This paper studies two-dimensional analysis of the surface state effect on current gain for a 4H-SiC bipolar junction transistor （BJT）. Simulation results indicate the mechanism of current gain degradation, which is...This paper studies two-dimensional analysis of the surface state effect on current gain for a 4H-SiC bipolar junction transistor （BJT）. Simulation results indicate the mechanism of current gain degradation, which is surface Fermi level pinning leading to a strong downward bending of the energy bands to form the channel of surface electron recombination current. The experimental results are well-matched with the simulation, which is modeled by exponential distributions of the interface state density replacing the single interface state trap. Furthermore, the simulation reveals that the oxide quality of the base emitter junction interface is very important for 4H-SiC BJT performance.展开更多
In this paper, a new structure of a 4H-SiC bipolar junction transistor （BJT） with a buried layer （BL） in the base is presented. The current gain shows an approximately 100% increase compared with that of the conve...In this paper, a new structure of a 4H-SiC bipolar junction transistor （BJT） with a buried layer （BL） in the base is presented. The current gain shows an approximately 100% increase compared with that of the conventional structure. This is attributed to the creation of a built-in electric field for the minority carriers to transport in the base which is explained based on 2D device simulations. The optimized design of the buried layer region is also considered by numeric simulations.展开更多
In this paper, a novel structure of a 4H-SiC lateral bipolar junction transistor （LBJT） with a base tield plate and double RESURF in the drift region is presented. Collector-base junction depletion extension in the ...In this paper, a novel structure of a 4H-SiC lateral bipolar junction transistor （LBJT） with a base tield plate and double RESURF in the drift region is presented. Collector-base junction depletion extension in the base region is restricted by the base field plate. Thin base as well as low base doping of the LBJT therefore can be achieved under the condition of avalanche breakdown. Simulation results show that thin base of 0.32 μm and base doping of 3 × 1017 cm 3 are obtained, and corresponding current gain is as high as 247 with avalanche breakdown voltage of 3309 V when the drift region length is 30 μm. Besides, an investigation of a 4H-SiC vertical BJT （VBJT） with comparable breakdown voltage （3357 V） shows that the minimum base width of 0.25 ~tm and base doping as high as 8 × 10^17 cm^-3 contribute to a maximum current gain of only 128.展开更多
This paper proposes a thermal analytical model of current gain for bipolar junction transistor-bipolar static induction transistor （BJT-BSIT） compound device in the low current operation. It also proposes a best the...This paper proposes a thermal analytical model of current gain for bipolar junction transistor-bipolar static induction transistor （BJT-BSIT） compound device in the low current operation. It also proposes a best thermal compensating factor to the compound device that indicates the relationship between the thermal variation rate of current gain and device structure. This is important for the design of compound device to be optimized. Finally, the analytical model is found to be in good agreement with numerical simulation and experimental results. The test results demonstrate that thermal variation rate of current gain is below 10% in 25 ℃-85 ℃ and 20% in -55 ℃-25 ℃.展开更多
A unified model of low temperature current gain of polysilicon emitter bipolar transistors based on effective recombination method is presented, incorporating band-gap narrowing, carrier freezing-out, tunneling of hol...A unified model of low temperature current gain of polysilicon emitter bipolar transistors based on effective recombination method is presented, incorporating band-gap narrowing, carrier freezing-out, tunneling of holes through polysilicon/silicon interface oxide layer and reduced mobility mechanism in polysilicon. The modeling results based on this model are in good agreement with experimental data.展开更多
Direct current（DC） and radio frequency（RF） performances of InP-based high electron mobility transistors（HEMTs）are investigated by Sentaurus TCAD. The physical models including hydrodynamic transport model, Shock...Direct current（DC） and radio frequency（RF） performances of InP-based high electron mobility transistors（HEMTs）are investigated by Sentaurus TCAD. The physical models including hydrodynamic transport model, Shockley–Read–Hall recombination, Auger recombination, radiative recombination, density gradient model and high field-dependent mobility are used to characterize the devices. The simulated results and measured results about DC and RF performances are compared, showing that they are well matched. However, the slight differences in channel current and pinch-off voltage may be accounted for by the surface defects resulting from oxidized InAlAs material in the gate-recess region. Moreover,the simulated frequency characteristics can be extrapolated beyond the test equipment limitation of 40 GHz, which gives a more accurate maximum oscillation frequency( f;) of 385 GHz.展开更多
A double balanced Gilbert-cell class-A amplifier bleeding mixer (DBGC CAAB mixer) is proposed and implemented. The injection current is utilized to amplify the local oscillator (LO) signal to improve the performance o...A double balanced Gilbert-cell class-A amplifier bleeding mixer (DBGC CAAB mixer) is proposed and implemented. The injection current is utilized to amplify the local oscillator (LO) signal to improve the performance of the transconductor stage. The DBGC CAAB mixer achieves a conversion gain of 17.5 dB at -14 dBm LO power, and the noise figure is suppressed from 45 dB to 10.7 dB. It is important to stress that the new configuration will not drain additional power in contrast to the former current bleeding mixers. This topology dramatically relieves the requirement of the LO power. The DBGC CAAB mixer is implemented by using 0.18-μm RFCMOS technology and operates at the 2.4 GHz ISM application with 10 MHz intermediate frequency. The power consumption is 12 mA at 1.5 V supply voltage. The DBGC CAAB mixer features the highest FOM figure within a wide range of LO power.展开更多
This paper proposes a gain scheduled control method for a doubly fed induction generator driven by a wind turbine. The purpose is to design a variable speed control system so as to extract the maximum power in the reg...This paper proposes a gain scheduled control method for a doubly fed induction generator driven by a wind turbine. The purpose is to design a variable speed control system so as to extract the maximum power in the region below the rated wind speed. Gain scheduled control approach is applied in order to achieve high performance over a wide range of wind speed. A double loop configuration is adopted. In the inner loop, the rotor speed is used as the scheduling parameter, while a function of wind and rotor speed is used as the scheduling parameter in the outer loop. It is verified in simulations that a high tracking performance has been achieved.展开更多
文摘This paper studies two-dimensional analysis of the surface state effect on current gain for a 4H-SiC bipolar junction transistor （BJT）. Simulation results indicate the mechanism of current gain degradation, which is surface Fermi level pinning leading to a strong downward bending of the energy bands to form the channel of surface electron recombination current. The experimental results are well-matched with the simulation, which is modeled by exponential distributions of the interface state density replacing the single interface state trap. Furthermore, the simulation reveals that the oxide quality of the base emitter junction interface is very important for 4H-SiC BJT performance.
