET and that calculated by Corvus is within 5% error, while the agreement between ionization chamber measurement and the calculation is within 3% error. In conclusion, MOSFET detectors are suitable for

A low specific on-resistance SOI MOSFET with dual gates and a recessed drain

International Nuclear Information System (INIS)

Luo Xiao-Rong; Hu Gang-Yi; Zhang Zheng-Yuan; Luo Yin-Chun; Fan Ye; Wang Xiao-Wei; Fan Yuan-Hang; Cai Jin-Yong; Wang Pei; Zhou Kun

2013-01-01

A low specific on-resistance (R on,sp ) integrable silicon-on-insulator (SOI) metal-oxide semiconductor field-effect transistor (MOSFET) is proposed and investigated by simulation. The MOSFET features a recessed drain as well as dual gates, which consist of a planar gate and a trench gate extended to the buried oxide layer (BOX) (DGRD MOSFET). First, the dual gates form dual conduction channels, and the extended trench gate also acts as a field plate to improve the electric field distribution. Second, the combination of the trench gate and the recessed drain widens the vertical conduction area and shortens the current path. Third, the P-type top layer not only enhances the drift doping concentration but also modulates the surface electric field distributions. All of these sharply reduce R on,sp and maintain a high breakdown voltage (BV). The BV of 233 V and R on,sp of 4.151 mΩ·cm 2 (V GS = 15 V) are obtained for the DGRD MOSFET with 15-μm half-cell pitch. Compared with the trench gate SOI MOSFET and the conventional MOSFET, R on,sp of the DGRD MOSFET decreases by 36% and 33% with the same BV, respectively. The trench gate extended to the BOX synchronously acts as a dielectric isolation trench, simplifying the fabrication processes. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Formation of a vertical MOSFET for charge sensing in a Si micro-fluidic channel

International Nuclear Information System (INIS)

Lyu, Hong-Kun; Kim, Dong-Sun; Shin, Jang-Kyoo; Choi, Pyung; Lee, Jong-Hyun; Park, Hey-Jung; Park, Chin-Sung; Lim, Geun-Bae

2004-01-01

We have formed a fluidic channel that can be used in micro-fluidic systems and fabricated a 3-dimensional vertical metal-oxide semiconductor field-effect transistor (vertical MOSFET) in the convex corner of a Si micro-fluidic channel by using an anisotropic tetramethyl ammonium hydroxide (TMAH) etching solution. A Au/Cr layer was used for the gate metal and might be useful for detecting charged biomolecules. The electrical characteristics of the vertical MOSFET and its operation as a chemical sensor were investigated. At V DS = -5 V and V GS = -5 V the drain current of the device was -22.5 μA and the threshold voltage was about -1.4 V. A non-planar, non-rectangular vertical MOSFET with a trapezoidal gate was transformed into an equivalent rectangularly based one by using a Schwartz-Christoffel transformation. The LEVEL1 device parameters of the vertical MOSFET were extracted from the measured electrical device characteristics and were used in the SPICE simulation for the vertical MOSFET. The measured and the simulated results for the vertical PMOSFET showed relatively good agreement. When the vertical MOSFET was dipped into a thiol DNA solution, the drain current decreased due to charged biomolecules probably being adsorbed on the gate, which indicates that a vertical MOSFET in a Si micro-fluidic channel might be useful for sensing charged biomolecules.

Design and simulation of a nanoelectronic DG MOSFET current source using artificial neural networks

International Nuclear Information System (INIS)

Djeffal, F.; Dibi, Z.; Hafiane, M.L.; Arar, D.

2007-01-01

The double gate (DG) MOSFET has received great attention in recent years owing to the inherent suppression of short channel effects (SCEs), excellent subthreshold slope (S), improved drive current (I ds ) and transconductance (gm), volume inversion for symmetric devices and excellent scalability. Therefore, simulation tools which can be applied to design nanoscale transistors in the future require new theory and modeling techniques that capture the physics of quantum transport accurately and efficiently. In this sense, this work presents the applicability of the artificial neural networks (ANN) for the design and simulation of a nanoelectronic DG MOSFET current source. The latter is based on the 2D numerical Non-Equilibrium Green's Function (NEGF) simulation of the current-voltage characteristics of an undoped symmetric DG MOSFET. Our results are discussed in order to obtain some new and useful information about the ULSI technology

Simultaneous On-State Voltage and Bond-Wire Resistance Monitoring of Silicon Carbide MOSFETs

DEFF Research Database (Denmark)

Baker, Nick; Luo, Haoze; Iannuzzo, Francesco

2017-01-01

the voltage between the kelvin-source and power-source can be used to specifically monitor bond-wire degradation. Meanwhile, the drain to kelvin-source voltage can be monitored to track defects in the semiconductor die or gate driver. Through an accelerated aging test on 20 A Silicon Carbide Metal......-Oxide-Semiconductor-Field-Effect Transistors (MOSFETs), it is shown that there are opposing trends in the evolution of the on-state resistances of both the bond-wires and the MOSFET die. In summary, after 50,000 temperature cycles, the resistance of the bond-wires increased by up to 2 mΩ, while the on-state resistance of the MOSFET dies...... decreased by approximately 1 mΩ. The conventional failure precursor (monitoring a single forward voltage) cannot distinguish between semiconductor die or bond-wire degradation. Therefore, the ability to monitor both these parameters due to the presence of an auxiliary-source terminal can provide more...

Application of MOSFET radiation detector for patient dosimetry

International Nuclear Information System (INIS)

Soubra, M.; Cygler, J.; Szanto, J.

1996-01-01

Purpose: A new direct reading Metal Oxide-Silicon Field Effect Transistor (MOSFET) based radiation detector system has been investigated in a variety of clinical radiotherapy procedures. The aim of this study is to report on the clinical applicability of such a device, its ease of use and on its dosimetric properties that include precision angular and energy dependence. Comparisons of patient dose measurements obtained by the MOSFET based system and the commonly used thermoluminescence dosimeters (TLD) and diodes are discussed. Material and Methods: A commercially available MOSFET dosimetry system that employs dual MOSFET dual bias arrangements has been used in this study. The detector is bonded with the epoxy to the end of a long (1.5 m) flexible cable whose other end is connected to a bias supply box operated by a battery. The bias box can accommodate up to 5 MOSFETs and after radiation exposure the dose can be determined by connecting the detectors to a pre calibrated reader. For the clinical evaluation 5 MOSFETs were used on patients undergoing total body irradiation (TBI) and high dose rate brachytherapy (HDR). The MOSFET detectors were taped to patient surface adjacent to the routinely used TLDs and/or diodes. To examine energy dependence the MOSFET sensitivity (mV/Gy) was determined in relation to a calibrated dose from 6 and 18 MV photon beams. The directional dependence was investigated by placing a MOSFET during irradiation in a special polystyrene insert that can be manually rotated to the required angle. Precision (reproducibility) measurements were made by exposing MOSFETs to multiple fractions of dose in the range of 3 x 10 -2 to 2 Gy. Results: In 3 of TBI trials the diodes measured average dose was within 1.0% of the prescribed dose compared to 3.7% for TLDs and 1.8% for MOSFETs. The MOSFETs average sensitivity for 6 MV was within 2% of the 18 MV photon beam. The reproducibility of MOSFET response was better than 3 % provided the dose per fraction is

Evaluation of the effects of thermal annealing temperature and high-k dielectrics on amorphous InGaZnO thin films by using pseudo-MOS transistors

International Nuclear Information System (INIS)

Lee, Se-Won; Cho, Won-Ju

2012-01-01

The effects of annealing temperatures and high-k gate dielectric materials on the amorphous In-Ga-Zn-O thin-film transistors (a-IGZO TFTs) were investigated using pseudo-metal-oxide semiconductor transistors (Ψ-MOSFETs), a method without conventional source/drain (S/D) layer deposition. Annealing of the a-IGZO film was carried out at 150 - 900 .deg. C in a N 2 ambient for 30 min. As the annealing temperature was increased, the electrical characteristics of Ψ-MOSFETs on a-IGZO were drastically improved. However, when the annealing temperature exceeded 700 .deg. C, a deterioration of the MOS parameters was observed, including a shift of the threshold voltage (V th ) in a negative direction, an increase in the subthreshold slope (SS) and hysteresis, a decrease in the field effect mobility (μ FE ), an increase in the trap density (N t ), and a decrease in the on/off ratio. Meanwhile, the high-k gate dielectrics enhanced the performance of a-IGZO Ψ-MOSFETs. The ZrO 2 gate dielectrics particularly exhibited excellent characteristics in terms of SS (128 mV/dec), μ FE (10.2 cm -2 /V·s), N t (1.1 x 10 12 cm -2 ), and on/off ratio (5.3 x 10 6 ). Accordingly, the Ψ-MOSFET structure is a useful method for rapid evaluation of the effects of the process and the material on a-IGZO TFTs without a conventional S/D layer deposition.

Spin-dependent transport properties of a GaMnAs-based vertical spin metal-oxide-semiconductor field-effect transistor structure

Energy Technology Data Exchange (ETDEWEB)

Kanaki, Toshiki, E-mail: kanaki@cryst.t.u-tokyo.ac.jp; Asahara, Hirokatsu; Ohya, Shinobu, E-mail: ohya@cryst.t.u-tokyo.ac.jp; Tanaka, Masaaki, E-mail: masaaki@ee.t.u-tokyo.ac.jp [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

2015-12-14

We fabricate a vertical spin metal-oxide-semiconductor field-effect transistor (spin-MOSFET) structure, which is composed of an epitaxial single-crystal heterostructure with a ferromagnetic-semiconductor GaMnAs source/drain, and investigate its spin-dependent transport properties. We modulate the drain-source current I{sub DS} by ∼±0.5% with a gate-source voltage of ±10.8 V and also modulate I{sub DS} by up to 60% with changing the magnetization configuration of the GaMnAs source/drain at 3.5 K. The magnetoresistance ratio is more than two orders of magnitude higher than that obtained in the previous studies on spin MOSFETs. Our result shows that a vertical structure is one of the hopeful candidates for spin MOSFET when the device size is reduced to a sub-micron or nanometer scale.

Spin-dependent transport properties of a GaMnAs-based vertical spin metal-oxide-semiconductor field-effect transistor structure

International Nuclear Information System (INIS)

Kanaki, Toshiki; Asahara, Hirokatsu; Ohya, Shinobu; Tanaka, Masaaki

2015-01-01

We fabricate a vertical spin metal-oxide-semiconductor field-effect transistor (spin-MOSFET) structure, which is composed of an epitaxial single-crystal heterostructure with a ferromagnetic-semiconductor GaMnAs source/drain, and investigate its spin-dependent transport properties. We modulate the drain-source current I DS by ∼±0.5% with a gate-source voltage of ±10.8 V and also modulate I DS by up to 60% with changing the magnetization configuration of the GaMnAs source/drain at 3.5 K. The magnetoresistance ratio is more than two orders of magnitude higher than that obtained in the previous studies on spin MOSFETs. Our result shows that a vertical structure is one of the hopeful candidates for spin MOSFET when the device size is reduced to a sub-micron or nanometer scale

Characterization of MOSFET dosimeters for low-dose measurements in maxillofacial anthropomorphic phantoms.

Science.gov (United States)

Koivisto, Juha H; Wolff, Jan E; Kiljunen, Timo; Schulze, Dirk; Kortesniemi, Mika

2015-07-08

The aims of this study were to characterize reinforced metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters to assess the measurement uncertainty, single exposure low-dose limit with acceptable accuracy, and the number of exposures required to attain the corresponding limit of the thermoluminescent dosimeters (TLD). The second aim was to characterize MOSFET dosimeter sensitivities for two dental photon energy ranges, dose dependency, dose rate dependency, and accumulated dose dependency. A further aim was to compare the performance of MOSFETs with those of TLDs in an anthropomorphic phantom head using a dentomaxillofacial CBCT device. The uncertainty was assessed by exposing 20 MOSFETs and a Barracuda MPD reference dosimeter. The MOSFET dosimeter sensitivities were evaluated for two photon energy ranges (50-90 kVp) using a constant dose and polymethylmethacrylate backscatter material. MOSFET and TLD comparative point-dose measurements were performed on an anthropomorphic phantom that was exposed with a clinical CBCT protocol. The MOSFET single exposure low dose limit (25% uncertainty, k = 2) was 1.69 mGy. An averaging of eight MOSFET exposures was required to attain the corresponding TLD (0.3 mGy) low-dose limit. The sensitivity was 3.09 ± 0.13 mV/mGy independently of the photon energy used. The MOSFET dosimeters did not present dose or dose rate sensitivity but, however, presented a 1% decrease of sensitivity per 1000 mV for accumulated threshold voltages between 8300 mV and 17500 mV. The point doses in an anthropomorphic phantom ranged for MOSFETs between 0.24 mGy and 2.29 mGy and for TLDs between 0.25 and 2.09 mGy, respectively. The mean difference was -8%. The MOSFET dosimeters presented statistically insignificant energy dependency. By averaging multiple exposures, the MOSFET dosimeters can achieve a TLD-comparable low-dose limit and constitute a feasible method for diagnostic dosimetry using anthropomorphic phantoms. However, for single in

Characterization of MOSFET dosimeters for low‐dose measurements in maxillofacial anthropomorphic phantoms

Science.gov (United States)

Wolff, Jan E.; Kiljunen, Timo; Schulze, Dirk; Kortesniemi, Mika

2015-01-01

The aims of this study were to characterize reinforced metal‐oxide‐semiconductor field‐effect transistor (MOSFET) dosimeters to assess the measurement uncertainty, single exposure low‐dose limit with acceptable accuracy, and the number of exposures required to attain the corresponding limit of the thermoluminescent dosimeters (TLD). The second aim was to characterize MOSFET dosimeter sensitivities for two dental photon energy ranges, dose dependency, dose rate dependency, and accumulated dose dependency. A further aim was to compare the performance of MOSFETs with those of TLDs in an anthropomorphic phantom head using a dentomaxillofacial CBCT device. The uncertainty was assessed by exposing 20 MOSFETs and a Barracuda MPD reference dosimeter. The MOSFET dosimeter sensitivities were evaluated for two photon energy ranges (50–90 kVp) using a constant dose and polymethylmethacrylate backscatter material. MOSFET and TLD comparative point‐dose measurements were performed on an anthropomorphic phantom that was exposed with a clinical CBCT protocol. The MOSFET single exposure low dose limit (25% uncertainty, k=2) was 1.69 mGy. An averaging of eight MOSFET exposures was required to attain the corresponding TLD (0.3 mGy) low‐dose limit. The sensitivity was 3.09±0.13 mV/mGy independently of the photon energy used. The MOSFET dosimeters did not present dose or dose rate sensitivity but, however, presented a 1% decrease of sensitivity per 1000 mV for accumulated threshold voltages between 8300 mV and 17500 mV. The point doses in an anthropomorphic phantom ranged for MOSFETs between 0.24 mGy and 2.29 mGy and for TLDs between 0.25 and 2.09 mGy, respectively. The mean difference was −8%. The MOSFET dosimeters presented statistically insignificant energy dependency. By averaging multiple exposures, the MOSFET dosimeters can achieve a TLD‐comparable low‐dose limit and constitute a feasible method for diagnostic dosimetry using anthropomorphic phantoms. However

Evaluation of the usefulness of a MOSFET detector in an anthropomorphic phantom for 6-MV photon beam.

Science.gov (United States)

Kohno, Ryosuke; Hirano, Eriko; Kitou, Satoshi; Goka, Tomonori; Matsubara, Kana; Kameoka, Satoru; Matsuura, Taeko; Ariji, Takaki; Nishio, Teiji; Kawashima, Mitsuhiko; Ogino, Takashi

2010-07-01

In order to evaluate the usefulness of a metal oxide-silicon field-effect transistor (MOSFET) detector as a in vivo dosimeter, we performed in vivo dosimetry using the MOSFET detector with an anthropomorphic phantom. We used the RANDO phantom as an anthropomorphic phantom, and dose measurements were carried out in the abdominal, thoracic, and head and neck regions for simple square field sizes of 10 x 10, 5 x 5, and 3 x 3 cm(2) with a 6-MV photon beam. The dose measured by the MOSFET detector was verified by the dose calculations of the superposition (SP) algorithm in the XiO radiotherapy treatment-planning system. In most cases, the measured doses agreed with the results of the SP algorithm within +/-3%. Our results demonstrated the utility of the MOSFET detector for in vivo dosimetry even in the presence of clinical tissue inhomogeneities.

Sub-1-V-60 nm vertical body channel MOSFET-based six-transistor static random access memory array with wide noise margin and excellent power delay product and its optimization with the cell ratio on static random access memory cell

Science.gov (United States)

Ogasawara, Ryosuke; Endoh, Tetsuo

2018-04-01

In this study, with the aim to achieve a wide noise margin and an excellent power delay product (PDP), a vertical body channel (BC)-MOSFET-based six-transistor (6T) static random access memory (SRAM) array is evaluated by changing the number of pillars in each part of a SRAM cell, that is, by changing the cell ratio in the SRAM cell. This 60 nm vertical BC-MOSFET-based 6T SRAM array realizes 0.84 V operation under the best PDP and up to 31% improvement of PDP compared with the 6T SRAM array based on a 90 nm planar MOSFET whose gate length and channel width are the same as those of the 60 nm vertical BC-MOSFET. Additionally, the vertical BC-MOSFET-based 6T SRAM array achieves an 8.8% wider read static noise margin (RSNM), a 16% wider write margin (WM), and an 89% smaller leakage. Moreover, it is shown that changing the cell ratio brings larger improvements of RSNM, WM, and write time in the vertical BC-MOSFET-based 6T SRAM array.

Angular dependence of the MOSFET dosimeter and its impact on in vivo surface dose measurement in breast cancer treatment.

Science.gov (United States)

Qin, S; Chen, T; Wang, L; Tu, Y; Yue, N; Zhou, J

2014-08-01

The focus of this study is the angular dependence of two types of Metal Oxide Semiconductor Field Effect Transistor (MOSFET) dosimeters (MOSFET20 and OneDose/OneDosePlus) when used for surface dose measurements. External beam radiationat different gantry angles were delivered to a cubic solid water phantom with a MOSFET placed on the top surface at CAX. The long axis of the MOSFET was oriented along the gantry axis of rotation, with the dosimeter (bubble side) facing the radiation source. MOSFET-measured surface doses were compared against calibrated radiochromic film readings. It was found that both types of MOSFET dosimeters exhibited larger than previously reported angular dependence when measuring surface dose in beams at large oblique angles. For the MOSFET20 dosimeter the measured surface dose deviation against film readings was as high as 17% when the incident angle was 72 degrees to the norm of the phantom surface. It is concluded that some MOSFET dosimeters may have a strong angular dependence when placed on the surface of water-equivalent material, even though they may have an isotropic angular response when surrounded by uniform medium. Extra on-surface calibration maybe necessary before using MOSFET dosimeters for skin dose measurement in tangential fields.

Calibration of a MOSFET detection system for 6-MV in vivo dosimetry

International Nuclear Information System (INIS)

Scalchi, Paolo; Francescon, P.

1998-01-01

Purpose: Metal oxide semiconductor field-effect transistor (MOSFET) detectors were calibrated to perform in vivo dosimetry during 6-MV treatments, both in normal setup and total body irradiation (TBI) conditions. Methods and Materials: MOSFET water-equivalent depth, dependence of the calibration factors (CFs) on the field sizes, MOSFET orientation, bias supply, accumulated dose, incidence angle, temperature, and spoiler-skin distance in TBI setup were investigated. MOSFET reproducibility was verified. The correlation between the water-equivalent midplane depth and the ratio of the exit MOSFET readout divided by the entrance MOSFET readout was studied. MOSFET midplane dosimetry in TBI setup was compared with thermoluminescent dosimetry in an anthropomorphic phantom. By using ionization chamber measurements, the TBI midplane dosimetry was also verified in the presence of cork as a lung substitute. Results: The water-equivalent depth of the MOSFET is about 0.8 mm or 1.8 mm, depending on which sensor side faces the beam. The field size also affects this quantity; Monte Carlo simulations allow driving this behavior by changes in the contaminating electron mean energy. The CFs vary linearly as a function of the square field side, for fields ranging from 5 x 5 to 30 x 30 cm 2 . In TBI setup, varying the spoiler-skin distance between 5 mm and 10 cm affects the CFs within 5%. The MOSFET reproducibility is about 3% (2 SD) for the doses normally delivered to the patients. The effect of the accumulated dose on the sensor response is negligible. For beam incidence ranging from 0 deg. to 90 deg. , the MOSFET response varies within 7%. No monotonic correlation between the sensor response and the temperature is apparent. Good correlation between the water-equivalent midplane depth and the ratio of the exit MOSFET readout divided by the entrance MOSFET readout was found (the correlation coefficient is about 1). The MOSFET midplane dosimetry relevant to the anthropomorphic phantom

Programmable automated transistor test system

International Nuclear Information System (INIS)

Truong, L.V.; Sundberg, G.R.

1986-01-01

The paper describes a programmable automated transistor test system (PATTS) and its utilization to evaluate bipolar transistors and Darlingtons, and such MOSFET and special types as can be accommodated with the PATTS base-drive. An application of a pulsed power technique at low duty cycles in a non-destructive test is used to examine the dynamic switching characteristic curves of power transistors. Data collection, manipulation, storage, and output are operator interactive but are guided and controlled by the system software. In addition a library of test data is established on disks, tapes, and hard copies for future reference

Characterization of a Common-Source Amplifier Using Ferroelectric Transistors

Science.gov (United States)

Hunt, Mitchell; Sayyah, Rana; MacLeond, Todd C.; Ho, Pat D.

2010-01-01

This paper presents empirical data that was collected through experiments using a FeFET in the established common-source amplifier circuit. The unique behavior of the FeFET lends itself to interesting and useful operation in this widely used common-source amplifier. The paper examines the effect of using a ferroelectric transistor for the amplifier. It also examines the effects of varying load resistance, biasing, and input voltages on the output signal and gives several examples of the output of the amplifier for a given input. The difference between a commonsource amplifier using a ferroelectric transistor and that using a MOSFET is addressed.

Modelling of parameters for asymmetric halo and symmetric DHDMG n-MOSFETs

Science.gov (United States)

De, Swapnadip; Sarkar, Angsuman; Sarkar, Chandan Kumar

2011-10-01

This article presents an analytical surface potential, threshold voltage and drain current model for asymmetric pocket-implanted, single-halo dual material gate and double-halo dual material gate (DHDMG) n-MOSFET (MOSFET, metal-oxide-semiconductor field-effect transistor) operating up to 40 nm regime. The model is derived by applying Gauss's law to a rectangular box, covering the entire depletion region. The asymmetric pocket-implanted model takes into account the effective doping concentration of the two linear pocket profiles at the source and the drain ends along with the inner fringing capacitances at both the source and the drain ends and the subthreshold drain and the substrate bias effect. Using the surface potential model, the threshold voltage and drain currents are estimated. The same model is used to find the characteristic parameters for dual-material gate (DMG) with halo implantations and double gate. The characteristic improvement is investigated. It is concluded that the DHDMG device structure exhibits better suppression of the short-channel effect (SCE) and the threshold voltage roll-off than DMG and double-gate MOSFET. The adequacy of the model is verified by comparing with two-dimensional device simulator DESSIS. A very good agreement of our model with DESSIS is obtained proving the validity of our model used in suppressing the SCEs.

Verification of the plan dosimetry for high dose rate brachytherapy using metal-oxide-semiconductor field effect transistor detectors

International Nuclear Information System (INIS)

Qi Zhenyu; Deng Xiaowu; Huang Shaomin; Lu Jie; Lerch, Michael; Cutajar, Dean; Rosenfeld, Anatoly

2007-01-01

The feasibility of a recently designed metal-oxide-semiconductor field effect transistor (MOSFET) dosimetry system for dose verification of high dose rate (HDR) brachytherapy treatment planning was investigated. MOSFET detectors were calibrated with a 0.6 cm 3 NE-2571 Farmer-type ionization chamber in water. Key characteristics of the MOSFET detectors, such as the energy dependence, that will affect phantom measurements with HDR 192 Ir sources were measured. The MOSFET detector was then applied to verify the dosimetric accuracy of HDR brachytherapy treatments in a custom-made water phantom. Three MOSFET detectors were calibrated independently, with the calibration factors ranging from 0.187 to 0.215 cGy/mV. A distance dependent energy response was observed, significant within 2 cm from the source. The new MOSFET detector has a good reproducibility ( 2 =1). It was observed that the MOSFET detectors had a linear response to dose until the threshold voltage reached approximately 24 V for 192 Ir source measurements. Further comparison of phantom measurements using MOSFET detectors with dose calculations by a commercial treatment planning system for computed tomography-based brachytherapy treatment plans showed that the mean relative deviation was 2.2±0.2% for dose points 1 cm away from the source and 2.0±0.1% for dose points located 2 cm away. The percentage deviations between the measured doses and the planned doses were below 5% for all the measurements. The MOSFET detector, with its advantages of small physical size and ease of use, is a reliable tool for quality assurance of HDR brachytherapy. The phantom verification method described here is universal and can be applied to other HDR brachytherapy treatments

The effect of ionizing radiation on analog characteristics of MOSFET

International Nuclear Information System (INIS)

Ren Diyuan; Yu Xuefeng; Lu Wu; Gao Wenyu; Fan Long; Zhang Guoqiang; Yan Rongliang

1994-01-01

The effects of 60 Co γ-ray on the linearity and output characteristics of MOSFETs were investigated. The relations of oxide-trapped charge and Si/SiO 2 interface state density to the decrease of mobility μ-bar and transconductance g m , and the shift of the output curves for both P-MOSFETs and N-MOSFETs were qualitatively described. It was shown that degradation of analog characteristics, for P-MOSFETs, resulted from both oxide-trapped charge and interface state, but the degradation for N-MOSFETs was mainly due to the increase of radiation induced Si-SiO 2 interface state density

Anomalous DIBL Effect in Fully Depleted SOI MOSFETs Using Nanoscale Gate-Recessed Channel Process

Directory of Open Access Journals (Sweden)

Avi Karsenty

2015-01-01

Full Text Available Nanoscale Gate-Recessed Channel (GRC Fully Depleted- (FD- SOI MOSFET device with a silicon channel thickness (tSi as low as 2.2 nm was first tested at room temperature for functionality check and then tested at low temperature (77 K for I-V characterizations. In spite of its FD-SOI nanoscale thickness and long channel feature, the device has surprisingly exhibited a Drain-Induced Barrier Lowering (DIBL effect at RT. However, this effect was suppressed at 77 K. If the apparition of such anomalous effect can be explained by a parasitic short channel transistor located at the edges of the channel, its suppression is explained by the decrease of the potential barrier between the drain and the channel when lowering the temperature.

A Unified Channel Charges Expression for Analytic MOSFET Modeling

Directory of Open Access Journals (Sweden)

Hugues Murray

2012-01-01

Full Text Available Based on a 1D Poissons equation resolution, we present an analytic model of inversion charges allowing calculation of the drain current and transconductance in the Metal Oxide Semiconductor Field Effect Transistor. The drain current and transconductance are described by analytical functions including mobility corrections and short channel effects (CLM, DIBL. The comparison with the Pao-Sah integral shows excellent accuracy of the model in all inversion modes from strong to weak inversion in submicronics MOSFET. All calculations are encoded with a simple C program and give instantaneous results that provide an efficient tool for microelectronics users.

Exploring the Short-Channel Characteristics of Asymmetric Junctionless Double-Gate Silicon-on-Nothing MOSFET

Science.gov (United States)

Saha, Priyanka; Banerjee, Pritha; Dash, Dinesh Kumar; Sarkar, Subir Kumar

2018-03-01

This paper presents an analytical model of an asymmetric junctionless double-gate (asymmetric DGJL) silicon-on-nothing metal-oxide-semiconductor field-effect transistor (MOSFET). Solving the 2-D Poisson's equation, the expressions for center potential and threshold voltage are calculated. In addition, the response of the device toward the various short-channel effects like hot carrier effect, drain-induced barrier lowering and threshold voltage roll-off has also been examined along with subthreshold swing and drain current characteristics. Performance analysis of the present model is also demonstrated by comparing its short-channel behavior with conventional DGJL MOSFET. The effect of variation of the device features due to the variation of device parameters is also studied. The simulated results obtained using 2D device simulator, namely ATLAS, are in good agreement with the analytical results, hence validating our derived model.

Characteristics and performance of a micro-MOSFET: An 'imageable' dosimeter for image-guided radiotherapy

International Nuclear Information System (INIS)

Rowbottom, Carl G.; Jaffray, David A.

2004-01-01

The performance and characteristics of a miniature metal oxide semiconductor field effect transistor (micro-MOSFET) detector was investigated for its potential application to integral system tests for image-guided radiotherapy. In particular, the position of peak response to a slit of radiation was determined for the three principal axes to define the co-ordinates for the center of the active volume of the detector. This was compared to the radiographically determined center of the micro-MOSFET visible using cone-beam CT. Additionally, the angular sensitivity of the micro-MOSFET was measured. The micro-MOSFETs are clearly visible on the cone-beam CT images, and produce no artifacts. The center of the active volume of the micro-MOSFET aligned with the center of the visible micro-MOSFET on the cone-beam CT images for the x and y axes to within 0.20 mm and 0.15 mm, respectively. In z, the long axis of the detector, the peak response was found to be 0.79 mm from the tip of the visible micro-MOSFET. Repeat experiments verified that the position of the peak response of the micro-MOSFET was reproducible. The micro-MOSFET response for 360 deg. of rotation in the axial plane to the micro-MOSFET was ±2%, consistent with values quoted by the manufacturer. The location of the active volume of the micro-MOSFETs under investigation can be determined from the centroid of the visible micro-MOSFET on cone-beam CT images. The CT centroid position corresponds closely to the center of the detector response to radiation. The ability to use the cone-beam CT to locate the active volume to within 0.20 mm allows their use in an integral system test for the imaging of and dose delivery to a phantom containing an array of micro-MOSFETs. The small angular sensitivity allows the investigation of noncoplanar beams

Hall effect mobility for SiC MOSFETs with increasing dose of nitrogen implantation into channel region

Science.gov (United States)

Noguchi, Munetaka; Iwamatsu, Toshiaki; Amishiro, Hiroyuki; Watanabe, Hiroshi; Kita, Koji; Yamakawa, Satoshi

2018-04-01

The Hall effect mobility (μHall) of the Si-face 4H-SiC metal–oxide–semiconductor field effect transistor (MOSFET) with a nitrogen (N)-implanted channel region was investigated by increasing the N dose. The μHall in the channel region was systematically examined regarding channel structures, that is, the surface and buried channels. It was experimentally demonstrated that increasing the N dose results in an improvement in μHall in the channel region due to the formation of the buried channel. However, further increase in N dose was found to decrease the μHall in the channel region, owing to the decrease in the electron mobility in the N-implanted bulk region.

Direct protein detection with a nano-interdigitated array gate MOSFET.

Science.gov (United States)

Tang, Xiaohui; Jonas, Alain M; Nysten, Bernard; Demoustier-Champagne, Sophie; Blondeau, Franoise; Prévot, Pierre-Paul; Pampin, Rémi; Godfroid, Edmond; Iñiguez, Benjamin; Colinge, Jean-Pierre; Raskin, Jean-Pierre; Flandre, Denis; Bayot, Vincent

2009-08-15

A new protein sensor is demonstrated by replacing the gate of a metal oxide semiconductor field effect transistor (MOSFET) with a nano-interdigitated array (nIDA). The sensor is able to detect the binding reaction of a typical antibody Ixodes ricinus immunosuppressor (anti-Iris) protein at a concentration lower than 1 ng/ml. The sensor exhibits a high selectivity and reproducible specific detection. We provide a simple model that describes the behavior of the sensor and explains the origin of its high sensitivity. The simulated and experimental results indicate that the drain current of nIDA-gate MOSFET sensor is significantly increased with the successive binding of the thiol layer, Iris and anti-Iris protein layers. It is found that the sensor detection limit can be improved by well optimizing the geometrical parameters of nIDA-gate MOSFET. This nanobiosensor, with real-time and label-free capabilities, can easily be used for the detection of other proteins, DNA, virus and cancer markers. Moreover, an on-chip associated electronics nearby the sensor can be integrated since its fabrication is compatible with complementary metal oxide semiconductor (CMOS) technology.

Investigation of a pulsed current annealing method in reusing MOSFET dosimeters for in vivo IMRT dosimetry

Energy Technology Data Exchange (ETDEWEB)

Luo, Guang-Wen; Qi, Zhen-Yu, E-mail: qizhy@sysucc.org.cn; Deng, Xiao-Wu [Department of Radiation Oncology, Sun Yat-Sen University Cancer Center and State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center of Cancer Medicine, Guangzhou 510060 (China); Rosenfeld, Anatoly [Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia)

2014-05-15

Purpose: To explore the feasibility of pulsed current annealing in reusing metal oxide semiconductor field-effect transistor (MOSFET) dosimeters forin vivo intensity modulated radiation therapy (IMRT) dosimetry. Methods: Several MOSFETs were irradiated atd{sub max} using a 6 MV x-ray beam with 5 V on the gate and annealed with zero bias at room temperature. The percentage recovery of threshold voltage shift during multiple irradiation-annealing cycles was evaluated. Key dosimetry characteristics of the annealed MOSFET such as the dosimeter's sensitivity, reproducibility, dose linearity, and linearity of response within the dynamic range were investigated. The initial results of using the annealed MOSFETs for IMRT dosimetry practice were also presented. Results: More than 95% of threshold voltage shift can be recovered after 24-pulse current continuous annealing in 16 min. The mean sensitivity degradation was found to be 1.28%, ranging from 1.17% to 1.52%, during multiple annealing procedures. Other important characteristics of the annealed MOSFET remained nearly consistent before and after annealing. Our results showed there was no statistically significant difference between the annealed MOSFETs and their control samples in absolute dose measurements for IMRT QA (p = 0.99). The MOSFET measurements agreed with the ion chamber results on an average of 0.16% ± 0.64%. Conclusions: Pulsed current annealing provides a practical option for reusing MOSFETs to extend their operational lifetime. The current annealing circuit can be integrated into the reader, making the annealing procedure fully automatic.

Investigation of a pulsed current annealing method in reusing MOSFET dosimeters for in vivo IMRT dosimetry.

Science.gov (United States)

Luo, Guang-Wen; Qi, Zhen-Yu; Deng, Xiao-Wu; Rosenfeld, Anatoly

2014-05-01

To explore the feasibility of pulsed current annealing in reusing metal oxide semiconductor field-effect transistor (MOSFET) dosimeters for in vivo intensity modulated radiation therapy (IMRT) dosimetry. Several MOSFETs were irradiated at d(max) using a 6 MV x-ray beam with 5 V on the gate and annealed with zero bias at room temperature. The percentage recovery of threshold voltage shift during multiple irradiation-annealing cycles was evaluated. Key dosimetry characteristics of the annealed MOSFET such as the dosimeter's sensitivity, reproducibility, dose linearity, and linearity of response within the dynamic range were investigated. The initial results of using the annealed MOSFETs for IMRT dosimetry practice were also presented. More than 95% of threshold voltage shift can be recovered after 24-pulse current continuous annealing in 16 min. The mean sensitivity degradation was found to be 1.28%, ranging from 1.17% to 1.52%, during multiple annealing procedures. Other important characteristics of the annealed MOSFET remained nearly consistent before and after annealing. Our results showed there was no statistically significant difference between the annealed MOSFETs and their control samples in absolute dose measurements for IMRT QA (p = 0.99). The MOSFET measurements agreed with the ion chamber results on an average of 0.16% ± 0.64%. Pulsed current annealing provides a practical option for reusing MOSFETs to extend their operational lifetime. The current annealing circuit can be integrated into the reader, making the annealing procedure fully automatic.

Investigation of a pulsed current annealing method in reusing MOSFET dosimeters for in vivo IMRT dosimetry

International Nuclear Information System (INIS)

Luo, Guang-Wen; Qi, Zhen-Yu; Deng, Xiao-Wu; Rosenfeld, Anatoly

2014-01-01

Purpose: To explore the feasibility of pulsed current annealing in reusing metal oxide semiconductor field-effect transistor (MOSFET) dosimeters forin vivo intensity modulated radiation therapy (IMRT) dosimetry. Methods: Several MOSFETs were irradiated atd max using a 6 MV x-ray beam with 5 V on the gate and annealed with zero bias at room temperature. The percentage recovery of threshold voltage shift during multiple irradiation-annealing cycles was evaluated. Key dosimetry characteristics of the annealed MOSFET such as the dosimeter's sensitivity, reproducibility, dose linearity, and linearity of response within the dynamic range were investigated. The initial results of using the annealed MOSFETs for IMRT dosimetry practice were also presented. Results: More than 95% of threshold voltage shift can be recovered after 24-pulse current continuous annealing in 16 min. The mean sensitivity degradation was found to be 1.28%, ranging from 1.17% to 1.52%, during multiple annealing procedures. Other important characteristics of the annealed MOSFET remained nearly consistent before and after annealing. Our results showed there was no statistically significant difference between the annealed MOSFETs and their control samples in absolute dose measurements for IMRT QA (p = 0.99). The MOSFET measurements agreed with the ion chamber results on an average of 0.16% ± 0.64%. Conclusions: Pulsed current annealing provides a practical option for reusing MOSFETs to extend their operational lifetime. The current annealing circuit can be integrated into the reader, making the annealing procedure fully automatic

Heavy-ion-induced, gate-rupture in power MOSFETs

International Nuclear Information System (INIS)

Fischer, T.A.

1987-01-01

A new, heavy-ion-induced, burnout mechanism has been experimentally observed in power metal-oxide-semiconductor field-effect transistors (MOSFETs). This mechanism occurs when a heavy, charged particle passes through the gate oxide region of n- or p-channel devices having sufficient gate-to-source or gate-to-drain bias. The gate-rupture leads to significant permanent degradation of the device. A proposed failure mechanism is discussed and experimentally verified. In addition, the absolute immunity of p-channel devices to heavy-ion-induced, semiconductor burnout is demonstrated and discussed along with new, non-destructive, burnout testing methods

Self-Consistent Study of Conjugated Aromatic Molecular Transistors

International Nuclear Information System (INIS)

Jing, Wang; Yun-Ye, Liang; Hao, Chen; Peng, Wang; Note, R.; Mizuseki, H.; Kawazoe, Y.

