Research on high voltage(HV)silicon carbide(SiC)power semiconductor devices has attracted much attention in recent years.This paper overviews the development and status of HV SiC devices.Meanwhile,benefits of HV SiC d...Research on high voltage(HV)silicon carbide(SiC)power semiconductor devices has attracted much attention in recent years.This paper overviews the development and status of HV SiC devices.Meanwhile,benefits of HV SiC devices are presented.The technologies and challenges for HV SiC device application in converter design are discussed.The state-of-the-art applications of HV SiC devices are also reviewed.展开更多
The effect of nitric oxide（NO） annealing on charge traps in the oxide insulator and transition layer in n-type4H–Si C metal–oxide–semiconductor（MOS） devices has been investigated using the time-dependent bias s...The effect of nitric oxide（NO） annealing on charge traps in the oxide insulator and transition layer in n-type4H–Si C metal–oxide–semiconductor（MOS） devices has been investigated using the time-dependent bias stress（TDBS）,capacitance–voltage（C–V）,and secondary ion mass spectroscopy（SIMS）.It is revealed that two main categories of charge traps,near interface oxide traps（Nniot） and oxide traps（Not）,have different responses to the TDBS and C–V characteristics in NO-annealed and Ar-annealed samples.The Nniotare mainly responsible for the hysteresis occurring in the bidirectional C–V characteristics,which are very close to the semiconductor interface and can readily exchange charges with the inner semiconductor.However,Not is mainly responsible for the TDBS induced C–V shifts.Electrons tunneling into the Not are hardly released quickly when suffering TDBS,resulting in the problem of the threshold voltage stability.Compared with the Ar-annealed sample,Nniotcan be significantly suppressed by the NO annealing,but there is little improvement of Not.SIMS results demonstrate that the Nniotare distributed within the transition layer,which correlated with the existence of the excess silicon.During the NO annealing process,the excess Si atoms incorporate into nitrogen in the transition layer,allowing better relaxation of the interface strain and effectively reducing the width of the transition layer and the density of Nniot.展开更多
A two-dimensional （2D） full band self-consistent ensemble Monte Carlo （MC） method for solving the quantum Boltzmann equation, including collision broadening and quantum potential corrections, is developed to exten...A two-dimensional （2D） full band self-consistent ensemble Monte Carlo （MC） method for solving the quantum Boltzmann equation, including collision broadening and quantum potential corrections, is developed to extend the MC method to the study of nano-scale semiconductor devices with obvious quantum mechanical （QM） effects. The quantum effects both in real space and momentum space in nano-scale semiconductor devices can be simulated. The effective mobility in the inversion layer of n and p channel MOSFET is simulated and compared with experimental data to verify this method. With this method 50nm ultra thin body silicon on insulator MOSFET are simulated. Results indicate that this method can be used to simulate the 2D QM effects in semiconductor devices including tunnelling effect.展开更多
In power electronics applications,the selection of condition monitoring methods significantly affects both the precision and complexity of the junction temperature evaluation,which is essential for the reliability ass...In power electronics applications,the selection of condition monitoring methods significantly affects both the precision and complexity of the junction temperature evaluation,which is essential for the reliability assessment of power semiconductor devices.This study begins with a failure mechanism analysis of state-of-the-art power semiconductor devices.Junction temperature measurement methods can be categorized into three distinct approaches:thermal image-based,thermal model-based,and temperature-sensitive electrical parameter(TSEP)-based methods.Their respective advantages and disadvantages are comprehensively compared.Moreover,condition monitoring of the ON-state voltage drop is summarized and benchmarked.ON-state voltage and junction temperature measurements are experimentally demonstrated in a standard three-phase converter,which provides superior measurement accuracy and rapid dynamic response characteristics.Additionally,this investigation is extended to measurement methods for TSEP in wide-bandgap semiconductors.展开更多
We propose a finite element method to investigate the phenomena of shock wave and to simulate the hydrodynamic model in semiconductor devices. An introduction of this model is discussed first. Then some scaling factor...We propose a finite element method to investigate the phenomena of shock wave and to simulate the hydrodynamic model in semiconductor devices. An introduction of this model is discussed first. Then some scaling factors and a relationship between the changing variables are discussed. And then, we use a finite element method （P1-iso-P2 element） to discrete the equations. Some boundary conditions are also discussed. Finally, a sub-micron n%＋-n-n^＋ silicon diode and Si MESFET device are simulated and the results are analyzed. Numerical results show that electronic fluids are transonic under some conditions.展开更多