文摘In this paper, a new structure of a 4H-SiC bipolar junction transistor （BJT） with a buried layer （BL） in the base is presented. The current gain shows an approximately 100% increase compared with that of the conventional structure. This is attributed to the creation of a built-in electric field for the minority carriers to transport in the base which is explained based on 2D device simulations. The optimized design of the buried layer region is also considered by numeric simulations.
基金supported by the Ministry of Education of China (Grant No. 20100101110056)the Natural Science Foundation for Distinguished Young Scholars of Zhejiang Province of China (Grant No. R1100468)
文摘In this paper, a novel structure of a 4H-SiC lateral bipolar junction transistor （LBJT） with a base tield plate and double RESURF in the drift region is presented. Collector-base junction depletion extension in the base region is restricted by the base field plate. Thin base as well as low base doping of the LBJT therefore can be achieved under the condition of avalanche breakdown. Simulation results show that thin base of 0.32 μm and base doping of 3 × 1017 cm 3 are obtained, and corresponding current gain is as high as 247 with avalanche breakdown voltage of 3309 V when the drift region length is 30 μm. Besides, an investigation of a 4H-SiC vertical BJT （VBJT） with comparable breakdown voltage （3357 V） shows that the minimum base width of 0.25 ~tm and base doping as high as 8 × 10^17 cm^-3 contribute to a maximum current gain of only 128.
文摘This paper proposes a thermal analytical model of current gain for bipolar junction transistor-bipolar static induction transistor （BJT-BSIT） compound device in the low current operation. It also proposes a best thermal compensating factor to the compound device that indicates the relationship between the thermal variation rate of current gain and device structure. This is important for the design of compound device to be optimized. Finally, the analytical model is found to be in good agreement with numerical simulation and experimental results. The test results demonstrate that thermal variation rate of current gain is below 10% in 25 ℃-85 ℃ and 20% in -55 ℃-25 ℃.
基金Supported by National Natural Science Foundation of China
文摘A unified model of low temperature current gain of polysilicon emitter bipolar transistors based on effective recombination method is presented, incorporating band-gap narrowing, carrier freezing-out, tunneling of holes through polysilicon/silicon interface oxide layer and reduced mobility mechanism in polysilicon. The modeling results based on this model are in good agreement with experimental data.
基金supported by the National Natural Science Foundation of China(Grant Nos.61404115 and 61434006)the Postdoctoral Science Foundation of Henan Province,China(Grant No.2014006)the Development Fund for Outstanding Young Teachers of Zhengzhou University(Grant No.1521317004)
文摘Direct current（DC） and radio frequency（RF） performances of InP-based high electron mobility transistors（HEMTs）are investigated by Sentaurus TCAD. The physical models including hydrodynamic transport model, Shockley–Read–Hall recombination, Auger recombination, radiative recombination, density gradient model and high field-dependent mobility are used to characterize the devices. The simulated results and measured results about DC and RF performances are compared, showing that they are well matched. However, the slight differences in channel current and pinch-off voltage may be accounted for by the surface defects resulting from oxidized InAlAs material in the gate-recess region. Moreover,the simulated frequency characteristics can be extrapolated beyond the test equipment limitation of 40 GHz, which gives a more accurate maximum oscillation frequency( f;) of 385 GHz.
文摘A double balanced Gilbert-cell class-A amplifier bleeding mixer (DBGC CAAB mixer) is proposed and implemented. The injection current is utilized to amplify the local oscillator (LO) signal to improve the performance of the transconductor stage. The DBGC CAAB mixer achieves a conversion gain of 17.5 dB at -14 dBm LO power, and the noise figure is suppressed from 45 dB to 10.7 dB. It is important to stress that the new configuration will not drain additional power in contrast to the former current bleeding mixers. This topology dramatically relieves the requirement of the LO power. The DBGC CAAB mixer is implemented by using 0.18-μm RFCMOS technology and operates at the 2.4 GHz ISM application with 10 MHz intermediate frequency. The power consumption is 12 mA at 1.5 V supply voltage. The DBGC CAAB mixer features the highest FOM figure within a wide range of LO power.
文摘This paper proposes a gain scheduled control method for a doubly fed induction generator driven by a wind turbine. The purpose is to design a variable speed control system so as to extract the maximum power in the region below the rated wind speed. Gain scheduled control approach is applied in order to achieve high performance over a wide range of wind speed. A double loop configuration is adopted. In the inner loop, the rotor speed is used as the scheduling parameter, while a function of wind and rotor speed is used as the scheduling parameter in the outer loop. It is verified in simulations that a high tracking performance has been achieved.
