In this work,the GaN p-MISFET with LPCVD-SiN_(x) is studied as a gate dielectric to improve device performance.By changing the Si/N stoichiometry of SiN_(x),it is found that the channel hole mobility can be effectivel...In this work,the GaN p-MISFET with LPCVD-SiN_(x) is studied as a gate dielectric to improve device performance.By changing the Si/N stoichiometry of SiN_(x),it is found that the channel hole mobility can be effectively enhanced with Si-rich SiN_(x) gate dielectric,which leads to a respectably improved drive current of GaN p-FET.The record high channel mobility of 19.4 cm2/(V∙s)was achieved in the device featuring an Enhancement-mode channel.Benefiting from the significantly improved channel mobility,the fabricated E-mode GaN p-MISFET is capable of delivering a decent-high current of 1.6 mA/mm,while simultaneously featuring a negative threshold-voltage(VTH)of–2.3 V(defining at a stringent criteria of 10μA/mm).The device also exhibits a well pinch-off at 0 V with low leakage current of 1 nA/mm.This suggests that a decent E-mode operation of the fabricated p-FET is obtained.In addition,the VTH shows excellent stability,while the threshold-voltage hysteresisΔVTH is as small as 0.1 V for a gate voltage swing up to–10 V,which is among the best results reported in the literature.The results indicate that optimizing the Si/N stoichiometry of LPCVD-SiN_(x) is a promising approach to improve the device performance of GaN p-MISFET.展开更多
We report an AlGaN channel high electron mobility transistor （HEMT） on a sapphire substrate with a 1000-nm A1xGa1-xN （x = 0-0.18）/GaN composite buffer layer, With a significant improvement of crystal quality, the ...We report an AlGaN channel high electron mobility transistor （HEMT） on a sapphire substrate with a 1000-nm A1xGa1-xN （x = 0-0.18）/GaN composite buffer layer, With a significant improvement of crystal quality, the device features a high product orris. #n. The AIGaN channel HEMTs presented show improved performance with respect to the conventional AIGaN channel HEMTs, including the on-resistance reduced from 31.2 to 8.1 Ω.mm, saturation drain current at 2 V gate bias promoted from 218 to 540 mA/mm, peak transconductance at 10 V drain bias promoted from 100 to a state-of-the-art value of 174 mS/ram, and reverse gate leakage current reduced from 1.85 × 10-3 to 2.15 × 10-5 mA/mm at VOD = -20 V.展开更多
This paper derives a non-stationary multiple-input multiple-output(MIMO) from the one-ring scattering model. The proposed channel model characterizes vehicular radio propagation channels with considerations of moving ...This paper derives a non-stationary multiple-input multiple-output(MIMO) from the one-ring scattering model. The proposed channel model characterizes vehicular radio propagation channels with considerations of moving base and mobile stations, which makes the angle of arrivals(AOAs) along with the angle of departures(AODs) time-variant. We introduce the methodology of including the time-variant impacts when characterizing non-stationary radio propagation channels through the geometrical channel modelling approach. We analyze the statistical properties of the proposed channel model including the local time-variant autocorrelation function(ACF) and the space cross-correlation functions(CCFs). We show that the model developed in this paper for non-stationary scenarios includes the existing one-ring wide-sense stationary channel model as its special case.展开更多
Given that satellite mobile channel is a time-varying channel,Adaptive Modulation and Coding(AMC) was proposed to provide robust and spectrally efficient transmission over satellite mobile channel.Three different kind...Given that satellite mobile channel is a time-varying channel,Adaptive Modulation and Coding(AMC) was proposed to provide robust and spectrally efficient transmission over satellite mobile channel.Three different kinds of channel environment were considered in this paper:the urban area,the rural area,and the open space.Four combinations of modulation and coding were designed to meet reliable communication on time-varying channel,and spectral efficiency and system throughput of these three kinds of channel environment were simulated.Based on the simulation results,this paper analysed the results and compared the performances of AMC with non-AMC system in these three kinds of channel environment.At last,we come to the conclusions:a system with AMC can achieve higher spectral efficiency and better system throughput;and the spectral efficiency and system throughput of AMC system will be higher on better satellite mobile channel.展开更多