We present in this paper a new method,based on measurements of conventional direct current-voltage(I-V) characteristics and transient voltage-time(V-t) characteristics during the discharge process,for determining capa...We present in this paper a new method,based on measurements of conventional direct current-voltage(I-V) characteristics and transient voltage-time(V-t) characteristics during the discharge process,for determining capacitance-voltage(C-V) characteris-tics of organic semiconductor devices.Derivatives of I-V and V-t,dI/dV and dV/dt,are related with C by a simple formula C=-V(dI/dV)/(dV/dt)The validity of the method is confirmed by experimental data measured from a set of single-organic-layer devices with different layer thicknesses.展开更多
Superjunction(SJ)is one of the most innovative concepts in the field of power semiconductor devices and is often referred to as a"milestone"in power MOS.Its balanced charge field modulation mechanism breaks ...Superjunction(SJ)is one of the most innovative concepts in the field of power semiconductor devices and is often referred to as a"milestone"in power MOS.Its balanced charge field modulation mechanism breaks through the strong dependency between the doping concentration in the drift region and the breakdown voltage V_(B)in conventional devices.This results in a reduction of the trade-off relationship between specific on-resistance R_(on,sp)and V_(B)from the conventional R_(on,sp)∝V_(B)^(2.5)to R_(on,sp)∝W·V_(B)^(1.32),and even to R_(on,sp)∝W·V_(B)^(1.03).As the exponential term coefficient decreases,R_(on,sp)decreases with the cell width W,exhibiting a development pattern reminiscent of"Moore's Law".This paper provides an overview of the latest research developments in SJ power semiconductor devices.Firstly,it introduces the minimum specific on-resistance R_(on,min)theory of SJ devices,along with its combination with special effects like 3-D depletion and tunneling,discussing the development of R_(on,min)theory in the wide bandgap SJ field.Subsequently,it discusses the latest advancements in silicon-based and wide bandgap SJ power devices.Finally,it introduces the homogenization field(HOF)and high-K voltage-sustaining layers derived from the concept of SJ charge balance.SJ has made significant progress in device performance,reliability,and integration,and in the future,it will continue to evolve through deeper integration with different materials,processes,and packaging technologies,enhancing the overall performance of semiconductor power devices.展开更多
The temperature dependence of some performance of 6H SiC unipolar power devices is analyzed theoretically.By employing the temperature dependent ionization coefficient and mobility of a silicon carbide,the analytica...The temperature dependence of some performance of 6H SiC unipolar power devices is analyzed theoretically.By employing the temperature dependent ionization coefficient and mobility of a silicon carbide,the analytical expressions of the temperature dependent performance,such as breakdown characteristics and on resistance of 6H SiC unipolar power devices are derived in a closed form.The analytical results are compared with the experimental results,with good accordance found in the breakdown characteristics.展开更多
The degradation mechanisms of Schottky p-GaN gate AlGaN/GaN HEMTs under high-temperature reverse bias(HTRB)stress were investigated and the evolution of the deep traps was identified using deep-level transient spectro...The degradation mechanisms of Schottky p-GaN gate AlGaN/GaN HEMTs under high-temperature reverse bias(HTRB)stress were investigated and the evolution of the deep traps was identified using deep-level transient spectroscopy.The saturation current of p-GaN gate AlGaN/GaN HEMTs decreased by 18.2%and the threshold voltage shifted positively by 11.6%after the degradation.An electron trap(at 369 K)and a hole trap(at 95 K)were observed in the AlGaN/GaN region,while another hole trap(at 359 K)was found in the p-GaN layer before the stress.Meanwhile,after the stress,the concentration and capture cross section of the hole traps increased in both the p-GaN layer and the AlGaN/GaN region.With regard to the electron trap in the AlGaN/GaN region,the capture cross section increased significantly but the electron trap concentration slightly decreased,which may increase the electron trapping,thereby reducing electrons in the two-dimensional electron gas.These factors result in a positive shift in the threshold voltage and a decrease in the output current.This work provides a new insight into understanding the threshold voltage instability of Schottky p-GaN gate AlGaN/GaN HEMTs.展开更多