2010-01-01

We study the current through conjugated aromatic molecular transistors modulated by a transverse field. The self-consistent calculation is realized with density function theory through the standard quantum chemistry software Gaussian03 and the non-equilibrium Green's function formalism. The calculated I – V curves controlled by the transverse field present the characteristics of different organic molecular transistors, the transverse field effect of which is improved by the substitutions of nitrogen atoms or fluorine atoms. On the other hand, the asymmetry of molecular configurations to the axis connecting two sulfur atoms is in favor of realizing the transverse field modulation. Suitably designed conjugated aromatic molecular transistors possess different I – V characteristics, some of them are similar to those of metal-oxide-semiconductor field-effect transistors (MOSFET). Some of the calculated molecular devices may work as elements in graphene electronics. Our results present the richness and flexibility of molecular transistors, which describe the colorful prospect of next generation devices. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Vertical Silicon Nanowire Field Effect Transistors with Nanoscale Gate-All-Around

Science.gov (United States)

Guerfi, Youssouf; Larrieu, Guilhem

2016-04-01

Nanowires are considered building blocks for the ultimate scaling of MOS transistors, capable of pushing devices until the most extreme boundaries of miniaturization thanks to their physical and geometrical properties. In particular, nanowires' suitability for forming a gate-all-around (GAA) configuration confers to the device an optimum electrostatic control of the gate over the conduction channel and then a better immunity against the short channel effects (SCE). In this letter, a large-scale process of GAA vertical silicon nanowire (VNW) MOSFETs is presented. A top-down approach is adopted for the realization of VNWs with an optimum reproducibility followed by thin layer engineering at nanoscale. Good overall electrical performances were obtained, with excellent electrostatic behavior (a subthreshold slope (SS) of 95 mV/dec and a drain induced barrier lowering (DIBL) of 25 mV/V) for a 15-nm gate length. Finally, a first demonstration of dual integration of n-type and p-type VNW transistors for the realization of CMOS inverter is proposed.

Spin Transport in Nondegenerate Si with a Spin MOSFET Structure at Room Temperature

Science.gov (United States)

Sasaki, Tomoyuki; Ando, Yuichiro; Kameno, Makoto; Tahara, Takayuki; Koike, Hayato; Oikawa, Tohru; Suzuki, Toshio; Shiraishi, Masashi

2014-09-01

Spin transport in nondegenerate semiconductors is expected to pave the way to the creation of spin transistors, spin logic devices, and reconfigurable logic circuits, because room-temperature (RT) spin transport in Si has already been achieved. However, RT spin transport has been limited to degenerate Si, which makes it difficult to produce spin-based signals because a gate electric field cannot be used to manipulate such signals. Here, we report the experimental demonstration of spin transport in nondegenerate Si with a spin metal-oxide-semiconductor field-effect transistor (MOSFET) structure. We successfully observe the modulation of the Hanle-type spin-precession signals, which is a characteristic spin dynamics in nondegenerate semiconductors. We obtain long spin transport of more than 20 μm and spin rotation greater than 4π at RT. We also observe gate-induced modulation of spin-transport signals at RT. The modulation of the spin diffusion length as a function of a gate voltage is successfully observed, which we attribute to the Elliott-Yafet spin relaxation mechanism. These achievements are expected to lead to the creation of practical Si-based spin MOSFETs.

Characteristics of mobile MOSFET dosimetry system for megavoltage photon beams.

Science.gov (United States)

Kumar, A Sathish; Sharma, S D; Ravindran, B Paul

2014-07-01

The characteristics of a mobile metal oxide semiconductor field effect transistor (mobile MOSFET) detector for standard bias were investigated for megavoltage photon beams. This study was performed with a brass alloy build-up cap for three energies namely Co-60, 6 and 15 MV photon beams. The MOSFETs were calibrated and the performance characteristics were analyzed with respect to dose rate dependence, energy dependence, field size dependence, linearity, build-up factor, and angular dependence for all the three energies. A linear dose-response curve was noted for Co-60, 6 MV, and 15 MV photons. The calibration factors were found to be 1.03, 1, and 0.79 cGy/mV for Co-60, 6 MV, and 15 MV photon energies, respectively. The calibration graph has been obtained to the dose up to 600 cGy, and the dose-response curve was found to be linear. The MOSFETs were found to be energy independent both for measurements performed at depth as well as on the surface with build-up. However, field size dependence was also analyzed for variable field sizes and found to be field size independent. Angular dependence was analyzed by keeping the MOSFET dosimeter in parallel and perpendicular orientation to the angle of incidence of the radiation with and without build-up on the surface of the phantom. The maximum variation for the three energies was found to be within ± 2% for the gantry angles 90° and 270°, the deviations without the build-up for the same gantry angles were found to be 6%, 25%, and 60%, respectively. The MOSFET response was found to be independent of dose rate for all three energies. The dosimetric characteristics of the MOSFET detector make it a suitable in vivo dosimeter for megavoltage photon beams.

Flat-roof phenomenon of dynamic equilibrium phase in the negative bias temperature instability effect on a power MOSFET

International Nuclear Information System (INIS)

Zhang Yue; Zhuo Qing-Qing; Liu Hong-Xia; Ma Xiao-Hua; Hao Yue

2014-01-01

The effect of the static negative bias temperature (NBT) stress on a p-channel power metal—oxide—semiconductor field-effect transistor (MOSFET) is investigated by experiment and simulation. The time evolution of the negative bias temperature instability (NBTI) degradation has the trend predicted by the reaction—diffusion (R—D) model but with an exaggerated time scale. The phenomena of the flat-roof section are observed under various stress conditions, which can be considered as the dynamic equilibrium phase in the R—D process. Based on the simulated results, the variation of the flat-roof section with the stress condition can be explained. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Low-frequency noise behavior of polysilicon emitter bipolar junction transistors: a review

Science.gov (United States)

Deen, M. Jamal; Pascal, Fabien

2003-05-01

For many analog integrated circuit applications, the polysilicon emitter bipolar junction transistor (PE-BJT) is still the preferred choice because of its higher operational frequency and lower noise performance characteristics compared to MOS transistors of similar active areas and at similar biasing currents. In this paper, we begin by motivating the reader with reasons why bipolar transistors are still of great interest for analog integrated circuits. This motivation includes a comparison between BJT and the MOSFET using a simple small-signal equivalent circuit to derive important parameters that can be used to compare these two technologies. An extensive review of the popular theories used to explain low frequency noise results is presented. However, in almost all instances, these theories have not been fully tested. The effects of different processing technologies and conditions on the noise performance of PE-BJTs is reviewed and a summary of some of the key technological steps and device parameters and their effects on noise is discussed. The effects of temperature and emitter geometries scaling is reviewed. It is shown that dispersion of the low frequency noise in ultra-small geometries is a serious issue since the rate of increase of the noise dispersion is faster than the noise itself as the emitter geometry is scaled to smaller values. Finally, some ideas for future research on PE-BJTs, some of which are also applicable to SiGe heteorjunction bipolar transistors and MOSFETs, are presented after the conclusions.

Characterization of MOSFET detectors for in vivo dosimetry in interventional radiology and for dose reconstruction in case of overexposure.

Science.gov (United States)

Bassinet, Céline; Huet, Christelle; Baumann, Marion; Etard, Cécile; Réhel, Jean-Luc; Boisserie, Gilbert; Debroas, Jacques; Aubert, Bernard; Clairand, Isabelle

2013-04-01

As MOSFET (Metal Oxide Semiconductor Field Effect Transistor) detectors allow dose measurements in real time, the interest in these dosimeters is growing. The aim of this study was to investigate the dosimetric properties of commercially available TN-502RD-H MOSFET silicon detectors (Best Medical Canada, Ottawa, Canada) in order to use them for in vivo dosimetry in interventional radiology and for dose reconstruction in case of overexposure. Reproducibility of the measurements, dose rate dependence, and dose response of the MOSFET detectors have been studied with a Co source. Influence of the dose rate, frequency, and pulse duration on MOSFET responses has also been studied in pulsed x-ray fields. Finally, in order to validate the integrated dose given by MOSFET detectors, MOSFETs and TLDs (LiF:Mg,Cu,P) were fixed on an Alderson-Rando phantom in the conditions of an interventional neuroradiology procedure, and their responses have been compared. The results of this study show the suitability of MOSFET detectors for in vivo dosimetry in interventional radiology and for dose reconstruction in case of accident, provided a well-corrected energy dependence, a pulse duration equal to or higher than 10 ms, and an optimized contact between the detector and the skin of the patient are achieved.

Estimation of computed tomography dose index in cone beam computed tomography: MOSFET measurements and Monte Carlo simulations.

Science.gov (United States)

Kim, Sangroh; Yoshizumi, Terry; Toncheva, Greta; Yoo, Sua; Yin, Fang-Fang; Frush, Donald

2010-05-01

To address the lack of accurate dose estimation method in cone beam computed tomography (CBCT), we performed point dose metal oxide semiconductor field-effect transistor (MOSFET) measurements and Monte Carlo (MC) simulations. A Varian On-Board Imager (OBI) was employed to measure point doses in the polymethyl methacrylate (PMMA) CT phantoms with MOSFETs for standard and low dose modes. A MC model of the OBI x-ray tube was developed using BEAMnrc/EGSnrc MC system and validated by the half value layer, x-ray spectrum and lateral and depth dose profiles. We compared the weighted computed tomography dose index (CTDIw) between MOSFET measurements and MC simulations. The CTDIw was found to be 8.39 cGy for the head scan and 4.58 cGy for the body scan from the MOSFET measurements in standard dose mode, and 1.89 cGy for the head and 1.11 cGy for the body in low dose mode, respectively. The CTDIw from MC compared well to the MOSFET measurements within 5% differences. In conclusion, a MC model for Varian CBCT has been established and this approach may be easily extended from the CBCT geometry to multi-detector CT geometry.

Application of MOSFET detectors for dosimetry in small animal radiography using short exposure times.

Science.gov (United States)

De Lin, Ming; Toncheva, Greta; Nguyen, Giao; Kim, Sangroh; Anderson-Evans, Colin; Johnson, G Allan; Yoshizumi, Terry T

2008-08-01

Digital subtraction angiography (DSA) X-ray imaging for small animals can be used for functional phenotyping given its ability to capture rapid physiological changes at high spatial and temporal resolution. The higher temporal and spatial requirements for small-animal imaging drive the need for short, high-flux X-ray pulses. However, high doses of ionizing radiation can affect the physiology. The purpose of this study was to verify and apply metal oxide semiconductor field effect transistor (MOSFET) technology to dosimetry for small-animal diagnostic imaging. A tungsten anode X-ray source was used to expose a tissue-equivalent mouse phantom. Dose measurements were made on the phantom surface and interior. The MOSFETs were verified with thermoluminescence dosimeters (TLDs). Bland-Altman analysis showed that the MOSFET results agreed with the TLD results (bias, 0.0625). Using typical small animal DSA scan parameters, the dose ranged from 0.7 to 2.2 cGy. Application of the MOSFETs in the small animal environment provided two main benefits: (1) the availability of results in near real-time instead of the hours needed for TLD processes and (2) the ability to support multiple exposures with different X-ray techniques (various of kVp, mA and ms) using the same MOSFET. This MOSFET technology has proven to be a fast, reliable small animal dosimetry method for DSA imaging and is a good system for dose monitoring for serial and gene expression studies.

Dose verification to cochlea during gamma knife radiosurgery of acoustic schwannoma using MOSFET dosimeter.

Science.gov (United States)

Sharma, Sunil D; Kumar, Rajesh; Akhilesh, Philomina; Pendse, Anil M; Deshpande, Sudesh; Misra, Basant K

2012-01-01

Dose verification to cochlea using metal oxide semiconductor field effect transistor (MOSFET) dosimeter using a specially designed multi slice head and neck phantom during the treatment of acoustic schwannoma by Gamma Knife radiosurgery unit. A multi slice polystyrene head phantom was designed and fabricated for measurement of dose to cochlea during the treatment of the acoustic schwannoma. The phantom has provision to position the MOSFET dosimeters at the desired location precisely. MOSFET dosimeters of 0.2 mm x 0.2 mm x 0.5 μm were used to measure the dose to the cochlea. CT scans of the phantom with MOSFETs in situ were taken along with Leksell frame. The treatment plans of five patients treated earlier for acoustic schwannoma were transferred to the phantom. Dose and coordinates of maximum dose point inside the cochlea were derived. The phantom along with the MOSFET dosimeters was irradiated to deliver the planned treatment and dose received by cochlea were measured. The treatment planning system (TPS) estimated and measured dose to the cochlea were in the range of 7.4 - 8.4 Gy and 7.1 - 8 Gy, respectively. The maximum variation between TPS calculated and measured dose to cochlea was 5%. The measured dose values were found in good agreement with the dose values calculated using the TPS. The MOSFET dosimeter can be a suitable choice for routine dose verification in the Gamma Knife radiosurgery.

Estimating effective dose to pediatric patients undergoing interventional radiology procedures using anthropomorphic phantoms and MOSFET dosimeters.

Science.gov (United States)

Miksys, Nelson; Gordon, Christopher L; Thomas, Karen; Connolly, Bairbre L

2010-05-01

The purpose of this study was to estimate the effective doses received by pediatric patients during interventional radiology procedures and to present those doses in "look-up tables" standardized according to minute of fluoroscopy and frame of digital subtraction angiography (DSA). Organ doses were measured with metal oxide semiconductor field effect transistor (MOSFET) dosimeters inserted within three anthropomorphic phantoms, representing children at ages 1, 5, and 10 years, at locations corresponding to radiosensitive organs. The phantoms were exposed to mock interventional radiology procedures of the head, chest, and abdomen using posteroanterior and lateral geometries, varying magnification, and fluoroscopy or DSA exposures. Effective doses were calculated from organ doses recorded by the MOSFET dosimeters and are presented in look-up tables according to the different age groups. The largest effective dose burden for fluoroscopy was recorded for posteroanterior and lateral abdominal procedures (0.2-1.1 mSv/min of fluoroscopy), whereas procedures of the head resulted in the lowest effective doses (0.02-0.08 mSv/min of fluoroscopy). DSA exposures of the abdomen imparted higher doses (0.02-0.07 mSv/DSA frame) than did those involving the head and chest. Patient doses during interventional procedures vary significantly depending on the type of procedure. User-friendly look-up tables may provide a helpful tool for health care providers in estimating effective doses for an individual procedure.

Silicon Power MOSFETs

Science.gov (United States)

Lauenstein, Jean-Marie; Casey, Megan; Campola, Michael; Ladbury, Raymond; Label, Kenneth; Wilcox, Ted; Phan, Anthony; Kim, Hak; Topper, Alyson

2017-01-01

Recent work for the NASA Electronic Parts and Packaging Program Power MOSFET task is presented. The Task technology focus, roadmap, and partners are given. Recent single-event effect test results on commercial, automotive, and radiation hardened trench power MOSFETs are summarized with an emphasis on risk of using commercial and automotive trench-gate power MOSFETs in space applications.

MOSFET Switching Circuit Protects Shape Memory Alloy Actuators

Science.gov (United States)

Gummin, Mark A.

2011-01-01

A small-footprint, full surface-mount-component printed circuit board employs MOSFET (metal-oxide-semiconductor field-effect transistor) power switches to switch high currents from any input power supply from 3 to 30 V. High-force shape memory alloy (SMA) actuators generally require high current (up to 9 A at 28 V) to actuate. SMA wires (the driving element of the actuators) can be quickly overheated if power is not removed at the end of stroke, which can damage the wires. The new analog driver prevents overheating of the SMA wires in an actuator by momentarily removing power when the end limit switch is closed, thereby allowing complex control schemes to be adopted without concern for overheating. Either an integral pushbutton or microprocessor-controlled gate or control line inputs switch current to the actuator until the end switch line goes from logic high to logic low state. Power is then momentarily removed (switched off by the MOSFET). The analog driver is suited to use with nearly any SMA actuator.

Optimization of process parameter variations on leakage current in in silicon-oninsulator vertical double gate mosfet device

Directory of Open Access Journals (Sweden)

K.E. Kaharudin

2015-12-01

Full Text Available This paper presents a study of optimizing input process parameters on leakage current (IOFF in silicon-on-insulator (SOI Vertical Double-Gate,Metal Oxide Field-Effect-Transistor (MOSFET by using L36 Taguchi method. The performance of SOI Vertical DG-MOSFET device is evaluated in terms of its lowest leakage current (IOFF value. An orthogonal array, main effects, signal-to-noise ratio (SNR and analysis of variance (ANOVA are utilized in order to analyze the effect of input process parameter variation on leakage current (IOFF. Based on the results, the minimum leakage current ((IOFF of SOI Vertical DG-MOSFET is observed to be 0.009 nA/µm or 9 ρA/µm while keeping the drive current (ION value at 434 µA/µm. Both the drive current (ION and leakage current (IOFF values yield a higher ION/IOFF ratio (48.22 x 106 for low power consumption application. Meanwhile, polysilicon doping tilt angle and polysilicon doping energy are recognized as the most dominant factors with each of the contributing factor effects percentage of 59% and 25%.

Real-Time In Vivo Dosimetry With MOSFET Detectors in Serial Tomotherapy for Head and Neck Cancer Patients

International Nuclear Information System (INIS)

Qi Zhenyu; Deng Xiaowu; Huang Shaomin; Shiu, Almon; Lerch, Michael; Metcalfe, Peter; Rosenfeld, Anatoly; Kron, Tomas

2011-01-01

Purpose: A real-time dose verification method using a recently designed metal oxide semiconductor field effect transistor (MOSFET) dosimetry system was evaluated for quality assurance (QA) of intensity-modulated radiation therapy (IMRT). Methods and Materials: Following the investigation of key parameters that might affect the accuracy of MOSFET measurements (i.e., source surface distance [SSD], field size, beam incident angles and radiation energy spectrum), the feasibility of this detector in IMRT dose verification was demonstrated by comparison with ion chamber measurements taken in an IMRT QA phantom. Real-time in vivo measurements were also performed with the MOSFET system during serial tomotherapy treatments administered to 8 head and neck cancer patients. Results: MOSFET sensitivity did not change with SSD. For field sizes smaller than 20 x 20 cm 2 , MOFET sensitivity varied within 1.0%. The detector angular response was isotropic within 2% over 360 o , and the observed sensitivity variation due to changes in the energy spectrum was negligible in 6-MV photons. MOSFET system measurements and ion chamber measurements agreed at all points in IMRT phantom plan verification, within 5%. The mean difference between 48 IMRT MOSFET-measured doses and calculated values in 8 patients was 3.33% and ranged from -2.20% to 7.89%. More than 90% of the total measurements had deviations of less than 5% from the planned doses. Conclusion: The MOSFET dosimetry system has been proven to be an effective tool in evaluating the actual dose within individual patients during IMRT treatment.

Real-time in vivo dosimetry with MOSFET detectors in serial tomotherapy for head and neck cancer patients.

Science.gov (United States)

Qi, Zhen-Yu; Deng, Xiao-Wu; Huang, Shao-Min; Shiu, Almon; Lerch, Michael; Metcalfe, Peter; Rosenfeld, Anatoly; Kron, Tomas

2011-08-01

A real-time dose verification method using a recently designed metal oxide semiconductor field effect transistor (MOSFET) dosimetry system was evaluated for quality assurance (QA) of intensity-modulated radiation therapy (IMRT). Following the investigation of key parameters that might affect the accuracy of MOSFET measurements (i.e., source surface distance [SSD], field size, beam incident angles and radiation energy spectrum), the feasibility of this detector in IMRT dose verification was demonstrated by comparison with ion chamber measurements taken in an IMRT QA phantom. Real-time in vivo measurements were also performed with the MOSFET system during serial tomotherapy treatments administered to 8 head and neck cancer patients. MOSFET sensitivity did not change with SSD. For field sizes smaller than 20 × 20 cm(2), MOFET sensitivity varied within 1.0%. The detector angular response was isotropic within 2% over 360°, and the observed sensitivity variation due to changes in the energy spectrum was negligible in 6-MV photons. MOSFET system measurements and ion chamber measurements agreed at all points in IMRT phantom plan verification, within 5%. The mean difference between 48 IMRT MOSFET-measured doses and calculated values in 8 patients was 3.33% and ranged from -2.20% to 7.89%. More than 90% of the total measurements had deviations of less than 5% from the planned doses. The MOSFET dosimetry system has been proven to be an effective tool in evaluating the actual dose within individual patients during IMRT treatment. Copyright © 2011 Elsevier Inc. All rights reserved.

Single-event burnout hardening of planar power MOSFET with partially widened trench source

Science.gov (United States)

Lu, Jiang; Liu, Hainan; Cai, Xiaowu; Luo, Jiajun; Li, Bo; Li, Binhong; Wang, Lixin; Han, Zhengsheng

2018-03-01

We present a single-event burnout (SEB) hardened planar power MOSFET with partially widened trench sources by three-dimensional (3D) numerical simulation. The advantage of the proposed structure is that the work of the parasitic bipolar transistor inherited in the power MOSFET is suppressed effectively due to the elimination of the most sensitive region (P-well region below the N+ source). The simulation result shows that the proposed structure can enhance the SEB survivability significantly. The critical value of linear energy transfer (LET), which indicates the maximum deposited energy on the device without SEB behavior, increases from 0.06 to 0.7 pC/μm. The SEB threshold voltage increases to 120 V, which is 80% of the rated breakdown voltage. Meanwhile, the main parameter characteristics of the proposed structure remain similar with those of the conventional planar structure. Therefore, this structure offers a potential optimization path to planar power MOSFET with high SEB survivability for space and atmospheric applications. Project supported by the National Natural Science Foundation of China (Nos. 61404161, 61404068, 61404169).

Serializing off-the-shelf MOSFETs by Magnetically Coupling Their Gate Electrodes

DEFF Research Database (Denmark)

Dimopoulos, Emmanouil; Munk-Nielsen, Stig

2013-01-01

While the semiconductor industry struggles with the inherent trade-offs of solid-state devices, serialization of power switches, like the Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) or the Insulated Gate Bipolar Transistor (IGBT), has been proven to be an advantageous alternative...... to acquire a high-efficient, high-voltage, fast-switching device. More than twenty years of research, on the serialization of solid-state devices, have resulted into several different stacking concepts. Among the prevailing ones, the gate balancing core technique, which has demonstrated very good performance...... in strings of high-power IGBT modules. In this paper, the limitations of the gate balancing core technique, when employed to serialize low or medium power off-the-shelf switches, are identified via experimental results. A new design specification for the interwinding capacitance of the employed transformer...

Geometric component of charge pumping current in nMOSFETs due to low-temperature irradiation

Science.gov (United States)

Witczak, S. C.; King, E. E.; Saks, N. S.; Lacoe, R. C.; Shaneyfelt, M. R.; Hash, G. L.; Hjalmarson, H. P.; Mayer, D. C.

2002-12-01

The geometric component of charge pumping current was examined in n-channel metal-oxide-silicon field effect transistors (MOSFETs) following low-temperature irradiation. In addition to the usual dependencies on channel length and gate bias transition time, the geometric component was found to increase with radiation-induced oxide-trapped charge density and decreasing temperature. A postirradiation injection of electrons into the gate oxide reduces the geometric component along with the density of oxide-trapped charge, which clearly demonstrates that the two are correlated. A fit of the injection data to a first-order model for trapping kinetics indicates that the electron trapping occurs predominantly at a single type of Coulomb-attractive trap site. The geometric component results primarily from the bulk recombination of channel electrons that fail to transport to the source or drain during the transition from inversion to accumulation. The radiation response of these transistors suggests that Coulomb scattering by oxide-trapped charge increases the bulk recombination at low temperatures by impeding electron transport. These results imply that the geometric component must be properly accounted for when charge pumping irradiated n-channel MOSFETs at low temperatures.

High efficiency grating couplers based on shared process with CMOS MOSFETs

International Nuclear Information System (INIS)

Qiu Chao; Sheng Zhen; Wu Ai-Min; Wang Xi; Zou Shi-Chang; Gan Fu-Wan; Li Le; Albert Pang

2013-01-01

Grating couplers are widely investigated as coupling interfaces between silicon-on-insulator waveguides and optical fibers. In this work, a high-efficiency and complementary metal—oxide—semiconductor (CMOS) process compatible grating coupler is proposed. The poly-Si layer used as a gate in the CMOS metal—oxide—semiconductor field effect transistor (MOSFET) is combined with a normal fully etched grating coupler, which greatly enhances its coupling efficiency. With optimal structure parameters, a coupling efficiency can reach as high as ∼ 70% at a wavelength of 1550 nm as indicated by simulation. From the angle of fabrication, all masks and etching steps are shared between MOSFETs and grating couplers, thereby making the high performance grating couplers easily integrated with CMOS circuits. Fabrication errors such as alignment shift are also simulated, showing that the device is quite tolerant in fabrication. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Statistical MOSFET Parameter Extraction with Parameter Selection for Minimal Point Measurement

Directory of Open Access Journals (Sweden)

Marga Alisjahbana

2013-11-01

Full Text Available A method to statistically extract MOSFET model parameters from a minimal number of transistor I(V characteristic curve measurements, taken during fabrication process monitoring. It includes a sensitivity analysis of the model, test/measurement point selection, and a parameter extraction experiment on the process data. The actual extraction is based on a linear error model, the sensitivity of the MOSFET model with respect to the parameters, and Newton-Raphson iterations. Simulated results showed good accuracy of parameter extraction and I(V curve fit for parameter deviations of up 20% from nominal values, including for a process shift of 10% from nominal.

MoS2 Negative-Capacitance Field-Effect Transistors with Subthreshold Swing below the Physics Limit.

Science.gov (United States)

Liu, Xingqiang; Liang, Renrong; Gao, Guoyun; Pan, Caofeng; Jiang, Chunsheng; Xu, Qian; Luo, Jun; Zou, Xuming; Yang, Zhenyu; Liao, Lei; Wang, Zhong Lin

2018-05-21

The Boltzmann distribution of electrons induced fundamental barrier prevents subthreshold swing (SS) from less than 60 mV dec -1 at room temperature, leading to high energy consumption of MOSFETs. Herein, it is demonstrated that an aggressive introduction of the negative capacitance (NC) effect of ferroelectrics can decisively break the fundamental limit governed by the "Boltzmann tyranny". Such MoS 2 negative-capacitance field-effect transistors (NC-FETs) with self-aligned top-gated geometry demonstrated here pull down the SS value to 42.5 mV dec -1 , and simultaneously achieve superior performance of a transconductance of 45.5 μS μm and an on/off ratio of 4 × 10 6 with channel length less than 100 nm. Furthermore, the inserted HfO 2 layer not only realizes a stable NC gate stack structure, but also prevents the ferroelectric P(VDF-TrFE) from fatigue with robust stability. Notably, the fabricated MoS 2 NC-FETs are distinctly different from traditional MOSFETs. The on-state current increases as the temperature decreases even down to 20 K, and the SS values exhibit nonlinear dependence with temperature due to the implementation of the ferroelectric gate stack. The NC-FETs enable fundamental applications through overcoming the Boltzmann limit in nanoelectronics and open up an avenue to low-power transistors needed for many exciting long-endurance portable consumer products. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In vivo measurements with MOSFET detectors in oropharynx and nasopharynx intensity-modulated radiation therapy

International Nuclear Information System (INIS)

Marcie, Serge; Charpiot, Elisabeth; Bensadoun, Rene-Jean; Ciais, Gaston; Herault, Joel; Costa, Andre; Gerard, Jean-Pierre

2005-01-01

Purpose: To evaluate the feasibility of in vivo measurements with metal oxide semiconductor field effect transistor (MOSFET) dosimeters for oropharynx and nasopharynx intensity-modulated radiation therapy (IMRT). Methods and Materials: During a 1-year period, in vivo measurements of the dose delivered to one or two points of the oral cavity by IMRT were obtained with MOSFET dosimeters. Measurements were obtained during each session of 48 treatment plans for 21 patients, all of whom were fitted with a custom-made mouth plate. Calculated and measured values were compared. Results: A total of 344 and 452 measurements were performed for the right and left sides, respectively, of the oral cavity. Seventy percent of the discrepancies between calculated and measured values were within ±5%. Uncertainties were due to interfraction patient positions, intrafraction patient movements, and interfraction MOSFET positions. Nevertheless, the discrepancies between the measured and calculated means were within ±5% for 92% and 95% of the right and left sides, respectively. Comparison of these discrepancies and the discrepancies between calculated values and measurements made on a phantom revealed that all differences were within ±5%. Conclusion: Our experience demonstrates the feasibility of in vivo measurements with MOSFET dosimeters for oropharynx and nasopharynx IMRT

A two dimensional analytical modeling of surface potential in triple metal gate (TMG) fully-depleted Recessed-Source/Drain (Re-S/D) SOI MOSFET

Science.gov (United States)

Priya, Anjali; Mishra, Ram Awadh

2016-04-01

In this paper, analytical modeling of surface potential is proposed for new Triple Metal Gate (TMG) fully depleted Recessed-Source/Dain Silicon On Insulator (SOI) Metal Oxide Semiconductor Field Effect Transistor (MOSFET). The metal with the highest work function is arranged near the source region and the lowest one near the drain. Since Recessed-Source/Drain SOI MOSFET has higher drain current as compared to conventional SOI MOSFET due to large source and drain region. The surface potential model developed by 2D Poisson's equation is verified by comparison to the simulation result of 2-dimensional ATLAS simulator. The model is compared with DMG and SMG devices and analysed for different device parameters. The ratio of metal gate length is varied to optimize the result.

Monte Carlo modeling of a High-Sensitivity MOSFET dosimeter for low- and medium-energy photon sources

International Nuclear Information System (INIS)

Wang, Brian; Kim, C.-H.; Xu, X. George

2004-01-01

Metal-oxide-semiconductor field effect transistor (MOSFET) dosimeters are increasingly utilized in radiation therapy and diagnostic radiology. While it is difficult to characterize the dosimeter responses for monoenergetic sources by experiments, this paper reports a detailed Monte Carlo simulation model of the High-Sensitivity MOSFET dosimeter using Monte Carlo N-Particle (MCNP) 4C. A dose estimator method was used to calculate the dose in the extremely thin sensitive volume. Efforts were made to validate the MCNP model using three experiments: (1) comparison of the simulated dose with the measurement of a Cs-137 source, (2) comparison of the simulated dose with analytical values, and (3) comparison of the simulated energy dependence with theoretical values. Our simulation results show that the MOSFET dosimeter has a maximum response at about 40 keV of photon energy. The energy dependence curve is also found to agree with the predicted value from theory within statistical uncertainties. The angular dependence study shows that the MOSFET dosimeter has a higher response (about 8%) when photons come from the epoxy side, compared with the kapton side for the Cs-137 source

Transistor Effect in Improperly Connected Transistors.

Science.gov (United States)

Luzader, Stephen; Sanchez-Velasco, Eduardo

1996-01-01

Discusses the differences between the standard representation and a realistic representation of a transistor. Presents an experiment that helps clarify the explanation of the transistor effect and shows why transistors should be connected properly. (JRH)

Nonplanar Nanoscale Fin Field Effect Transistors on Textile, Paper, Wood, Stone, and Vinyl via Soft Material-Enabled Double-Transfer Printing.

Science.gov (United States)

Rojas, Jhonathan P; Torres Sevilla, Galo A; Alfaraj, Nasir; Ghoneim, Mohamed T; Kutbee, Arwa T; Sridharan, Ashvitha; Hussain, Muhammad Mustafa

2015-05-26

The ability to incorporate rigid but high-performance nanoscale nonplanar complementary metal-oxide semiconductor (CMOS) electronics with curvilinear, irregular, or asymmetric shapes and surfaces is an arduous but timely challenge in enabling the production of wearable electronics with an in situ information-processing ability in the digital world. Therefore, we are demonstrating a soft-material enabled double-transfer-based process to integrate flexible, silicon-based, nanoscale, nonplanar, fin-shaped field effect transistors (FinFETs) and planar metal-oxide-semiconductor field effect transistors (MOSFETs) on various asymmetric surfaces to study their compatibility and enhanced applicability in various emerging fields. FinFET devices feature sub-20 nm dimensions and state-of-the-art, high-κ/metal gate stacks, showing no performance alteration after the transfer process. A further analysis of the transferred MOSFET devices, featuring 1 μm gate length, exhibits an ION value of nearly 70 μA/μm (VDS = 2 V, VGS = 2 V) and a low subthreshold swing of around 90 mV/dec, proving that a soft interfacial material can act both as a strong adhesion/interposing layer between devices and final substrate as well as a means to reduce strain, which ultimately helps maintain the device's performance with insignificant deterioration even at a high bending state.

Verification of eye lens dose in IMRT by MOSFET measurement.

Science.gov (United States)

Wang, Xuetao; Li, Guangjun; Zhao, Jianling; Song, Ying; Xiao, Jianghong; Bai, Sen

2018-04-17

The eye lens is recognized as one of the most radiosensitive structures in the human body. The widespread use of intensity-modulated radiotherapy (IMRT) complicates dose verification and necessitates high standards of dose computation. The purpose of this work was to assess the computed dose accuracy of eye lens through measurements using a metal-oxide-semiconductor field-effect transistor (MOSFET) dosimetry system. Sixteen clinical IMRT plans of head and neck patients were copied to an anthropomorphic head phantom. Measurements were performed using the MOSFET dosimetry system based on the head phantom. Two MOSFET detectors were imbedded in the eyes of the head phantom as the left and the right lens, covered by approximately 5-mm-thick paraffin wax. The measurement results were compared with the calculated values with a dose grid size of 1 mm. Sixteen IMRT plans were delivered, and 32 measured lens doses were obtained for analysis. The MOSFET dosimetry system can be used to verify the lens dose, and our measurements showed that the treatment planning system used in our clinic can provide adequate dose assessment in eye lenses. The average discrepancy between measurement and calculation was 6.7 ± 3.4%, and the largest discrepancy was 14.3%, which met the acceptability criterion set by the American Association of Physicists in Medicine Task Group 53 for external beam calculation for multileaf collimator-shaped fields in buildup regions. Copyright © 2018 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

A new DG nanoscale TFET based on MOSFETs by using source gate electrode: 2D simulation and an analytical potential model

Science.gov (United States)

Ramezani, Zeinab; Orouji, Ali A.

2017-08-01

This paper suggests and investigates a double-gate (DG) MOSFET, which emulates tunnel field effect transistors (M-TFET). We have combined this novel concept into a double-gate MOSFET, which behaves as a tunneling field effect transistor by work function engineering. In the proposed structure, in addition to the main gate, we utilize another gate over the source region with zero applied voltage and a proper work function to convert the source region from N+ to P+. We check the impact obtained by varying the source gate work function and source doping on the device parameters. The simulation results of the M-TFET indicate that it is a suitable case for a switching performance. Also, we present a two-dimensional analytic potential model of the proposed structure by solving the Poisson's equation in x and y directions and by derivatives from the potential profile; thus, the electric field is achieved. To validate our present model, we use the SILVACO ATLAS device simulator. The analytical results have been compared with it.

Band-to-band tunneling in a carbon nanotube metal-oxide-semiconductor field-effect transistor is dominated by phonon assisted tunneling

OpenAIRE

Koswatta, Siyuranga O.; Lundstrom, Mark S.; Nikonov, Dmitri E.

2007-01-01

Band-to-band tunneling (BTBT) devices have recently gained a lot of interest due to their potential for reducing power dissipation in integrated circuits. We have performed extensive simulations for the BTBT operation of carbon nanotube metal-oxide-semiconductor field-effect transistors (CNT-MOSFETs) using the non-equilibrium Green's functions formalism for both ballistic and dissipative quantum transport. In comparison with recently reported experimental data (Y. Lu et al, J. Am. Chem. Soc.,...

Nonlinear Parasitic Capacitance Modelling of High Voltage Power MOSFETs in Partial SOI Process

DEFF Research Database (Denmark)

Fan, Lin; Knott, Arnold; Jørgensen, Ivan Harald Holger

2016-01-01

: off-state, sub-threshold region, and on-state in the linear region. A high voltage power MOSFET is designed in a partial Silicon on Insulator (SOI) process, with the bulk as a separate terminal. 3D plots and contour plots of the capacitances versus bias voltages for the transistor summarize...

A two-dimensional analytical model for channel potential and threshold voltage of short channel dual material gate lightly doped drain MOSFET

International Nuclear Information System (INIS)

Tripathi Shweta

2014-01-01

An analytical model for the channel potential and the threshold voltage of the short channel dual-material-gate lightly doped drain (DMG-LDD) metal—oxide—semiconductor field-effect transistor (MOSFET) is presented using the parabolic approximation method. The proposed model takes into account the effects of the LDD region length, the LDD region doping, the lengths of the gate materials and their respective work functions, along with all the major geometrical parameters of the MOSFET. The impact of the LDD region length, the LDD region doping, and the channel length on the channel potential is studied in detail. Furthermore, the threshold voltage of the device is calculated using the minimum middle channel potential, and the result obtained is compared with the DMG MOSFET threshold voltage to show the improvement in the threshold voltage roll-off. It is shown that the DMG-LDD MOSFET structure alleviates the problem of short channel effects (SCEs) and the drain induced barrier lowering (DIBL) more efficiently. The proposed model is verified by comparing the theoretical results with the simulated data obtained by using the commercially available ATLAS™ 2D device simulator. (interdisciplinary physics and related areas of science and technology)

A two-dimensional analytical model for channel potential and threshold voltage of short channel dual material gate lightly doped drain MOSFET

Science.gov (United States)

Shweta, Tripathi

2014-11-01

An analytical model for the channel potential and the threshold voltage of the short channel dual-material-gate lightly doped drain (DMG-LDD) metal—oxide—semiconductor field-effect transistor (MOSFET) is presented using the parabolic approximation method. The proposed model takes into account the effects of the LDD region length, the LDD region doping, the lengths of the gate materials and their respective work functions, along with all the major geometrical parameters of the MOSFET. The impact of the LDD region length, the LDD region doping, and the channel length on the channel potential is studied in detail. Furthermore, the threshold voltage of the device is calculated using the minimum middle channel potential, and the result obtained is compared with the DMG MOSFET threshold voltage to show the improvement in the threshold voltage roll-off. It is shown that the DMG-LDD MOSFET structure alleviates the problem of short channel effects (SCEs) and the drain induced barrier lowering (DIBL) more efficiently. The proposed model is verified by comparing the theoretical results with the simulated data obtained by using the commercially available ATLAS™ 2D device simulator.