In this paper, the bit error rate (BER) performance for typical mobile radio channels is simulated and analyzed based on a tapped delay line model. The investigation is focused on the propagation environments determin...In this paper, the bit error rate (BER) performance for typical mobile radio channels is simulated and analyzed based on a tapped delay line model. The investigation is focused on the propagation environments determined by the average delay profile and the Doppler spectra. The profile characteristics and their influences on channel behavior are also examined.展开更多
On the basis of thermodynamic and kinetic consideration of Ge-O system,high-pressure oxidation(HPO)on Ge was proposed to suppress the GeO desorption during the thermal oxidation and significant improvements of Ge/GeO2...On the basis of thermodynamic and kinetic consideration of Ge-O system,high-pressure oxidation(HPO)on Ge was proposed to suppress the GeO desorption during the thermal oxidation and significant improvements of Ge/GeO2-based gate stacks have been achieved.It is found that the post oxidation annealing at lower temperatures is helpful to passivate the interface defects at the Ge/GeO2 stack generated by the conventional thermal oxidation,while the high-quality GeO2 bulk properties can only be achieved by HPO that grows GeO2 film at high temperatures without the GeO desorption.This paper reviews the advantage of HPO on the formation of Ge/GeO2 stacks in terms of Ge/GeO2 interface and GeO2 bulk properties.展开更多
TD-SCDMA has been decided as the standard for TDD mode of the 3rd Generation mobile radio system by International Telecommunications Union (ITU),it is a important breakthrough in a century communication history. A nov...TD-SCDMA has been decided as the standard for TDD mode of the 3rd Generation mobile radio system by International Telecommunications Union (ITU),it is a important breakthrough in a century communication history. A novel downlink multiuser transmission scheme Joint Transmission (JT) is proposed based on the reciprocity that in the case of TDD the same channel impulse responses are valid for both the uplink and the downlink, it can enhance system performance and reduce system complexity. Because no channel estimation is necessary at the MSs, the data detection effort is dramatically reduced. This paper apply JT in Time Division CDMA (TD-SCDMA) and analyze its proformance in contrast to state of the art TD-CDMA transceivers. The computer simulation results illustrate the superiority of the novel scheme in terms of the system performance in the downlink of TD-SCDMA.展开更多
基金This work was supported in part by the Natural Science Foundation of China under Grant 62174019in part by the Guangdong Basic and Applied Basic Research Foundation China under Grant 2021B1515140039in part by the Zhuhai Industry-University Research Cooperation Project under Grant ZH22017001210041PWC.
文摘In this work,the GaN p-MISFET with LPCVD-SiN_(x) is studied as a gate dielectric to improve device performance.By changing the Si/N stoichiometry of SiN_(x),it is found that the channel hole mobility can be effectively enhanced with Si-rich SiN_(x) gate dielectric,which leads to a respectably improved drive current of GaN p-FET.The record high channel mobility of 19.4 cm2/(V∙s)was achieved in the device featuring an Enhancement-mode channel.Benefiting from the significantly improved channel mobility,the fabricated E-mode GaN p-MISFET is capable of delivering a decent-high current of 1.6 mA/mm,while simultaneously featuring a negative threshold-voltage(VTH)of–2.3 V(defining at a stringent criteria of 10μA/mm).The device also exhibits a well pinch-off at 0 V with low leakage current of 1 nA/mm.This suggests that a decent E-mode operation of the fabricated p-FET is obtained.In addition,the VTH shows excellent stability,while the threshold-voltage hysteresisΔVTH is as small as 0.1 V for a gate voltage swing up to–10 V,which is among the best results reported in the literature.The results indicate that optimizing the Si/N stoichiometry of LPCVD-SiN_(x) is a promising approach to improve the device performance of GaN p-MISFET.