Influences of swift heavy ion(SHI)irradiation induced defects on electronic properties of the bulk SnSe_(2)based FETs are explored.Latent tracks and amounts of Se vacancies in the irradiated SnSe_(2)were confirmed.Red...Influences of swift heavy ion(SHI)irradiation induced defects on electronic properties of the bulk SnSe_(2)based FETs are explored.Latent tracks and amounts of Se vacancies in the irradiated SnSe_(2)were confirmed.Red shift of the A1g peak indicates that the resonance frequency of the phonons is reduced due to the defect generation in SnSe_(2).The source–drain current Ids increased at ion fluence of 1×10^(10)ions·cm^(-2),which was attributeded to the irradiation caused Se vacancies,which hence increases the concentration of conduction electrons.The carrier mobility was about 16.9 cm^(2)·V^(-1)·s^(-1)for the devices irradiated at ion fluence of 1×10^(9)ions·cm^(-2),which benefited from heavy ion irradiation enhanced interlayer coupling.The mechanism of device performance optimization after irradiation is discussed in detail.This work provides evidence that,given the electronic properties of two-dimensional material-based device,vacancies and interlayer coupling effects caused by SHI irradiation should not be ignored.展开更多
In this study,we present the fabrication of vertical SnO/β-Ga_(2)O_(3) heterojunction diode(HJD)via radio frequency(RF)reactive magnetron sputtering.The valence and conduction band offsets betweenβ-Ga_(2)O_(3) and S...In this study,we present the fabrication of vertical SnO/β-Ga_(2)O_(3) heterojunction diode(HJD)via radio frequency(RF)reactive magnetron sputtering.The valence and conduction band offsets betweenβ-Ga_(2)O_(3) and SnO are determined to be 2.65and 0.75 eV,respectively,through X-ray photoelectron spectroscopy,showing a type-Ⅱband alignment.Compared to its Schottky barrier diode(SBD)counterpart,the HJD presents a comparable specific ON-resistances(R_(on,sp))of 2.8 mΩ·cm^(2) and lower reverse leakage current(I_R),leading to an enhanced reverse blocking characteristics with breakdown voltage(BV)of 1675 V and power figure of merit(PFOM)of 1.0 GW/cm~2.This demonstrates the high quality of the SnO/β-Ga_(2)O_(3) heterojunction interface.Silvaco TCAD simulation further reveals that electric field crowding at the edge of anode for the SBD was greatly depressed by the introduction of SnO film,revealing the potential application of SnO/β-Ga_(2)O_(3) heterojunction in the futureβ-Ga_(2)O_(3)-based power devices.data mining,AI training,and similar technologies,are reserved.展开更多
Black phosphorus （BP）, an attractive two-dimensional （2D） semiconductor, is widely used in the fields of optoelec- tronic devices, biomedicine, and chemical sensing. Silver ion （Ag＋）, a commonly used additive i...Black phosphorus （BP）, an attractive two-dimensional （2D） semiconductor, is widely used in the fields of optoelec- tronic devices, biomedicine, and chemical sensing. Silver ion （Ag＋）, a commonly used additive in food industry, can sterilize and keep food fresh. But excessive intake of Ag＋ will harm human health. Therefore, high sensitive, fast and simple Ag＋ detection method is significant. Here, a high-performance BP field effect transistor （FET） sensor is fabricated for Ag＋ detection with high sensitivity, rapid detection speed, and wide detection concentration range. The detection limit for Ag＋ is 10 l0 mol/L. Testing time for each sample by this method is 60 s. Besides, the mechanism of BP-FET sensor for Ag＋ detection is investigated systematically. The simple BP-FET sensor may inspire some relevant research and potential applications, such as providing an effective method for the actual detection of Ag＋, especially in wimessed inspections field of food.展开更多
Superjunction technology is believed to reach the optimal specific on-resistance and breakdown voltage trade-off.It has become a mainstream technology in silicon high-voltage metal oxide semiconductor field effect tra...Superjunction technology is believed to reach the optimal specific on-resistance and breakdown voltage trade-off.It has become a mainstream technology in silicon high-voltage metal oxide semiconductor field effect transistor devices.Numerous efforts have been conducted to employ the same concept in silicon carbide devices.These works are summarized here.展开更多
Metal halide perovskites, as a novel class of semiconductor optoelectronic materials, combine the excellent optoelectronic properties of inorganic semiconductors with the advantages of low-cost, printable fabrication ...Metal halide perovskites, as a novel class of semiconductor optoelectronic materials, combine the excellent optoelectronic properties of inorganic semiconductors with the advantages of low-cost, printable fabrication typical of organic semiconductors, making them a cutting-edge research focus in the field of semiconductor optoelectronic devices.展开更多
Characteristic finite difference fractional step schemes are put forward. The electric potential equation is described by a seven-point finite difference scheme, and the electron and hole concentration equations are t...Characteristic finite difference fractional step schemes are put forward. The electric potential equation is described by a seven-point finite difference scheme, and the electron and hole concentration equations are treated by a kind of characteristic finite difference fractional step methods. The temperature equation is described by a fractional step method. Thick and thin grids are made use of to form a complete set. Piecewise threefold quadratic interpolation, symmetrical extension, calculus of variations, commutativity of operator product, decomposition of high order difference operators and prior estimates are also made use of. Optimal order estimates in l2 norm are derived to determine the error of the approximate solution. The well-known problem is thorongley and completely solred.展开更多