I-V Characteristics of a Static Random Access Memory Cell Utilizing Ferroelectric Transistors

Science.gov (United States)

Laws, Crystal; Mitchell, Cody; Hunt, Mitchell; Ho, Fat D.; MacLeod, Todd C.

2012-01-01

I-V characteristics for FeFET different than that of MOSFET Ferroelectric layer features hysteresis trend whereas MOSFET behaves same for both increasing and decreasing VGS FeFET I-V characteristics doesn't show dependence on VDS A Transistor with different channel length and width as well as various resistance and input voltages give different results As resistance values increased, the magnitude of the drain current decreased.

Effect of stacking order on device performance of bilayer black phosphorene-field-effect transistor

International Nuclear Information System (INIS)

Mukhopadhyay, A.; Banerjee, L.; Sengupta, A.; Rahaman, H.

2015-01-01

We investigate the effect of stacking order of bilayer black phosphorene on the device properties of p-MOSFET and n-MOSFET. Two layers of black phosphorus are stacked in three different orders and are used as channel material in both n-MOSFET and p-MOSFET devices. The effects of different stacking orders on electron and hole effective masses and output characteristics of MOSFETs, such as ON currents, ON/OFF ratio, and transconductance are analyzed. Our results show that about 1.37 times and 1.49 times increase in ON current is possible along armchair and zigzag directions, respectively, 55.11% variation in transconductance is possible along armchair direction, by changing stacking orders (AA, AB, and AC) and about 8 times increase in ON current is achievable by changing channel orientation (armchair or zigzag) in p-MOSFET. About 14.8 mV/V drain induced barrier lowering is observed for both p-MOSFET and n-MOSFET, which signifies good immunity to short channel effects

Effect of stacking order on device performance of bilayer black phosphorene-field-effect transistor

Energy Technology Data Exchange (ETDEWEB)

Mukhopadhyay, A., E-mail: arnabm.electinstru@gmail.com; Banerjee, L.; Sengupta, A.; Rahaman, H. [School of VLSI Technology, IIEST, Shibpur, Howrah 711103 (India)

2015-12-14

We investigate the effect of stacking order of bilayer black phosphorene on the device properties of p-MOSFET and n-MOSFET. Two layers of black phosphorus are stacked in three different orders and are used as channel material in both n-MOSFET and p-MOSFET devices. The effects of different stacking orders on electron and hole effective masses and output characteristics of MOSFETs, such as ON currents, ON/OFF ratio, and transconductance are analyzed. Our results show that about 1.37 times and 1.49 times increase in ON current is possible along armchair and zigzag directions, respectively, 55.11% variation in transconductance is possible along armchair direction, by changing stacking orders (AA, AB, and AC) and about 8 times increase in ON current is achievable by changing channel orientation (armchair or zigzag) in p-MOSFET. About 14.8 mV/V drain induced barrier lowering is observed for both p-MOSFET and n-MOSFET, which signifies good immunity to short channel effects.

Auger generation as an intrinsic limit to tunneling field-effect transistor performance

International Nuclear Information System (INIS)

Teherani, James T.; Agarwal, Sapan; Chern, Winston; Antoniadis, Dimitri A.; Solomon, Paul M.; Yablonovitch, Eli

2016-01-01

Many in the microelectronics field view tunneling field-effect transistors (TFETs) as society's best hope for achieving a >10× power reduction for electronic devices; however, despite a decade of considerable worldwide research, experimental TFET results have significantly underperformed simulations and conventional MOSFETs. To explain the discrepancy between TFET experiments and simulations, we investigate the parasitic leakage current due to Auger generation, an intrinsic mechanism that cannot be mitigated with improved material quality or better device processing. We expose the intrinsic link between the Auger and band-to-band tunneling rates, highlighting the difficulty of increasing one without the other. From this link, we show that Auger generation imposes a fundamental limit on ultimate TFET performance.

Auger generation as an intrinsic limit to tunneling field-effect transistor performance

Energy Technology Data Exchange (ETDEWEB)

Teherani, James T., E-mail: j.teherani@columbia.edu [Department of Electrical Engineering, Columbia University, New York, New York 10027 (United States); Agarwal, Sapan [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States); Chern, Winston; Antoniadis, Dimitri A. [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Solomon, Paul M. [IBM T.J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Yablonovitch, Eli [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States)

2016-08-28

Many in the microelectronics field view tunneling field-effect transistors (TFETs) as society's best hope for achieving a >10× power reduction for electronic devices; however, despite a decade of considerable worldwide research, experimental TFET results have significantly underperformed simulations and conventional MOSFETs. To explain the discrepancy between TFET experiments and simulations, we investigate the parasitic leakage current due to Auger generation, an intrinsic mechanism that cannot be mitigated with improved material quality or better device processing. We expose the intrinsic link between the Auger and band-to-band tunneling rates, highlighting the difficulty of increasing one without the other. From this link, we show that Auger generation imposes a fundamental limit on ultimate TFET performance.

Investigation of veritcal graded channel doping in nanoscale fully-depleted SOI-MOSFET

Science.gov (United States)

Ramezani, Zeinab; Orouji, Ali A.

2016-10-01

For achieving reliable transistor, we investigate an amended channel doping (ACD) engineering which improves the electrical and thermal performances of fully-depleted silicon-on-insulator (SOI) MOSFET. We have called the proposed structure with the amended channel doping engineering as ACD-SOI structure and compared it with a conventional fully-depleted SOI MOSFET (C-SOI) with uniform doping distribution using 2-D ATLAS simulator. The amended channel doping is a vertical graded doping that is distributed from the surface of structure with high doping density to the bottom of channel, near the buried oxide, with low doping density. Short channel effects (SCEs) and leakage current suppress due to high barrier height near the source region and electric field modification in the ACD-SOI in comparison with the C-SOI structure. Furthermore, by lower electric field and electron temperature near the drain region that is the place of hot carrier generation, we except the improvement of reliability and gate induced drain lowering (GIDL) in the proposed structure. Undesirable Self heating effect (SHE) that become a critical challenge for SOI MOSFETs is alleviated in the ACD-SOI structure because of utilizing low doping density near the buried oxide. Thus, refer to accessible results, the ACD-SOI structure with graded distribution in vertical direction is a reliable device especially in low power and high temperature applications.

Performance characteristics of mobile MOSFET dosimeter for kilovoltage X-rays used in image guided radiotherapy.

Science.gov (United States)

Kumar, A Sathish; Singh, I Rabi Raja; Sharma, S D; Ravindran, B Paul

2015-01-01

The main objective of this study was to investigate the characteristics of metal oxide semiconductor field effect transistor (MOSFET) dosimeter for kilovoltage (kV) X-ray beams in order to perform the in vivo dosimetry during image guidance in radiotherapy. The performance characteristics of high sensitivity MOSFET dosimeters were investigated for 80, 90, 100, 110, 120, and 125 kV X-ray beams used for imaging in radiotherapy. This study was performed using Clinac 2100 C/D medical electron linear accelerator with on-board imaging and kV cone beam computed tomography system. The characteristics studied in this work include energy dependence, angular dependence, and linearity. The X-ray beam outputs were measured as per American Association of Physicists in Medicine (AAPM) TG 61 recommendations using PTW parallel plate (PP) ionization chamber, which was calibrated in terms of air kerma (Nk) by the National Standard Laboratory. The MOSFET dosimeters were calibrated against the PP ionization chamber for all the kV X-ray beams and the calibration coefficient was found to be 0.11 cGy/mV with a standard deviation of about ±1%. The response of MOSFET was found to be energy independent for the kV X-ray energies used in this study. The response of the MOSFET dosimeter was also found independent of angle of incidence for the gantry angles in the range of 0° to 360° in-air as well as at 3 cm depth in tissue equivalent phantom.

1T Pixel Using Floating-Body MOSFET for CMOS Image Sensors

Directory of Open Access Journals (Sweden)

Guo-Neng Lu

2009-01-01

Full Text Available We present a single-transistor pixel for CMOS image sensors (CIS. It is a floating-body MOSFET structure, which is used as photo-sensing device and source-follower transistor, and can be controlled to store and evacuate charges. Our investigation into this 1T pixel structure includes modeling to obtain analytical description of conversion gain. Model validation has been done by comparing theoretical predictions and experimental results. On the other hand, the 1T pixel structure has been implemented in different configurations, including rectangular-gate and ring-gate designs, and variations of oxidation parameters for the fabrication process. The pixel characteristics are presented and discussed.

1T Pixel Using Floating-Body MOSFET for CMOS Image Sensors.

Science.gov (United States)

Lu, Guo-Neng; Tournier, Arnaud; Roy, François; Deschamps, Benoît

2009-01-01

We present a single-transistor pixel for CMOS image sensors (CIS). It is a floating-body MOSFET structure, which is used as photo-sensing device and source-follower transistor, and can be controlled to store and evacuate charges. Our investigation into this 1T pixel structure includes modeling to obtain analytical description of conversion gain. Model validation has been done by comparing theoretical predictions and experimental results. On the other hand, the 1T pixel structure has been implemented in different configurations, including rectangular-gate and ring-gate designs, and variations of oxidation parameters for the fabrication process. The pixel characteristics are presented and discussed.

Non-Planar Nano-Scale Fin Field Effect Transistors on Textile, Paper, Wood, Stone, and Vinyl via Soft Material-Enabled Double-Transfer Printing

KAUST Repository

Rojas, Jhonathan Prieto; Sevilla, Galo T.; Alfaraj, Nasir; Ghoneim, Mohamed T.; Kutbee, Arwa T.; Sridharan, Ashvitha; Hussain, Muhammad Mustafa

2015-01-01

The ability to incorporate rigid but high-performance nano-scale non-planar complementary metal-oxide semiconductor (CMOS) electronics with curvilinear, irregular, or asymmetric shapes and surfaces is an arduous but timely challenge in enabling the production of wearable electronics with an in-situ information-processing ability in the digital world. Therefore, we are demonstrating a soft-material enabled double-transfer-based process to integrate flexible, silicon-based, nano-scale, non-planar, fin-shaped field effect transistors (FinFETs) and planar metal-oxide-semiconductor field effect transistors (MOSFETs) on various asymmetric surfaces to study their compatibility and enhanced applicability in various emerging fields. FinFET devices feature sub-20 nm dimensions and state-of-the-art, high-κ/metal gate stack, showing no performance alteration after the transfer process. A further analysis of the transferred MOSFET devices, featuring 1 μm gate length exhibits ION ~70 μA/μm (VDS = 2 V, VGS = 2 V) and a low sub-threshold swing of around 90 mV/dec, proving that a soft interfacial material can act both as a strong adhesion/interposing layer between devices and final substrate as well as a means to reduce strain, which ultimately helps maintain the device’s performance with insignificant deterioration even at a high bending state.

Non-Planar Nano-Scale Fin Field Effect Transistors on Textile, Paper, Wood, Stone, and Vinyl via Soft Material-Enabled Double-Transfer Printing

KAUST Repository

Rojas, Jhonathan Prieto

2015-05-01

The ability to incorporate rigid but high-performance nano-scale non-planar complementary metal-oxide semiconductor (CMOS) electronics with curvilinear, irregular, or asymmetric shapes and surfaces is an arduous but timely challenge in enabling the production of wearable electronics with an in-situ information-processing ability in the digital world. Therefore, we are demonstrating a soft-material enabled double-transfer-based process to integrate flexible, silicon-based, nano-scale, non-planar, fin-shaped field effect transistors (FinFETs) and planar metal-oxide-semiconductor field effect transistors (MOSFETs) on various asymmetric surfaces to study their compatibility and enhanced applicability in various emerging fields. FinFET devices feature sub-20 nm dimensions and state-of-the-art, high-κ/metal gate stack, showing no performance alteration after the transfer process. A further analysis of the transferred MOSFET devices, featuring 1 μm gate length exhibits ION ~70 μA/μm (VDS = 2 V, VGS = 2 V) and a low sub-threshold swing of around 90 mV/dec, proving that a soft interfacial material can act both as a strong adhesion/interposing layer between devices and final substrate as well as a means to reduce strain, which ultimately helps maintain the device’s performance with insignificant deterioration even at a high bending state.

Improved operation of graded-channel SOI nMOSFETs down to liquid helium temperature

Science.gov (United States)

Pavanello, Marcelo Antonio; de Souza, Michelly; Ribeiro, Thales Augusto; Martino, João Antonio; Flandre, Denis

2016-11-01

This paper presents the operation of Graded-Channel (GC) Silicon-On-Insulator (SOI) nMOSFETs at low temperatures down to liquid helium temperature in comparison to standard uniformly doped transistors. Devices from two different technologies have been measured and show that the mobility increase rate with temperature for GC SOI transistors is similar to uniformly doped devices for temperatures down to 90 K. However, at liquid helium temperature the rate of mobility increase is larger in GC SOI than in standard devices because of the different mobility scattering mechanisms. The analog properties of GC SOI devices have been investigated down to 4.16 K and show that because of its better transconductance and output conductance, an intrinsic voltage gain improvement with temperature is also obtained for devices in the whole studied temperature range. GC devices are also capable of reducing the impact ionization due to the high electric field in the drain region, increasing the drain breakdown voltage of fully-depleted SOI MOSFETs at any studied temperature and the kink voltage at 4.16 K.

Impacts of gate bias and its variation on gamma-ray irradiation resistance of SiC MOSFETs

Energy Technology Data Exchange (ETDEWEB)

Murata, Koichi; Mitomo, Satoshi; Matsuda, Takuma; Yokoseki, Takashi [Saitama University, Sakuraku (Japan); National Institutes for Quantum and Radiological Science and Technology (QST), Takasaki (Japan); Makino, Takahiro; Onoda, Shinobu; Takeyama, Akinori; Ohshima, Takeshi [National Institutes for Quantum and Radiological Science and Technology (QST), Takasaki (Japan); Okubo, Shuichi; Tanaka, Yuki; Kandori, Mikio; Yoshie, Toru [Sanken Electric Co., Ltd., Niiza, Saitama (Japan); Hijikata, Yasuto [Saitama University, Sakuraku (Japan)

2017-04-15

Gamma-ray irradiation into vertical type n-channel hexagonal (4H)-silicon carbide (SiC) metal-oxide-semiconductor field effect transistors (MOSFETs) was performed under various gate biases. The threshold voltage for the MOSFETs irradiated with a constant positive gate bias showed a large negative shift, and the shift slightly recovered above 100 kGy. For MOSFETs with non- and a negative constant biases, no significant change in threshold voltage, V{sub th}, was observed up to 400 kGy. By changing the gate bias from positive bias to either negative or non-bias, the V{sub th} significantly recovered from the large negative voltage shift induced by 50 kGy irradiation with positive gate bias after only 10 kGy irradiation with either negative or zero bias. It indicates that the positive charges generated in the gate oxide near the oxide-SiC interface due to irradiation were removed or recombined instantly by the irradiation under zero or negative biases. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

InGaAsP Mach-Zehnder interferometer optical modulator monolithically integrated with InGaAs driver MOSFET on a III-V CMOS photonics platform.

Science.gov (United States)

Park, Jin-Kown; Takagi, Shinichi; Takenaka, Mitsuru

2018-02-19

We demonstrated the monolithic integration of a carrier-injection InGaAsP Mach-Zehnder interferometer (MZI) optical modulator and InGaAs metal-oxide-semiconductor field-effect transistor (MOSFET) on a III-V-on-insulator (III-V-OI) wafer. A low-resistivity lateral PIN junction was formed along an InGaAsP rib waveguide by Zn diffusion and Ni-InGaAsP alloy, enabling direct driving of the InGaAsP optical modulator by the InGaAs MOSFET. A π phase shift of the InGaAsP optical modulator was obtained through the injection of a drain current from the InGaAs MOSFET with a gate voltage of approximately 1 V. This proof-of-concept demonstration of the monolithic integration of the InGaAsP optical modulator and InGaAs driver MOSFET will enable us to develop high-performance and low-power electronic-photonic integrated circuits on a III-V CMOS photonics platform.

Electronic system for data acquisition to study radiation effects on operating MOSFET transistors

International Nuclear Information System (INIS)

Alves de Oliveira, Juliano; Assis de Melo, Marco Antônio; Guazzelli da Silveira, Marcilei A.; Medina, Nilberto H.

2014-01-01

In this work we present the development of an acquisition system for characterizing transistors under X-ray radiation. The system is able to carry out the acquisition and to storage characteristic transistor curves. To test the acquisition system we have submitted polarized P channel MOS transistors under continuous 10-keV X-ray doses up to 1500 krad. The characterization system can operate in the saturation region or in the linear region in order to observe the behavior of the currents or voltages involved during the irradiation process. Initial tests consisted of placing the device under test (DUT) in front of the X-ray beam direction, while its drain current was constantly monitored through the prototype generated in this work, the data are stored continuously and system behavior was monitored during the test. In order to observe the behavior of the DUT during the radiation tests, we used an acquisition system that consists of an ultra-low consumption16-bit Texas Instruments MSP430 microprocessor. Preliminary results indicate linear behavior of the voltage as a function of the exposure time and fast recovery. These features may be favorable to use this device as a radiation dosimeter to monitor low rate X-ray

Intrinsic Nonlinearities and Layout Impacts of 100 V Integrated Power MOSFETs in Partial SOI Process

DEFF Research Database (Denmark)

Fan, Lin; Knott, Arnold; Jørgensen, Ivan Harald Holger

Parasitic capacitances of power semiconductors are a part of the key design parameters of state-of-the-art very high frequency (VHF) power supplies. In this poster, four 100 V integrated power MOSFETs with different layout structures are designed, implemented, and analyzed in a 0.18 ȝm partial...... Silicon-on-Insulator (SOI) process with a die area 2.31 mm2.  A small-signal model of power MOSFETs is proposed to systematically analyze the nonlinear parasitic capacitances in different transistor states: off-state, sub-threshold region, and on-state in the linear region. 3D plots are used to summarize...

Silicon nanotube field effect transistor with core-shell gate stacks for enhanced high-performance operation and area scaling benefits

KAUST Repository

Fahad, Hossain M.; Smith, Casey; Rojas, Jhonathan Prieto; Hussain, Muhammad Mustafa

2011-01-01

We introduce the concept of a silicon nanotube field effect transistor whose unique core-shell gate stacks help achieve full volume inversion by giving a surge in minority carrier concentration in the near vicinity of the ultrathin channel and at the same time rapid roll-off at the source and drain junctions constituting velocity saturation-induced higher drive current-enhanced high performance per device with efficient real estate consumption. The core-shell gate stacks also provide superior short channel effects control than classical planar metal oxide semiconductor field effect transistor (MOSFET) and gate-all-around nanowire FET. The proposed device offers the true potential to be an ideal blend for quantum ballistic transport study of device property control by bottom-up approach and high-density integration compatibility using top-down state-of-the-art complementary metal oxide semiconductor flow. © 2011 American Chemical Society.

Silicon nanotube field effect transistor with core-shell gate stacks for enhanced high-performance operation and area scaling benefits

KAUST Repository

Fahad, Hossain M.

2011-10-12

We introduce the concept of a silicon nanotube field effect transistor whose unique core-shell gate stacks help achieve full volume inversion by giving a surge in minority carrier concentration in the near vicinity of the ultrathin channel and at the same time rapid roll-off at the source and drain junctions constituting velocity saturation-induced higher drive current-enhanced high performance per device with efficient real estate consumption. The core-shell gate stacks also provide superior short channel effects control than classical planar metal oxide semiconductor field effect transistor (MOSFET) and gate-all-around nanowire FET. The proposed device offers the true potential to be an ideal blend for quantum ballistic transport study of device property control by bottom-up approach and high-density integration compatibility using top-down state-of-the-art complementary metal oxide semiconductor flow. © 2011 American Chemical Society.

Influence of gate recess on the electronic characteristics of β-Ga2O3 MOSFETs

Science.gov (United States)

Lv, Yuanjie; Mo, Jianghui; Song, Xubo; He, Zezhao; Wang, Yuangang; Tan, Xin; Zhou, Xingye; Gu, Guodong; Guo, Hongyu; Feng, Zhihong

2018-05-01

Gallium oxide (Ga2O3) metal-oxide-semiconductor field-effect transistors (MOSFETs) were fabricated with gate recess depths of 110 nm and 220 nm, respectively. The gate recess was formed by dry plasma etching with Cr metal as the mask. The fabricated devices with a 25-nm HfO2 gate dielectric both showed a low off-state drain current of about 1.8 × 10-10 A/mm. The effects of recess depth on the electronic characteristics of Ga2O3 MOSFETs were investigated. Upon increasing the recess depth from 110 nm to 220 nm, the saturated drain current decreased from 20.7 mA/mm to 2.6 mA/mm, while the threshold voltage moved increased to +3 V. Moreover, the breakdown voltage increased from 122 V to 190 V. This is mainly because the inverted-trapezoidal gate played the role of a gate-field plate, which suppressed the peak electric field close to the gate.

A Distance Detector with a Strip Magnetic MOSFET and Readout Circuit.

Science.gov (United States)

Sung, Guo-Ming; Lin, Wen-Sheng; Wang, Hsing-Kuang

2017-01-10

This paper presents a distance detector composed of two separated metal-oxide semiconductor field-effect transistors (MOSFETs), a differential polysilicon cross-shaped Hall plate (CSHP), and a readout circuit. The distance detector was fabricated using 0.18 μm 1P6M Complementary Metal-Oxide Semiconductor (CMOS) technology to sense the magnetic induction perpendicular to the chip surface. The differential polysilicon CSHP enabled the magnetic device to not only increase the magnetosensitivity but also eliminate the offset voltage generated because of device mismatch and Lorentz force. Two MOSFETs generated two drain currents with a quadratic function of the differential Hall voltages at CSHP. A readout circuit-composed of a current-to-voltage converter, a low-pass filter, and a difference amplifier-was designed to amplify the current difference between two drains of MOSFETs. Measurements revealed that the electrostatic discharge (ESD) could be eliminated from the distance sensor by grounding it to earth; however, the sensor could be desensitized by ESD in the absence of grounding. The magnetic influence can be ignored if the magnetic body (human) stays far from the magnetic sensor, and the measuring system is grounded to earth by using the ESD wrist strap (Strap E-GND). Both 'no grounding' and 'grounding to power supply' conditions were unsuitable for measuring the induced Hall voltage.

Performance of a 100V Half-Bridge MOSFET Driver, Type MIC4103, Over a Wide Temperature Range

Science.gov (United States)

Patterson, Richard L.; Hammoud, Ahmad

2011-01-01

The operation of a high frequency, high voltage MOSFET (metal-oxide semiconductor field-effect transistors) driver was investigated over a wide temperature regime that extended beyond its specified range. The Micrel MIC4103 is a 100V, non-inverting, dual driver that is designed to independently drive both high-side and low-side N-channel MOSFETs. It features fast propagation delay times and can drive 1000 pF load with 10ns rise times and 6 ns fall times [1]. The device consumes very little power, has supply under-voltage protection, and is rated for a -40 C to +125 C junction temperature range. The floating high-side driver of the chip can sustain boost voltages up to 100 V. Table I shows some of the device manufacturer s specification.

Non-Stoichiometric SixN Metal-Oxide-Semiconductor Field-Effect Transistor for Compact Random Number Generator with 0.3 Mbit/s Generation Rate

Science.gov (United States)

Matsumoto, Mari; Ohba, Ryuji; Yasuda, Shin-ichi; Uchida, Ken; Tanamoto, Tetsufumi; Fujita, Shinobu

2008-08-01

The demand for random numbers for security applications is increasing. A conventional random number generator using thermal noise can generate unpredictable high-quality random numbers, but the circuit is extremely large because of large amplifier circuit for a small thermal signal. On the other hand, a pseudo-random number generator is small but the quality of randomness is bad. For a small circuit and a high quality of randomness, we purpose a non-stoichiometric SixN metal-oxide-semiconductor field-effect transistor (MOSFET) noise source device. This device generates a very large noise signal without an amplifier circuit. As a result, it is shown that, utilizing a SiN MOSFET, we can attain a compact random number generator with a high generation rate near 1 Mbit/s, which is suitable for almost all security applications.

Electron-electron scattering-induced channel hot electron injection in nanoscale n-channel metal-oxide-semiconductor field-effect-transistors with high-k/metal gate stacks

International Nuclear Information System (INIS)

Tsai, Jyun-Yu; Liu, Kuan-Ju; Lu, Ying-Hsin; Liu, Xi-Wen; Chang, Ting-Chang; Chen, Ching-En; Ho, Szu-Han; Tseng, Tseung-Yuen; Cheng, Osbert; Huang, Cheng-Tung; Lu, Ching-Sen

2014-01-01

This work investigates electron-electron scattering (EES)-induced channel hot electron (CHE) injection in nanoscale n-channel metal-oxide-semiconductor field-effect-transistors (n-MOSFETs) with high-k/metal gate stacks. Many groups have proposed new models (i.e., single-particle and multiple-particle process) to well explain the hot carrier degradation in nanoscale devices and all mechanisms focused on Si-H bond dissociation at the Si/SiO 2 interface. However, for high-k dielectric devices, experiment results show that the channel hot carrier trapping in the pre-existing high-k bulk defects is the main degradation mechanism. Therefore, we propose a model of EES-induced CHE injection to illustrate the trapping-dominant mechanism in nanoscale n-MOSFETs with high-k/metal gate stacks.

Simultaneous On-State Voltage and Bond-Wire Resistance Monitoring of Silicon Carbide MOSFETs

Directory of Open Access Journals (Sweden)

Nick Baker

2017-03-01

Full Text Available In fast switching power semiconductors, the use of a fourth terminal to provide the reference potential for the gate signal—known as a kelvin-source terminal—is becoming common. The introduction of this terminal presents opportunities for condition monitoring systems. This article demonstrates how the voltage between the kelvin-source and power-source can be used to specifically monitor bond-wire degradation. Meanwhile, the drain to kelvin-source voltage can be monitored to track defects in the semiconductor die or gate driver. Through an accelerated aging test on 20 A Silicon Carbide Metal-Oxide-Semiconductor-Field-Effect Transistors (MOSFETs, it is shown that there are opposing trends in the evolution of the on-state resistances of both the bond-wires and the MOSFET die. In summary, after 50,000 temperature cycles, the resistance of the bond-wires increased by up to 2 mΩ, while the on-state resistance of the MOSFET dies decreased by approximately 1 mΩ. The conventional failure precursor (monitoring a single forward voltage cannot distinguish between semiconductor die or bond-wire degradation. Therefore, the ability to monitor both these parameters due to the presence of an auxiliary-source terminal can provide more detailed information regarding the aging process of a device.

Molecular sensing using monolayer floating gate, fully depleted SOI MOSFET acting as an exponential transducer.

Science.gov (United States)

Takulapalli, Bharath R

2010-02-23

Field-effect transistor-based chemical sensors fall into two broad categories based on the principle of signal transduction-chemiresistor or Schottky-type devices and MOSFET or inversion-type devices. In this paper, we report a new inversion-type device concept-fully depleted exponentially coupled (FDEC) sensor, using molecular monolayer floating gate fully depleted silicon on insulator (SOI) MOSFET. Molecular binding at the chemical-sensitive surface lowers the threshold voltage of the device inversion channel due to a unique capacitive charge-coupling mechanism involving interface defect states, causing an exponential increase in the inversion channel current. This response of the device is in opposite direction when compared to typical MOSFET-type sensors, wherein inversion current decreases in a conventional n-channel sensor device upon addition of negative charge to the chemical-sensitive device surface. The new sensor architecture enables ultrahigh sensitivity along with extraordinary selectivity. We propose the new sensor concept with the aid of analytical equations and present results from our experiments in liquid phase and gas phase to demonstrate the new principle of signal transduction. We present data from numerical simulations to further support our theory.

Ionizing Radiation Effects on the Noise of 65 nm CMOS Transistors for Pixel Sensor Readout at Extreme Total Dose Levels

CERN Document Server

Re, V.; Manghisoni, M.; Riceputi, E.; Traversi, G.; Ratti, L.

2018-01-01

This paper is focused on the study of the noise performance of 65 nm CMOS transistors at extremely high total ionizing dose (TID) levels of the order of several hundreds of Mrad(SiO2). Noise measurements are reported and discussed, analyzing radiation effects on 1/ f noise and channel thermal noise. In nMOSFETs, up to 10 Mrad(SiO2), the experimental behavior is consistent with a damage mechanism mainly associ- ated with lateral isolation oxides, and can be modeled by parasitic transistors turning on after irradiation and contributing to the total noise of the device. At very high dose, these parasitic transistors tend to be turned off by negative charge accumulating in interface states and compensating radiation-induced positive charge building up inside thick isolation oxides. Effects associated with ionization and hydrogen transport in spacer oxides may become dominant at 600 Mrad(SiO2) and may explain the observed noise behavior at extremely high TID. The results of this analysis provide an understanding o...

Monte Carlo simulation of MOSFET detectors for high-energy photon beams using the PENELOPE code

Science.gov (United States)

Panettieri, Vanessa; Amor Duch, Maria; Jornet, Núria; Ginjaume, Mercè; Carrasco, Pablo; Badal, Andreu; Ortega, Xavier; Ribas, Montserrat

2007-01-01

The aim of this work was the Monte Carlo (MC) simulation of the response of commercially available dosimeters based on metal oxide semiconductor field effect transistors (MOSFETs) for radiotherapeutic photon beams using the PENELOPE code. The studied Thomson&Nielsen TN-502-RD MOSFETs have a very small sensitive area of 0.04 mm2 and a thickness of 0.5 µm which is placed on a flat kapton base and covered by a rounded layer of black epoxy resin. The influence of different metallic and Plastic water™ build-up caps, together with the orientation of the detector have been investigated for the specific application of MOSFET detectors for entrance in vivo dosimetry. Additionally, the energy dependence of MOSFET detectors for different high-energy photon beams (with energy >1.25 MeV) has been calculated. Calculations were carried out for simulated 6 MV and 18 MV x-ray beams generated by a Varian Clinac 1800 linear accelerator, a Co-60 photon beam from a Theratron 780 unit, and monoenergetic photon beams ranging from 2 MeV to 10 MeV. The results of the validation of the simulated photon beams show that the average difference between MC results and reference data is negligible, within 0.3%. MC simulated results of the effect of the build-up caps on the MOSFET response are in good agreement with experimental measurements, within the uncertainties. In particular, for the 18 MV photon beam the response of the detectors under a tungsten cap is 48% higher than for a 2 cm Plastic water™ cap and approximately 26% higher when a brass cap is used. This effect is demonstrated to be caused by positron production in the build-up caps of higher atomic number. This work also shows that the MOSFET detectors produce a higher signal when their rounded side is facing the beam (up to 6%) and that there is a significant variation (up to 50%) in the response of the MOSFET for photon energies in the studied energy range. All the results have shown that the PENELOPE code system can

Monte Carlo simulation of MOSFET detectors for high-energy photon beams using the PENELOPE code.

Science.gov (United States)

Panettieri, Vanessa; Duch, Maria Amor; Jornet, Núria; Ginjaume, Mercè; Carrasco, Pablo; Badal, Andreu; Ortega, Xavier; Ribas, Montserrat

2007-01-07

The aim of this work was the Monte Carlo (MC) simulation of the response of commercially available dosimeters based on metal oxide semiconductor field effect transistors (MOSFETs) for radiotherapeutic photon beams using the PENELOPE code. The studied Thomson&Nielsen TN-502-RD MOSFETs have a very small sensitive area of 0.04 mm(2) and a thickness of 0.5 microm which is placed on a flat kapton base and covered by a rounded layer of black epoxy resin. The influence of different metallic and Plastic water build-up caps, together with the orientation of the detector have been investigated for the specific application of MOSFET detectors for entrance in vivo dosimetry. Additionally, the energy dependence of MOSFET detectors for different high-energy photon beams (with energy >1.25 MeV) has been calculated. Calculations were carried out for simulated 6 MV and 18 MV x-ray beams generated by a Varian Clinac 1800 linear accelerator, a Co-60 photon beam from a Theratron 780 unit, and monoenergetic photon beams ranging from 2 MeV to 10 MeV. The results of the validation of the simulated photon beams show that the average difference between MC results and reference data is negligible, within 0.3%. MC simulated results of the effect of the build-up caps on the MOSFET response are in good agreement with experimental measurements, within the uncertainties. In particular, for the 18 MV photon beam the response of the detectors under a tungsten cap is 48% higher than for a 2 cm Plastic water cap and approximately 26% higher when a brass cap is used. This effect is demonstrated to be caused by positron production in the build-up caps of higher atomic number. This work also shows that the MOSFET detectors produce a higher signal when their rounded side is facing the beam (up to 6%) and that there is a significant variation (up to 50%) in the response of the MOSFET for photon energies in the studied energy range. All the results have shown that the PENELOPE code system can successfully

Characterization of high-sensitivity metal oxide semiconductor field effect transistor dosimeters system and LiF:Mg,Cu,P thermoluminescence dosimeters for use in diagnostic radiology

International Nuclear Information System (INIS)

Dong, S.L.; Chu, T.C.; Lan, G.Y.; Wu, T.H.; Lin, Y.C.; Lee, J.S.

2002-01-01

Monitoring radiation exposure during diagnostic radiographic procedures has recently become an area of interest. In recent years, the LiF:Mg,Cu,P thermoluminescence dosimeter (TLD-100H) and the highly sensitive metal oxide semiconductor field effect transistor (MOSFET) dosimeter were introduced as good candidates for entrance skin dose measurements in diagnostic radiology. In the present study, the TLD-100H and the MOSFET dosimeters were evaluated for sensitivity, linearity, energy, angular dependence, and post-exposure response. Our results indicate that the TLD-100H dosimeter has excellent linearity within diagnostic energy ranges and its sensitivity variations were under 3% at tube potentials from 40 Vp to 125 kVp. Good linearity was also observed with the MOSFET dosimeter, but in low-dose regions the values are less reliable and were found to be a function of the tube potentials. Both dosimeters also presented predictable angular dependence in this study. Our findings suggest that the TLD-100H dosimeter is more appropriate for low-dose diagnostic procedures such as chest and skull projections. The MOSFET dosimeter system is valuable for entrance skin dose measurement with lumbar spine projections and certain fluoroscopic procedures

Experience of using MOSFET detectors for dose verification measurements in an end-to-end 192Ir brachytherapy quality assurance system.

Science.gov (United States)

Persson, Maria; Nilsson, Josef; Carlsson Tedgren, Åsa

Establishment of an end-to-end system for the brachytherapy (BT) dosimetric chain could be valuable in clinical quality assurance. Here, the development of such a system using MOSFET (metal oxide semiconductor field effect transistor) detectors and experience gained during 2 years of use are reported with focus on the performance of the MOSFET detectors. A bolus phantom was constructed with two implants, mimicking prostate and head & neck treatments, using steel needles and plastic catheters to guide the 192 Ir source and house the MOSFET detectors. The phantom was taken through the BT treatment chain from image acquisition to dose evaluation. During the 2-year evaluation-period, delivered doses were verified a total of 56 times using MOSFET detectors which had been calibrated in an external 60 Co beam. An initial experimental investigation on beam quality differences between 192 Ir and 60 Co is reported. The standard deviation in repeated MOSFET measurements was below 3% in the six measurement points with dose levels above 2 Gy. MOSFET measurements overestimated treatment planning system doses by 2-7%. Distance-dependent experimental beam quality correction factors derived in a phantom of similar size as that used for end-to-end tests applied on a time-resolved measurement improved the agreement. MOSFET detectors provide values stable over time and function well for use as detectors for end-to-end quality assurance purposes in 192 Ir BT. Beam quality correction factors should address not only distance from source but also phantom dimensions. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Numerical simulation of long-term radiation effects for MOSFETs

International Nuclear Information System (INIS)

Wei Yuan; Xie Honggang; Gong Ding; Zhu Jinhui; Niu Shengli; Huang Liuxing

2013-01-01

A coupled algorithm is introduced to simulate the long-term radiation effects of MOSFETs, which combines particle transport with semiconductor governing equations. The former is dealt with Monte-Carlo method, and the latter is solved by finite-volume method. The trapped charge in SiO 2 and the free charge in Si are both described by the drift-diffusion model, and the deposited energy by incident particles can be coupled with the continuous equations of charge, acting as a source item. The discrete form of governing equations is obtained using the finite-volume method, and the numerical solutions of these equations are the long-term radiation response result of MOSFETs. The threshold voltage shift and off-state leakage current of an irradiated MOSFET are simulated with the coupled algorithm respectively, showing a good accordance with results by other calculations. (authors)

Clinical application of a OneDose MOSFET for skin dose measurements during internal mammary chain irradiation with high dose rate brachytherapy in carcinoma of the breast.