基金Supported by the National Science and Technology Major Project of China under Grant No 2013ZX02308-002National Natural Science Foundation of China under Grant Nos 11435010 and 61474086
文摘We report an AlGaN channel high electron mobility transistor （HEMT） on a sapphire substrate with a 1000-nm A1xGa1-xN （x = 0-0.18）/GaN composite buffer layer, With a significant improvement of crystal quality, the device features a high product orris. #n. The AIGaN channel HEMTs presented show improved performance with respect to the conventional AIGaN channel HEMTs, including the on-resistance reduced from 31.2 to 8.1 Ω.mm, saturation drain current at 2 V gate bias promoted from 218 to 540 mA/mm, peak transconductance at 10 V drain bias promoted from 100 to a state-of-the-art value of 174 mS/ram, and reverse gate leakage current reduced from 1.85 × 10-3 to 2.15 × 10-5 mA/mm at VOD = -20 V.
基金supported by Shandong Agricultural University Funding of First-class DisciplinesShandong Agricultural University Key Cultivation Discipline Funding for NSFC Proposers+1 种基金supported by Grant of Beihang University Beidou Technology Transformation and Industrialization (BARI1709)Open Project of National Engineering Research Center for Information Technology in Agriculture (No.KF2015W003)
文摘This paper derives a non-stationary multiple-input multiple-output(MIMO) from the one-ring scattering model. The proposed channel model characterizes vehicular radio propagation channels with considerations of moving base and mobile stations, which makes the angle of arrivals(AOAs) along with the angle of departures(AODs) time-variant. We introduce the methodology of including the time-variant impacts when characterizing non-stationary radio propagation channels through the geometrical channel modelling approach. We analyze the statistical properties of the proposed channel model including the local time-variant autocorrelation function(ACF) and the space cross-correlation functions(CCFs). We show that the model developed in this paper for non-stationary scenarios includes the existing one-ring wide-sense stationary channel model as its special case.
文摘Given that satellite mobile channel is a time-varying channel,Adaptive Modulation and Coding(AMC) was proposed to provide robust and spectrally efficient transmission over satellite mobile channel.Three different kinds of channel environment were considered in this paper:the urban area,the rural area,and the open space.Four combinations of modulation and coding were designed to meet reliable communication on time-varying channel,and spectral efficiency and system throughput of these three kinds of channel environment were simulated.Based on the simulation results,this paper analysed the results and compared the performances of AMC with non-AMC system in these three kinds of channel environment.At last,we come to the conclusions:a system with AMC can achieve higher spectral efficiency and better system throughput;and the spectral efficiency and system throughput of AMC system will be higher on better satellite mobile channel.
文摘In this paper, the bit error rate (BER) performance for typical mobile radio channels is simulated and analyzed based on a tapped delay line model. The investigation is focused on the propagation environments determined by the average delay profile and the Doppler spectra. The profile characteristics and their influences on channel behavior are also examined.
基金The author would like to thank Prof.Akira Toriumi,Prof.Kita Koji,Prof.Kosuke Nagashio,and Dr.Tomonori Nishimura at the University of Tokyo for their continuous support and encouragement,which induced the main results reviewed in this paper.
文摘On the basis of thermodynamic and kinetic consideration of Ge-O system,high-pressure oxidation(HPO)on Ge was proposed to suppress the GeO desorption during the thermal oxidation and significant improvements of Ge/GeO2-based gate stacks have been achieved.It is found that the post oxidation annealing at lower temperatures is helpful to passivate the interface defects at the Ge/GeO2 stack generated by the conventional thermal oxidation,while the high-quality GeO2 bulk properties can only be achieved by HPO that grows GeO2 film at high temperatures without the GeO desorption.This paper reviews the advantage of HPO on the formation of Ge/GeO2 stacks in terms of Ge/GeO2 interface and GeO2 bulk properties.
文摘TD-SCDMA has been decided as the standard for TDD mode of the 3rd Generation mobile radio system by International Telecommunications Union (ITU),it is a important breakthrough in a century communication history. A novel downlink multiuser transmission scheme Joint Transmission (JT) is proposed based on the reciprocity that in the case of TDD the same channel impulse responses are valid for both the uplink and the downlink, it can enhance system performance and reduce system complexity. Because no channel estimation is necessary at the MSs, the data detection effort is dramatically reduced. This paper apply JT in Time Division CDMA (TD-SCDMA) and analyze its proformance in contrast to state of the art TD-CDMA transceivers. The computer simulation results illustrate the superiority of the novel scheme in terms of the system performance in the downlink of TD-SCDMA.