The weak solutions to the stationary quantum drift-diffusion equations （QDD） for semiconductor devices are investigated in one space dimension. The proofs are based on a reformulation of the system as a fourth-order...The weak solutions to the stationary quantum drift-diffusion equations （QDD） for semiconductor devices are investigated in one space dimension. The proofs are based on a reformulation of the system as a fourth-order elliptic boundary value problem by using an exponential variable transformation. The techniques of a priori estimates and Leray-Schauder＇s fixed-point theorem are employed to prove the existence. Furthermore, the uniqueness of solutions and the semiclassical limit δ→0 from QDD to the classical drift-diffusion （DD） model are studied.展开更多
Metal-tip/Pr0.7Ca0.3MnO3/Pt devices possess two types of I-V hysteresis： clockwise vs counter clockwise depending on the tip materials. The criteria for categorization of these two types of devices can be simply base...Metal-tip/Pr0.7Ca0.3MnO3/Pt devices possess two types of I-V hysteresis： clockwise vs counter clockwise depending on the tip materials. The criteria for categorization of these two types of devices can be simply based on whether the Gibbs free energy of oxidation for the metal tip is lower or higher than that of PCMO, respectively. While the clockwise hysteresis can be attributed to electric field induced oxidation/reduction, the counter clockwise hysteresis can be explained by oxygen vacancy migration in an electrical field. Alternating-current conductance spectra also reveal distinct hopping barriers between these two categories of devices at high resistive states.展开更多
The mathematical model of a semiconductor device is governed by a system of quasi-linear partial differential equations.The electric potential equation is approximated by a mixed finite element method,and the concentr...The mathematical model of a semiconductor device is governed by a system of quasi-linear partial differential equations.The electric potential equation is approximated by a mixed finite element method,and the concentration equations are approximated by a standard Galerkin method.We estimate the error of the numerical solutions in the sense of the Lqnorm.To linearize the full discrete scheme of the problem,we present an efficient two-grid method based on the idea of Newton iteration.The main procedures are to solve the small scaled nonlinear equations on the coarse grid and then deal with the linear equations on the fine grid.Error estimation for the two-grid solutions is analyzed in detail.It is shown that this method still achieves asymptotically optimal approximations as long as a mesh size satisfies H=O(h^1/2).Numerical experiments are given to illustrate the efficiency of the two-grid method.展开更多
The transient behavior of a semiconductor device consists of a Poisson equation for the electric potential and of two nonlinear parabolic equations for the electron density and hole density. The electric potential equ...The transient behavior of a semiconductor device consists of a Poisson equation for the electric potential and of two nonlinear parabolic equations for the electron density and hole density. The electric potential equation is discretized by a mixed finite element method. The electron and hole density equations are treated by implicit-explicit multistep finite element methods. The schemes are very efficient. The optimal order error estimates both in time and space are derived.展开更多
To some extent,the operational quickness of semiconductor devices depends on the transmission time of an electron through semiconductor nanostructures.However,the calculation of transmission time is very difficult,tha...To some extent,the operational quickness of semiconductor devices depends on the transmission time of an electron through semiconductor nanostructures.However,the calculation of transmission time is very difficult,thanks to both the contentious definition of the transmission time in quantum mechanics and the complicated effective potential functions experienced by electrons in semiconductor devices.Here,based on an improved transfer matrix method to numerically solve the Schr?dinger equation and H G Winful’s relationship to calculate the dwell time,we develop a numerical approach to evaluate the transmission time of an electron in semiconductor devices.Compared to the exactly resolvable case of the rectangular potential barrier,the established numerical approach possesses high precision and small error,which may be employed to explore the dynamic response and operating speed of semiconductor devices.This proposed numerical method is successfully applied to the calculation of dwell time for an electron in double rectangular potential barriers and the dependence of transmission time on the number of potential barriers is revealed.展开更多
基金This work made use of the Engineering Research Center Shared Facilities supported by the Engineering Research Center Program of the National Science Foundation and DOE under ARPA-E and Power America Program and the CURENT Industry Partnership Program.