Science.gov (United States)

Kinhikar, Rajesh A; Sharma, Pramod K; Tambe, Chandrashekhar M; Mahantshetty, Umesh M; Sarin, Rajiv; Deshpande, Deepak D; Shrivastava, Shyam K

2006-07-21

In our earlier study, we experimentally evaluated the characteristics of a newly designed metal oxide semiconductor field effect transistor (MOSFET) OneDose in-vivo dosimetry system for Ir-192 (380 keV) energy and the results were compared with thermoluminescent dosimeters (TLDs). We have now extended the same study to the clinical application of this MOSFET as an in-vivo dosimetry system. The MOSFET was used during high dose rate brachytherapy (HDRBT) of internal mammary chain (IMC) irradiation for a carcinoma of the breast. The aim of this study was to measure the skin dose during IMC irradiation with a MOSFET and a TLD and compare it with the calculated dose with a treatment planning system (TPS). The skin dose was measured for ten patients. All the patients' treatment was planned on a PLATO treatment planning system. TLD measurements were performed to compare the accuracy of the measured results from the MOSFET. The mean doses measured with the MOSFET and the TLD were identical (0.5392 Gy, 15.85% of the prescribed dose). The mean dose was overestimated by the TPS and was 0.5923 Gy (17.42% of the prescribed dose). The TPS overestimated the skin dose by 9% as verified by the MOSFET and TLD. The MOSFET provides adequate in-vivo dosimetry for HDRBT. Immediate readout after irradiation, small size, permanent storage of dose and ease of use make the MOSFET a viable alternative for TLDs.

Cross-point-type spin-transfer-torque magnetoresistive random access memory cell with multi-pillar vertical body channel MOSFET

Science.gov (United States)

Sasaki, Taro; Endoh, Tetsuo

2018-04-01

In this paper, from the viewpoint of cell size and sensing margin, the impact of a novel cross-point-type one transistor and one magnetic tunnel junction (1T–1MTJ) spin-transfer-torque magnetoresistive random access memory (STT-MRAM) cell with a multi-pillar vertical body channel (BC) MOSFET is shown for high density and wide sensing margin STT-MRAM, with a 10 ns writing period and 1.2 V V DD. For that purpose, all combinations of n/p-type MOSFETs and bottom/top-pin MTJs are compared, where the diameter of MTJ (D MTJ) is scaled down from 55 to 15 nm and the tunnel magnetoresistance (TMR) ratio is increased from 100 to 200%. The results show that, benefiting from the proposed STT-MRAM cell with no back bias effect, the MTJ with a high TMR ratio (200%) can be used in the design of smaller STT-MRAM cells (over 72.6% cell size reduction), which is a difficult task for conventional planar MOSFET based design.

Long-Term Reliability of a Hard-Switched Boost Power Processing Unit Utilizing SiC Power MOSFETs

Science.gov (United States)

Ikpe, Stanley A.; Lauenstein, Jean-Marie; Carr, Gregory A.; Hunter, Don; Ludwig, Lawrence L.; Wood, William; Iannello, Christopher J.; Del Castillo, Linda Y.; Fitzpatrick, Fred D.; Mojarradi, Mohammad M.;

Multi-frequency inversion-charge pumping for charge separation and mobility analysis in high-k/InGaAs metal-oxide-semiconductor field-effect transistors

Energy Technology Data Exchange (ETDEWEB)

Djara, V.; Cherkaoui, K.; Negara, M. A.; Hurley, P. K., E-mail: paul.hurley@tyndall.ie [Tyndall National Institute, University College Cork, Dyke Parade, Cork (Ireland)

2015-11-28

An alternative multi-frequency inversion-charge pumping (MFICP) technique was developed to directly separate the inversion charge density (N{sub inv}) from the trapped charge density in high-k/InGaAs metal-oxide-semiconductor field-effect transistors (MOSFETs). This approach relies on the fitting of the frequency response of border traps, obtained from inversion-charge pumping measurements performed over a wide range of frequencies at room temperature on a single MOSFET, using a modified charge trapping model. The obtained model yielded the capture time constant and density of border traps located at energy levels aligned with the InGaAs conduction band. Moreover, the combination of MFICP and pulsed I{sub d}-V{sub g} measurements enabled an accurate effective mobility vs N{sub inv} extraction and analysis. The data obtained using the MFICP approach are consistent with the most recent reports on high-k/InGaAs.

Silicon on ferroelectic insulator field effect transistor (SOF-FET) a new device for the next generation ultra low power circuits

Science.gov (United States)

Es-Sakhi, Azzedin D.

Field effect transistors (FETs) are the foundation for all electronic circuits and processors. These devices have progressed massively to touch its final steps in sub-nanometer level. Left and right proposals are coming to rescue this progress. Emerging nano-electronic devices (resonant tunneling devices, single-atom transistors, spin devices, Heterojunction Transistors rapid flux quantum devices, carbon nanotubes, and nanowire devices) took a vast share of current scientific research. Non-Si electronic materials like III-V heterostructure, ferroelectric, carbon nanotubes (CNTs), and other nanowire based designs are in developing stage to become the core technology of non-classical CMOS structures. FinFET present the current feasible commercial nanotechnology. The scalability and low power dissipation of this device allowed for an extension of silicon based devices. High short channel effect (SCE) immunity presents its major advantage. Multi-gate structure comes to light to improve the gate electrostatic over the channel. The new structure shows a higher performance that made it the first candidate to substitute the conventional MOSFET. The device also shows a future scalability to continue Moor's Law. Furthermore, the device is compatible with silicon fabrication process. Moreover, the ultra-low-power (ULP) design required a subthreshold slope lower than the thermionic-emission limit of 60mV/ decade (KT/q). This value was unbreakable by the new structure (SOI-FinFET). On the other hand most of the previews proposals show the ability to go beyond this limit. However, those pre-mentioned schemes have publicized a very complicated physics, design difficulties, and process non-compatibility. The objective of this research is to discuss various emerging nano-devices proposed for ultra-low-power designs and their possibilities to replace the silicon devices as the core technology in the future integrated circuit. This thesis proposes a novel design that exploits the

Charge deposition model for investigating SE-microdose effect in trench power MOSFETs

Science.gov (United States)

Xin, Wan; Weisong, Zhou; Daoguang, Liu; Hanliang, Bo; Jun, Xu

2015-05-01

It was demonstrated that heavy ions can induce large current—voltage (I-V) characteristics shift in commercial trench power MOSFETs, named single event microdose effect (SE-microdose effect). A model is presented to describe this effect. This model calculates the charge deposition by a single heavy ion hitting oxide and the subsequent charge transport under an electric field. Holes deposited at the SiO2/Si interface by a Xe ion are calculated by using this model. The calculated results were then used in Sentaurus TCAD software to simulate a trench power MOSFET's I-V curve shift after a Xe ion has hit it. The simulation results are consistent with the related experiment's data. In the end, several factors which affect the SE-microdose effect in trench power MOSFETs are investigated by using this model.

Impact of intrinsic parameter fluctuations on the performance of In0.75Ga0.25As implant free MOSFETs

International Nuclear Information System (INIS)

Seoane, N; Garcia-Loureiro, A; Aldegunde, M; Kalna, K; Asenov, A

2009-01-01

We investigate the level of statistical variability in implant free (IF) MOSFETs, which are one of the most promising candidates III–V channels implementation. We report results for the threshold voltage (V T ) fluctuations in aggressively scaled IF III–V MOSFETs induced by random discrete dopants in the δ-doping plane obtained using 3D drift–diffusion (D–D) device simulations. The D–D simulator is meticulously calibrated against results obtained from ensemble Monte Carlo device simulations. The simulated 30, 20 and 15 nm gate length In 0.75 Ga 0.25 As channel IF transistors exhibit threshold voltage standard deviations of 42, 58 and 61 mV, respectively, at a drain voltage of 0.1 V. At a drain voltage of 0.8 V, the threshold voltage standard deviations increase to 55, 71 and 81 mV, respectively. While the standard deviations of V T in the 30 and 20 nm IF MOSFETs are close to those observed in bulk Si MOSFETs with equivalent gate lengths, the threshold voltage standard deviation in the 15 nm gate length IF MOSFET is lower

Clinical application of a OneDose(TM) MOSFET for skin dose measurements during internal mammary chain irradiation with high dose rate brachytherapy in carcinoma of the breast

International Nuclear Information System (INIS)

Kinhikar, Rajesh A; Sharma, Pramod K; Tambe, Chandrashekhar M; Mahantshetty, Umesh M; Sarin, Rajiv; Deshpande, Deepak D; Shrivastava, Shyam K

2006-01-01

In our earlier study, we experimentally evaluated the characteristics of a newly designed metal oxide semiconductor field effect transistor (MOSFET) OneDose(TM) in-vivo dosimetry system for Ir-192 (380 keV) energy and the results were compared with thermoluminescent dosimeters (TLDs). We have now extended the same study to the clinical application of this MOSFET as an in-vivo dosimetry system. The MOSFET was used during high dose rate brachytherapy (HDRBT) of internal mammary chain (IMC) irradiation for a carcinoma of the breast. The aim of this study was to measure the skin dose during IMC irradiation with a MOSFET and a TLD and compare it with the calculated dose with a treatment planning system (TPS). The skin dose was measured for ten patients. All the patients' treatment was planned on a PLATO treatment planning system. TLD measurements were performed to compare the accuracy of the measured results from the MOSFET. The mean doses measured with the MOSFET and the TLD were identical (0.5392 Gy, 15.85% of the prescribed dose). The mean dose was overestimated by the TPS and was 0.5923 Gy (17.42% of the prescribed dose). The TPS overestimated the skin dose by 9% as verified by the MOSFET and TLD. The MOSFET provides adequate in-vivo dosimetry for HDRBT. Immediate readout after irradiation, small size, permanent storage of dose and ease of use make the MOSFET a viable alternative for TLDs. (note)

Evaluation of linear array MOSFET detectors for in vivo dosimetry to measure rectal dose in HDR brachytherapy.

Science.gov (United States)

Haughey, Aisling; Coalter, George; Mugabe, Koki

2011-09-01

The study aimed to assess the suitability of linear array metal oxide semiconductor field effect transistor detectors (MOSFETs) as in vivo dosimeters to measure rectal dose in high dose rate brachytherapy treatments. The MOSFET arrays were calibrated with an Ir192 source and phantom measurements were performed to check agreement with the treatment planning system. The angular dependence, linearity and constancy of the detectors were evaluated. For in vivo measurements two sites were investigated, transperineal needle implants for prostate cancer and Fletcher suites for cervical cancer. The MOSFETs were inserted into the patients' rectum in theatre inside a modified flatus tube. The patients were then CT scanned for treatment planning. Measured rectal doses during treatment were compared with point dose measurements predicted by the TPS. The MOSFETs were found to require individual calibration factors. The calibration was found to drift by approximately 1% ±0.8 per 500 mV accumulated and varies with distance from source due to energy dependence. In vivo results for prostate patients found only 33% of measured doses agreed with the TPS within ±10%. For cervix cases 42% of measured doses agreed with the TPS within ±10%, however of those not agreeing variations of up to 70% were observed. One of the most limiting factors in this study was found to be the inability to prevent the MOSFET moving internally between the time of CT and treatment. Due to the many uncertainties associated with MOSFETs including calibration drift, angular dependence and the inability to know their exact position at the time of treatment, we consider them to be unsuitable for in vivo dosimetry in rectum for HDR brachytherapy.

Evaluation of linear array MOSFET detectors for in vivo dosimetry to measure rectal dose in DHR brachytherapy

International Nuclear Information System (INIS)

Haughey, A.; Coalter, G.; Mugabe, K.

2011-01-01

Full text: The study aimed to assess the suitability of linear array metal oxide semiconductor field effect transistor detectors (MOSFETs) as in vivo dosimeters to measure rectal dose in high dose rate brachytherapy treatments. The MOSFET arrays were calibrated with an Ir192 source and phantom measurements were performed to check agreement with the treatment planning system. The angular dependence, linearity and constancy of the detectors were evaluated. For in vivo measurements two sites were investigated, transperineal needle implants for prostate cancer and Fletcher suites for cervical cancer. The MOSFETs were inserted into the patients' rectum in theatre inside a modified flatus tube. The patients were then CT scanned for treatment planning. Measured rectal doses during treatment were compared with point dose measurements predicted by the TPS. The MOSFETs were found to require individual calibration factors. The calibration was found to drift by approximately 1% ±0.8 per 500 mV accumulated and varies with distance from source due to energy dependence. In vivo results for prostate patients found only 33% of measured doses agreed with the TPS within ±1O%. For cervix cases 42% of measured doses agreed with the TPS within ± 10%, however of those not agreeing variations of up to 70% were observed. One of the most limiting factors in this study was found to be the inability to prevent the MOSFET moving internally between the time of CT and treatment. Due to the many uncertainties associated with MOSFETs including calibration drift, angular dependence and the inability to know their exact position at the time of treatment, we consider them to be unsuitable for in vivo dosimetry in rectum for HDR brachytherapy. (author)

Generation of uniaxial tensile strain of over 1% on a Ge substrate for short-channel strained Ge n-type Metal–Insulator–Semiconductor Field-Effect Transistors with SiGe stressors

International Nuclear Information System (INIS)

Moriyama, Yoshihiko; Kamimuta, Yuuichi; Ikeda, Keiji; Tezuka, Tsutomu

2012-01-01

Tensile strain of over 1% in Ge stripes sandwiched between a pair of SiGe source-drain stressors was demonstrated. The Metal–Oxide–Semiconductor Field-Effect Transistor (MOSFET)-like structures were fabricated on a (001)-Ge substrate having SiO 2 dummy-gate stripes with widths down to 26 nm. Recess-regions adjacent to the dummy-gate stripes were formed by an anisotropic wet etching technique. A damage-free and well-controlled anisotropic wet etching process is developed in order to avoid plasma-induced damage during a conventional Reactive-ion Etching process. The SiGe stressors were epitaxially grown on the recesses to simulate strained Ge n-channel Metal–Insulator–Semiconductor Field-Effect Transistors (MISFETs) having high electron mobility. A micro-Raman spectroscopy measurement revealed tensile strain in the narrow Ge regions which became higher for narrower regions. Tensile strain of up to 1.2% was evaluated from the measurement under an assumption of uniaxial strain configuration. These results strongly suggest that higher electron mobility than the upper limit for a Si-MOSFET is obtainable in short-channel strained Ge-nMISFETs with the embedded SiGe stressors.

Reduction in the interface-states density of metal-oxide-semiconductor field-effect transistors fabricated on high-index Si (114) surfaces by using an external magnetic field

International Nuclear Information System (INIS)

Molina, J.; De La Hidalga, J.; Gutierrez, E.

2014-01-01

After fabrication of Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) devices on high-index silicon (114) surfaces, their threshold voltage (Vth) and interface-states density (Dit) characteristics were measured under the influence of an externally applied magnetic field of B = 6 μT at room temperature. The electron flow of the MOSFET's channel presents high anisotropy on Si (114), and this effect is enhanced by using an external magnetic field B, applied parallel to the Si (114) surface but perpendicular to the electron flow direction. This special configuration results in the channel electrons experiencing a Lorentzian force which pushes the electrons closer to the Si (114)-SiO 2 interface and therefore to the special morphology of the Si (114) surface. Interestingly, Dit evaluation of n-type MOSFETs fabricated on Si (114) surfaces shows that the Si (114)-SiO 2 interface is of high quality so that Dit as low as ∼10 10  cm −2 ·eV −1 are obtained for MOSFETs with channels aligned at specific orientations. Additionally, using both a small positive Vds ≤ 100 mV and B = 6 μT, the former Dit is reduced by 35% in MOSFETs whose channels are aligned parallel to row-like nanostructures formed atop Si (114) surfaces (channels having a 90° rotation), whereas Dit is increased by 25% in MOSFETs whose channels are aligned perpendicular to these nanostructures (channels having a 0° rotation). From these results, the special morphology of a high-index Si (114) plane having nanochannels on its surface opens the possibility to reduce the electron-trapping characteristics of MOSFET devices having deep-submicron features and operating at very high frequencies

Impact of oxide thickness on SEGR failure in vertical power MOSFETs: Development of a semi-empirical expression

International Nuclear Information System (INIS)

Titus, J.L.; Wheatley, C.F.; Burton, D.I.; Mouret, I.; Allenspach, M.; Brews, J.; Schrimpf, R.; Galloway, K.; Pease, R.L.

1995-01-01

This paper investigates the role that the gate oxide thickness (T ox ) plays on the gate and drain failure threshold voltages required to induce the onset of single-event gate rupture (SEGR). The impact of gate oxide thickness on SEGR is experimentally determined from vertical power metal-oxide semiconductor field-effect transistors (MOSFETs) having identical process and design parameters, except for the gate oxide thickness. Power MOSFETs from five variants were specially fabricated with nominal gate oxide thicknesses of 30, 50, 70, 100, and 150 nm. Devices from each variant were characterized to mono-energetic ion beams of Nickel, Bromine, Iodine, and Gold, Employing different bias conditions, failure thresholds for the onset of SEGR were determined for each oxide thickness. Applying these experimental test results, the previously published empirical expression is extended to include the effects of gate oxide thickness. In addition, observations of ion angle, temperature, cell geometry, channel conductivity, and curvature at high drain voltages are briefly discussed

Commissioning of a MOSFET in-vivo patient dose verification system

International Nuclear Information System (INIS)

Jenetsky, G.O.; Brown, R.L.

2004-01-01

Full text: TLD dosimetry has long been used for in-vivo measurements in estimating absorbed dose to critical structures on patients. Preparing TLDs for measurement, and then obtaining the results is a time consuming process taking many hours. The Thomson-Neilson 'MOSFET 20' (Metal Oxide Semiconducting Field Effect Transistor) dose assessment system, allows for in-vivo measurements (preparation and results) within minutes. Before being used clinically for dose verification, the MOSFETs were tested against the manufacturer's technical specifications, and compared with results from TLDs measured under controlled experiments and patient measurements. Standard sensitivity MOSFETs (TN-502RD) were used with the bias supply set to High sensitivity range. MOSFETs were tested for linearity (5-100cGy) and their calibration factors obtained for all energies (6MV, 18MV, 6MeV, 12MeV, 16MeV, 20MeV) using the method described by Ramani. MOSFETs and TLDs were exposed to a 6MV beam for 50MU at various depths (RW3 solid water phantom) and field sizes and compared to results taken with an ion chamber. Measurements using both systems were also taken at beam edge and 5mm and 10mm out of the field. Eleven patients, who had lens dose assessment requests were measured with both TLDs and MOSFETs and a paired t-test was performed on the results. On two patients, multiple (nine and four) MOSFET measurements were taken and the range of results compared to the range obtained from the TLDs. MOSFET linearity obtained co-efficients of R 2 ≥ 0.996 for all energies, this compared to R 2 ≥ 0.996 recorded by both Ramani and Chaung. The y-intercept values varied from 0 to -2.0mV. Greatest variation between calibration factors, measured for each energy, was 7.5%, this is substantially greater than 3.8% quoted by the manufacturer. For the measurements taken at varying depths and field sizes both TLDs and MOSFETs agreed with the ion chamber results ±IcGy. Measurements taken at beam edge varied ±6c

An Overview of High-k Oxides on Hydrogenated-Diamond for Metal-Oxide-Semiconductor Capacitors and Field-Effect Transistors

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Jiangwei Liu

2018-06-01

Full Text Available Thanks to its excellent intrinsic properties, diamond is promising for applications of high-power electronic devices, ultraviolet detectors, biosensors, high-temperature tolerant gas sensors, etc. Here, an overview of high-k oxides on hydrogenated-diamond (H-diamond for metal-oxide-semiconductor (MOS capacitors and MOS field-effect transistors (MOSFETs is demonstrated. Fabrication routines for the H-diamond MOS capacitors and MOSFETs, band configurations of oxide/H-diamond heterointerfaces, and electrical properties of the MOS and MOSFETs are summarized and discussed. High-k oxide insulators are deposited using atomic layer deposition (ALD and sputtering deposition (SD techniques. Electrical properties of the H-diamond MOS capacitors with high-k oxides of ALD-Al2O3, ALD-HfO2, ALD-HfO2/ALD-Al2O3 multilayer, SD-HfO2/ALD-HfO2 bilayer, SD-TiO2/ALD-Al2O3 bilayer, and ALD-TiO2/ALD-Al2O3 bilayer are discussed. Analyses for capacitance-voltage characteristics of them show that there are low fixed and trapped charge densities for the ALD-Al2O3/H-diamond and SD-HfO2/ALD-HfO2/H-diamond MOS capacitors. The k value of 27.2 for the ALD-TiO2/ALD-Al2O3 bilayer is larger than those of the other oxide insulators. Drain-source current versus voltage curves show distinct pitch-off and p-type channel characteristics for the ALD-Al2O3/H-diamond, SD-HfO2/ALD-HfO2/H-diamond, and ALD-TiO2/ALD-Al2O3/H-diamond MOSFETs. Understanding of fabrication routines and electrical properties for the high-k oxide/H-diamond MOS electronic devices is meaningful for the fabrication of high-performance H-diamond MOS capacitor and MOSFET gas sensors.

Semi-classical noise investigation for sub-40nm metal-oxide-semiconductor field-effect transistors

International Nuclear Information System (INIS)

Spathis, C.; Birbas, A.; Georgakopoulou, K.

2015-01-01

Device white noise levels in short channel Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) dictate the performance and reliability of high-frequency circuits ranging from high-speed microprocessors to Low-Noise Amplifiers (LNAs) and microwave circuits. Recent experimental noise measurements with very short devices demonstrate the existence of suppressed shot noise, contrary to the predictions of classical channel thermal noise models. In this work we show that, as the dimensions continue to shrink, shot noise has to be considered when the channel resistance becomes comparable to the barrier resistance at the source-channel junction. By adopting a semi-classical approach and taking retrospectively into account transport, short-channel and quantum effects, we investigate the partitioning between shot and thermal noise, and formulate a predictive model that describes the noise characteristics of modern devices

Semi-classical noise investigation for sub-40nm metal-oxide-semiconductor field-effect transistors

Energy Technology Data Exchange (ETDEWEB)

Spathis, C., E-mail: cspathis@ece.upatras.gr; Birbas, A.; Georgakopoulou, K. [Department of Electrical and Computer Engineering, University of Patras, Patras 26500 (Greece)

2015-08-15

Device white noise levels in short channel Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) dictate the performance and reliability of high-frequency circuits ranging from high-speed microprocessors to Low-Noise Amplifiers (LNAs) and microwave circuits. Recent experimental noise measurements with very short devices demonstrate the existence of suppressed shot noise, contrary to the predictions of classical channel thermal noise models. In this work we show that, as the dimensions continue to shrink, shot noise has to be considered when the channel resistance becomes comparable to the barrier resistance at the source-channel junction. By adopting a semi-classical approach and taking retrospectively into account transport, short-channel and quantum effects, we investigate the partitioning between shot and thermal noise, and formulate a predictive model that describes the noise characteristics of modern devices.

Charge deposition model for investigating SE-microdose effect in trench power MOSFETs

International Nuclear Information System (INIS)

Wan Xin; Zhou Weisong; Liu Daoguang; Bo Hanliang; Xu Jun

2015-01-01

It was demonstrated that heavy ions can induce large current—voltage (I–V) characteristics shift in commercial trench power MOSFETs, named single event microdose effect (SE-microdose effect). A model is presented to describe this effect. This model calculates the charge deposition by a single heavy ion hitting oxide and the subsequent charge transport under an electric field. Holes deposited at the SiO 2 /Si interface by a Xe ion are calculated by using this model. The calculated results were then used in Sentaurus TCAD software to simulate a trench power MOSFET's I–V curve shift after a Xe ion has hit it. The simulation results are consistent with the related experiment's data. In the end, several factors which affect the SE-microdose effect in trench power MOSFETs are investigated by using this model. (paper)

MOSFET dosimetry on modern radiation oncology modalities

International Nuclear Information System (INIS)

Rosenfeld, A.B.

2002-01-01

The development of MOSFET dosimetry is presented with an emphasis on the development of a scanning MOSFET dosimetry system for modern radiation oncology modalities. Fundamental aspects of MOSFETs in relation to their use as dosemeters are briefly discussed. The performance of MOSFET dosemeters in conformal radiotherapy, hadron therapy, intensity-modulated radiotherapy and microbeam radiation therapy is compared with other dosimetric techniques. In particular the application of MOSFET dosemeters in the characterisation and quality assurance of the steep dose gradients associated with the penumbra of some modern radiation oncology modalities is investigated. A new in vivo, on-line, scanning MOSFET read out system is also presented. The system has the ability to read out multiple MOSFET dosemeters with excellent spatial resolution and temperature stability and minimal slow border trapping effects. (author)

Extra source implantation for suppression floating-body effect in partially depleted SOI MOSFETs

International Nuclear Information System (INIS)

Chen Jing; Luo Jiexin; Wu Qingqing; Chai Zhan; Huang Xiaolu; Wei Xing; Wang Xi

2012-01-01

Silicon-on-insulate (SOI) MOSFETs offer benefits over bulk competitors for fully isolation and smaller junction capacitance. The performance of partially depleted (PD) SOI MOSFETs, though, is not good enough. Since the body is floating, the extra holes (for nMOSFETs) in this region accumulate, causing body potential arise, which of course degrades the performance of the device. How to suppress the floating-body effect becomes critical. There are mainly two ways for the goal. One is to employ body-contact structures, and the other SiGe source/drain structures. However, the former consumes extra area, not welcomed in the state-of-the-art chips design. The latter is not compatible with the traditional CMOS technology. Finding a structure both saving area and compatible technology is the most urgent for PD SOI MOSFETs. Recently, we have developed a new structure with extra heavy boron implantation in the source region for PD SOI nMOSFETs. It consumes no extra area and is also compatible with CMOS technology. The device is found to be free of kink effect in simulation, which implies the floating-body effect is greatly suppressed. In addition, the mechanisms of the kink-free, as well as the impact of different implanting conditions are interpreted.

Signal Processing for Wireless Communication MIMO System with Nano- Scaled CSDG MOSFET based DP4T RF Switch.

Science.gov (United States)

Srivastava, Viranjay M

2015-01-01

In the present technological expansion, the radio frequency integrated circuits in the wireless communication technologies became useful because of the replacement of increasing number of functions, traditional hardware components by modern digital signal processing. The carrier frequencies used for communication systems, now a day, shifted toward the microwave regime. The signal processing for the multiple inputs multiple output wireless communication system using the Metal- Oxide-Semiconductor Field-Effect-Transistor (MOSFET) has been done a lot. In this research the signal processing with help of nano-scaled Cylindrical Surrounding Double Gate (CSDG) MOSFET by means of Double- Pole Four-Throw Radio-Frequency (DP4T RF) switch, in terms of Insertion loss, Isolation, Reverse isolation and Inter modulation have been analyzed. In addition to this a channel model has been presented. Here, we also discussed some patents relevant to the topic.

Investigation of Short Channel Effect on Vertical Structures in Nanoscale MOSFET

Directory of Open Access Journals (Sweden)

Munawar A. Riyadi

2009-12-01

Full Text Available The recent development of MOSFET demands innovative approach to maintain the scaling into nanoscale dimension. This paper focuses on the physical nature of vertical MOSFET in nanoscale regime. Vertical structure is one of the promising devices in further scaling, with relaxed-lithography feature in the manufacture. The comparison of vertical and lateral MOSFET performance for nanoscale channel length (Lch is demonstrated with the help of numerical tools. The evaluation of short channel effect (SCE parameters, i.e. threshold voltage roll-off, subthreshold swing (SS, drain induced barrier lowering (DIBL and leakage current shows the considerable advantages as well as its thread-off in implementing the structure, in particular for nanoscale regime.

Interface Engineering and Gate Dielectric Engineering for High Performance Ge MOSFETs

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Jiabao Sun

2015-01-01

Full Text Available In recent years, germanium has attracted intensive interests for its promising applications in the microelectronics industry. However, to achieve high performance Ge channel devices, several critical issues still have to be addressed. Amongst them, a high quality gate stack, that is, a low defect interface layer and a dielectric layer, is of crucial importance. In this work, we first review the existing methods of interface engineering and gate dielectric engineering and then in more detail we discuss and compare three promising approaches (i.e., plasma postoxidation, high pressure oxidation, and ozone postoxidation. It has been confirmed that these approaches all can significantly improve the overall performance of the metal-oxide-semiconductor field effect transistor (MOSFET device.

In vivo dosimetry in radio-surgery using MOSFET and micro MOSFET

International Nuclear Information System (INIS)

Sors, Aurelie

2010-01-01

The author reports a study which aimed at assessing MOSFETs and micro-MOSFETs as in vivo surface dosimeters in 6 MV radio-surgery fixed beams for minimum field sizes of 6 x 6 square millimetres. The developed calibration method is adapted to small beams and MOSFET technology. It allows a reduced number of measurements to perform calibration. Moreover, a new equivalent square formula increases the accuracy of the determination of the actual dose delivered in small beams. Obtained results show that MOSFETs and micro-MOSFETs can be used as in vivo dosimeters when located at the surface

Lg = 100 nm In0.7Ga0.3As quantum well metal-oxide semiconductor field-effect transistors with atomic layer deposited beryllium oxide as interfacial layer

International Nuclear Information System (INIS)

Koh, D.; Kwon, H. M.; Kim, T.-W.; Veksler, D.; Gilmer, D.; Kirsch, P. D.; Kim, D.-H.; Hudnall, Todd W.; Bielawski, Christopher W.; Maszara, W.; Banerjee, S. K.

2014-01-01

In this study, we have fabricated nanometer-scale channel length quantum-well (QW) metal-oxide-semiconductor field effect transistors (MOSFETs) incorporating beryllium oxide (BeO) as an interfacial layer. BeO has high thermal stability, excellent electrical insulating characteristics, and a large band-gap, which make it an attractive candidate for use as a gate dielectric in making MOSFETs. BeO can also act as a good diffusion barrier to oxygen owing to its small atomic bonding length. In this work, we have fabricated In 0.53 Ga 0.47 As MOS capacitors with BeO and Al 2 O 3 and compared their electrical characteristics. As interface passivation layer, BeO/HfO 2 bilayer gate stack presented effective oxide thickness less 1 nm. Furthermore, we have demonstrated In 0.7 Ga 0.3 As QW MOSFETs with a BeO/HfO 2 dielectric, showing a sub-threshold slope of 100 mV/dec, and a transconductance (g m,max ) of 1.1 mS/μm, while displaying low values of gate leakage current. These results highlight the potential of atomic layer deposited BeO for use as a gate dielectric or interface passivation layer for III–V MOSFETs at the 7 nm technology node and/or beyond

Establishing a standard calibration methodology for MOSFET detectors in computed tomography dosimetry

International Nuclear Information System (INIS)

Brady, S. L.; Kaufman, R. A.

2012-01-01

Purpose: The use of metal-oxide-semiconductor field-effect transistor (MOSFET) detectors for patient dosimetry has increased by ∼25% since 2005. Despite this increase, no standard calibration methodology has been identified nor calibration uncertainty quantified for the use of MOSFET dosimetry in CT. This work compares three MOSFET calibration methodologies proposed in the literature, and additionally investigates questions relating to optimal time for signal equilibration and exposure levels for maximum calibration precision. Methods: The calibration methodologies tested were (1) free in-air (FIA) with radiographic x-ray tube, (2) FIA with stationary CT x-ray tube, and (3) within scatter phantom with rotational CT x-ray tube. Each calibration was performed at absorbed dose levels of 10, 23, and 35 mGy. Times of 0 min or 5 min were investigated for signal equilibration before or after signal read out. Results: Calibration precision was measured to be better than 5%–7%, 3%–5%, and 2%–4% for the 10, 23, and 35 mGy respective dose levels, and independent of calibration methodology. No correlation was demonstrated for precision and signal equilibration time when allowing 5 min before or after signal read out. Differences in average calibration coefficients were demonstrated between the FIA with CT calibration methodology 26.7 ± 1.1 mV cGy −1 versus the CT scatter phantom 29.2 ± 1.0 mV cGy −1 and FIA with x-ray 29.9 ± 1.1 mV cGy −1 methodologies. A decrease in MOSFET sensitivity was seen at an average change in read out voltage of ∼3000 mV. Conclusions: The best measured calibration precision was obtained by exposing the MOSFET detectors to 23 mGy. No signal equilibration time is necessary to improve calibration precision. A significant difference between calibration outcomes was demonstrated for FIA with CT compared to the other two methodologies. If the FIA with a CT calibration methodology was used to create calibration coefficients for the

Establishing a standard calibration methodology for MOSFET detectors in computed tomography dosimetry.

Science.gov (United States)

Brady, S L; Kaufman, R A

2012-06-01

The use of metal-oxide-semiconductor field-effect transistor (MOSFET) detectors for patient dosimetry has increased by ~25% since 2005. Despite this increase, no standard calibration methodology has been identified nor calibration uncertainty quantified for the use of MOSFET dosimetry in CT. This work compares three MOSFET calibration methodologies proposed in the literature, and additionally investigates questions relating to optimal time for signal equilibration and exposure levels for maximum calibration precision. The calibration methodologies tested were (1) free in-air (FIA) with radiographic x-ray tube, (2) FIA with stationary CT x-ray tube, and (3) within scatter phantom with rotational CT x-ray tube. Each calibration was performed at absorbed dose levels of 10, 23, and 35 mGy. Times of 0 min or 5 min were investigated for signal equilibration before or after signal read out. Calibration precision was measured to be better than 5%-7%, 3%-5%, and 2%-4% for the 10, 23, and 35 mGy respective dose levels, and independent of calibration methodology. No correlation was demonstrated for precision and signal equilibration time when allowing 5 min before or after signal read out. Differences in average calibration coefficients were demonstrated between the FIA with CT calibration methodology 26.7 ± 1.1 mV cGy(-1) versus the CT scatter phantom 29.2 ± 1.0 mV cGy(-1) and FIA with x-ray 29.9 ± 1.1 mV cGy(-1) methodologies. A decrease in MOSFET sensitivity was seen at an average change in read out voltage of ~3000 mV. The best measured calibration precision was obtained by exposing the MOSFET detectors to 23 mGy. No signal equilibration time is necessary to improve calibration precision. A significant difference between calibration outcomes was demonstrated for FIA with CT compared to the other two methodologies. If the FIA with a CT calibration methodology was used to create calibration coefficients for the eventual use for phantom dosimetry, a measurement error ~12

Retos Sobre el Modelado del Transistor de Compuerta Flotante de Múltiples Entradas en Circuitos Integrados

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Agustín Santiago Medina Vázquez

2012-11-01

Full Text Available En este artículo se presentan las consideraciones que hay que adoptar para el uso del transistor de compuerta flotante de múltiples entradas para el diseño de circuitos integrados analógicos. Para ello se presentan las principales características de este transistor así como sus principales ventajas con respecto al transistor MOSFET convencional que este dispositivo ofrece. También, se exponen los principales problemas que han frenado el uso de este dispositivo en el ámbito comercial debido a la falta de modelos precisos.

In vivo dosimetry using a linear Mosfet-array dosimeter to determine the urethra dose in 125I permanent prostate implants.

Science.gov (United States)

Bloemen-van Gurp, Esther J; Murrer, Lars H P; Haanstra, Björk K C; van Gils, Francis C J M; Dekker, Andre L A J; Mijnheer, Ben J; Lambin, Philippe

2009-01-01

In vivo dosimetry during brachytherapy of the prostate with (125)I seeds is challenging because of the high dose gradients and low photon energies involved. We present the results of a study using metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters to evaluate the dose in the urethra after a permanent prostate implantation procedure. Phantom measurements were made to validate the measurement technique, determine the measurement accuracy, and define action levels for clinical measurements. Patient measurements were performed with a MOSFET array in the urinary catheter immediately after the implantation procedure. A CT scan was performed, and dose values, calculated by the treatment planning system, were compared to in vivo dose values measured with MOSFET dosimeters. Corrections for temperature dependence of the MOSFET array response and photon attenuation in the catheter on the in vivo dose values are necessary. The overall uncertainty in the measurement procedure, determined in a simulation experiment, is 8.0% (1 SD). In vivo dose values were obtained for 17 patients. In the high-dose region (> 100 Gy), calculated and measured dose values agreed within 1.7% +/- 10.7% (1 SD). In the low-dose region outside the prostate (MOSFET detectors are suitable for in vivo dosimetry during (125)I brachytherapy of prostate cancer. An action level of +/- 16% (2 SD) for detection of errors in the implantation procedure is achievable after validation of the detector system and measurement conditions.

Quantum confinement effects and source-to-drain tunneling in ultra-scaled double-gate silicon n-MOSFETs

International Nuclear Information System (INIS)

Jiang Xiang-Wei; Li Shu-Shen

2012-01-01

By using the linear combination of bulk band (LCBB) method incorporated with the top of the barrier splitting (TBS) model, we present a comprehensive study on the quantum confinement effects and the source-to-drain tunneling in the ultra-scaled double-gate (DG) metal—oxide—semiconductor field-effect transistors (MOSFETs). A critical body thickness value of 5 nm is found, below which severe valley splittings among different X valleys for the occupied charge density and the current contributions occur in ultra-thin silicon body structures. It is also found that the tunneling current could be nearly 100% with an ultra-scaled channel length. Different from the previous simulation results, it is found that the source-to-drain tunneling could be effectively suppressed in the ultra-thin body thickness (2.0 nm and below) by the quantum confinement and the tunneling could be suppressed down to below 5% when the channel length approaches 16 nm regardless of the body thickness. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Monte Carlo simulation of MOSFET dosimeter for electron backscatter using the GEANT4 code.