文摘Research on high voltage(HV)silicon carbide(SiC)power semiconductor devices has attracted much attention in recent years.This paper overviews the development and status of HV SiC devices.Meanwhile,benefits of HV SiC devices are presented.The technologies and challenges for HV SiC device application in converter design are discussed.The state-of-the-art applications of HV SiC devices are also reviewed.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61404098 and 61274079)the Doctoral Fund of Ministry of Education of China(Grant No.20130203120017)+2 种基金the National Key Basic Research Program of China(Grant No.2015CB759600)the National Grid Science&Technology Project,China(Grant No.SGRI-WD-71-14-018)the Key Specific Project in the National Science&Technology Program,China(Grant Nos.2013ZX02305002-002 and 2015CB759600)
文摘The effect of nitric oxide（NO） annealing on charge traps in the oxide insulator and transition layer in n-type4H–Si C metal–oxide–semiconductor（MOS） devices has been investigated using the time-dependent bias stress（TDBS）,capacitance–voltage（C–V）,and secondary ion mass spectroscopy（SIMS）.It is revealed that two main categories of charge traps,near interface oxide traps（Nniot） and oxide traps（Not）,have different responses to the TDBS and C–V characteristics in NO-annealed and Ar-annealed samples.The Nniotare mainly responsible for the hysteresis occurring in the bidirectional C–V characteristics,which are very close to the semiconductor interface and can readily exchange charges with the inner semiconductor.However,Not is mainly responsible for the TDBS induced C–V shifts.Electrons tunneling into the Not are hardly released quickly when suffering TDBS,resulting in the problem of the threshold voltage stability.Compared with the Ar-annealed sample,Nniotcan be significantly suppressed by the NO annealing,but there is little improvement of Not.SIMS results demonstrate that the Nniotare distributed within the transition layer,which correlated with the existence of the excess silicon.During the NO annealing process,the excess Si atoms incorporate into nitrogen in the transition layer,allowing better relaxation of the interface strain and effectively reducing the width of the transition layer and the density of Nniot.
基金Project supported by the Special Foundation for State Major Basic Research Program of China （Grant No G2000035602） and the National Natural Science Foundation of China （Grant No 90307006）.
文摘A two-dimensional （2D） full band self-consistent ensemble Monte Carlo （MC） method for solving the quantum Boltzmann equation, including collision broadening and quantum potential corrections, is developed to extend the MC method to the study of nano-scale semiconductor devices with obvious quantum mechanical （QM） effects. The quantum effects both in real space and momentum space in nano-scale semiconductor devices can be simulated. The effective mobility in the inversion layer of n and p channel MOSFET is simulated and compared with experimental data to verify this method. With this method 50nm ultra thin body silicon on insulator MOSFET are simulated. Results indicate that this method can be used to simulate the 2D QM effects in semiconductor devices including tunnelling effect.
文摘In power electronics applications,the selection of condition monitoring methods significantly affects both the precision and complexity of the junction temperature evaluation,which is essential for the reliability assessment of power semiconductor devices.This study begins with a failure mechanism analysis of state-of-the-art power semiconductor devices.Junction temperature measurement methods can be categorized into three distinct approaches:thermal image-based,thermal model-based,and temperature-sensitive electrical parameter(TSEP)-based methods.Their respective advantages and disadvantages are comprehensively compared.Moreover,condition monitoring of the ON-state voltage drop is summarized and benchmarked.ON-state voltage and junction temperature measurements are experimentally demonstrated in a standard three-phase converter,which provides superior measurement accuracy and rapid dynamic response characteristics.Additionally,this investigation is extended to measurement methods for TSEP in wide-bandgap semiconductors.