Science.gov (United States)

Chow, James C L; Leung, Michael K K

2008-06-01

The aim of this study is to investigate the influence of the body of the metal-oxide-semiconductor field effect transistor (MOSFET) dosimeter in measuring the electron backscatter from lead. The electron backscatter factor (EBF), which is defined as the ratio of dose at the tissue-lead interface to the dose at the same point without the presence of backscatter, was calculated by the Monte Carlo simulation using the GEANT4 code. Electron beams with energies of 4, 6, 9, and 12 MeV were used in the simulation. It was found that in the presence of the MOSFET body, the EBFs were underestimated by about 2%-0.9% for electron beam energies of 4-12 MeV, respectively. The trend of the decrease of EBF with an increase of electron energy can be explained by the small MOSFET dosimeter, mainly made of epoxy and silicon, not only attenuated the electron fluence of the electron beam from upstream, but also the electron backscatter generated by the lead underneath the dosimeter. However, this variation of the EBF underestimation is within the same order of the statistical uncertainties as the Monte Carlo simulations, which ranged from 1.3% to 0.8% for the electron energies of 4-12 MeV, due to the small dosimetric volume. Such small EBF deviation is therefore insignificant when the uncertainty of the Monte Carlo simulation is taken into account. Corresponding measurements were carried out and uncertainties compared to Monte Carlo results were within +/- 2%. Spectra of energy deposited by the backscattered electrons in dosimetric volumes with and without the lead and MOSFET were determined by Monte Carlo simulations. It was found that in both cases, when the MOSFET body is either present or absent in the simulation, deviations of electron energy spectra with and without the lead decrease with an increase of the electron beam energy. Moreover, the softer spectrum of the backscattered electron when lead is present can result in a reduction of the MOSFET response due to stronger

A two-dimensional (2D) analytical subthreshold swing and transconductance model of underlap dual-material double-gate (DMDG) MOSFET for analog/RF applications

Science.gov (United States)

Narendar, Vadthiya; Rai, Saurabh; Tiwari, Siddharth; Mishra, R. A.

2016-12-01

The double-gate (DG) metal-oxide-semiconductor field effect transistors (MOSFETs) are the choice of technology in sub -100 nm regime of leading microelectronics industry. To enhance the analog and RF performance of DG MOSFET, an underlap dual-material (DM) DG MOSFET device structure has been considered because, it has the advantages of both underlap as well as that of dual-material gate (DMG). A 2D analytical surface potential, subthreshold current, subthreshold swing as well as transconductance modelling of underlap DMDG MOSFET has been done by solving the Poisson's equation. It has also been found that, numerically simulated data approves the analytically modelled data with commendable accuracy. As underlap length (Lun) increases, a substantial reduction of subthreshold current due to enhanced gate control over channel regime is observed. DMG structure facilitates to improve the average velocity of carriers which leads to superior drive current of the device. The underlap DMDG MOSFET device structure demonstrates an ameliorated subthreshold characteristic. The analog figure of merits (FOMs) such as transconductance (gm), transconductance generation factor (TGF), output conductance (gd), early voltage (VEA), intrinsic gain (AV) and RF FOMs namely cut-off frequency (fT), gain frequency product (GFP), transconductance frequency product (TFP) and gain transconductance frequency product (GTFP) have been evaluated. The aforesaid analysis revels that, the device is best suited for communication related Analog/RF applications.

Impact of back-gate bias on the hysteresis effect in partially depleted SOI MOSFETs

International Nuclear Information System (INIS)

Luo Jie-Xin; Chen Jing; Zhou Jian-Hua; Wu Qing-Qing; Chai Zhan; Yu Tao; Wang Xi

2012-01-01

The hysteresis effect in the output characteristics, originating from the floating body effect, has been measured in partially depleted (PD) silicon-on-insulator (SOI) MOSFETs at different back-gate biases. I D hysteresis has been developed to clarify the hysteresis characteristics. The fabricated devices show the positive and negative peaks in the I D hysteresis. The experimental results show that the I D hysteresis is sensitive to the back gate bias in 0.13-μm PD SOI MOSFETs and does not vary monotonously with the back-gate bias. Based on the steady-state Shockley-Read-Hall (SRH) recombination theory, we have successfully interpreted the impact of the back-gate bias on the hysteresis effect in PD SOI MOSFETs. (condensed matter: structural, mechanical, and thermal properties)

Effect of traps and defects on high temperature performance of Ge channel junctionless nanowire transistors

Directory of Open Access Journals (Sweden)

Chuanchuan Sun

2017-07-01

Full Text Available We investigate the effect of traps and defects on high temperature performance of p-type germanium-on-insulator (GOI based junctionless nanowire transistors (JNTs at temperatures ranging from 300 to 450 K. Temperature dependence of the main electrical parameters, such as drive current (Ion, leakage current (Ioff, threshold voltage (Vt, transconductance (Gm and subthreshold slope (SS are extracted and compared with the reported results of conventional inversion mode (IM MOSFETs and Si based JNTs. The results show that the high interface trap density (Dit and defects can degrade high temperature reliability of GOI based JNTs significantly, in terms of Ioff, Vt variation, Gm-max and SS values. The Ioff is much more dependent on temperature than Ion and mainly affected by trap-assisted-tunneling (TAT current. The Vt variation with temperature is larger than that for IM MOSFETs and SOI based JNTs, which can be mostly attributed to the high Dit. The high Dit can also induce high SS values. The maximum Gm has a weak dependence on temperature and is significantly influenced by neutral defects scattering. Limiting the Dit and neutral defect densities is critical for the reliability of GOI based JNTs working at high temperatures.

Analysis of gate underlap channel double gate MOS transistor for electrical detection of bio-molecules

Science.gov (United States)

Ajay; Narang, Rakhi; Saxena, Manoj; Gupta, Mridula

2015-12-01

In this paper, an analytical model for gate drain underlap channel Double-Gate Metal-Oxide-Semiconductor Field-Effect Transistor (DG-MOSFET) for label free electrical detection of biomolecules has been proposed. The conformal mapping technique has been used to derive the expressions for surface potential, lateral electric field, energy bands (i.e. conduction and valence band) and threshold voltage (Vth). Subsequently a full drain current model to analyze the sensitivity of the biosensor has been developed. The shift in the threshold voltage and drain current (after the biomolecules interaction with the gate underlap channel region of the MOS transistor) has been used as a sensing metric. All the characteristic trends have been verified through ATLAS (SILVACO) device simulation results.

Effects of silicon carbide MOSFETs on the efficiency and power quality of a microgrid-connected inverter

International Nuclear Information System (INIS)

Ding, Xiaofeng; Chen, Feida; Du, Min; Guo, Hong; Ren, Suping

2017-01-01

Highlights: •The characteristics comparison between SiC-inverter and Si-inverter is implemented, considering thermal effects. •The voltage distortion of inverters is modeling from the perspective of the behaviors of the device. •The efficiency of the microgrid-connected inverter has been greatly increased by replacing Si with SiC. •The SiC microgrid-connected inverter has smaller voltage distortion and less harmonic current than those of Si-inverter. •The proposed analytical model has been validated by the experimental test. -- Abstract: With the expanding power demands and increasing use of renewable energy resources, microgrids have been widely supported. Wide bandgap semiconductor devices with higher blocking voltage capabilities and higher switching speeds, such as silicon carbide (SiC) devices, will become a critical component in building microgrids. This paper describes a comprehensive investigation of the effects of SiC Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) on the efficiency and power quality of the inverters used in low voltage microgrids compared with conventional inverters based on silicon (Si) Insulated-gate Bipolar Transistors (IGBTs). First, the characteristics of both SiC and Si are measured by a double pulse test (DPT), considering thermal effects. Then, conduction and switching losses under different temperatures are calculated based on DPT results. Second, phase voltage distortions are modeled and calculated according to the tested switching and conduction characteristics of SiC, resulting in harmonic components in the phase current. Finally, an experiment is implemented. The experimental results show that the SiC-inverter greatly increases the energy efficiency and improves the power quality in the microgrid; these results are consistent with the analytical results.

Analysis of the background noise of field effect transistors in MOS complementary technology and application in the construction of a current-sensitive integrated amplifier

International Nuclear Information System (INIS)

Beuville, E.

1989-10-01

A low noise amplifier for use in high energy physics is developed. The origin and the mechanisms of the noise in MOSFET transistors is carried out with the aim of minimizing such effects in amplifiers. The research is applied in the construction of a current-sensitive integrated amplifier. The time scale continuous filtering principle is used and allows the detection of particles arriving in the counter in a random distribution. The rules which must be taken into account in the construction of an analog integrated circuit are shown [fr

Radiation resistance of wide-bandgap semiconductor power transistors

Energy Technology Data Exchange (ETDEWEB)

Hazdra, Pavel; Popelka, Stanislav [Department of Microelectronics, Czech Technical University in Prague (Czech Republic)

2017-04-15

Radiation resistance of state-of-the-art commercial wide-bandgap power transistors, 1700 V 4H-SiC power MOSFETs and 200 V GaN HEMTs, to the total ionization dose was investigated. Transistors were irradiated with 4.5 MeV electrons with doses up to 2000 kGy. Electrical characteristics and introduced defects were characterized by current-voltage (I-V), capacitance-voltage (C-V), and deep level transient spectroscopy (DLTS) measurements. Results show that already low doses of 4.5 MeV electrons (>1 kGy) cause a significant decrease in threshold voltage of SiC MOSFETs due to embedding of the positive charge into the gate oxide. On the other hand, other parameters like the ON-state resistance are nearly unchanged up to the dose of 20 kGy. At 200 kGy, the threshold voltage returns back close to its original value, however, the ON-state resistance increases and transconductance is lowered. This effect is caused by radiation defects introduced into the low-doped drift region which decrease electron concentration and mobility. GaN HEMTs exhibit significantly higher radiation resistance. They keep within the datasheet specification up to doses of 2000 kGy. Absence of dielectric layer beneath the gate and high concentration of carriers in the two dimensional electron gas channel are the reasons of higher radiation resistance of GaN HEMTs. Their degradation then occurs at much higher doses due to electron mobility degradation. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

MOSFET-based high voltage double square-wave pulse generator with an inductive adder configuration

Energy Technology Data Exchange (ETDEWEB)

Zhao, Xin [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang, Qiaogen, E-mail: hvzhang@mail.xjtu.edu.cn [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Long, Jinghua [College of Physics, Shenzhen University, Shenzhen 518060 (China); Lei, Yunfei; Liu, Jinyuan [Institute of Optoelectronics, Shenzhen University, Shenzhen 518060 (China)

2015-09-01

This paper presents a fast MOSFET-based solid-state pulse generator for high voltage double square-wave pulses. The generator consists mainly of an inductive adder system stacked of 20 solid-state modules. Each of the modules has 18 power MOSFETs in parallel, which are triggered by individual drive circuits; these drive circuits themselves are synchronously triggered by a signal from avalanche transistors. Our experiments demonstrate that the output pulses with amplitude of 8.1 kV and peak current of about 405 A are available at a load impedance of 20 Ω. The pulse has a double square-wave form with a rise and fall time of 40 ns and 26 ns, respectively and bottom flatness better than 12%. The interval time of the double square-wave pulses can be adjustable by varying the interval time of the trigger pulses.

Schottky barrier MOSFET systems and fabrication thereof

Science.gov (United States)

Welch, J.D.

1997-09-02

(MOS) device systems-utilizing Schottky barrier source and drain to channel region junctions are disclosed. Experimentally derived results which demonstrate operation of fabricated N-channel and P-channel Schottky barrier (MOSFET) devices, and of fabricated single devices with operational characteristics similar to (CMOS) and to a non-latching (SRC) are reported. Use of essentially non-rectifying Schottky barriers in (MOS) structures involving highly doped and the like and intrinsic semiconductor to allow non-rectifying interconnection of, and electrical accessing of device regions is also disclosed. Insulator effected low leakage current device geometries and fabrication procedures therefore are taught. Selective electrical interconnection of drain to drain, source to drain, or source to source, of N-channel and/or P-channel Schottky barrier (MOSFET) devices formed on P-type, N-type and Intrinsic semiconductor allows realization of Schottky Barrier (CMOS), (MOSFET) with (MOSFET) load, balanced differential (MOSFET) device systems and inverting and non-inverting single devices with operating characteristics similar to (CMOS), which devices can be utilized in modulation, as well as in voltage controlled switching and effecting a direction of rectification. 89 figs.

Near interface traps in SiO{sub 2}/4H-SiC metal-oxide-semiconductor field effect transistors monitored by temperature dependent gate current transient measurements

Energy Technology Data Exchange (ETDEWEB)

Fiorenza, Patrick; La Magna, Antonino; Vivona, Marilena; Roccaforte, Fabrizio [Consiglio Nazionale delle Ricerche-Istituto per la Microelettronica e Microsistemi (CNR-IMM), Strada VIII 5, Zona Industriale 95121 Catania (Italy)

2016-07-04

This letter reports on the impact of gate oxide trapping states on the conduction mechanisms in SiO{sub 2}/4H-SiC metal-oxide-semiconductor field effect transistors (MOSFETs). The phenomena were studied by gate current transient measurements, performed on n-channel MOSFETs operated in “gate-controlled-diode” configuration. The measurements revealed an anomalous non-steady conduction under negative bias (V{sub G} > |20 V|) through the SiO{sub 2}/4H-SiC interface. The phenomenon was explained by the coexistence of a electron variable range hopping and a hole Fowler-Nordheim (FN) tunnelling. A semi-empirical modified FN model with a time-depended electric field is used to estimate the near interface traps in the gate oxide (N{sub trap} ∼ 2 × 10{sup 11} cm{sup −2}).

COMPARATIVE ANALYSIS OF QUANTUM EFFECTS IN NANOSCALE MULTIGATE MOSFETS USING VARIATIONAL APPROACH

Directory of Open Access Journals (Sweden)

V. PALANICHAMY

2015-02-01

Full Text Available In this work, the performance of multiple-gate SOI MOSFETs is analysed using variational approach including quantum effects. An analytical model is derived to accounting the quantum effects at the silicon (Si/silicon dioxide (SiO2 interface. A general procedure is used for calculating the quantum inversion charge density. Using this inversion charge density, the drain current is obtained. Our model results are compared with the simulation results and its shows very good agreement. Our results highlighted that cylindrical surrounding gate MOSFET is a good candidate to obtain the high drain current compared with other two devices.

Characterization of MOSFET dosimeter angular dependence in three rotational axes measured free-in-air and in soft-tissue equivalent material.

Science.gov (United States)

Koivisto, Juha; Kiljunen, Timo; Wolff, Jan; Kortesniemi, Mika

2013-09-01

When performing dose measurements on an X-ray device with multiple angles of irradiation, it is necessary to take the angular dependence of metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters into account. The objective of this study was to investigate the angular sensitivity dependence of MOSFET dosimeters in three rotational axes measured free-in-air and in soft-tissue equivalent material using dental photon energy. Free-in-air dose measurements were performed with three MOSFET dosimeters attached to a carbon fibre holder. Soft tissue measurements were performed with three MOSFET dosimeters placed in a polymethylmethacrylate (PMMA) phantom. All measurements were made in the isocenter of a dental cone-beam computed tomography (CBCT) scanner using 5º angular increments in the three rotational axes: axial, normal-to-axial and tangent-to-axial. The measurements were referenced to a RADCAL 1015 dosimeter. The angular sensitivity free-in-air (1 SD) was 3.7 ± 0.5 mV/mGy for axial, 3.8 ± 0.6 mV/mGy for normal-to-axial and 3.6 ± 0.6 mV/mGy for tangent-to-axial rotation. The angular sensitivity in the PMMA phantom was 3.1 ± 0.1 mV/mGy for axial, 3.3 ± 0.2 mV/mGy for normal-to-axial and 3.4 ± 0.2 mV/mGy for tangent-to-axial rotation. The angular sensitivity variations are considerably smaller in PMMA due to the smoothing effect of the scattered radiation. The largest decreases from the isotropic response were observed free-in-air at 90° (distal tip) and 270° (wire base) in the normal-to-axial and tangent-to-axial rotations, respectively. MOSFET dosimeters provide us with a versatile dosimetric method for dental radiology. However, due to the observed variation in angular sensitivity, MOSFET dosimeters should always be calibrated in the actual clinical settings for the beam geometry and angular range of the CBCT exposure.

Characterization of MOSFET dosimeter angular dependence in three rotational axes measured free-in-air and in soft-tissue equivalent material

International Nuclear Information System (INIS)

Koivisto, Juha; Kiljunen, Timo; Wolff, Jan; Kortesniemi, Mika

2013-01-01

When performing dose measurements on an X-ray device with multiple angles of irradiation, it is necessary to take the angular dependence of metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters into account. The objective of this study was to investigate the angular sensitivity dependence of MOSFET dosimeters in three rotational axes measured free-in-air and in soft-tissue equivalent material using dental photon energy. Free-in-air dose measurements were performed with three MOSFET dosimeters attached to a carbon fibre holder. Soft tissue measurements were performed with three MOSFET dosimeters placed in a polymethylmethacrylate (PMMA) phantom. All measurements were made in the isocenter of a dental cone-beam computed tomography (CBCT) scanner using 5° angular increments in the three rotational axes: axial, normal-to-axial and tangent-to-axial. The measurements were referenced to a RADCAL 1015 dosimeter. The angular sensitivity free-in-air (1 SD) was 3.7 ± 0.5 mV/mGy for axial, 3.8 ± 0.6 mV/mGy for normal-to-axial and 3.6 ± 0.6 mV/mGy for tangent-to-axial rotation. The angular sensitivity in the PMMA phantom was 3.1 ± 0.1 mV/mGy for axial, 3.3 ± 0.2 mV/mGy for normal-to-axial and 3.4 ± 0.2 mV/mGy for tangent-to-axial rotation. The angular sensitivity variations are considerably smaller in PMMA due to the smoothing effect of the scattered radiation. The largest decreases from the isotropic response were observed free-in-air at 90° (distal tip) and 270° (wire base) in the normal-to-axial and tangent-to-axial rotations, respectively. MOSFET dosimeters provide us with a versatile dosimetric method for dental radiology. However, due to the observed variation in angular sensitivity, MOSFET dosimeters should always be calibrated in the actual clinical settings for the beam geometry and angular range of the CBCT exposure. (author)

Effect on the insulation material of a MOSFET device submitted to a standard diagnostic radiation beam

International Nuclear Information System (INIS)

De Magalhaes, C M S; Dos Santos, L A P; Souza, D do N; Maia, A F

2010-01-01

MOSFET electronic devices have been used for dosimetry in radiology and radiotherapy. Several communications show that due to the radiation exposure defects appear on the semiconductor crystal lattice. Actually, the structure of a MOSFET consists of three materials: a semiconductor, a metal and an insulator between them. The MOSFET is a quadripolar device with a common terminal: gate-source is the input; drain-source is the output. The gate controls the electrical current passing through semiconductor medium by the field effect because the silicon oxide acts as insulating material. The proposal of this work is to show some radiation effects on the insulator of a MOSFET device. A 6430 Keithley sub-femtoamp SourceMeter was used to verify how the insulating material layer in the structure of the device varies with the radiation exposure. We have used the IEC 61267 standard radiation X-ray beams generated from a Pantak industrial unit in the radiation energy range of computed tomography. This range was chosen because we are using the MOSFET device as radiation detector for dosimetry in computed tomography. The results showed that the behaviour of the electrical current of the device is different in the insulator and semiconductor structures.

Improvement of Mosfet Characteristics

OpenAIRE

Ranbir Singh

1990-01-01

By inclusion of a semi-dielectric layer, a novel MOSFET Structure, the T-MOSFET, and its integrated circuit version are presented. Both for the enhancement mode and the depletion mode, equivalent circuit models are developed. Also, the high frequency behaviour is explained by a model and the behaviour of a T-MOSFET under different conditions is given.

III-V Ultra-Thin-Body InGaAs/InAs MOSFETs for Low Standby Power Logic Applications

Science.gov (United States)

Huang, Cheng-Ying

As device scaling continues to sub-10-nm regime, III-V InGaAs/InAs metal- oxide-semiconductor ?eld-e?ect transistors (MOSFETs) are promising candidates for replacing Si-based MOSFETs for future very-large-scale integration (VLSI) logic applications. III-V InGaAs materials have low electron effective mass and high electron velocity, allowing higher on-state current at lower VDD and reducing the switching power consumption. However, III-V InGaAs materials have a narrower band gap and higher permittivity, leading to large band-to-band tunneling (BTBT) leakage or gate-induced drain leakage (GIDL) at the drain end of the channel, and large subthreshold leakage due to worse electrostatic integrity. To utilize III-V MOSFETs in future logic circuits, III-V MOSFETs must have high on-state performance over Si MOSFETs as well as very low leakage current and low standby power consumption. In this dissertation, we will report InGaAs/InAs ultra-thin-body MOSFETs. Three techniques for reducing the leakage currents in InGaAs/InAs MOSFETs are reported as described below. 1) Wide band-gap barriers: We developed AlAs0.44Sb0.56 barriers lattice-match to InP by molecular beam epitaxy (MBE), and studied the electron transport in In0.53Ga0.47As/AlAs 0.44Sb0.56 heterostructures. The InGaAs channel MOSFETs using AlAs0.44Sb0.56 bottom barriers or p-doped In0.52 Al0.48As barriers were demonstrated, showing significant suppression on the back barrier leakage. 2) Ultra-thin channels: We investigated the electron transport in InGaAs and InAs ultra-thin quantum wells and ultra-thin body MOSFETs (t ch ~ 2-4 nm). For high performance logic, InAs channels enable higher on-state current, while for low power logic, InGaAs channels allow lower BTBT leakage current. 3) Source/Drain engineering: We developed raised InGaAs and recessed InP source/drain spacers. The raised InGaAs source/drain spacers improve electrostatics, reducing subthreshold leakage, and smooth the electric field near drain, reducing

Silicon-Carbide Power MOSFET Performance in High Efficiency Boost Power Processing Unit for Extreme Environments

Science.gov (United States)

Ikpe, Stanley A.; Lauenstein, Jean-Marie; Carr, Gregory A.; Hunter, Don; Ludwig, Lawrence L.; Wood, William; Del Castillo, Linda Y.; Fitzpatrick, Fred; Chen, Yuan

2016-01-01

Silicon-Carbide device technology has generated much interest in recent years. With superior thermal performance, power ratings and potential switching frequencies over its Silicon counterpart, Silicon-Carbide offers a greater possibility for high powered switching applications in extreme environment. In particular, Silicon-Carbide Metal-Oxide- Semiconductor Field-Effect Transistors' (MOSFETs) maturing process technology has produced a plethora of commercially available power dense, low on-state resistance devices capable of switching at high frequencies. A novel hard-switched power processing unit (PPU) is implemented utilizing Silicon-Carbide power devices. Accelerated life data is captured and assessed in conjunction with a damage accumulation model of gate oxide and drain-source junction lifetime to evaluate potential system performance at high temperature environments.

Improved Gate Dielectric Deposition and Enhanced Electrical Stability for Single-Layer MoS2 MOSFET with an AlN Interfacial Layer.

Science.gov (United States)

Qian, Qingkai; Li, Baikui; Hua, Mengyuan; Zhang, Zhaofu; Lan, Feifei; Xu, Yongkuan; Yan, Ruyue; Chen, Kevin J

2016-06-09

Transistors based on MoS2 and other TMDs have been widely studied. The dangling-bond free surface of MoS2 has made the deposition of high-quality high-k dielectrics on MoS2 a challenge. The resulted transistors often suffer from the threshold voltage instability induced by the high density traps near MoS2/dielectric interface or inside the gate dielectric, which is detrimental for the practical applications of MoS2 metal-oxide-semiconductor field-effect transistor (MOSFET). In this work, by using AlN deposited by plasma enhanced atomic layer deposition (PEALD) as an interfacial layer, top-gate dielectrics as thin as 6 nm for single-layer MoS2 transistors are demonstrated. The AlN interfacial layer not only promotes the conformal deposition of high-quality Al2O3 on the dangling-bond free MoS2, but also greatly enhances the electrical stability of the MoS2 transistors. Very small hysteresis (ΔVth) is observed even at large gate biases and high temperatures. The transistor also exhibits a low level of flicker noise, which clearly originates from the Hooge mobility fluctuation instead of the carrier number fluctuation. The observed superior electrical stability of MoS2 transistor is attributed to the low border trap density of the AlN interfacial layer, as well as the small gate leakage and high dielectric strength of AlN/Al2O3 dielectric stack.

A Highly Responsive Silicon Nanowire/Amplifier MOSFET Hybrid Biosensor.

Science.gov (United States)

Lee, Jieun; Jang, Jaeman; Choi, Bongsik; Yoon, Jinsu; Kim, Jee-Yeon; Choi, Yang-Kyu; Kim, Dong Myong; Kim, Dae Hwan; Choi, Sung-Jin

2015-07-21

This study demonstrates a hybrid biosensor comprised of a silicon nanowire (SiNW) integrated with an amplifier MOSFET to improve the current response of field-effect-transistor (FET)-based biosensors. The hybrid biosensor is fabricated using conventional CMOS technology, which has the potential advantage of high density and low noise performance. The biosensor shows a current response of 5.74 decades per pH for pH detection, which is 2.5 × 10(5) times larger than that of a single SiNW sensor. In addition, we demonstrate charged polymer detection using the biosensor, with a high current change of 4.5 × 10(5) with a 500 nM concentration of poly(allylamine hydrochloride). In addition, we demonstrate a wide dynamic range can be obtained by adjusting the liquid gate voltage. We expect that this biosensor will be advantageous and practical for biosensor applications which requires lower noise, high speed, and high density.

Dosimetry investigation of MOSFET for clinical IMRT dose verification.

Science.gov (United States)

Deshpande, Sudesh; Kumar, Rajesh; Ghadi, Yogesh; Neharu, R M; Kannan, V

2013-06-01

In IMRT, patient-specific dose verification is followed regularly at each centre. Simple and efficient dosimetry techniques play a very important role in routine clinical dosimetry QA. The MOSFET dosimeter offers several advantages over the conventional dosimeters such as its small detector size, immediate readout, immediate reuse, multiple point dose measurements. To use the MOSFET as routine clinical dosimetry system for pre-treatment dose verification in IMRT, a comprehensive set of experiments has been conducted, to investigate its linearity, reproducibility, dose rate effect and angular dependence for 6 MV x-ray beam. The MOSFETs shows a linear response with linearity coefficient of 0.992 for a dose range of 35 cGy to 427 cGy. The reproducibility of the MOSFET was measured by irradiating the MOSFET for ten consecutive irradiations in the dose range of 35 cGy to 427 cGy. The measured reproducibility of MOSFET was found to be within 4% up to 70 cGy and within 1.4% above 70 cGy. The dose rate effect on the MOSFET was investigated in the dose rate range 100 MU/min to 600 MU/min. The response of the MOSFET varies from -1.7% to 2.1%. The angular responses of the MOSFETs were measured at 10 degrees intervals from 90 to 270 degrees in an anticlockwise direction and normalized at gantry angle zero and it was found to be in the range of 0.98 ± 0.014 to 1.01 ± 0.014. The MOSFETs were calibrated in a phantom which was later used for IMRT verification. The measured calibration coefficients were found to be 1 mV/cGy and 2.995 mV/cGy in standard and high sensitivity mode respectively. The MOSFETs were used for pre-treatment dose verification in IMRT. Nine dosimeters were used for each patient to measure the dose in different plane. The average variation between calculated and measured dose at any location was within 3%. Dose verification using MOSFET and IMRT phantom was found to quick and efficient and well suited for a busy radiotherapy

2D Quantum Mechanical Study of Nanoscale MOSFETs

Science.gov (United States)

Svizhenko, Alexei; Anantram, M. P.; Govindan, T. R.; Biegel, B.; Kwak, Dochan (Technical Monitor)

2000-01-01

With the onset of quantum confinement in the inversion layer in nanoscale MOSFETs, behavior of the resonant level inevitably determines all device characteristics. While most classical device simulators take quantization into account in some simplified manner, the important details of electrostatics are missing. Our work addresses this shortcoming and provides: (a) a framework to quantitatively explore device physics issues such as the source-drain and gate leakage currents, DIBL, and threshold voltage shift due to quantization, and b) a means of benchmarking quantum corrections to semiclassical models (such as density-gradient and quantum-corrected MEDICI). We have developed physical approximations and computer code capable of realistically simulating 2-D nanoscale transistors, using the non-equilibrium Green's function (NEGF) method. This is the most accurate full quantum model yet applied to 2-D device simulation. Open boundary conditions and oxide tunneling are treated on an equal footing. Electrons in the ellipsoids of the conduction band are treated within the anisotropic effective mass approximation. We present the results of our simulations of MIT 25, 50 and 90 nm "well-tempered" MOSFETs and compare them to those of classical and quantum corrected models. The important feature of quantum model is smaller slope of Id-Vg curve and consequently higher threshold voltage. Surprisingly, the self-consistent potential profile shows lower injection barrier in the channel in quantum case. These results are qualitatively consistent with ID Schroedinger-Poisson calculations. The effect of gate length on gate-oxide leakage and subthreshold current has been studied. The shorter gate length device has an order of magnitude smaller current at zero gate bias than the longer gate length device without a significant trade-off in on-current. This should be a device design consideration.

Gadolinium oxide coated fully depleted silicon-on-insulator transistors for thermal neutron dosimetry

Energy Technology Data Exchange (ETDEWEB)

Vitale, Steven A., E-mail: steven.vitale@ll.mit.edu; Gouker, Pascale M.

2013-09-01

Fully depleted silicon-on-insulator transistors coated with gadolinium oxide are shown to be effective thermal neutron dosimeters. The theoretical neutron detection efficiency is calculated to be higher for Gd{sub 2}O{sub 3} than for other practical converter materials. Proof-of-concept dosimeter devices were fabricated and tested during thermal neutron irradiation. The transistor current changes linearly with neutron dose, consistent with increasing positive charge in the SOI buried oxide layer generated by ionization from high energy {sup 157}Gd(n,γ){sup 158}Gd conversion electrons. The measured neutron sensitivity is approximately 1/6 the maximum theoretical value, possibly due to electron–hole recombination or conversion electron loss in interconnect wiring above the transistors. -- Highlights: • A novel Gd{sub 2}O{sub 3} coated FDSOI MOSFET thermal neutron dosimeter is presented. • Dosimeter can detect charges generated from {sup 157}Gd(n,γ){sup 158}Gd conversion electrons. • Measured neutron sensitivity is comparable to that calculated theoretically. • Dosimeter requires zero power during operation, enabling new application areas.

A New Nonlinear Model of Body Resistance in Nanometer PD SOI MOSFETs

Directory of Open Access Journals (Sweden)

Arash Daghighi

2011-01-01

Full Text Available In this paper, a nonlinear model for the body resistance of a 45nm PD SOI MOSFET is developed. This model verified on the base of the small signal three-dimensional simulation results. In this paper by using the three-dimensional simulation of ISE-TCAD software, the indicating factors of body resistance in nanometer transistors and then are shown, using the surface potential model. A mathematical relation to calculat the body resistance incorporating device width and body potential was derived. Excellent agreement was obtained by comparing the model outputs and three-dimensional simulation results.

Drain Current Modulation of a Single Drain MOSFET by Lorentz Force for Magnetic Sensing Application.

Science.gov (United States)

Chatterjee, Prasenjit; Chow, Hwang-Cherng; Feng, Wu-Shiung

2016-08-30

This paper reports a detailed analysis of the drain current modulation of a single-drain normal-gate n channel metal-oxide semiconductor field effect transistor (n-MOSFET) under an on-chip magnetic field. A single-drain n-MOSFET has been fabricated and placed in the center of a square-shaped metal loop which generates the on-chip magnetic field. The proposed device designed is much smaller in size with respect to the metal loop, which ensures that the generated magnetic field is approximately uniform. The change of drain current and change of bulk current per micron device width has been measured. The result shows that the difference drain current is about 145 µA for the maximum applied magnetic field. Such changes occur from the applied Lorentz force to push out the carriers from the channel. Based on the drain current difference, the change in effective mobility has been detected up to 4.227%. Furthermore, a detailed investigation reveals that the device behavior is quite different in subthreshold and saturation region. A change of 50.24 µA bulk current has also been measured. Finally, the device has been verified for use as a magnetic sensor with sensitivity 4.084% (29.6 T(-1)), which is very effective as compared to other previously reported works for a single device.

Microdose Induced Drain Leakage Effects in Power Trench MOSFETs: Experiment and Modeling

Science.gov (United States)

Zebrev, Gennady I.; Vatuev, Alexander S.; Useinov, Rustem G.; Emeliyanov, Vladimir V.; Anashin, Vasily S.; Gorbunov, Maxim S.; Turin, Valentin O.; Yesenkov, Kirill A.

2014-08-01

We study experimentally and theoretically the micro-dose induced drain-source leakage current in the trench power MOSFETs under irradiation with high-LET heavy ions. We found experimentally that cumulative increase of leakage current occurs by means of stochastic spikes corresponding to a strike of single heavy ion into the MOSFET gate oxide. We simulate this effect with the proposed analytic model allowing to describe (including Monte Carlo methods) both the deterministic (cumulative dose) and stochastic (single event) aspects of the problem. Based on this model the survival probability assessment in space heavy ion environment with high LETs was proposed.

Study of an Insulated Gate Bipolar Transistor (IGBT) and its connection in series. Application at a chopper 1500V-5A-10kHz

International Nuclear Information System (INIS)

Gros, P.

1993-01-01

In the frame of the tokamak ITER (International Thermonuclear Experimental Reactor) we have studied, for neutral particle injection, a converter with at least two static interrupters by Mosfet transistor, bipolar transistor or Insulated Gate Bipolar Transistor (IGBT). After a comparison between these three types of transistors, by the simulating software MICROCAP, a serial of tests has shown the advantages of the IGBT. A command, associated with two IGBT of equivalent characteristics, has given a simple and efficacious solution. The performances are: (1) between two blockages: 50 ns without overvoltage, (2) between two cut-off: 60 ns. 40 figs; 30 refs; 10 annexes

Carbon nanotube transistor based high-frequency electronics

Science.gov (United States)

Schroter, Michael

At the nanoscale carbon nanotubes (CNTs) have higher carrier mobility and carrier velocity than most incumbent semiconductors. Thus CNT based field-effect transistors (FETs) are being considered as strong candidates for replacing existing MOSFETs in digital applications. In addition, the predicted high intrinsic transit frequency and the more recent finding of ways to achieve highly linear transfer characteristics have inspired investigations on analog high-frequency (HF) applications. High linearity is extremely valuable for an energy efficient usage of the frequency spectrum, particularly in mobile communications. Compared to digital applications, the much more relaxed constraints for CNT placement and lithography combined with already achieved operating frequencies of at least 10 GHz for fabricated devices make an early entry in the low GHz HF market more feasible than in large-scale digital circuits. Such a market entry would be extremely beneficial for funding the development of production CNTFET based process technology. This talk will provide an overview on the present status and feasibility of HF CNTFET technology will be given from an engineering point of view, including device modeling, experimental results, and existing roadblocks. Carbon nanotube transistor based high-frequency electronics.

High performance germanium MOSFETs

International Nuclear Information System (INIS)

Saraswat, Krishna; Chui, Chi On; Krishnamohan, Tejas; Kim, Donghyun; Nayfeh, Ammar; Pethe, Abhijit

2006-01-01

Ge is a very promising material as future channel materials for nanoscale MOSFETs due to its high mobility and thus a higher source injection velocity, which translates into higher drive current and smaller gate delay. However, for Ge to become main-stream, surface passivation and heterogeneous integration of crystalline Ge layers on Si must be achieved. We have demonstrated growth of fully relaxed smooth single crystal Ge layers on Si using a novel multi-step growth and hydrogen anneal process without any graded buffer SiGe layer. Surface passivation of Ge has been achieved with its native oxynitride (GeO x N y ) and high-permittivity (high-k) metal oxides of Al, Zr and Hf. High mobility MOSFETs have been demonstrated in bulk Ge with high-k gate dielectrics and metal gates. However, due to their smaller bandgap and higher dielectric constant, most high mobility materials suffer from large band-to-band tunneling (BTBT) leakage currents and worse short channel effects. We present novel, Si and Ge based heterostructure MOSFETs, which can significantly reduce the BTBT leakage currents while retaining high channel mobility, making them suitable for scaling into the sub-15 nm regime. Through full band Monte-Carlo, Poisson-Schrodinger and detailed BTBT simulations we show a dramatic reduction in BTBT and excellent electrostatic control of the channel, while maintaining very high drive currents in these highly scaled heterostructure DGFETs. Heterostructure MOSFETs with varying strained-Ge or SiGe thickness, Si cap thickness and Ge percentage were fabricated on bulk Si and SOI substrates. The ultra-thin (∼2 nm) strained-Ge channel heterostructure MOSFETs exhibited >4x mobility enhancements over bulk Si devices and >10x BTBT reduction over surface channel strained SiGe devices

High performance germanium MOSFETs

Energy Technology Data Exchange (ETDEWEB)

Saraswat, Krishna [Department of Electrical Engineering, Stanford University, Stanford, CA 94305 (United States)]. E-mail: saraswat@stanford.edu; Chui, Chi On [Department of Electrical Engineering, Stanford University, Stanford, CA 94305 (United States); Krishnamohan, Tejas [Department of Electrical Engineering, Stanford University, Stanford, CA 94305 (United States); Kim, Donghyun [Department of Electrical Engineering, Stanford University, Stanford, CA 94305 (United States); Nayfeh, Ammar [Department of Electrical Engineering, Stanford University, Stanford, CA 94305 (United States); Pethe, Abhijit [Department of Electrical Engineering, Stanford University, Stanford, CA 94305 (United States)

2006-12-15

Ge is a very promising material as future channel materials for nanoscale MOSFETs due to its high mobility and thus a higher source injection velocity, which translates into higher drive current and smaller gate delay. However, for Ge to become main-stream, surface passivation and heterogeneous integration of crystalline Ge layers on Si must be achieved. We have demonstrated growth of fully relaxed smooth single crystal Ge layers on Si using a novel multi-step growth and hydrogen anneal process without any graded buffer SiGe layer. Surface passivation of Ge has been achieved with its native oxynitride (GeO {sub x}N {sub y} ) and high-permittivity (high-k) metal oxides of Al, Zr and Hf. High mobility MOSFETs have been demonstrated in bulk Ge with high-k gate dielectrics and metal gates. However, due to their smaller bandgap and higher dielectric constant, most high mobility materials suffer from large band-to-band tunneling (BTBT) leakage currents and worse short channel effects. We present novel, Si and Ge based heterostructure MOSFETs, which can significantly reduce the BTBT leakage currents while retaining high channel mobility, making them suitable for scaling into the sub-15 nm regime. Through full band Monte-Carlo, Poisson-Schrodinger and detailed BTBT simulations we show a dramatic reduction in BTBT and excellent electrostatic control of the channel, while maintaining very high drive currents in these highly scaled heterostructure DGFETs. Heterostructure MOSFETs with varying strained-Ge or SiGe thickness, Si cap thickness and Ge percentage were fabricated on bulk Si and SOI substrates. The ultra-thin ({approx}2 nm) strained-Ge channel heterostructure MOSFETs exhibited >4x mobility enhancements over bulk Si devices and >10x BTBT reduction over surface channel strained SiGe devices.