文摘We propose a finite element method to investigate the phenomena of shock wave and to simulate the hydrodynamic model in semiconductor devices. An introduction of this model is discussed first. Then some scaling factors and a relationship between the changing variables are discussed. And then, we use a finite element method （P1-iso-P2 element） to discrete the equations. Some boundary conditions are also discussed. Finally, a sub-micron n%＋-n-n^＋ silicon diode and Si MESFET device are simulated and the results are analyzed. Numerical results show that electronic fluids are transonic under some conditions.
基金supported by the Shanghai Committee of Science and Technology, China (Grant No. 08Jc1402300)
文摘We present in this paper a new method,based on measurements of conventional direct current-voltage(I-V) characteristics and transient voltage-time(V-t) characteristics during the discharge process,for determining capacitance-voltage(C-V) characteris-tics of organic semiconductor devices.Derivatives of I-V and V-t,dI/dV and dV/dt,are related with C by a simple formula C=-V(dI/dV)/(dV/dt)The validity of the method is confirmed by experimental data measured from a set of single-organic-layer devices with different layer thicknesses.
文摘Superjunction(SJ)is one of the most innovative concepts in the field of power semiconductor devices and is often referred to as a"milestone"in power MOS.Its balanced charge field modulation mechanism breaks through the strong dependency between the doping concentration in the drift region and the breakdown voltage V_(B)in conventional devices.This results in a reduction of the trade-off relationship between specific on-resistance R_(on,sp)and V_(B)from the conventional R_(on,sp)∝V_(B)^(2.5)to R_(on,sp)∝W·V_(B)^(1.32),and even to R_(on,sp)∝W·V_(B)^(1.03).As the exponential term coefficient decreases,R_(on,sp)decreases with the cell width W,exhibiting a development pattern reminiscent of"Moore's Law".This paper provides an overview of the latest research developments in SJ power semiconductor devices.Firstly,it introduces the minimum specific on-resistance R_(on,min)theory of SJ devices,along with its combination with special effects like 3-D depletion and tunneling,discussing the development of R_(on,min)theory in the wide bandgap SJ field.Subsequently,it discusses the latest advancements in silicon-based and wide bandgap SJ power devices.Finally,it introduces the homogenization field(HOF)and high-K voltage-sustaining layers derived from the concept of SJ charge balance.SJ has made significant progress in device performance,reliability,and integration,and in the future,it will continue to evolve through deeper integration with different materials,processes,and packaging technologies,enhancing the overall performance of semiconductor power devices.
文摘The temperature dependence of some performance of 6H SiC unipolar power devices is analyzed theoretically.By employing the temperature dependent ionization coefficient and mobility of a silicon carbide,the analytical expressions of the temperature dependent performance,such as breakdown characteristics and on resistance of 6H SiC unipolar power devices are derived in a closed form.The analytical results are compared with the experimental results,with good accordance found in the breakdown characteristics.
基金supported by the National Natural Science Foundation of China(Grant No.12374395)the Chinese Insti-tute of Electronics(CIE)-SmartChip Research Project.
文摘The degradation mechanisms of Schottky p-GaN gate AlGaN/GaN HEMTs under high-temperature reverse bias(HTRB)stress were investigated and the evolution of the deep traps was identified using deep-level transient spectroscopy.The saturation current of p-GaN gate AlGaN/GaN HEMTs decreased by 18.2%and the threshold voltage shifted positively by 11.6%after the degradation.An electron trap(at 369 K)and a hole trap(at 95 K)were observed in the AlGaN/GaN region,while another hole trap(at 359 K)was found in the p-GaN layer before the stress.Meanwhile,after the stress,the concentration and capture cross section of the hole traps increased in both the p-GaN layer and the AlGaN/GaN region.With regard to the electron trap in the AlGaN/GaN region,the capture cross section increased significantly but the electron trap concentration slightly decreased,which may increase the electron trapping,thereby reducing electrons in the two-dimensional electron gas.These factors result in a positive shift in the threshold voltage and a decrease in the output current.This work provides a new insight into understanding the threshold voltage instability of Schottky p-GaN gate AlGaN/GaN HEMTs.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12375261,12175287,12205350,and 62234013)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2022424).
文摘Influences of swift heavy ion(SHI)irradiation induced defects on electronic properties of the bulk SnSe_(2)based FETs are explored.Latent tracks and amounts of Se vacancies in the irradiated SnSe_(2)were confirmed.Red shift of the A1g peak indicates that the resonance frequency of the phonons is reduced due to the defect generation in SnSe_(2).The source–drain current Ids increased at ion fluence of 1×10^(10)ions·cm^(-2),which was attributeded to the irradiation caused Se vacancies,which hence increases the concentration of conduction electrons.The carrier mobility was about 16.9 cm^(2)·V^(-1)·s^(-1)for the devices irradiated at ion fluence of 1×10^(9)ions·cm^(-2),which benefited from heavy ion irradiation enhanced interlayer coupling.The mechanism of device performance optimization after irradiation is discussed in detail.This work provides evidence that,given the electronic properties of two-dimensional material-based device,vacancies and interlayer coupling effects caused by SHI irradiation should not be ignored.
基金supported by the National Natural Science Foundation of China(NSFC,No.62074048)the Key Research and Development Plan of Anhui Province(No.2022f04020007)the Natural Science Foundation of Anhui Province(No.2208085MF177)。
文摘In this study,we present the fabrication of vertical SnO/β-Ga_(2)O_(3) heterojunction diode(HJD)via radio frequency(RF)reactive magnetron sputtering.The valence and conduction band offsets betweenβ-Ga_(2)O_(3) and SnO are determined to be 2.65and 0.75 eV,respectively,through X-ray photoelectron spectroscopy,showing a type-Ⅱband alignment.Compared to its Schottky barrier diode(SBD)counterpart,the HJD presents a comparable specific ON-resistances(R_(on,sp))of 2.8 mΩ·cm^(2) and lower reverse leakage current(I_R),leading to an enhanced reverse blocking characteristics with breakdown voltage(BV)of 1675 V and power figure of merit(PFOM)of 1.0 GW/cm~2.This demonstrates the high quality of the SnO/β-Ga_(2)O_(3) heterojunction interface.Silvaco TCAD simulation further reveals that electric field crowding at the edge of anode for the SBD was greatly depressed by the introduction of SnO film,revealing the potential application of SnO/β-Ga_(2)O_(3) heterojunction in the futureβ-Ga_(2)O_(3)-based power devices.data mining,AI training,and similar technologies,are reserved.
基金Project support by the National Natural Science Foundation of China(Grant Nos.61605131 and 61435010)the Shenzhen Science and Technology Research Fund,China(Grant No.JCYJ20150324141711624)
文摘Black phosphorus （BP）, an attractive two-dimensional （2D） semiconductor, is widely used in the fields of optoelec- tronic devices, biomedicine, and chemical sensing. Silver ion （Ag＋）, a commonly used additive in food industry, can sterilize and keep food fresh. But excessive intake of Ag＋ will harm human health. Therefore, high sensitive, fast and simple Ag＋ detection method is significant. Here, a high-performance BP field effect transistor （FET） sensor is fabricated for Ag＋ detection with high sensitivity, rapid detection speed, and wide detection concentration range. The detection limit for Ag＋ is 10 l0 mol/L. Testing time for each sample by this method is 60 s. Besides, the mechanism of BP-FET sensor for Ag＋ detection is investigated systematically. The simple BP-FET sensor may inspire some relevant research and potential applications, such as providing an effective method for the actual detection of Ag＋, especially in wimessed inspections field of food.
基金supported by the National Key Research and Development Program(No.2016YFB0400500)the Key Research and Development Projects in Guangdong Province(No.2019B010144001)。
文摘Superjunction technology is believed to reach the optimal specific on-resistance and breakdown voltage trade-off.It has become a mainstream technology in silicon high-voltage metal oxide semiconductor field effect transistor devices.Numerous efforts have been conducted to employ the same concept in silicon carbide devices.These works are summarized here.
文摘Metal halide perovskites, as a novel class of semiconductor optoelectronic materials, combine the excellent optoelectronic properties of inorganic semiconductors with the advantages of low-cost, printable fabrication typical of organic semiconductors, making them a cutting-edge research focus in the field of semiconductor optoelectronic devices.