Extraction method of interfacial injected charges for SiC power MOSFETs

Science.gov (United States)

Wei, Jiaxing; Liu, Siyang; Li, Sheng; Song, Haiyang; Chen, Xin; Li, Ting; Fang, Jiong; Sun, Weifeng

2018-01-01

An improved novel extraction method which can characterize the injected charges along the gate oxide interface for silicon carbide (SiC) power metal-oxide-semiconductor field-effect transistors (MOSFETs) is proposed. According to the different interface situations of the channel region and the junction FET (JFET) region, the gate capacitance versus gate voltage (Cg-Vg) curve of the device can be divided into three relatively independent parts, through which the locations and the types of the charges injected in to the oxide above the interface can be distinguished. Moreover, the densities of these charges can also be calculated by the amplitudes of the shifts in the Cg-Vg curve. The correctness of this method is proved by TCAD simulations. Moreover, experiments on devices stressed by unclamped-inductive-switching (UIS) stress and negative bias temperature stress (NBTS) are performed to verify the validity of this method.

Simulation study of ballistic spin-MOSFET devices with ferromagnetic channels based on some Heusler and oxide compounds

Science.gov (United States)

Graziosi, Patrizio; Neophytou, Neophytos

2018-02-01

Newly emerged materials from the family of Heuslers and complex oxides exhibit finite bandgaps and ferromagnetic behavior with Curie temperatures much higher than even room temperature. In this work, using the semiclassical top-of-the-barrier FET model, we explore the operation of a spin-MOSFET that utilizes such ferromagnetic semiconductors as channel materials, in addition to ferromagnetic source/drain contacts. Such a device could retain the spin polarization of injected electrons in the channel, the loss of which limits the operation of traditional spin transistors with non-ferromagnetic channels. We examine the operation of four material systems that are currently considered some of the most prominent known ferromagnetic semiconductors: three Heusler-type alloys (Mn2CoAl, CrVZrAl, and CoVZrAl) and one from the oxide family (NiFe2O4). We describe their band structures by using data from DFT (Density Functional Theory) calculations. We investigate under which conditions high spin polarization and significant ION/IOFF ratio, two essential requirements for the spin-MOSFET operation, are both achieved. We show that these particular Heusler channels, in their bulk form, do not have adequate bandgap to provide high ION/IOFF ratios and have small magnetoconductance compared to state-of-the-art devices. However, with confinement into ultra-narrow sizes down to a few nanometers, and by engineering their spin dependent contact resistances, they could prove promising channel materials for the realization of spin-MOSFET transistor devices that offer combined logic and memory functionalities. Although the main compounds of interest in this paper are Mn2CoAl, CrVZrAl, CoVZrAl, and NiFe2O4 alone, we expect that the insight we provide is relevant to other classes of such materials as well.

Investigation of high mobility pseudomorphic SiGe p-channels in Si MOSFETS at low and high electric fields

International Nuclear Information System (INIS)

Palmer, Martin John

2001-01-01

Silicon Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs) for high speed, high current applications are rapidly approaching the physical and financial limits of the technology. This opens opportunities for the incorporation of materials with intrinsically better transport characteristics. An alloy of silicon and germanium is one such material that is gaining much recognition as the active component of MOSFETs and as the secondary structures (such as the gate electrode). This work examines a batch of buried channel Si 0.64 Ge 0.36 p-MOSFETs, with a minimum effective length of 0.35 μm, under different bias conditions and at different temperatures. High current and transconductance enhancements are apparent at long gate lengths. The carrier mobility is up to a factor of 2.5 times that of silicon at room temperature and 7.5 times at 4 K. A clear trend of decreasing peak mobility with decreasing silicon cap thickness is evident. Simulations show that scattering caused by the roughness of the SiO 2 /Si interface dominates, rather than alloy scattering or Si/SiGe roughness, even for a buried channel. This scattering increases with the proximity of the carriers to the interface. An increase of interface trap density with decreasing cap thickness, demonstrates that segregated germanium exists some distance into the cap and interferes with the oxidation process. This will increase scattering through increased SiO 2 /Si roughness and increased trapped charge. The short channel, high field results are comparable or slightly worse than those of silicon due to lower saturation drift velocity. However, fitting to a drift-diffusion model shows an apparent increase in saturation velocity for short channels, especially at low temperatures. This effect correlates with the low field mobility and is greater for devices containing SiGe. This is an indication of velocity overshoot, which may enhance the performance of SiGe MOSFETs at deep submicron gate lengths. (author)

Ge{sub 0.83}Sn{sub 0.17} p-channel metal-oxide-semiconductor field-effect transistors: Impact of sulfur passivation on gate stack quality

Energy Technology Data Exchange (ETDEWEB)

Lei, Dian; Wang, Wei; Gong, Xiao, E-mail: elegong@nus.edu.sg, E-mail: yeo@ieee.org; Liang, Gengchiau; Yeo, Yee-Chia, E-mail: elegong@nus.edu.sg, 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), 3 Research Link, Singapore 117602 (Singapore); Tok, Eng-Soon [Department of Physics, National University of Singapore, Singapore 117551 (Singapore)

2016-01-14

The effect of room temperature sulfur passivation of the surface of Ge{sub 0.83}Sn{sub 0.17} prior to high-k dielectric (HfO{sub 2}) deposition is investigated. X-ray photoelectron spectroscopy (XPS) was used to examine the chemical bonding at the interface of HfO{sub 2} and Ge{sub 0.83}Sn{sub 0.17}. Sulfur passivation is found to be effective in suppressing the formation of both Ge oxides and Sn oxides. A comparison of XPS results for sulfur-passivated and non-passivated Ge{sub 0.83}Sn{sub 0.17} samples shows that sulfur passivation of the GeSn surface could also suppress the surface segregation of Sn atoms. In addition, sulfur passivation reduces the interface trap density D{sub it} at the high-k dielectric/Ge{sub 0.83}Sn{sub 0.17} interface from the valence band edge to the midgap of Ge{sub 0.83}Sn{sub 0.17}, as compared with a non-passivated control. The impact of the improved D{sub it} is demonstrated in Ge{sub 0.83}Sn{sub 0.17} p-channel metal-oxide-semiconductor field-effect transistors (p-MOSFETs). Ge{sub 0.83}Sn{sub 0.17} p-MOSFETs with sulfur passivation show improved subthreshold swing S, intrinsic transconductance G{sub m,int}, and effective hole mobility μ{sub eff} as compared with the non-passivated control. At a high inversion carrier density N{sub inv} of 1 × 10{sup 13 }cm{sup −2}, sulfur passivation increases μ{sub eff} by 25% in Ge{sub 0.83}Sn{sub 0.17} p-MOSFETs.

Modeling of cylindrical surrounding gate MOSFETs including the fringing field effects

International Nuclear Information System (INIS)

Gupta, Santosh K.; Baishya, Srimanta

2013-01-01

A physically based analytical model for surface potential and threshold voltage including the fringing gate capacitances in cylindrical surround gate (CSG) MOSFETs has been developed. Based on this a subthreshold drain current model has also been derived. This model first computes the charge induced in the drain/source region due to the fringing capacitances and considers an effective charge distribution in the cylindrically extended source/drain region for the development of a simple and compact model. The fringing gate capacitances taken into account are outer fringe capacitance, inner fringe capacitance, overlap capacitance, and sidewall capacitance. The model has been verified with the data extracted from 3D TCAD simulations of CSG MOSFETs and was found to be working satisfactorily. (semiconductor devices)

Double gate graphene nanoribbon field effect transistor with single halo pocket in channel region

Science.gov (United States)

Naderi, Ali

2016-01-01

A new structure for graphene nanoribbon field-effect transistors (GNRFETs) is proposed and investigated using quantum simulation with a nonequilibrium Green's function (NEGF) method. Tunneling leakage current and ambipolar conduction are known effects for MOSFET-like GNRFETs. To minimize these issues a novel structure with a simple change of the GNRFETs by using single halo pocket in the intrinsic channel region, "Single Halo GNRFET (SH-GNRFET)", is proposed. An appropriate halo pocket at source side of channel is used to modify potential distribution of the gate region and weaken band to band tunneling (BTBT). In devices with materials like Si in channel region, doping type of halo and source/drain regions are different. But, here, due to the smaller bandgap of graphene, the mentioned doping types should be the same to reduce BTBT. Simulations have shown that in comparison with conventional GNRFET (C-GNRFET), an SH-GNRFET with appropriately halo doping results in a larger ON current (Ion), smaller OFF current (Ioff), a larger ON-OFF current ratio (Ion/Ioff), superior ambipolar characteristics, a reduced power-delay product and lower delay time.

On substrate dopant engineering for ET-SOI MOSFETs with UT-BOX

International Nuclear Information System (INIS)

Wu Hao; Xu Miao; Wan Guangxing; Zhu Huilong; Zhao Lichuan; Tong Xiaodong; Zhao Chao; Chen Dapeng; Ye Tianchun

2014-01-01

The importance of substrate doping engineering for extremely thin SOI MOSFETs with ultra-thin buried oxide (ES-UB-MOSFETs) is demonstrated by simulation. A new substrate/backgate doping engineering, lateral non-uniform dopant distributions (LNDD) is investigated in ES-UB-MOSFETs. The effects of LNDD on device performance, V t -roll-off, channel mobility and random dopant fluctuation (RDF) are studied and optimized. Fixing the long channel threshold voltage (V t ) at 0.3 V, ES-UB-MOSFETs with lateral uniform doping in the substrate and forward back bias can scale only to 35 nm, meanwhile LNDD enables ES-UB-MOSFETs to scale to a 20 nm gate length, which is 43% smaller. The LNDD degradation is 10% of the carrier mobility both for nMOS and pMOS, but it is canceled out by a good short channel effect controlled by the LNDD. Fixing V t at 0.3 V, in long channel devices, due to more channel doping concentration for the LNDD technique, the RDF in LNDD controlled ES-UB-MOSFETs is worse than in back-bias controlled ES-UB-MOSFETs, but in the short channel, the RDF for LNDD controlled ES-UB-MOSFET is better due to its self-adaption of substrate doping engineering by using a fixed thickness inner-spacer. A novel process flow to form LNDD is proposed and simulated. (semiconductor devices)

A novel double gate MOSFET by symmetrical insulator packets with improved short channel effects

Science.gov (United States)

Ramezani, Zeinab; Orouji, Ali A.

2018-03-01

In this article, we study a novel double-gate SOI MOSFET structure incorporating insulator packets (IPs) at the junction between channel and source/drain (S/D) ends. The proposed MOSFET has great strength in inhibiting short channel effects and OFF-state current that are the main problems compared with conventional one due to the significant suppressed penetrations of both the lateral electric field and the carrier diffusion from the S/D into the channel. Improvement of the hot electron reliability, the ON to OFF drain current ratio, drain-induced barrier lowering, gate-induced drain leakage and threshold voltage over conventional double-gate SOI MOSFETs, i.e. without IPs, is displayed with the simulation results. This study is believed to improve the CMOS device reliability and is suitable for the low-power very-large-scale integration circuits.

Optimization of Fluorine Plasma Treatment for Interface Improvement on HfO2/In0.53Ga0.47As MOSFETs

Directory of Open Access Journals (Sweden)

Yen-Ting Chen

2012-03-01

Full Text Available This paper reports significant improvements in the electrical performance of In0.53Ga0.47As metal-oxide-semiconductor field-effect transistors (MOSFET by a post-gate CF4/O2 plasma treatment. The optimum condition of CF4/O2 plasma treatment has been systematically studied and found to be 30 W for 3–5 min. Approximately 5× reduction in interface trap density from 2.8 × 1012 to 4.9 × 1011 cm−2eV−1 has been demonstrated with fluorine (F incorporation. Subthreshold swing has been improved from 127 to 109 mV/dec. Effective channel mobility has been enhanced from 826 to 1,144 cm2/Vs.

Behavior of MOSFET Amplifier in Radiation Fields

International Nuclear Information System (INIS)

Sharshar, K.A.A.; Ashry, M.

2000-01-01

MOSFET type 2 N 3823 characteristics and its application as an amplifier are analyzed including the effects of gamma, electron beam 1.5 MeV 25 m A and neutron flux. The 1-V characteristics, transfer curve, and the frequency response of the amplifier, and the amplification factor(A v 0 are discussed with MOSFET circuit parameters. The drain current and the amplitude of the output signal decrease as the absorbed dose increases. The measured values of the amplified signal are attenuated by 30% and 6% after exposing the MOSFET to gamma radiation and electron beam at the same dose respectively. Also for exposure to 4x10 13 N/cm 3 neutrons decreased the measured value of the amplified signal by 73% of the initial values. The decrease in the gain of the MOSFET is due to the degradation of the transconductance. It is also noticed that percentage of the decrease depends on the type of radiation

Operation of SOI P-Channel Field Effect Transistors, CHT-PMOS30, under Extreme Temperatures

Science.gov (United States)

Patterson, Richard; Hammoud, Ahmad

2009-01-01

Electronic systems are required to operate under extreme temperatures in NASA planetary exploration and deep space missions. Electronics on-board spacecraft must also tolerate thermal cycling between extreme temperatures. Thermal management means are usually included in today s spacecraft systems to provide adequate temperature for proper operation of the electronics. These measures, which may include heating elements, heat pipes, radiators, etc., however add to the complexity in the design of the system, increases its cost and weight, and affects its performance and reliability. Electronic parts and circuits capable of withstanding and operating under extreme temperatures would reflect in improvement in system s efficiency, reducing cost, and improving overall reliability. Semiconductor chips based on silicon-on-insulator (SOI) technology are designed mainly for high temperature applications and find extensive use in terrestrial well-logging fields. Their inherent design offers advantages over silicon devices in terms of reduced leakage currents, less power consumption, faster switching speeds, and good radiation tolerance. Little is known, however, about their performance at cryogenic temperatures and under wide thermal swings. Experimental investigation on the operation of SOI, N-channel field effect transistors under wide temperature range was reported earlier [1]. This work examines the performance of P-channel devices of these SOI transistors. The electronic part investigated in this work comprised of a Cissoid s CHT-PMOS30, high temperature P-channel MOSFET (metal-oxide semiconductor field-effect transistor) device [2]. This high voltage, medium-power transistor is designed for geothermal well logging applications, aerospace and avionics, and automotive industry, and is specified for operation in the temperature range of -55 C to +225 C. Table I shows some specifications of this transistor [2]. The CHT-PMOS30 device was characterized at various temperatures

Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

Science.gov (United States)

Schwarze, G. E.; Frasca, A. J.

1991-01-01

The effects of neutron and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10(exp 13) n/sq cm and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are presented. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed.

Characterization of a Common-Gate Amplifier Using Ferroelectric Transistors

Science.gov (United States)

Hunt, Mitchell; Sayyah, Rana; MacLeod, Todd C.; Ho, Fat D.

2011-01-01

In this paper, the empirical data collected through experiments performed using a FeFET in the common-gate amplifier circuit is presented. The FeFET common-gate amplifier was characterized by varying all parameters in the circuit, such as load resistance, biasing of the transistor, and input voltages. Due to the polarization of the ferroelectric layer, the particular behavior of the FeFET common-gate amplifier presents interesting results. Furthermore, the differences between a FeFET common-gate amplifier and a MOSFET common-gate amplifier are examined.

High performance tunnel field-effect transistor by gate and source engineering.

Science.gov (United States)

Huang, Ru; Huang, Qianqian; Chen, Shaowen; Wu, Chunlei; Wang, Jiaxin; An, Xia; Wang, Yangyuan

2014-12-19

As one of the most promising candidates for future nanoelectronic devices, tunnel field-effect transistors (TFET) can overcome the subthreshold slope (SS) limitation of MOSFET, whereas high ON-current, low OFF-current and steep switching can hardly be obtained at the same time for experimental TFETs. In this paper, we developed a new nanodevice technology based on TFET concepts. By designing the gate configuration and introducing the optimized Schottky junction, a multi-finger-gate TFET with a dopant-segregated Schottky source (mFSB-TFET) is proposed and experimentally demonstrated. A steeper SS can be achieved in the fabricated mFSB-TFET on the bulk Si substrate benefiting from the coupled quantum band-to-band tunneling (BTBT) mechanism, as well as a high I(ON)/I(OFF) ratio (∼ 10(7)) at V(DS) = 0.2 V without an area penalty. By compatible SOI CMOS technology, the fabricated Si mFSB-TFET device was further optimized with a high ION/IOFF ratio of ∼ 10(8) and a steeper SS of over 5.5 decades of current. A minimum SS of below 60 mV dec(-1) was experimentally obtained, indicating its dominant quantum BTBT mechanism for switching.

Novel failure mechanism and improvement for split-gate trench MOSFET with large current under unclamped inductive switch stress

Science.gov (United States)

Tian, Ye; Yang, Zhuo; Xu, Zhiyuan; Liu, Siyang; Sun, Weifeng; Shi, Longxing; Zhu, Yuanzheng; Ye, Peng; Zhou, Jincheng

2018-04-01

In this paper, a novel failure mechanism under unclamped inductive switch (UIS) for Split-Gate Trench Metal Oxide Semiconductor Field Effect Transistor (MOSFET) with large current is investigated. The device sample is tested and analyzed in detail. The simulation results demonstrate that the nonuniform potential distribution of the source poly should be responsible for the failure. Three structures are proposed and verified available to improve the device UIS ruggedness by TCAD simulation. The best one of the structures the device with source metal inserting into source poly through contacts in the field oxide is carried out and measured. The results demonstrate that the optimized structure can balance the trade-off between the UIS ruggedness and the static characteristics.

Image guided IMRT dosimetry using anatomy specific MOSFET configurations.

Science.gov (United States)

Amin, Md Nurul; Norrlinger, Bern; Heaton, Robert; Islam, Mohammad

2008-06-23

We have investigated the feasibility of using a set of multiple MOSFETs in conjunction with the mobile MOSFET wireless dosimetry system, to perform a comprehensive and efficient quality assurance (QA) of IMRT plans. Anatomy specific MOSFET configurations incorporating 5 MOSFETs have been developed for a specially designed IMRT dosimetry phantom. Kilovoltage cone beam computed tomography (kV CBCT) imaging was used to increase the positional precision and accuracy of the detectors and phantom, and so minimize dosimetric uncertainties in high dose gradient regions. The effectiveness of the MOSFET based dose measurements was evaluated by comparing the corresponding doses measured by an ion chamber. For 20 head and neck IMRT plans the agreement between the MOSFET and ionization chamber dose measurements was found to be within -0.26 +/- 0.88% and 0.06 +/- 1.94% (1 sigma) for measurement points in the high dose and low dose respectively. A precision of 1 mm in detector positioning was achieved by using the X-Ray Volume Imaging (XVI) kV CBCT system available with the Elekta Synergy Linear Accelerator. Using the anatomy specific MOSFET configurations, simultaneous measurements were made at five strategically located points covering high dose and low dose regions. The agreement between measurements and calculated doses by the treatment planning system for head and neck and prostate IMRT plans was found to be within 0.47 +/- 2.45%. The results indicate that a cylindrical phantom incorporating multiple MOSFET detectors arranged in an anatomy specific configuration, in conjunction with image guidance, can be utilized to perform a comprehensive and efficient quality assurance of IMRT plans.

Peripheral dose measurement in high-energy photon radiotherapy with the implementation of MOSFET.

Science.gov (United States)

Vlachopoulou, Vassiliki; Malatara, Georgia; Delis, Harry; Theodorou, Kiki; Kardamakis, Dimitrios; Panayiotakis, George

2010-11-28

To study the peripheral dose (PD) from high-energy photon beams in radiotherapy using the metal oxide semiconductor field effect transistor (MOSFET) dose verification system. The radiation dose absorbed by the MOSFET detector was calculated taking into account the manufacturer's Correction Factor, the Calibration Factor and the threshold voltage shift. PD measurements were carried out for three different field sizes (5 cm × 5 cm, 10 cm × 10 cm and 15 cm × 15 cm) and for various depths with the source to surface distance set at 100 cm. Dose measurements were realized on the central axis and then at distances (1 to 18 cm) parallel to the edge of the field, and were expressed as the percentage PD (% PD) with respect to the maximum dose (d(max)). The accuracy of the results was evaluated with respect to a calibrated 0.3 cm(3) ionization chamber. The reproducibility was expressed in terms of standard deviation (s) and coefficient of variation. % PD is higher near the phantom surface and drops to a minimum at the depth of d(max), and then tends to become constant with depth. Internal scatter radiation is the predominant source of PD and the depth dependence is determined by the attenuation of the primary photons. Closer to the field edge, where internal scatter from the phantom dominates, the % PD increases with depth because the ratio of the scatter to primary increases with depth. A few centimeters away from the field, where collimator scatter and leakage dominate, the % PD decreases with depth, due to attenuation by the water. The % PD decreases almost exponentially with the increase of distance from the field edge. The decrease of the % PD is more than 60% and can reach up to 90% as the measurement point departs from the edge of the field. For a given distance, the % PD is significantly higher for larger field sizes, due to the increase of the scattering volume. Finally, the measured PD obtained with MOSFET is higher than that obtained with an ionization chamber

Fundamentals of bias temperature instability in MOS transistors characterization methods, process and materials impact, DC and AC modeling

CERN Document Server

2016-01-01

This book aims to cover different aspects of Bias Temperature Instability (BTI). BTI remains as an important reliability concern for CMOS transistors and circuits. Development of BTI resilient technology relies on utilizing artefact-free stress and measurement methods and suitable physics-based models for accurate determination of degradation at end-of-life, and understanding the gate insulator process impact on BTI. This book discusses different ultra-fast characterization techniques for recovery artefact free BTI measurements. It also covers different direct measurements techniques to access pre-existing and newly generated gate insulator traps responsible for BTI. The book provides a consistent physical framework for NBTI and PBTI respectively for p- and n- channel MOSFETs, consisting of trap generation and trapping. A physics-based compact model is presented to estimate measured BTI degradation in planar Si MOSFETs having differently processed SiON and HKMG gate insulators, in planar SiGe MOSFETs and also...

Modeling quantization effects in field effect transistors

International Nuclear Information System (INIS)

Troger, C.

2001-06-01

Numerical simulation in the field of semiconductor device development advanced to a valuable, cost-effective and flexible facility. The most widely used simulators are based on classical models, as they need to satisfy time and memory constraints. To improve the performance of field effect transistors such as MOSFETs and HEMTs these devices are continuously scaled down in their dimensions. Consequently the characteristics of such devices are getting more and more determined by quantum mechanical effects arising from strong transversal fields in the channel. In this work an approach based on a two-dimensional electron gas is used to describe the confinement of the carriers. Quantization is considered in one direction only. For the derivation of a one-dimensional Schroedinger equation in the effective mass framework a non-parabolic correction for the energy dispersion due to Kane is included. For each subband a non-parabolic dispersion relation characterized by subband masses and subband non-parabolicity coefficients is introduced and the parameters are calculated via perturbation theory. The method described in this work has been implemented in a software tool that performs a self-consistent solution of Schroedinger- and Poisson-equation for a one-dimensional cut through a MOS structure or heterostructure. The calculation of the carrier densities is performed assuming Fermi-Dirac statistics. In the case of a MOS structure a metal or a polysilicon gate is considered and an arbitrary gate bulk voltage can be applied. This allows investigating quantum mechanical effects in capacity calculations, to compare the simulated data with measured CV curves and to evaluate the results obtained with a quantum mechanical correction for the classical electron density. The behavior of the defined subband parameters is compared to the value of the mass and the non-parabolicity coefficient from the model due to Kane. Finally the presented characterization of the subbands is applied

In vivo dosimetry in intraoperative electron radiotherapy: microMOSFETs, radiochromic films and a general-purpose linac.

Science.gov (United States)

López-Tarjuelo, Juan; Bouché-Babiloni, Ana; Morillo-Macías, Virginia; de Marco-Blancas, Noelia; Santos-Serra, Agustín; Quirós-Higueras, Juan David; Ferrer-Albiach, Carlos

2014-10-01

In vivo dosimetry is desirable for the verification, recording, and eventual correction of treatment in intraoperative electron radiotherapy (IOERT). Our aim is to share our experience of metal oxide semiconductor field-effect transistors (MOSFETs) and radiochromic films with patients undergoing IOERT using a general-purpose linac. We used MOSFETs inserted into sterile bronchus catheters and radiochromic films that were cut, digitized, and sterilized by means of gas plasma. In all, 59 measurements were taken from 27 patients involving 15 primary tumors (seven breast and eight non-breast tumors) and 12 relapses. Data were subjected to an outliers' analysis and classified according to their compatibility with the relevant doses. Associations were sought regarding the type of detector, breast and non-breast irradiation, and the radiation oncologist's assessment of the difficulty of detector placement. At the same time, 19 measurements were carried out at the tumor bed with both detectors. MOSFET measurements ([Formula: see text]  = 93.5 %, sD  =  6.5 %) were not significantly shifted from film measurements ([Formula: see text]  =  96.0 %, sD  =  5.5 %; p  =  0.109), and no associations were found (p = 0.526, p = 0.295,  and p = 0.501, respectively). As regards measurements performed at the tumor bed with both detectors, MOSFET measurements ([Formula: see text]  =  95.0 %, sD  =  5.4 % were not significantly shifted from film measurements ([Formula: see text]  =  96.4 %, sD  =  5.0 %; p  =  0.363). In vivo dosimetry can produce satisfactory results at every studied location with a general-purpose linac. Detector choice should depend on user factors, not on the detector performance itself. Surgical team collaboration is crucial to success.

Gamma response study of radiation sensitive MOSFETs for their use as gamma radiation sensor

Energy Technology Data Exchange (ETDEWEB)

Srivastava, Saurabh; Kumar, A. Vinod [Radiation Safety Systems Division, Bhabha Atomic Research Centre, Mumbai (India); Aggarwal, Bharti; Singh, Arvind; Topkar, Anita, E-mail: anita@barc.gov.in [Electronics Division, Bhabha Atomic Research Centre, Mumbai (India)

2016-05-23

Continuous monitoring of gamma dose is important in various fields like radiation therapy, space-related research, nuclear energy programs and high energy physics experiment facilities. The present work is focused on utilization of radiation-sensitive Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs) to monitor gamma radiation doses. Static characterization of these detectors was performed to check their expected current-voltage relationship. Threshold voltage and transconductance per unit gate to source voltage (K factor) were calculated from the experimental data. The detector was exposed to gamma radiation in both, with and without gate bias voltage conditions, and change in threshold voltage was monitored at different gamma doses. The experimental data was fitted to obtain equation for dependence of threshold voltage on gamma dose. More than ten times increase in sensitivity was observed in biased condition (+3 V) compared to the unbiased case.

Analysis of switching characteristics for negative capacitance ultra-thin-body germanium-on-insulator MOSFETs

Science.gov (United States)

Pi-Ho Hu, Vita; Chiu, Pin-Chieh

2018-04-01

The impact of device parameters on the switching characteristics of negative capacitance ultra-thin-body (UTB) germanium-on-insulator (NC-GeOI) MOSFETs is analyzed. NC-GeOI MOSFETs with smaller gate length (L g), EOT, and buried oxide thickness (T box) and thicker ferroelectric layer thickness (T FE) exhibit larger subthreshold swing improvements over GeOI MOSFETs due to better capacitance matching. Compared with GeOI MOSFETs, NC-GeOI MOSFETs exhibit better switching time due to improvements in effective drive current (I eff) and subthreshold swing. NC-GeOI MOSFET exhibits larger ST improvements at V dd = 0.3 V (-82.9%) than at V dd = 0.86 V (-9.7%), because NC-GeOI MOSFET shows 18.2 times higher I eff than the GeOI MOSFET at V dd = 0.3 V, while 2.5 times higher I eff at V dd = 0.86 V. This work provides the device design guideline of NC-GeOI MOSFETs for ultra-low power applications.

SU-G-IeP3-02: Characteristics of In-Vivo MOSFET Dosimeters for Diagnostic X-Ray Low-Dose Measurements

Energy Technology Data Exchange (ETDEWEB)

Li, S; Ali, S; Harper, K; Liang, Q; Serratore, D [Temple University Hospital, Philadelphia, PA (United States)

2016-06-15

Purpose: To correct in-vivo metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters dependence on X-ray energy, dose and dose rate, and temperature in order to measure doses or exposures on several anatomic points of interest undergoing some routine radiographs. Methods: A mobile MOSFET system (BEST Medical) was carefully calibrated with X-ray at kVp of 70, 80, 100, 120, and 138 kVp, phantom temperatures at 0, 21, and 43 oC, and exposure range from 0.01 to 10 R confirmed with Raysafe and RadCal dosimeters. The MOSFETS were placed on the midline bladder or uterus, left pelvic iliac artery, left abdominal above iliac crest, abdominal midline anterior at inferior margin of stomach, and left pectoral of a large and a small body-size cadavers undergoing AP/PA chest and lumber spine radiographs using manual and automatic exposure control (AEC) with and without lead shielding. MOSTFETs and TLD chips were also placed on the stomach, sigmoid, pubic symphysis, left and right pelvic walls of another cadaver for AP pelvic manual or AEC radiography prior to and after a left hip metal implant. Results: Individual MOSFET detectors had various low-dose limits in ranged from 0.03 to 0.08 R, nonlinear response to X-ray energy, and significant temperature effect of 15%. By accumulating 10 manual exposures and 20 AEC exposures, we achieved dose measured accuracy of 6%. There were up to 8 fold increases for AEC exposure of spine and chest X-ray procedure from no shielding to with shielding. For pelvic radiography, exposure to public symphysis was the highest even higher than that of the skin. After hip implant, AEC pelvic radiograph increase exposure by 30 to 200% consistent with results of TLDs. Conclusion: Dependence of energy, temperature and dose limit were accurately corrected. We have found significant exposure for those clinical pr°ocedures and the study provided evidences for developing new clinical procedures.

Hole mobility enhancement of p-MOSFETs using global and local Ge-channel technologies

International Nuclear Information System (INIS)

Takagi, Shinichi; Tezuka, T.; Irisawa, T.; Nakaharai, S.; Maeda, T.; Numata, T.; Ikeda, K.; Sugiyama, N.

2006-01-01

Mobility enhancement technologies have currently been recognized as mandatory for future scaled MOSFETs. In this paper, we review our recent results on high hole mobility p-MOSFETs using global/local SiGe or Ge channels. There are two directions for introducing SiGe or Ge channels into Si CMOS platform. One is to use SiGe or Ge global substrates and the other is to form SiGe or Ge-channel regions locally on Si wafers. In both cases, the Ge condensation technique, where Ge-channel layers are formed by oxidizing SiGe films on SOI substrates, are effectively utilized. As for the global technologies, ultrathin GOI substrates are prepared and used to fabricate high mobility GOI p-MOSFETs. As for the local technologies, SGOI or GOI channels are formed locally in the active area of p-MOSFETs on SOI wafers. It is shown that the hole mobility enhancement factor of as high as 10 is obtained in locally fabricated p-MOSFETs through the effects of high-Ge content and the compressive strain. Furthermore, the local Ge-channel technologies are combined with global SiGe or Ge substrates for pursuing the optimal and individual design of n-MOSFETs and p-MOSFETs on a single Si wafer. The CMOS device composed of strained-Si n-MOSFETs and SGOI p-MOSFETs is successfully integrated on a same wafer, which is a promising CMOS structure under deep sub 100 nm technology nodes

Charge based DC compact modeling of bulk FinFET transistor

Science.gov (United States)

Cerdeira, A.; Garduño, I.; Tinoco, J.; Ritzenthaler, R.; Franco, J.; Togo, M.; Chiarella, T.; Claeys, C.

2013-09-01

Multiple-gate MOSFETs became an industrial reality in the last years. Due to a pragmatic trade-off between CMOS process baselines compatibility, improved performance compared to planar bulk architecture, and cost, bulk FinFETs emerged as the technological solution to provide downscaling for the 14/22 nm technological nodes. In this work, a charge based DC compact model based on the SDDG Model is demonstrated for this new generation of FinFET transistors and describes continuously the transistor characteristics in all operating regions. Validating the model against two bulk FinFET baselines (NMOS, PMOS, various gate lengths and EOT), an excellent agreement is found for transfer and output characteristics (linear and saturation regimes), transconductance/output conductance, and gm/IDS characteristics. Temperature dependence is also taken into account and validated (T range from 25 °C up to 175 °C).

Comparison between Si/SiO_2 and InP/Al_2O_3 based MOSFETs

International Nuclear Information System (INIS)

Akbari Tochaei, A.; Arabshahi, H.; Benam, M. R.; Vatan-Khahan, A.; Abedininia, M.

2016-01-01

Electron transport properties of InP-based MOSFET as a new channel material with Al_2O_3 as a high-k dielectric oxide layer in comparison with Si-based MOSFET are studied by the ensemble Monte Carlo simulation method in which the conduction band valleys in InP are based on three valley models with consideration of quantum effects (effective potential approach). I_d–V_d characteristics for Si-based MOSFET are in good agreement with theoretical and experimental results. Our results show that I_d of InP-based MOSFET is about 2 times that of Si-based MOSFET. We simulated the diagrams of longitudinal and transverse electric fields, conduction band edge, average electron velocity, and average electron energy for Si-based MOSFET and compared the results with those for InP-based MOSFET. Our results, as was expected, show that the transverse electric field, the conduction band edge, the electron velocity, and the electron energy in a channel in the InP-based MOSFET are greater than those for Si-based MOSFET. But the longitudinal electric field behaves differently at different points of the channel.

Single-Event Gate Rupture in Power MOSFETs: A New Radiation Hardness Assurance Approach

Science.gov (United States)

Lauenstein, Jean-Marie

2011-01-01

Almost every space mission uses vertical power metal-semiconductor-oxide field-effect transistors (MOSFETs) in its power-supply circuitry. These devices can fail catastrophically due to single-event gate rupture (SEGR) when exposed to energetic heavy ions. To reduce SEGR failure risk, the off-state operating voltages of the devices are derated based upon radiation tests at heavy-ion accelerator facilities. Testing is very expensive. Even so, data from these tests provide only a limited guide to on-orbit performance. In this work, a device simulation-based method is developed to measure the response to strikes from heavy ions unavailable at accelerator facilities but posing potential risk on orbit. This work is the first to show that the present derating factor, which was established from non-radiation reliability concerns, is appropriate to reduce on-orbit SEGR failure risk when applied to data acquired from ions with appropriate penetration range. A second important outcome of this study is the demonstration of the capability and usefulness of this simulation technique for augmenting SEGR data from accelerator beam facilities. The mechanisms of SEGR are two-fold: the gate oxide is weakened by the passage of the ion through it, and the charge ionized along the ion track in the silicon transiently increases the oxide electric field. Most hardness assurance methodologies consider the latter mechanism only. This work demonstrates through experiment and simulation that the gate oxide response should not be neglected. In addition, the premise that the temporary weakening of the oxide due to the ion interaction with it, as opposed to due to the transient oxide field generated from within the silicon, is validated. Based upon these findings, a new approach to radiation hardness assurance for SEGR in power MOSFETs is defined to reduce SEGR risk in space flight projects. Finally, the potential impact of accumulated dose over the course of a space mission on SEGR

Quantum Corrections to the 'Atomistic' MOSFET Simulations

Science.gov (United States)

Asenov, Asen; Slavcheva, G.; Kaya, S.; Balasubramaniam, R.

2000-01-01

We have introduced in a simple and efficient manner quantum mechanical corrections in our 3D 'atomistic' MOSFET simulator using the density gradient formalism. We have studied in comparison with classical simulations the effect of the quantum mechanical corrections on the simulation of random dopant induced threshold voltage fluctuations, the effect of the single charge trapping on interface states and the effect of the oxide thickness fluctuations in decanano MOSFETs with ultrathin gate oxides. The introduction of quantum corrections enhances the threshold voltage fluctuations but does not affect significantly the amplitude of the random telegraph noise associated with single carrier trapping. The importance of the quantum corrections for proper simulation of oxide thickness fluctuation effects has also been demonstrated.

Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

International Nuclear Information System (INIS)

Schwarze, G.E.; Frasca, A.J.

1994-01-01

The effects of neutrons and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10 13 n/cm 2 and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are given in this paper. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed

MOSFET dosimeter depth-dose measurements in heterogeneous tissue-equivalent phantoms at diagnostic x-ray energies

International Nuclear Information System (INIS)

Jones, A.K.; Pazik, F.D.; Hintenlang, D.E.; Bolch, W.E.