基金This work is supported by the Major State Basic Research Program of China (19990328), the National Tackling Key Problem Program, the National Science Foundation of China (10271066 and 0372052), and the Doctorate Foundation of the Ministry of Education of China (20030422047).
文摘Characteristic finite difference fractional step schemes are put forward. The electric potential equation is described by a seven-point finite difference scheme, and the electron and hole concentration equations are treated by a kind of characteristic finite difference fractional step methods. The temperature equation is described by a fractional step method. Thick and thin grids are made use of to form a complete set. Piecewise threefold quadratic interpolation, symmetrical extension, calculus of variations, commutativity of operator product, decomposition of high order difference operators and prior estimates are also made use of. Optimal order estimates in l2 norm are derived to determine the error of the approximate solution. The well-known problem is thorongley and completely solred.
文摘The weak solutions to the stationary quantum drift-diffusion equations （QDD） for semiconductor devices are investigated in one space dimension. The proofs are based on a reformulation of the system as a fourth-order elliptic boundary value problem by using an exponential variable transformation. The techniques of a priori estimates and Leray-Schauder＇s fixed-point theorem are employed to prove the existence. Furthermore, the uniqueness of solutions and the semiclassical limit δ→0 from QDD to the classical drift-diffusion （DD） model are studied.
基金Supported by the Knowledge Innovation Project of Chinese Academy of Sciences under Grant No KJCX2-SW-W26, and the National Natural Science Foundation of China under Grant Nos 90406017 and 10427402.
文摘Metal-tip/Pr0.7Ca0.3MnO3/Pt devices possess two types of I-V hysteresis： clockwise vs counter clockwise depending on the tip materials. The criteria for categorization of these two types of devices can be simply based on whether the Gibbs free energy of oxidation for the metal tip is lower or higher than that of PCMO, respectively. While the clockwise hysteresis can be attributed to electric field induced oxidation/reduction, the counter clockwise hysteresis can be explained by oxygen vacancy migration in an electrical field. Alternating-current conductance spectra also reveal distinct hopping barriers between these two categories of devices at high resistive states.
基金Project supported by the State Key Program of National Natural Science Foundation of China(No.11931003)the National Natural Science Foundation of China(Nos.41974133,11671157,11971410)。
文摘The mathematical model of a semiconductor device is governed by a system of quasi-linear partial differential equations.The electric potential equation is approximated by a mixed finite element method,and the concentration equations are approximated by a standard Galerkin method.We estimate the error of the numerical solutions in the sense of the Lqnorm.To linearize the full discrete scheme of the problem,we present an efficient two-grid method based on the idea of Newton iteration.The main procedures are to solve the small scaled nonlinear equations on the coarse grid and then deal with the linear equations on the fine grid.Error estimation for the two-grid solutions is analyzed in detail.It is shown that this method still achieves asymptotically optimal approximations as long as a mesh size satisfies H=O(h^1/2).Numerical experiments are given to illustrate the efficiency of the two-grid method.
文摘The transient behavior of a semiconductor device consists of a Poisson equation for the electric potential and of two nonlinear parabolic equations for the electron density and hole density. The electric potential equation is discretized by a mixed finite element method. The electron and hole density equations are treated by implicit-explicit multistep finite element methods. The schemes are very efficient. The optimal order error estimates both in time and space are derived.
基金supported jointly by the National Natural Science Foundation of China(11864009 and 62164005)the Guangxi Natural Science Foundation of China(2021JJB110053)
文摘To some extent,the operational quickness of semiconductor devices depends on the transmission time of an electron through semiconductor nanostructures.However,the calculation of transmission time is very difficult,thanks to both the contentious definition of the transmission time in quantum mechanics and the complicated effective potential functions experienced by electrons in semiconductor devices.Here,based on an improved transfer matrix method to numerically solve the Schr?dinger equation and H G Winful’s relationship to calculate the dwell time,we develop a numerical approach to evaluate the transmission time of an electron in semiconductor devices.Compared to the exactly resolvable case of the rectangular potential barrier,the established numerical approach possesses high precision and small error,which may be employed to explore the dynamic response and operating speed of semiconductor devices.This proposed numerical method is successfully applied to the calculation of dwell time for an electron in double rectangular potential barriers and the dependence of transmission time on the number of potential barriers is revealed.