2005-01-01

The objective of the present study was to explore the use of the TN-1002RD metal-oxide-semiconductor field effect transistor (MOSFET) dosimeter for measuring tissue depth dose at diagnostic photon energies in both homogeneous and heterogeneous tissue-equivalent materials. Three cylindrical phantoms were constructed and utilized as a prelude to more complex measurements within tomographic physical phantoms of pediatric patients. Each cylindrical phantom was constructed as a stack of seven 5-cm-diameter and 1-cm-thick discs of materials radiographically representative of either soft tissue (S), bone (B), or lung tissue (L) at diagnostic photon energies. In addition to a homogeneous phantom of soft tissue (SSSSSSS), two heterogeneous phantoms were constructed: SSBBSSS and SBLLBSS. MOSFET dosimeters were then positioned at the interface of each disc, and the phantoms were then irradiated at 66 kVp and 200 mAs. Measured values of absorbed dose at depth were then compared to predicated values of point tissue dose as determined via Monte Carlo radiation transport modeling. At depths exceeding 2 cm, experimental results matched the computed values of dose with high accuracy regardless of the dosimeter orientation (epoxy bubble facing toward or away from the x-ray beam). Discrepancies were noted, however, between measured and calculated point doses near the surface of the phantom (surface to 2 cm depth) when the dosimeters were oriented with the epoxy bubble facing the x-ray beam. These discrepancies were largely eliminated when the dosimeters were placed with the flat side facing the x-ray beam. It is therefore recommended that the MOSFET dosimeters be oriented with their flat sides facing the beam when they are used at shallow depths or on the surface of either phantoms or patients

Investigation of the potential barrier lowering for quasi-ballistic transport in short channel MOSFETs

International Nuclear Information System (INIS)

Lee, Jaehong; Kwon, Yongmin; Ji, Junghwan; Shin, Hyungcheol

2011-01-01

In this paper, the quasi-ballistic carrier transport in short channel MOSFETs is investigated from the point of potential barrier lowering. To investigate the ballistic characteristic of transistors, we extracted the channel backscattering coefficient and the ballistic ratio from experimental data obtained by RF C-V and DC I-V measurements. Two factors that modulate the potential barrier height, besides the gate bias, are considered in this work: the drain bias (V DS ) and the channel doping concentration (N A ). We extract the critical length by calculating the potential drop in the channel region and conclude that the drain bias and the channel doping concentration affect the quasi-ballistic carrier transport.

p-MOSFET total dose dosimeter

Science.gov (United States)

Buehler, Martin G. (Inventor); Blaes, Brent R. (Inventor)

1994-01-01

A p-MOSFET total dose dosimeter where the gate voltage is proportional to the incident radiation dose. It is configured in an n-WELL of a p-BODY substrate. It is operated in the saturation region which is ensured by connecting the gate to the drain. The n-well is connected to zero bias. Current flow from source to drain, rather than from peripheral leakage, is ensured by configuring the device as an edgeless MOSFET where the source completely surrounds the drain. The drain junction is the only junction not connected to zero bias. The MOSFET is connected as part of the feedback loop of an operational amplifier. The operational amplifier holds the drain current fixed at a level which minimizes temperature dependence and also fixes the drain voltage. The sensitivity to radiation is made maximum by operating the MOSFET in the OFF state during radiation soak.

Tunneling field effect transistor technology

CERN Document Server

Chan, Mansun

2016-01-01

This book provides a single-source reference to the state-of-the art in tunneling field effect transistors (TFETs). Readers will learn the TFETs physics from advanced atomistic simulations, the TFETs fabrication process and the important roles that TFETs will play in enabling integrated circuit designs for power efficiency. · Provides comprehensive reference to tunneling field effect transistors (TFETs); · Covers all aspects of TFETs, from device process to modeling and applications; · Enables design of power-efficient integrated circuits, with low power consumption TFETs.

Drying Temperature Dependence of Sol-gel Spin Coated Bilayer Composite ZnO/TiO2 Thin Films for Extended Gate Field Effect Transistor pH Sensor

Science.gov (United States)

Rahman, R. A.; Zulkefle, M. A.; Yusoff, K. A.; Abdullah, W. F. H.; Rusop, M.; Herman, S. H.

2018-03-01

This study presents an investigation on zinc oxide (ZnO) and titanium dioxide (TiO2) bilayer film applied as the sensing membrane for extended-gate field effect transistor (EGFET) for pH sensing application. The influences of the drying temperatures on the pH sensing capability of ZnO/TiO2 were investigated. The sensing performance of the thin films were measured by connecting the thin film to a commercial MOSFET to form the extended gates. By varying the drying temperature, we found that the ZnO/TiO2 thin film dried at 150°C gave the highest sensitivity compared to other drying conditions, with the sensitivity value of 48.80 mV/pH.

Design Dependent Cutoff Frequency of Nanotransistors Near the Ultimate Performance Limit

Science.gov (United States)

Kordrostami, Zoheir; Sheikhi, M. Hossein; Zarifkar, Abbas

2012-12-01

We have studied the effect of different structural designs of double gate MOSFETs (DG-MOSFETs) and carbon nanotube field effect transistors (CNTFETs) on the cutoff frequency (fT). The effects of metallic contacts with Schottky barriers, gate work function, dual material gate (DMG), halo doped channel and lightly doped drain and source (LDDS) architectures on the fT have been investigated for DG-MOSFETs and CNTFETs and the design dependent fT for both types of transistors has been studied for the first time. The simulations are based on the Schrödinger-Poisson solvers developed for each nanotransistor separately. The ballistic limit has been studied as the ultimate performance limit of the DG-MOSFETs and CNTFETs. The results of this paper, for the first time, show how some designations used for modification of short channel effects or current-voltage characteristics affect the fT. The results revealed that the cutoff frequencies of both types of the transistors exhibit the same behavior with changing design parameters. We have shown that the Schottky barriers, parasitic capacitances and halo doping reduce the fT and have proposed the DMG and LDDS artchitectures as ways to increase the fT for DG-MOSFETs and CNTFETs for the first time.

Simulation for silicon-compatible InGaAs-based junctionless field-effect transistor using InP buffer layer

Science.gov (United States)

Seo, Jae Hwa; Cho, Seongjae; Kang, In Man

2013-10-01

In this paper, we present the optimized performances of indium gallium arsenide (InGaAs)-based compound junctionless field-effect transistors (JLFETs) using an indium phosphide (InP) buffer layer. The proposed InGaAs-InP material combination with little lattice mismatch provides a significant improvement in current drivability securing various potential applications. Device optimization is performed in terms of primary dc parameters and characterization is investigated by two-dimensional (2D) technology computer-aided design simulations. The optimization variables were the channel doping concentration (Nch), the buffer doping concentration (Nbf), and the channel thickness (Tch). For the optimally designed InGaAs JLFET, on-state current (Ion) of 325 µA µm-1, subthreshold swing (S) of 80 mV dec-1, and current ratio (Ion/Ioff) of 109 were obtained. In the end, the results are compared with the data of silicon (Si)-based JL MOSFETs to confirm the improvements.

High performance tunnel field-effect transistor by gate and source engineering

International Nuclear Information System (INIS)

Huang, Ru; Huang, Qianqian; Chen, Shaowen; Wu, Chunlei; Wang, Jiaxin; An, Xia; Wang, Yangyuan

2014-01-01

As one of the most promising candidates for future nanoelectronic devices, tunnel field-effect transistors (TFET) can overcome the subthreshold slope (SS) limitation of MOSFET, whereas high ON-current, low OFF-current and steep switching can hardly be obtained at the same time for experimental TFETs. In this paper, we developed a new nanodevice technology based on TFET concepts. By designing the gate configuration and introducing the optimized Schottky junction, a multi-finger-gate TFET with a dopant-segregated Schottky source (mFSB-TFET) is proposed and experimentally demonstrated. A steeper SS can be achieved in the fabricated mFSB-TFET on the bulk Si substrate benefiting from the coupled quantum band-to-band tunneling (BTBT) mechanism, as well as a high I ON /I OFF ratio (∼10 7 ) at V DS  = 0.2 V without an area penalty. By compatible SOI CMOS technology, the fabricated Si mFSB-TFET device was further optimized with a high I ON /I OFF ratio of ∼10 8 and a steeper SS of over 5.5 decades of current. A minimum SS of below 60 mV dec −1 was experimentally obtained, indicating its dominant quantum BTBT mechanism for switching. (paper)

Aging precursors and degradation effects of SiC-MOSFET modules under highly accelerated power cycling conditions

DEFF Research Database (Denmark)

Luo, Haoze; Iannuzzo, Francesco; Blaabjerg, Frede

2017-01-01

A highly accelerated power cycling test platform using current source converter for SiC-MOSFET power modules is proposed. The control principles of delta and average junction temperatures are introduced. By using isolated thermal fibers, the junction temperature (Tj) variations can be monitored...... and compared. As a result, the effects of degradation on the static and dynamic characteristics during conventional operation are discussed. Finally, the research results can help examine the failure precursors and then estimate the remaining useful lifetime of SiC MOSFET modules....

Dual-Material Gate Approach to Suppression of Random-Dopant-Induced Characteristic Fluctuation in 16 nm Metal-Oxide-Semiconductor Field-Effect-Transistor Devices

Science.gov (United States)

Li, Yiming; Lee, Kuo-Fu; Yiu, Chun-Yen; Chiu, Yung-Yueh; Chang, Ru-Wei

2011-04-01

In this work, we explore for the first time dual-material gate (DMG) and inverse DMG devices for suppressing the random-dopant (RD)-induced characteristic fluctuation in 16 nm metal-oxide-semiconductor field-effect-transistor (MOSFET) devices. The physical mechanism of suppressing the characteristic fluctuation of DMG devices is observed and discussed. The achieved improvement in suppressing the RD-induced threshold voltage, on-state current, and off-state current fluctuations are 28, 12.3, and 59%, respectively. To further suppress the fluctuations, an approach that combines the DMG method and channel-doping-profile engineering is also advanced and explored. The results of our study show that among the suppression techniques, the use of the DMG device with an inverse lateral asymmetric channel-doping-profile has good immunity to fluctuation.

Neutron and gamma irradiation effects on power semiconductor switches

Science.gov (United States)

Schwarze, G. E.; Frasca, A. J.

1990-01-01

The performance characteristics of high power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN Bipolar Junction Transistors (BJTs), and Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). BJTs show a rapid decrease in gain, blocking voltage, and storage time for neutron irradiation, and MOSFETs show a rapid decrease in the gate threshold voltage for gamma irradiation.

A study of s new power semiconductor insulated gate bipolar transistor (IGBT) characteristics and its application to automotive ignition

International Nuclear Information System (INIS)

Rabah, K.V.O.

1995-05-01

Assessment has been made of the problem of the on-resistance and temperature effects in the three power transistor combinations, such as Darlington-types or IGBT. The IGBT is a device in which the drain of the MOSFET feeds the bipolar base in monolithic (IC and Power on the same chip) to give it both the MOS and bipolar advantages. The high temperature operating characteristics of the device are discussed and compared to that of power bipolar transistor. Unlike the power bipolar transistor whose operating current density shows current crowding at above forward collector current of 4Amps and forward voltage drop above 0.4V, the IGBT is found to maintain its high current density above forward collector of current 1Amp (or a forward voltage drop above 1.2V). The results also indicate that these devices (IGBTs) can be interdigited (paralleled) without current hogging problems if the forward conduction occurs at forward voltage drops in excess of 1.2V, and this makes it the best candidate for automotive ignition power switches. (author). 20 refs, 10 figs, 1 tab

Performance Enhancement of Power Transistors and Radiation effect

International Nuclear Information System (INIS)

Hassn, Th.A.A.

2012-01-01

The main objective of this scientific research is studying the characteristic of bipolar junction transistor device and its performance under radiation fields and temperature effect as a control element in many power circuits. In this work we present the results of experimental measurements and analytical simulation of gamma – radiation effects on the electrical characteristics and operation of power transistor types 2N3773, 2N3055(as complementary silicon power transistor are designed for general-purpose switching and amplifier applications), three samples of each type were irradiated by gamma radiation with doses, 1 K rad, 5 K rad, 10 K rad, 30 K rad, and 10 Mrad, the experimental data are utilized to establish an analytical relation between the total absorbed dose of gamma irradiation and corresponding to effective density of generated charge in the internal structure of transistor, the electrical parameters which can be measured to estimate the generated defects in the power transistor are current gain, collector current and collected emitter leakage current , these changes cause the circuit to case proper functioning. Collector current and transconductance of each device are calibrated as a function of irradiated dose. Also the threshold voltage and transistor gain can be affected and also calibrated as a function of dose. A silicon NPN power transistor type 2N3773 intended for general purpose applications, were used in this work. It was designed for medium current and high power circuits. Performance and characteristic were discusses under temperature and gamma radiation doses. Also the internal junction thermal system of the transistor represented in terms of a junction thermal resistance (Rjth). The thermal resistance changed by ΔRjth, due to the external intended, also due to the gamma doses intended. The final result from the model analysis reveals that the emitter-bias configuration is quite stable by resistance ratio RB/RE. Also the current

Transistor Small Signal Analysis under Radiation Effects

International Nuclear Information System (INIS)

Sharshar, K.A.A.

2004-01-01

A Small signal transistor parameters dedicate the operation of bipolar transistor before and after exposed to gamma radiation (1 Mrad up to 5 Mrads) and electron beam(1 MeV, 25 mA) with the same doses as a radiation sources, the electrical parameters of the device are changed. The circuit Model has been discussed.Parameters, such as internal emitter resistance (re), internal base resistance, internal collector resistance (re), emitter base photocurrent (Ippe) and base collector photocurrent (Ippe). These parameters affect on the operation of the device in its applications, which work as an effective element, such as current gain (hFE≡β)degradation it's and effective parameter in the device operation. Also the leakage currents (IcBO) and (IEBO) are most important parameters, Which increased with radiation doses. Theoretical representation of the change in the equivalent circuit for NPN and PNP bipolar transistor were discussed, the input and output parameters of the two types were discussed due to the change in small signal input resistance of the two types. The emitter resistance(re) were changed by the effect of gamma and electron beam irradiation, which makes a change in the role of matching impedances between transistor stages. Also the transistor stability factors S(Ico), S(VBE) and S(β are detected to indicate the transistor operations after exposed to radiation fields. In low doses the gain stability is modified due to recombination of induced charge generated during device fabrication. Also the load resistance values are connected to compensate the effect

A novel self-aligned oxygen (SALOX) implanted SOI MOSFET device structure

Science.gov (United States)

Tzeng, J. C.; Baerg, W.; Ting, C.; Siu, B.

The morphology of the novel self-aligned oxygen implanted SOI (SALOX SOI) [1] MOSFET was studied. The channel silicon of SALOX SOI was confirmed to be undamaged single crystal silicon and was connected with the substrate. Buried oxide formed by oxygen implantation in this SALOX SOI structure was shown by a cross section transmission electron micrograph (X-TEM) to be amorphous. The source/drain silicon on top of the buried oxide was single crystal, as shown by the transmission electron diffraction (TED) pattern. The source/drain regions were elevated due to the buried oxide volume expansion. A sharp silicon—silicon dioxide interface between the source/drain silicon and buried oxide was observed by Auger electron spectroscopy (AES). Well behaved n-MOS transistor current voltage characteristics were obtained and showed no I-V kink.

Novel technique of source and drain engineering for dual-material double-gate (DMDG) SOI MOSFETS

Science.gov (United States)

Yadav, Himanshu; Malviya, Abhishek Kumar; Chauhan, R. K.

2018-04-01

The dual-metal dual-gate (DMDG) SOI has been used with Dual Sided Source and Drain Engineered 50nm SOI MOSFET with various high-k gate oxide. It has been scrutinized in this work to enhance its electrical performance. The proposed structure is designed by creating Dual Sided Source and Drain Modification and its characteristics are evaluated on ATLAS device simulator. The consequence of this dual sided assorted doping on source and drain side of the DMDG transistor has better leakage current immunity and heightened ION current with higher ION to IOFF Ratio. Which thereby vesting the proposed device appropriate for low power digital applications.

High voltage MOSFET switching circuit

Science.gov (United States)

McEwan, Thomas E.

1994-01-01

The problem of source lead inductance in a MOSFET switching circuit is compensated for by adding an inductor to the gate circuit. The gate circuit inductor produces an inductive spike which counters the source lead inductive drop to produce a rectangular drive voltage waveform at the internal gate-source terminals of the MOSFET.

Recent progress in photoactive organic field-effect transistors.

Science.gov (United States)

Wakayama, Yutaka; Hayakawa, Ryoma; Seo, Hoon-Seok

2014-04-01

Recent progress in photoactive organic field-effect transistors (OFETs) is reviewed. Photoactive OFETs are divided into light-emitting (LE) and light-receiving (LR) OFETs. In the first part, LE-OFETs are reviewed from the viewpoint of the evolution of device structures. Device performances have improved in the last decade with the evolution of device structures from single-layer unipolar to multi-layer ambipolar transistors. In the second part, various kinds of LR-OFETs are featured. These are categorized according to their functionalities: phototransistors, non-volatile optical memories, and photochromism-based transistors. For both, various device configurations are introduced: thin-film based transistors for practical applications, single-crystalline transistors to investigate fundamental physics, nanowires, multi-layers, and vertical transistors based on new concepts.

Recent progress in photoactive organic field-effect transistors

International Nuclear Information System (INIS)

Wakayama, Yutaka; Hayakawa, Ryoma; Seo, Hoon-Seok

2014-01-01

Recent progress in photoactive organic field-effect transistors (OFETs) is reviewed. Photoactive OFETs are divided into light-emitting (LE) and light-receiving (LR) OFETs. In the first part, LE-OFETs are reviewed from the viewpoint of the evolution of device structures. Device performances have improved in the last decade with the evolution of device structures from single-layer unipolar to multi-layer ambipolar transistors. In the second part, various kinds of LR-OFETs are featured. These are categorized according to their functionalities: phototransistors, non-volatile optical memories, and photochromism-based transistors. For both, various device configurations are introduced: thin-film based transistors for practical applications, single-crystalline transistors to investigate fundamental physics, nanowires, multi-layers, and vertical transistors based on new concepts. (review)

Two-dimensional model for subthreshold current and subthreshold swing of graded-channel dual-material double-gate (GCDMDG) MOSFETs

Science.gov (United States)

Goel, Ekta; Kumar, Sanjay; Singh, Balraj; Singh, Kunal; Jit, Satyabrata

2017-06-01

The subthreshold performance of graded-channel dual-material double-gate (GCDMDG) MOSFETs is examined through two-dimensional (2D) analytical modeling of subthreshold-current (SC) and subthreshold-swing (SS). The potential function obtained by using the parabolic approach to solve the 2D Poisson's equation, has been used to formulate SC and SS characteristics of the device. The variations of SS against different device parameters have been obtained with the help of effective conduction path parameter. The SC and SS characteristics of the GCDMDG MOS transistor have been compared with those of the dual-material double-gate (DMDG) and simple graded-channel double-gate (GCDG) MOS structures to show its better subthreshold characteristics over the latter two devices. The results of the developed model are well-agreed with the commercially available SILVACO ATLAS™ simulator data.

Dosimetric evaluation of a new OneDose MOSFET for Ir-192 energy

International Nuclear Information System (INIS)

Kinhikar, Rajesh A; Sharma, Pramod K; Tambe, Chandrashekhar M; Deshpande, Deepak D

2006-01-01

The purpose of this study was to investigate dosimetry (reproducibility, energy correction, relative response with distance from source, linearity with threshold dose, rate of fading, temperature and angular dependence) of a newly designed OneDose TM MOSFET patient dosimetry system for use in HDR brachytherapy with Ir-192 energy. All measurements were performed with a MicroSelectron HDR unit and OneDose MOSFET detectors. All dosimeters were normalized to 3 min post-irradiation to minimize fading effects. All dosimeters gave reproducible readings with mean deviation of 1.8% (SD 0.4) and 2.4% (SD 0.6) for 0 0 and 180 0 incidences, respectively. The mean energy correction factor was found to be 1.1 (range 1.06-1.12). Overall, there was 60% and 40% mean response of the MOSFET at 2 and 3 cm, respectively, from the source. MOSFET results showed good agreement with TLD and parallel plate ion chamber. Linear dose response with threshold voltage shift was observed with applied doses of 0.3 Gy-5 Gy with Ir-192 energy. Linearity (R 2 = 1) was observed in the MOSFET signal with the applied dose range of 0.3 Gy-5 Gy with Ir-192 energy. Fading effects were less than 1% after 10 min and the MOSFET detectors stayed stable (within 5%) over a period of 1 month. The MOSFET response was found to be decreased by approximately 1.5% at 37 deg. C compared to 20 deg. C. The isotropic response of the MOSFET was found to be within ±6%. A maximum deviation of 5.5% was obtained between 0 deg. and 180 deg. for both the axes and this should be considered in clinical applications. The small size, cable-less, instant readout, permanent storage of dose and ease of use make the MOSFET a novel dosimeter and beneficial to patients for skin dose measurements with HDRBT using an Ir-192 source compared to the labour demanding and time-consuming TLDs

A CMOS matrix for extracting MOSFET parameters before and after irradiation

International Nuclear Information System (INIS)

Blaes, B.R.; Buehler, M.G.; Lin, Y.S.; Hicks, K.A.

1988-01-01

An addressable matrix of 16 n- and 16 p-MOSFETs has been designed to extract the DC MOSFET parameters for all dc gate bias conditions before and after irradiation. The matrix contains four sets of MOSFETs each with four different geometries that can be biased independently before and after irradiation. Thus the worst-case bias scenarios can be determined. The MOSFET matrix was fabricated at a silicon foundry using a radiation-soft CMOS p-well LOCOS process. Cobalt 60 irradiation results for the n-MOSFETs showed a very low threshold voltage shift of -3mV/krad(Si); whereas, the p-MOSFETs showed 21 mV/krad(Si). The worst-case threshold voltage shift occurred for the n-MOSFET with a gate bias of 5V during anneal, but for the p-MOSFETs, biasing did not affect the shift in the threshold voltage. A parasitic MOSFET dominated the leakage of the n-MOSFET biased with 5V on the gate during irradiation

Radiation effect on silicon transistors in mixed neutrons-gamma environment

Science.gov (United States)

Assaf, J.; Shweikani, R.; Ghazi, N.

2014-10-01

The effects of gamma and neutron irradiations on two different types of transistors, Junction Field Effect Transistor (JFET) and Bipolar Junction Transistor (BJT), were investigated. Irradiation was performed using a Syrian research reactor (RR) (Miniature Neutron Source Reactor (MNSR)) and a gamma source (Co-60 cell). For RR irradiation, MCNP code was used to calculate the absorbed dose received by the transistors. The experimental results showed an overall decrease in the gain factors of the transistors after irradiation, and the JFETs were more resistant to the effects of radiation than BJTs. The effect of RR irradiation was also greater than that of gamma source for the same dose, which could be because neutrons could cause more damage than gamma irradiation.

High mobility polymer gated organic field effect transistor using zinc ...

Indian Academy of Sciences (India)

Organic thin film transistors were fabricated using evaporated zinc phthalocyanine as the active layer. Parylene film ... At room temperature, these transistors exhibit p-type conductivity with field-effect ... Keywords. Organic semiconductor; field effect transistor; phthalocyanine; high mobility. ... The evaporation rate was kept at ...

Molecular materials for organic field-effect transistors

International Nuclear Information System (INIS)

Mori, T

2008-01-01

Organic field-effect transistors are important applications of thin films of molecular materials. A variety of materials have been explored for improving the performance of organic transistors. The materials are conventionally classified as p-channel and n-channel, but not only the performance but also even the carrier polarity is greatly dependent on the combinations of organic semiconductors and electrode materials. In this review, particular emphasis is laid on multi-sulfur compounds such as tetrathiafulvalenes and metal dithiolates. These compounds are components of highly conducting materials such as organic superconductors, but are also used in organic transistors. The charge-transfer complexes are used in organic transistors as active layers as well as electrodes. (topical review)

Ultrashort Channel Length Black Phosphorus Field-Effect Transistors.

Science.gov (United States)

Miao, Jinshui; Zhang, Suoming; Cai, Le; Scherr, Martin; Wang, Chuan

2015-09-22

This paper reports high-performance top-gated black phosphorus (BP) field-effect transistors with channel lengths down to 20 nm fabricated using a facile angle evaporation process. By controlling the evaporation angle, the channel length of the transistors can be reproducibly controlled to be anywhere between 20 and 70 nm. The as-fabricated 20 nm top-gated BP transistors exhibit respectable on-state current (174 μA/μm) and transconductance (70 μS/μm) at a VDS of 0.1 V. Due to the use of two-dimensional BP as the channel material, the transistors exhibit relatively small short channel effects, preserving a decent on-off current ratio of 10(2) even at an extremely small channel length of 20 nm. Additionally, unlike the unencapsulated BP devices, which are known to be chemically unstable in ambient conditions, the top-gated BP transistors passivated by the Al2O3 gate dielectric layer remain stable without noticeable degradation in device performance after being stored in ambient conditions for more than 1 week. This work demonstrates the great promise of atomically thin BP for applications in ultimately scaled transistors.

Vertically aligned carbon nanotube field-effect transistors

KAUST Repository

Li, Jingqi

2012-10-01

Vertically aligned carbon nanotube field-effect transistors (CNTFETs) have been developed using pure semiconducting carbon nanotubes. The source and drain were vertically stacked, separated by a dielectric, and the carbon nanotubes were placed on the sidewall of the stack to bridge the source and drain. Both the effective gate dielectric and gate electrode were normal to the substrate surface. The channel length is determined by the dielectric thickness between source and drain electrodes, making it easier to fabricate sub-micrometer transistors without using time-consuming electron beam lithography. The transistor area is much smaller than the planar CNTFET due to the vertical arrangement of source and drain and the reduced channel area. © 2012 Elsevier Ltd. All rights reserved.

Comparison between Si/SiO{sub 2} and InP/Al{sub 2}O{sub 3} based MOSFETs

Energy Technology Data Exchange (ETDEWEB)

Akbari Tochaei, A., E-mail: amirakbari182@gmail.com; Arabshahi, H.; Benam, M. R. [Payame Noor University, Department of Physics (Iran, Islamic Republic of); Vatan-Khahan, A.; Abedininia, M. [Khayyam University, Department of Physics (Iran, Islamic Republic of)

2016-11-15

Electron transport properties of InP-based MOSFET as a new channel material with Al{sub 2}O{sub 3} as a high-k dielectric oxide layer in comparison with Si-based MOSFET are studied by the ensemble Monte Carlo simulation method in which the conduction band valleys in InP are based on three valley models with consideration of quantum effects (effective potential approach). I{sub d}–V{sub d} characteristics for Si-based MOSFET are in good agreement with theoretical and experimental results. Our results show that I{sub d} of InP-based MOSFET is about 2 times that of Si-based MOSFET. We simulated the diagrams of longitudinal and transverse electric fields, conduction band edge, average electron velocity, and average electron energy for Si-based MOSFET and compared the results with those for InP-based MOSFET. Our results, as was expected, show that the transverse electric field, the conduction band edge, the electron velocity, and the electron energy in a channel in the InP-based MOSFET are greater than those for Si-based MOSFET. But the longitudinal electric field behaves differently at different points of the channel.

Compact modeling of nanoscale triple-gate junctionless transistors covering drift-diffusion to quasi-ballistic carrier transport

Science.gov (United States)

Oproglidis, T. A.; Karatsori, T. A.; Barraud, S.; Ghibaudo, G.; Dimitriadis, C. A.

2018-04-01

In this work, we extend our analytical compact model for nanoscale junctionless triple-gate (JL TG) MOSFETs, capturing carrier transport from drift-diffusion to quasi-ballistic regime. This is based on a simple formulation of the low-field mobility extracted from experimental data using the Y-function method, taking into account the ballistic carrier motion and an increased carrier scattering in process-induced defects near the source/drain regions. The case of a Schottky junction in non-ideal ohmic contact at the drain side was also taken into account by modifying the threshold voltage and ideality factor of the JL transistor. The model is validated with experimental data for n-channel JL TG MOSFETs with channel length varying from 95 down to 25 nm. It can be easily implemented as a compact model for use in Spice circuit simulators.

Radiation-induced off-state leakage current in commercial power MOSFETs

International Nuclear Information System (INIS)

Dodd, Paul Emerson; Shaneyfelt, Marty Ray; Draper, Bruce Leroy; Felix, James Andrew; Schwank, James Ralph; Dalton, Scott Matthew

2005-01-01

The total dose hardness of several commercial power MOSFET technologies is examined. After exposure to 20 krad(SiO 2 ) most of the n- and p-channel devices examined in this work show substantial (2 to 6 orders of magnitude) increases in off-state leakage current. For the n-channel devices, the increase in radiation-induced leakage current follows standard behavior for moderately thick gate oxides, i.e., the increase in leakage current is dominated by large negative threshold voltage shifts, which cause the transistor to be partially on even when no bias is applied to the gate electrode. N-channel devices biased during irradiation show a significantly larger leakage current increase than grounded devices. The increase in leakage current for the p-channel devices, however, was unexpected. For the p-channel devices, it is shown using electrical characterization and simulation that the radiation-induced leakage current increase is related to an increase in the reverse bias leakage characteristics of the gated diode which is formed by the drain epitaxial layer and the body. This mechanism does not significantly contribute to radiation-induced leakage current in typical p-channel MOS transistors. The p-channel leakage current increase is nearly identical for both biased and grounded irradiations and therefore has serious implications for long duration missions since even devices which are usually powered off could show significant degradation and potentially fail.

A new memory effect (MSD) in fully depleted SOI MOSFETs

Science.gov (United States)

Bawedin, M.; Cristoloveanu, S.; Yun, J. G.; Flandre, D.

2005-09-01

We demonstrate that the transconductance and drain current of fully depleted MOSFETs can display an interesting time-dependent hysteresis. This new memory effect, called meta-stable dip (MSD), is mainly due to the long carrier generation lifetime in the silicon film. Our parametric analysis shows that the memory window can be adjusted in view of practical applications. Various measurement conditions and devices with different doping, front oxide and silicon film thicknesses are systematically explored. The MSD effect can be generalized to several fully depleted CMOS technologies. The MSD mechanism is discussed and validated by two-dimensional simulations results.

Power-MOSFET Voltage Regulator

Science.gov (United States)

Miller, W. N.; Gray, O. E.

1982-01-01

Ninety-six parallel MOSFET devices with two-stage feedback circuit form a high-current dc voltage regulator that also acts as fully-on solid-state switch when fuel-cell out-put falls below regulated voltage. Ripple voltage is less than 20 mV, transient recovery time is less than 50 ms. Parallel MOSFET's act as high-current dc regulator and switch. Regulator can be used wherever large direct currents must be controlled. Can be applied to inverters, industrial furnaces photovoltaic solar generators, dc motors, and electric autos.

MOSFET-like CNFET based logic gate library for low-power application: a comparative study

International Nuclear Information System (INIS)

Gowri Sankar, P. A.; Udhayakumar, K.

2014-01-01

The next generation of logic gate devices are expected to depend upon radically new technologies mainly due to the increasing difficulties and limitations of existing CMOS technology. MOSFET like CNFETs should ideally be the best devices to work with for high-performance VLSI. This paper presents results of a comprehensive comparative study of MOSFET-like carbon nanotube field effect transistors (CNFETs) technology based logic gate library for high-speed, low-power operation than conventional bulk CMOS libraries. It focuses on comparing four promising logic families namely: complementary-CMOS (C-CMOS), transmission gate (TG), complementary pass logic (CPL) and Domino logic (DL) styles are presented. Based on these logic styles, the proposed library of static and dynamic NAND-NOR logic gates, XOR, multiplexer and full adder functions are implemented efficiently and carefully analyzed with a test bench to measure propagation delay and power dissipation as a function of supply voltage. This analysis provides the right choice of logic style for low-power, high-speed applications. Proposed logic gates libraries are simulated using Synopsys HSPICE based on the standard 32 nm CNFET model. The simulation results demonstrate that, it is best to use C-CMOS logic style gates that are implemented in CNFET technology which are superior in performance compared to other logic styles, because of their low average power-delay-product (PDP). The analysis also demonstrates how the optimum supply voltage varies with logic styles in ultra-low power systems. The robustness of the proposed logic gate library is also compared with conventional and state-art of CMOS logic gate libraries. (semiconductor integrated circuits)

In vivo dosimetry in intraoperative electron radiotherapy. microMOSFETs, radiochromic films and a general-purpose linac

Energy Technology Data Exchange (ETDEWEB)

Lopez-Tarjuelo, Juan; Marco-Blancas, Noelia de; Santos-Serra, Agustin; Quiros-Higueras, Juan David [Consorcio Hospitalario Provincial de Castellon, Servicio de Radiofisica y Proteccion Radiologica, Castellon de la Plana (Spain); Bouche-Babiloni, Ana; Morillo-Macias, Virginia; Ferrer-Albiach, Carlos [Consorcio Hospitalario Provincial de Castellon, Servicio de Oncologia Radioterapica, Castellon de la Plana (Spain)

2014-11-15

In vivo dosimetry is desirable for the verification, recording, and eventual correction of treatment in intraoperative electron radiotherapy (IOERT). Our aim is to share our experience of metal oxide semiconductor field-effect transistors (MOSFETs) and radiochromic films with patients undergoing IOERT using a general-purpose linac. We used MOSFETs inserted into sterile bronchus catheters and radiochromic films that were cut, digitized, and sterilized by means of gas plasma. In all, 59 measurements were taken from 27 patients involving 15 primary tumors (seven breast and eight non-breast tumors) and 12 relapses. Data were subjected to an outliers' analysis and classified according to their compatibility with the relevant doses. Associations were sought regarding the type of detector, breast and non-breast irradiation, and the radiation oncologist's assessment of the difficulty of detector placement. At the same time, 19 measurements were carried out at the tumor bed with both detectors. MOSFET measurements (D = 93.5 %, s{sub D} = 6.5 %) were not significantly shifted from film measurements (D = 96.0 %, s{sub D} = 5.5 %; p = 0.109), and no associations were found (p = 0.526, p = 0.295, and p = 0.501, respectively). As regards measurements performed at the tumor bed with both detectors, MOSFET measurements (D = 95.0 %, s{sub D} = 5.4 %) were not significantly shifted from film measurements (D = 96.4 %, s{sub D} = 5.0 %; p = 0.363). In vivo dosimetry can produce satisfactory results at every studied location with a general-purpose linac. Detector choice should depend on user factors, not on the detector performance itself. Surgical team collaboration is crucial to success. (orig.) [German] Die In-vivo-Dosimetrie ist wuenschenswert fuer die Ueberpruefung, Registrierung und die eventuelle Korrektur der Behandlungen in der IOERT (''Intraoperative Electron Radiation Therapy''). Unser Ziel ist die Veroeffentlichung unserer Erfahrungen beim

Small field electron beam dosimetry using MOSFET detector.

Science.gov (United States)

Amin, Md Nurul; Heaton, Robert; Norrlinger, Bern; Islam, Mohammad K

2010-10-04

The dosimetry of very small electron fields can be challenging due to relative shifts in percent depth-dose curves, including the location of dmax, and lack of lateral electronic equilibrium in an ion chamber when placed in the beam. Conventionally a small parallel plate chamber or film is utilized to perform small field electron beam dosimetry. Since modern radiotherapy departments are becoming filmless in favor of electronic imaging, an alternate and readily available clinical dosimeter needs to be explored. We have studied the performance of MOSFET as a relative dosimeter in small field electron beams. The reproducibility, linearity and sensitivity of a high-sensitivity microMOSFET were investigated for clinical electron beams. In addition, the percent depth doses, output factors and profiles have been measured in a water tank with MOSFET and compared with those measured by an ion chamber for a range of field sizes from 1 cm diameter to 10 cm × 10 cm for 6, 12, 16 and 20 MeV beams. Similar comparative measurements were also per-formed with MOSFET and films in solid water phantom. The MOSFET sensitivity was found to be practically constant over the range of field sizes investigated. The dose response was found to be linear and reproducible (within ± 1% for 100 cGy). An excellent agreement was observed among the central axis depth dose curves measured using MOSFET, film and ion chamber. The output factors measured with MOSFET for small fields agreed to within 3% with those measured by film dosimetry. Overall results indicate that MOSFET can be utilized to perform dosimetry for small field electron beam.

Ultra-low specific on-resistance SOI double-gate trench-type MOSFET

International Nuclear Information System (INIS)

Lei Tianfei; Luo Xiaorong; Ge Rui; Chen Xi; Wang Yuangang; Yao Guoliang; Jiang Yongheng; Zhang Bo; Li Zhaoji

2011-01-01

An ultra-low specific on-resistance (R on,sp ) silicon-on-insulator (SOI) double-gate trench-type MOSFET (DG trench MOSFET) is proposed. The MOSFET features double gates and an oxide trench: the oxide trench is in the drift region, one trench gate is inset in the oxide trench and one trench gate is extended into the buried oxide. Firstly, the double gates reduce R on,sp by forming dual conduction channels. Secondly, the oxide trench not only folds the drift region, but also modulates the electric field, thereby reducing device pitch and increasing the breakdown voltage (BV). ABV of 93 V and a R on,sp of 51.8 mΩ·mm 2 is obtained for a DG trench MOSFET with a 3 μm half-cell pitch. Compared with a single-gate SOI MOSFET (SG MOSFET) and a single-gate SOI MOSFET with an oxide trench (SG trench MOSFET), the R on,sp of the DG trench MOSFET decreases by 63.3% and 33.8% at the same BV, respectively. (semiconductor devices)

Gate Control Coefficient Effect on CNFET Characteristic

International Nuclear Information System (INIS)

Sanudin, Rahmat; Ma'Radzi, Ahmad Alabqari; Nayan, Nafarizal

2009-01-01

The development of carbon nanotube field-effect transistor (CNFET) as alternative to existing transistor technology has long been published and discussed. The emergence of this device offers new material and structure in building a transistor. This paper intends to do an analysis of gate control coefficient effect on CNFET performance. The analysis is based on simulation study of current-voltage (I-V) characteristic of ballistic CNFET. The simulation study used the MOSFET-like CNFET mathematical model to establish the device output characteristic. Based on the analysis of simulation result, it is found that the gate control coefficient contributes to a significant effect on the performance of CNFET. The result also shown the parameter could help to improve the device performance in terms of its output and response as well. Nevertheless, the characteristic of the carbon nanotube that acts as the channel is totally important in determining the performance of the transistor as a whole.

Nanometer size field effect transistors for terahertz detectors

International Nuclear Information System (INIS)

Knap, W; Rumyantsev, S; Coquillat, D; Dyakonova, N; Teppe, F; Vitiello, M S; Tredicucci, A; Blin, S; Shur, M; Nagatsuma, T

2013-01-01

Nanometer size field effect transistors can operate as efficient resonant or broadband terahertz detectors, mixers, phase shifters and frequency multipliers at frequencies far beyond their fundamental cut-off frequency. This work is an overview of some recent results concerning the application of nanometer scale field effect transistors for the detection of terahertz radiation. (paper)

Research of shot noise based on realistic nano-MOSFETs

Directory of Open Access Journals (Sweden)

Xiaofei Jia

2017-05-01

Full Text Available Experimental measurements and simulation results have shown that the dominant noise source of current noise changes from thermal noise to shot noise with scaling of MOSFET, and shot noise were suppressed by Fermi and Coulomb interactions. In this paper, Shot noise test system is established, and experimental results proved that shot noise were suppressed, and the expressions of shot noise in realistic nano-MOSFETs are derived with considering Fermi effect, Coulomb interaction and the combination of the both co-existence, respectively. On this basis, the variation of shot noise with voltage, temperature and source-drain doping were researched. The results we obtained are consistent with those from experiments and the theoretically explanation is given. At the same time, the shot noise test system is suitable for traditional nanoscale electronic components; the shot noise model is suitable for nanoscale MOSFET.

Radiation effect of doping and bias conditions on NPN bipolar junction transistors

International Nuclear Information System (INIS)

Xi Shanbin; Wang Yiyuan; Xu Fayue; Zhou Dong; Li Ming; Wang Fei; Wang Zhikuan; Yang Yonghui; Lu Wu

2011-01-01

In this paper,we investigate 60 Co γ-ray irradiation effects and annealing behaviors of NPN bipolar junction transistors of the same manufacturing technology but different doping concentrations. The transistors of different doping concentrations differ in responses of the radiation effect. More degradation was observed with the transistors of low concentration-doped NPN transistors than the high concentration-doped NPN transistors. The results also demonstrate that reverse-biased transistors are more sensitive to radiation than the forward-biased ones. Mechanisms of the radiation responses are analyzed. (authors)

Direct tumor in vivo dosimetry in highly-conformal radiotherapy: A feasibility study of implantable MOSFETs for hypofractionated extracranial treatments using the Cyberknife system

International Nuclear Information System (INIS)

Scalchi, Paolo; Righetto, Roberto; Cavedon, Carlo; Francescon, Paolo; Colombo, Federico

2010-01-01

Purpose: In highly-conformal radiotherapy, due to the complexity of both beam configurations and dose distributions, traditional in vivo dosimetry is unpractical or even impossible. The ideal dosimeter would be implanted inside the planning treatment volume so that it can directly measure the total delivered dose during each fraction with no additional uncertainty due to calculation models. The aim of this work is to verify if implantable metal oxide semiconductors field effect transistors (MOSFETs) can achieve a sufficient degree of dosimetric accuracy when used inside extracranial targets undergoing radiotherapy treatments using the Cyberknife system. Methods: Based on the preliminary findings of this study, new prototypes for high dose fractionations were developed to reduce the time dependence for long treatment delivery times. These dosimeters were recently cleared and are marketed as DVS-HFT. Multiple measurements were performed using both Virtual Water and water phantoms to characterize implantable MOSFETs under the Cyberknife beams, and included the reference-dosimetry consistency, the dependence of the response on the collimator size, on the daily delivered dose, and the time irradiation modality. Finally a Cyberknife prostate treatment simulation using a body phantom was conducted, and both MOSFET and ionization readings were compared to Monte Carlo calculations. The feasibility analysis was conducted based on the ratios of the absorbed dose divided by the dose reading, named as ''further calibration factor'' (FCF). Results: The average FCFs resulted to be 0.98 for the collimator dependence test, and about 1.00 for the reference-dosimetry test, the dose-dependence test, and the time-dependence test. The average FCF of the prostate treatment simulation test was 0.99. Conclusions: The obtained results are well within DVS specifications, that is, the factory calibration is still valid for such kind of treatments using the Cyberknife system, with no need of

Separation Test Method for Investigation of Current Density Effects on Bond Wires of SiC Power MOSFET Modules

DEFF Research Database (Denmark)

Luo, Haoze; Iannuzzo, Francesco; Blaabjerg, Frede

2017-01-01

and average temperature during the test. By analyzing the output characteristics of the linear region of MOSFET, the constraint relations among the gate voltage, on-state voltage drop and junction temperature are revealed in this paper. The one-to-one correspondence between gate voltage and conduction power...... loss can be used to adjust the current density under fixed temperature swing and average temperature. The commercial Silicon Carbide (SiC) MOSFET modules are tested to experimentally verify the proposed method. Finally, the effectiveness of proposed test method is validated by the experimental results....

Radiation tolerance of Si{sub 1−y}C{sub y} source/drain n-type metal oxide semiconductor field effect transistors with different carbon concentrations

Energy Technology Data Exchange (ETDEWEB)

Nakashima, Toshiyuki, E-mail: nakashima_t@cdk.co.jp [Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki (Japan); Chuo Denshi Kogyo Co., Ltd., 3400 Kohoyama, Matsubase, Uki, Kumamoto (Japan); Asai, Yuki; Hori, Masato; Yoneoka, Masashi; Tsunoda, Isao; Takakura, Kenichiro [Kumamoto National College of Technology, 2659-2 Suya, Koshi, Kumamoto 861-1102 (Japan); Gonzalez, Mireia Bargallo [Institut de Microelectronica de Barcelona (Centre Nacional de Microelectronica — Consejo Superior de Investigaciones Cientificas) Campus UAB, 08193 Bellaterra (Spain); Simoen, Eddy [imec, Kapeldreef 75, B-3001 Leuven (Belgium); Claeys, Cor [imec, Kapeldreef 75, B-3001 Leuven (Belgium); Department of Electrical Engineering, KU Leuven, Kasteelpark Arenberg 10, B-3001 Leuven (Belgium); Yoshino, Kenji [Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki (Japan)

2014-04-30

The 2-MeV electron radiation damage of silicon–carbon source/drain (S/D) n-type metal oxide semiconductor field effect transistors with different carbon (C) concentrations is studied. Before irradiation, an enhancement of the electron mobility with C concentration of the S/D stressors is clearly observed. On the other hand, after electron irradiation, both the threshold voltage shift and the maximum electron mobility degradation are independent on the C concentration for all electron fluences studied. These results indicate that the strain induced electron mobility enhancement due to the C doping is retained after irradiation in the studied devices. - Highlights: • We have investigated the electron irradiation effect of the Si{sub 1−y}C{sub y} S/D n-MOSFETs. • The threshold voltage variations by irradiation are independent on the C doping. • The electron-mobility decreased for all C concentrations by electron irradiation. • The strain induced mobility enhancement effect is retained after irradiation.

Organic semiconductors for organic field-effect transistors

International Nuclear Information System (INIS)

Yamashita, Yoshiro

2009-01-01

The advantages of organic field-effect transistors (OFETs), such as low cost, flexibility and large-area fabrication, have recently attracted much attention due to their electronic applications. Practical transistors require high mobility, large on/off ratio, low threshold voltage and high stability. Development of new organic semiconductors is key to achieving these parameters. Recently, organic semiconductors have been synthesized showing comparable mobilities to amorphous-silicon-based FETs. These materials make OFETs more attractive and their applications have been attempted. New organic semiconductors resulting in high-performance FET devices are described here and the relationship between transistor characteristics and chemical structure is discussed. (topical review)

Organic semiconductors for organic field-effect transistors

Directory of Open Access Journals (Sweden)

Yoshiro Yamashita

2009-01-01

Full Text Available The advantages of organic field-effect transistors (OFETs, such as low cost, flexibility and large-area fabrication, have recently attracted much attention due to their electronic applications. Practical transistors require high mobility, large on/off ratio, low threshold voltage and high stability. Development of new organic semiconductors is key to achieving these parameters. Recently, organic semiconductors have been synthesized showing comparable mobilities to amorphous-silicon-based FETs. These materials make OFETs more attractive and their applications have been attempted. New organic semiconductors resulting in high-performance FET devices are described here and the relationship between transistor characteristics and chemical structure is discussed.

MOSFET assessment of radiation dose delivered to mice using the Small Animal Radiation Research Platform (SARRP).

Science.gov (United States)

Ngwa, Wilfred; Korideck, Houari; Chin, Lee M; Makrigiorgos, G Mike; Berbeco, Ross I

2011-12-01

The Small Animal Radiation Research Platform (SARRP) is a novel isocentric irradiation system that enables state-of-the-art image-guided radiotherapy research to be performed with animal models. This paper reports the results obtained from investigations assessing the radiation dose delivered by the SARRP to different anatomical target volumes in mice. Surgically implanted metal oxide semiconductor field effect transistors (MOSFET) dosimeters were employed for the dose assessment. The results reveal differences between the calculated and measured dose of -3.5 to 0.5%, -5.2 to -0.7%, -3.9 to 0.5%, -5.9 to 2.5%, -5.5 to 0.5%, and -4.3 to 0% for the left kidney, liver, pancreas, prostate, left lung, and brain, respectively. Overall, the findings show less than 6% difference between the delivered and calculated dose, without tissue heterogeneity corrections. These results provide a useful assessment of the need for tissue heterogeneity corrections in SARRP dose calculations for clinically relevant tumor model sites.

3D assembly of carbon nanotubes for fabrication of field-effect transistors through nanomanipulation and electron-beam-induced deposition

International Nuclear Information System (INIS)

Yu, Ning; Shi, Qing; Wang, Huaping; Huang, Qiang; Fukuda, Toshio; Nakajima, Masahiro; Yang, Zhan; Sun, Lining

2017-01-01

Three-dimensional carbon nanotube field-effect transistors (3D CNTFETs) possess predictable characteristics that rival those of planar CNTFETs and Si-based MOSFETs. However, due to the lack of a reliable assembly technology, they are rarely reported on, despite the amount of attention they receive. To address this problem, we propose the novel concept of a 3D CNTFET and develop its assembly strategy based on nanomanipulation and the electron-beam-induced deposition (EBID) technique inside a scanning electron microscope (SEM). In particular, the electrodes in our transistor design are three metallic cuboids of the same size, and their front, top and back surfaces are all wrapped up in CNTs. The assembly strategy is employed to build the structure through a repeated basic process of pick-up, placement, fixing and cutting of CNTs. The pick-up and placement is performed through one nanomanipulator with four degrees of freedom. Fixing is carried out through the EBID technique so as to improve the mechanical and electrical characteristics of the CNT/electrodes connection. CNT cutting is undertaken using the typical method of electrical breakdown. Experimental results showed that two CNTs were successfully assembled on the front sides of the cubic electrodes. This validates our assembly method for the 3D CNTFET. Also, when contact resistance was measured, tens of kilohms of resistance was observed at the CNT-EBID deposition-FET electrodes junction.. This manifests the electrical reliability of our assembly strategy. (paper)

Ambipolar charge transport in organic field-effect transistors

NARCIS (Netherlands)

Smits, E.C.P.; Anthopoulos, T.D.; Setayesh, S.; Veenendaal, van E.; Coehoorn, R.; Blom, P.W.M.; Boer, de B.; Leeuw, de D.M.

2006-01-01

A model describing charge transport in disordered ambipolar organic field-effect transistors is presented. The basis of this model is the variable-range hopping in an exponential density of states developed for disordered unipolar organic transistors. We show that the model can be used to calculate

Practical applications of SiC-MOSFETs and further developments

Science.gov (United States)

Furuhashi, Masayuki; Tomohisa, Shingo; Kuroiwa, Takeharu; Yamakawa, Satoshi

2016-03-01

The next generation power modules using SiC-MOSFETs have been developed for over ten years. From our successful results, we have released SiC power modules which have been used in railway vehicles, industrial machines and home appliances, etc. Low on-resistance 3.3 kV SiC-MOSFETs have been realized by JFET doping and they demonstrated a loss reduction of 55% in a traction inverter compared to a conventional system. In the case of a 1.2 kV MOSFET, a 1 cm2 die verified that it can control a large current of over 600 A. For home appliances, we reduce the trade-off between the threshold voltage and channel mobility by a new gate oxide process. High threshold voltage SiC-MOSFETs having a low on-resistance contribute to the low cost installation of SiC-MOSFETs into air conditioners and achieved a loss reduction of 45% in DC converters. For further reduction of conduction loss, we investigated new structures and technologies. Trench SiC-MOSFETs having a bottom p-well verify lower on-resistance and a larger SCSOA than those of planar MOSFETs. The optimization of the dopant concentration in the drift layer and a reduction of wafer thickness verified the reduction of on-resistance. They are expected to contribute to a lower power loss.

Practical applications of SiC-MOSFETs and further developments

International Nuclear Information System (INIS)

Furuhashi, Masayuki; Tomohisa, Shingo; Kuroiwa, Takeharu; Yamakawa, Satoshi

2016-01-01

The next generation power modules using SiC-MOSFETs have been developed for over ten years. From our successful results, we have released SiC power modules which have been used in railway vehicles, industrial machines and home appliances, etc. Low on-resistance 3.3 kV SiC-MOSFETs have been realized by JFET doping and they demonstrated a loss reduction of 55% in a traction inverter compared to a conventional system. In the case of a 1.2 kV MOSFET, a 1 cm 2 die verified that it can control a large current of over 600 A. For home appliances, we reduce the trade-off between the threshold voltage and channel mobility by a new gate oxide process. High threshold voltage SiC-MOSFETs having a low on-resistance contribute to the low cost installation of SiC-MOSFETs into air conditioners and achieved a loss reduction of 45% in DC converters. For further reduction of conduction loss, we investigated new structures and technologies. Trench SiC-MOSFETs having a bottom p-well verify lower on-resistance and a larger SCSOA than those of planar MOSFETs. The optimization of the dopant concentration in the drift layer and a reduction of wafer thickness verified the reduction of on-resistance. They are expected to contribute to a lower power loss. (paper)

A novel δ-doped partially insulated dopant-segregated Schottky barrier SOI MOSFET for analog/RF applications

International Nuclear Information System (INIS)

Patil, Ganesh C; Qureshi, S

2011-01-01

In this paper, a comparative analysis of single-gate dopant-segregated Schottky barrier (DSSB) SOI MOSFET and raised source/drain ultrathin-body SOI MOSFET (RSD UTB) has been carried out to explore the thermal efficiency, scalability and analog/RF performance of these devices. A novel p-type δ-doped partially insulated DSSB SOI MOSFET (DSSB Pi-OX-δ) has been proposed to reduce the self-heating effect and to improve the high-frequency performance of DSSB SOI MOSFET over RSD UTB. The improved analog/RF figures of merit such as transconductance, transconductance generation factor, unity-gain frequency, maximum oscillation frequency, short-circuit current gain and unilateral power gain in DSSB Pi-OX-δ MOSFET show the suitability of this device for analog/RF applications. The reduced drain-induced barrier lowering, subthreshold swing and parasitic capacitances also make this device highly scalable. By using mixed-mode simulation capability of MEDICI simulator a cascode amplifier has been implemented using all the structures (RSD UTB, DSSB SOI and DSSB Pi-OX-δ MOSFETs). The results of this implementation show that the gain-bandwidth product in the case of DSSB Pi-OX-δ MOSFET has improved by 50% as compared to RSD UTB and by 20% as compared to DSSB SOI MOSFET. The detailed fabrication flow of DSSB Pi-OX-δ MOSFET has been proposed which shows that with the bare minimum of steps the performance of DSSB SOI MOSFET can be improved significantly in comparison to RSD UTB

Nonlinear photoresponse of field effect transistors terahertz detectors at high irradiation intensities

International Nuclear Information System (INIS)

But, D. B.; Drexler, C.; Ganichev, S. D.; Sakhno, M. V.; Sizov, F. F.; Dyakonova, N.; Drachenko, O.; Gutin, A.; Knap, W.

2014-01-01

Terahertz power dependence of the photoresponse of field effect transistors, operating at frequencies from 0.1 to 3 THz for incident radiation power density up to 100 kW/cm 2 was studied for Si metal–oxide–semiconductor field-effect transistors and InGaAs high electron mobility transistors. The photoresponse increased linearly with increasing radiation intensity up to the kW/cm 2 range. Nonlinearity followed by saturation of the photoresponse was observed for all investigated field effect transistors for intensities above several kW/cm 2 . The observed photoresponse nonlinearity is explained by nonlinearity and saturation of the transistor channel current. A theoretical model of terahertz field effect transistor photoresponse at high intensity was developed. The model explains quantitative experimental data both in linear and nonlinear regions. Our results show that dynamic range of field effect transistors is very high and can extend over more than six orders of magnitudes of power densities (from ∼0.5 mW/cm 2 to ∼5 kW/cm 2 )

Thermal drift reduction with multiple bias current for MOSFET dosimeters

Energy Technology Data Exchange (ETDEWEB)

Carvajal, M A; Martinez-Olmos, A; Morales, D P; Lopez-Villanueva, J A; Palma, A J [Departamento de Electronica y TecnologIa de Computadores, ETSIIT, Universidad de Granada, E-18071 Granada (Spain); Lallena, A M, E-mail: carvajal@ugr.es [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, E-18071 Granada (Spain)

2011-06-21

New thermal compensation methods suitable for p-channel MOSFET (pMOS) dosimeters with the usual dose readout procedure based on a constant drain current are presented. Measuring the source-drain voltage shifts for two or three different drain currents and knowing the value of the zero-temperature coefficient drain current, I{sub ZTC}, the thermal drift of source-drain or threshold voltages can be significantly reduced. Analytical expressions for the thermal compensation have been theoretically deduced on the basis of a linear dependence on temperature of the parameters involved. The proposed thermal modelling has been experimentally proven. These methods have been applied to a group of ten commercial pMOS transistors (3N163). The thermal coefficients of the source-drain voltage and the threshold voltage were reduced from -3.0 mV deg. C{sup -1}, in the worst case, down to -70 {mu}V deg. C{sup -1}. This means a thermal drift of -2.4 mGy deg. C{sup -1} for the dosimeter. When analysing the thermal drifts of all the studied transistors, in the temperature range from 19 to 36 deg. C, uncertainty was obtained in the threshold voltage due to a thermal drift of {+-}9mGy (2 SD), a commonly acceptable value in most radiotherapy treatments. The procedures described herein provide thermal drift reduction comparable to that of other technological or numerical strategies, but can be used in a very simple and low-cost dosimetry sensor.

Switching transients in high-frequency high-power converters using power MOSFET's

Science.gov (United States)

Sloane, T. H.; Owen, H. A., Jr.; Wilson, T. G.

1979-01-01

The use of MOSFETs in a high-frequency high-power dc-to-dc converter is investigated. Consideration is given to the phenomena associated with the paralleling of MOSFETs and to the effect of stray circuit inductances on the converter circuit performance. Analytical relationships between various time constants during the turning-on and turning-off intervals are derived which provide estimates of plateau and peak levels during these intervals.

Performance characteristics of a microMOSFET as an in vivo dosimeter in radiation therapy

International Nuclear Information System (INIS)

Ramaseshan, R; Kohli, K S; Zhang, T J; Lam, T; Norlinger, B; Hallil, A; Islam, M

2004-01-01

The commercially available microMOSFET dosimeter was characterized for its dosimetric properties in radiotherapy treatments. The MOSFET exhibited excellent correlation with the dose and was linear in the range of 5-500 cGy. No measurable effect in response was observed in the temperature range of 20-40 0 C. No significant change in response was observed by changing the dose rate between 100 and 600 monitor units (MU) min -1 or change in the dose per pulse. A 3% post-irradiation fading was observed within the first 5 h of exposure and thereafter it remained stable up to 60 h. A uniform energy response was observed in the therapy range between 4 MV and 18 MV. However, below 0.6 MeV (Cs-132), the MOSFET response increased with the decrease in energy. The MOSFET also had a uniform dose response in 6-20 MeV electron beams. The directional dependence of MOSFET was within ±2% for all the energies studied. The inherent build-up of the MOSFET was evaluated dosimetrically and found to have varying water equivalent thickness, depending on the energy and the side of the beam entry. At depth, a single calibration factor obtained by averaging the MOSFET response over different field sizes, energies, orientation and depths reproduced the ion chamber measured dose to within 5%. The stereotactic and the penumbral measurements demonstrated that the MOSFET could be used in a high gradient field such as IMRT. The study showed that the microMOSFET dosimeter could be used as an in vivo dosimeter to verify the dose delivery to the patient to within ±5%

An Updated Perspective of Single Event Gate Rupture and Single Event Burnout in Power MOSFETs

Science.gov (United States)

Titus, Jeffrey L.

2013-06-01

Studies over the past 25 years have shown that heavy ions can trigger catastrophic failure modes in power MOSFETs [e.g., single-event gate rupture (SEGR) and single-event burnout (SEB)]. In 1996, two papers were published in a special issue of the IEEE Transaction on Nuclear Science [Johnson, Palau, Dachs, Galloway and Schrimpf, “A Review of the Techniques Used for Modeling Single-Event Effects in Power MOSFETs,” IEEE Trans. Nucl. Sci., vol. 43, no. 2, pp. 546-560, April. 1996], [Titus and Wheatley, “Experimental Studies of Single-Event Gate Rupture and Burnout in Vertical Power MOSFETs,” IEEE Trans. Nucl. Sci., vol. 43, no. 2, pp. 533-545, Apr. 1996]. Those two papers continue to provide excellent information and references with regard to SEB and SEGR in vertical planar MOSFETs. This paper provides updated references/information and provides an updated perspective of SEB and SEGR in vertical planar MOSFETs as well as provides references/information to other device types that exhibit SEB and SEGR effects.

Comparative study of leakage power in CNTFET over MOSFET device

International Nuclear Information System (INIS)

Sinha Sanjeet Kumar; Chaudhury Saurabh

2014-01-01

A comparison of the CNTFET device with the MOSFET device in the nanometer regime is reported. The characteristics of both devices are observed as varying the oxide thickness. Thereafter, we have analyzed the effect of the chiral vector and the temperature on the threshold voltage of the CNTFET device. After simulation on the HSPICE tool, we observed that the high threshold voltage can be achieved at a low chiral vector pair. It is also observed that the effect of temperature on the threshold voltage of the CNTFET is negligibly small. After that, we have analyzed the channel length variation and their impact on the threshold voltage of the CNTFET as well as MOSFET devices. We found an anomalous effect from our simulation result that the threshold voltage increases with decreasing the channel length in CNTFET devices; this is contrary to the well known short channel effect. It is observed that at below the 10 nm channel length, the threshold voltage is increased rapidly in the case of the CNTFET device, whereas in the case of the MOSFET device, the threshold voltage decreases drastically. (semiconductor devices)

Enhanced transconductance in a double-gate graphene field-effect transistor

Science.gov (United States)

Hwang, Byeong-Woon; Yeom, Hye-In; Kim, Daewon; Kim, Choong-Ki; Lee, Dongil; Choi, Yang-Kyu

2018-03-01

Multi-gate transistors, such as double-gate, tri-gate and gate-all-around transistors are the most advanced Si transistor structure today. Here, a genuine double-gate transistor with a graphene channel is experimentally demonstrated. The top and bottom gates of the double-gate graphene field-effect transistor (DG GFET) are electrically connected so that the conductivity of the graphene channel can be modulated simultaneously by both the top and bottom gate. A single-gate graphene field-effect transistor (SG GFET) with only the top gate is also fabricated as a control device. For systematical analysis, the transfer characteristics of both GFETs were measured and compared. Whereas the maximum transconductance of the SG GFET was 17.1 μS/μm, that of the DG GFET was 25.7 μS/μm, which is approximately a 50% enhancement. The enhancement of the transconductance was reproduced and comprehensively explained by a physics-based compact model for GFETs. The investigation of the enhanced transfer characteristics of the DG GFET in this work shows the possibility of a multi-gate architecture for high-performance graphene transistor technology.

Ultra Low Energy Binary Decision Diagram Circuits Using Few Electron Transistors

Science.gov (United States)

Saripalli, Vinay; Narayanan, Vijay; Datta, Suman

Novel medical applications involving embedded sensors, require ultra low energy dissipation with low-to-moderate performance (10kHz-100MHz) driving the conventional MOSFETs into sub-threshold operation regime. In this paper, we present an alternate ultra-low power computing architecture using Binary Decision Diagram based logic circuits implemented using Single Electron Transistors (SETs) operating in the Coulomb blockade regime with very low supply voltages. We evaluate the energy - performance tradeoff metrics of such BDD circuits using time domain Monte Carlo simulations and compare them with the energy-optimized CMOS logic circuits. Simulation results show that the proposed approach achieves better energy-delay characteristics than CMOS realizations.

Organic field-effect transistors using single crystals

International Nuclear Information System (INIS)

Hasegawa, Tatsuo; Takeya, Jun

2009-01-01

Organic field-effect transistors using small-molecule organic single crystals are developed to investigate fundamental aspects of organic thin-film transistors that have been widely studied for possible future markets for 'plastic electronics'. In reviewing the physics and chemistry of single-crystal organic field-effect transistors (SC-OFETs), the nature of intrinsic charge dynamics is elucidated for the carriers induced at the single crystal surfaces of molecular semiconductors. Materials for SC-OFETs are first reviewed with descriptions of the fabrication methods and the field-effect characteristics. In particular, a benchmark carrier mobility of 20-40 cm 2 Vs -1 , achieved with thin platelets of rubrene single crystals, demonstrates the significance of the SC-OFETs and clarifies material limitations for organic devices. In the latter part of this review, we discuss the physics of microscopic charge transport by using SC-OFETs at metal/semiconductor contacts and along semiconductor/insulator interfaces. Most importantly, Hall effect and electron spin resonance (ESR) measurements reveal that interface charge transport in molecular semiconductors is properly described in terms of band transport and localization by charge traps. (topical review)

Uniformity of fully gravure printed organic field-effect transistors

International Nuclear Information System (INIS)

Hambsch, M.; Reuter, K.; Stanel, M.; Schmidt, G.; Kempa, H.; Fuegmann, U.; Hahn, U.; Huebler, A.C.

2010-01-01

Fully mass-printed organic field-effect transistors were made completely by means of gravure printing. Therefore a special printing layout was developed in order to avoid register problems in print direction. Upon using this layout, contact pads for source-drain electrodes of the transistors are printed together with the gate electrodes in one and the same printing run. More than 50,000 transistors have been produced and by random tests a yield of approximately 75% has been determined. The principle suitability of the gravure printed transistors for integrated circuits has been shown by the realization of ring oscillators.

Organic tunnel field effect transistors

KAUST Repository

Tietze, Max Lutz; Lussem, Bjorn; Liu, Shiyi

2017-01-01

Various examples are provided for organic tunnel field effect transistors (OTFET), and methods thereof. In one example, an OTFET includes a first intrinsic layer (i-layer) of organic semiconductor material disposed over a gate insulating layer

Effect of initial material on the electrolytic parameters of field-effect transistors

International Nuclear Information System (INIS)

Antonov, A.V.; Sinitsyn, V.N.; Fursov, V.V.

1978-01-01

The effect of initial material parameters upon the main electric characteristics of field transistors at room and optimum (170 deg C) temperatures is studied. For that purpose, the values of parasitic resistances rsub(s), specific resistances rho and steepness S of field transistors, depending on temperature and electrical conditions were measured. The output volt-ampere characteristics of the transistors at room and optimum temperatures are given. An analysis of the results obtained permits to conclude that there is an unambiguous relationship between rho and rsub(s). Impact ionization is shown to occur for field transistors with lower rho at lower drain voltage. When manufacturing field transistors designed for operation at low temperatures, one should remember that a minimum rho may restrict maximum possible steepness. When designing field transistors with optimum noise characteristics, one should variate not only such material parameters as mobility and carrier density, but also select optimum geometry

Large-Signal DG-MOSFET Modelling for RFID Rectification

Directory of Open Access Journals (Sweden)

R. Rodríguez

2016-01-01

Full Text Available This paper analyses the undoped DG-MOSFETs capability for the operation of rectifiers for RFIDs and Wireless Power Transmission (WPT at microwave frequencies. For this purpose, a large-signal compact model has been developed and implemented in Verilog-A. The model has been numerically validated with a device simulator (Sentaurus. It is found that the number of stages to achieve the optimal rectifier performance is inferior to that required with conventional MOSFETs. In addition, the DC output voltage could be incremented with the use of appropriate mid-gap metals for the gate, as TiN. Minor impact of short channel effects (SCEs on rectification is also pointed out.

Monte Carlo simulation using the PENELOPE code with an ant colony algorithm to study MOSFET detectors

Energy Technology Data Exchange (ETDEWEB)

Carvajal, M A; Palma, A J [Departamento de Electronica y Tecnologia de Computadores, Universidad de Granada, E-18071 Granada (Spain); Garcia-Pareja, S [Servicio de Radiofisica Hospitalaria, Hospital Regional Universitario ' Carlos Haya' , Avda Carlos Haya, s/n, E-29010 Malaga (Spain); Guirado, D [Servicio de RadiofIsica, Hospital Universitario ' San Cecilio' , Avda Dr Oloriz, 16, E-18012 Granada (Spain); Vilches, M [Servicio de Fisica y Proteccion Radiologica, Hospital Regional Universitario ' Virgen de las Nieves' , Avda Fuerzas Armadas, 2, E-18014 Granada (Spain); Anguiano, M; Lallena, A M [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, E-18071 Granada (Spain)], E-mail: carvajal@ugr.es, E-mail: garciapareja@gmail.com, E-mail: dguirado@ugr.es, E-mail: mvilches@ugr.es, E-mail: mangui@ugr.es, E-mail: ajpalma@ugr.es, E-mail: lallena@ugr.es

2009-10-21

In this work we have developed a simulation tool, based on the PENELOPE code, to study the response of MOSFET devices to irradiation with high-energy photons. The energy deposited in the extremely thin silicon dioxide layer has been calculated. To reduce the statistical uncertainties, an ant colony algorithm has been implemented to drive the application of splitting and Russian roulette as variance reduction techniques. In this way, the uncertainty has been reduced by a factor of {approx}5, while the efficiency is increased by a factor of above 20. As an application, we have studied the dependence of the response of the pMOS transistor 3N163, used as a dosimeter, with the incidence angle of the radiation for three common photons sources used in radiotherapy: a {sup 60}Co Theratron-780 and the 6 and 18 MV beams produced by a Mevatron KDS LINAC. Experimental and simulated results have been obtained for gantry angles of 0 deg., 15 deg., 30 deg., 45 deg., 60 deg. and 75 deg. The agreement obtained has permitted validation of the simulation tool. We have studied how to reduce the angular dependence of the MOSFET response by using an additional encapsulation made of brass in the case of the two LINAC qualities considered.

Cryogenic switched MOSFET characterization

Science.gov (United States)

1981-01-01

Both p channel and n channel enhancement mode MOSFETs can be readily switched on and off at temperatures as low as 2.8 K so that switch sampled readout of a VLWIR Ge:Ga focal plane is electronically possible. Noise levels as low as 100 rms electrons per sample (independent of sample rate) can be achieved using existing p channel MOSFETs, at overall rates up to 30,000 samples/second per multiplexed channel (e.g., 32 detectors at a rate of almost 1,000 frames/second). Run of the mill devices, including very low power dissipation n channel FETs would still permit noise levels of the order of 500 electrons/sample.

Criteria for setting the width of CCD front end transistor to reach minimum pixel noise

International Nuclear Information System (INIS)

Fasoli, L.; Sampietro, M.

1996-01-01

The paper gives the criteria to calculate the width of the front end transistor integrated next to the charge sensing electrode of CCD's or, in general, of semiconductor detectors, in order to reach the minimum noise in the readout of the signal charge. The paper, for the first time, accounts for white, series and parallel, and 1/f noise contribution. In addition, it points out two different design criteria depending whether a JFET or a MOSFET is used. The attention given to the JFET is due to a lower 1/f noise component, which makes these transistors more and more appealing as input devices in very high resolution detectors. The paper shows that there is a characteristic width of the FET gate that practically doesn't depend on the noise sources but depends only on the capacitance seen by the charge sensing electrode of the detector, making possible the optimum design of the transistor prior to the knowledge of the real values of the spectral density of the noise sources, which are usually precisely known only at the end of the fabrication process. The paper shows that the pixel noise raises sharply as the transistor gate width departs from its optimum value

The effect and mechanism of the bipolar junction transistor in different temperature

International Nuclear Information System (INIS)

Wang Dong; Lu Wu; Ren Diyuan; Li Aiwu; Kuang Zhibing

2007-01-01

The annealing-effect of bipolar junction transistor in different temperature is investigated. It is found that the anneal of the bipolar transistor is related to the annealing-temperature, and the annealing-effect of the different type transistor is dissimilar. The possible mechanism is discussed. (authors)

Ferroelectric field-effect transistors based on solution-processed electrochemically exfoliated graphene

Science.gov (United States)

Heidler, Jonas; Yang, Sheng; Feng, Xinliang; Müllen, Klaus; Asadi, Kamal

2018-06-01

Memories based on graphene that could be mass produced using low-cost methods have not yet received much attention. Here we demonstrate graphene ferroelectric (dual-gate) field effect transistors. The graphene has been obtained using electrochemical exfoliation of graphite. Field-effect transistors are realized using a monolayer of graphene flakes deposited by the Langmuir-Blodgett protocol. Ferroelectric field effect transistor memories are realized using a random ferroelectric copolymer poly(vinylidenefluoride-co-trifluoroethylene) in a top gated geometry. The memory transistors reveal ambipolar behaviour with both electron and hole accumulation channels. We show that the non-ferroelectric bottom gate can be advantageously used to tune the on/off ratio.

SU-F-T-474: Evaluation of Dose Perturbation, Temperature and Sensitivity Variation With Accumulated Dose of MOSFET Detector

Energy Technology Data Exchange (ETDEWEB)

Ganesan, B; Prakasarao, A; Singaravelu, G [Anna University, Chennai, TamilNadu (India); Palraj, T; Rai, R [Dr. Rai Memorial Cancer Institute, Chennai, TamilNadu (India)

2016-06-15

Purpose: The use of mega voltage gamma and x-ray sources with their skin sparring qualities in radiation therapy has been a boon in relieving patient discomfort and allowing high tumor doses to be given with fewer restrictions due to radiation effects in the skin. However, high doses given to deep tumors may require careful consideration of dose distribution in the buildup region in order to avoid irreparable damage to the skin. Methods: To measure the perturbation of MOSFET detector in Co60,6MV and 15MV the detector was placed on the surface of the phantom covered with the brass build up cap. To measure the effect of temperature the MOSFET detector was kept on the surface of hot water polythene container and the radiation was delivere. In order to measure the sensitivity variation with accumulated dose Measurements were taken by delivering the dose of 200 cGy to MOSFET until the MOSFET absorbed dose comes to 20,000 cGy Results: the Measurement was performed by positioning the bare MOSFET and MOSFET with brass build up cap on the top surface of the solid water phantom for various field sizes in order to find whether there is any attenuation caused in the dose distribution. The response of MOSFET was monitored for temperature ranging from 42 degree C to 22 degree C. The integrated dose dependence of MOSFET dosimeter sensitivity over different energy is not well characterized. This work investigates the dual-bias MOSFET dosimeter sensitivity response to 6 MV and 15 MV beams. Conclusion: From this study it is observed that unlike diode, bare MOSFET does not perturb the radiation field.. It is observed that the build-up influences the temperature dependency of MOSFET and causes some uncertainty in the readings. In the case of sensitivity variation with accumulated dose MOSFET showed higher sensitivity with dose accumulation for both the energies.

SU-F-T-474: Evaluation of Dose Perturbation, Temperature and Sensitivity Variation With Accumulated Dose of MOSFET Detector

International Nuclear Information System (INIS)

Ganesan, B; Prakasarao, A; Singaravelu, G; Palraj, T; Rai, R

2016-01-01

Purpose: The use of mega voltage gamma and x-ray sources with their skin sparring qualities in radiation therapy has been a boon in relieving patient discomfort and allowing high tumor doses to be given with fewer restrictions due to radiation effects in the skin. However, high doses given to deep tumors may require careful consideration of dose distribution in the buildup region in order to avoid irreparable damage to the skin. Methods: To measure the perturbation of MOSFET detector in Co60,6MV and 15MV the detector was placed on the surface of the phantom covered with the brass build up cap. To measure the effect of temperature the MOSFET detector was kept on the surface of hot water polythene container and the radiation was delivere. In order to measure the sensitivity variation with accumulated dose Measurements were taken by delivering the dose of 200 cGy to MOSFET until the MOSFET absorbed dose comes to 20,000 cGy Results: the Measurement was performed by positioning the bare MOSFET and MOSFET with brass build up cap on the top surface of the solid water phantom for various field sizes in order to find whether there is any attenuation caused in the dose distribution. The response of MOSFET was monitored for temperature ranging from 42 degree C to 22 degree C. The integrated dose dependence of MOSFET dosimeter sensitivity over different energy is not well characterized. This work investigates the dual-bias MOSFET dosimeter sensitivity response to 6 MV and 15 MV beams. Conclusion: From this study it is observed that unlike diode, bare MOSFET does not perturb the radiation field.. It is observed that the build-up influences the temperature dependency of MOSFET and causes some uncertainty in the readings. In the case of sensitivity variation with accumulated dose MOSFET showed higher sensitivity with dose accumulation for both the energies.

Saving Moore’s Law Down To 1 nm Channels With Anisotropic Effective Mass

Science.gov (United States)

Ilatikhameneh, Hesameddin; Ameen, Tarek; Novakovic, Bozidar; Tan, Yaohua; Klimeck, Gerhard; Rahman, Rajib

2016-08-01

Scaling transistors’ dimensions has been the thrust for the semiconductor industry in the last four decades. However, scaling channel lengths beyond 10 nm has become exceptionally challenging due to the direct tunneling between source and drain which degrades gate control, switching functionality, and worsens power dissipation. Fortunately, the emergence of novel classes of materials with exotic properties in recent times has opened up new avenues in device design. Here, we show that by using channel materials with an anisotropic effective mass, the channel can be scaled down to 1 nm and still provide an excellent switching performance in phosphorene nanoribbon MOSFETs. To solve power consumption challenge besides dimension scaling in conventional transistors, a novel tunnel transistor is proposed which takes advantage of anisotropic mass in both ON- and OFF-state of the operation. Full-band atomistic quantum transport simulations of phosphorene nanoribbon MOSFETs and TFETs based on the new design have been performed as a proof.

SOI N-Channel Field Effect Transistors, CHT-NMOS80, for Extreme Temperatures