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
Considering the impacts of ideal factor n, VBE and band gap changes with the temperature on current gain, the current gain expression has been corrected to make the results closer to the actual test. Besides, the acce...Considering the impacts of ideal factor n, VBE and band gap changes with the temperature on current gain, the current gain expression has been corrected to make the results closer to the actual test. Besides, the accelerating lifetime study method in the constant temperature-humidity stress is used to estimate the reliability of the same batch transistors. Applying the revised findings from the expression, the current gains before and after the test are compared and analyzed, and, according to the degradation data of the current gain, the transistor lifetimes in the test stress are respectively extrapolated in the different failure criteria.展开更多
Due to the backscattered parasitic current from the barriers,the current gain of the widely used amplifier is far from ideal.In this work,we demonstrate a vertical Au/Al2O3/BP/MoS2 tunneling hot-electron transfer ampl...Due to the backscattered parasitic current from the barriers,the current gain of the widely used amplifier is far from ideal.In this work,we demonstrate a vertical Au/Al2O3/BP/MoS2 tunneling hot-electron transfer amplifier with a hot-electron emitter-base junction and a p-n junction as the base-collector barrier.Fairly monoenergetic electrons traverse through the ultrathin Al2O3 dielectric via tunneling,which are accelerated and shifted to the collector region.The devices exhibit a high current on-off ratio of>105 and a high current density(JC)of∼1,000 A/cm2 at the same time.Notably,this work demonstrates a common-emitter current gain(β)value of 1,384 with a nanowatt power consumption at room temperature,which is a record high value among the all 2D based hot-electron transistors.Furthermore,the temperature dependent performance is investigated,and theβvalue of 1,613 is obtained at 150 K.Therefore,this work presents the potential of 2D based transistors for high-performance applications.展开更多
A novel 4H-SiC BJT of high current gain with a suppressing surface traps effect has been proposed. It is effective to improve the current gain due to the lower electrons density in the surface region by extending the ...A novel 4H-SiC BJT of high current gain with a suppressing surface traps effect has been proposed. It is effective to improve the current gain due to the lower electrons density in the surface region by extending the emitter metal to overlap the passivation layer on the extrinsic base surface. The electrons trapped in the extrinsic base surface induce the degeneration of Si C BJTs device performance. By modulating the electron recombination rate, the novel structure can increase the current gain to 63.2% compared with conventional ones with the compatible process technology. Optimized sizes are an overlapped metal length of 4 m, as well as an oxide layer thickness of 50 nm.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
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.
文摘Considering the impacts of ideal factor n, VBE and band gap changes with the temperature on current gain, the current gain expression has been corrected to make the results closer to the actual test. Besides, the accelerating lifetime study method in the constant temperature-humidity stress is used to estimate the reliability of the same batch transistors. Applying the revised findings from the expression, the current gains before and after the test are compared and analyzed, and, according to the degradation data of the current gain, the transistor lifetimes in the test stress are respectively extrapolated in the different failure criteria.
基金This work was supported by the National Key Research and Development Program of Ministry of Science and Technology(Nos.2018YFA0703704 and 2018YFB0406603)the National Natural Science Foundation of China(Nos.61851403,51872084,61704052,61811540408,51872084,and 61704051)as well as the Natural Science Foundation of Hunan Province(Nos.2017RS3021 and 2017JJ3033).
文摘Due to the backscattered parasitic current from the barriers,the current gain of the widely used amplifier is far from ideal.In this work,we demonstrate a vertical Au/Al2O3/BP/MoS2 tunneling hot-electron transfer amplifier with a hot-electron emitter-base junction and a p-n junction as the base-collector barrier.Fairly monoenergetic electrons traverse through the ultrathin Al2O3 dielectric via tunneling,which are accelerated and shifted to the collector region.The devices exhibit a high current on-off ratio of>105 and a high current density(JC)of∼1,000 A/cm2 at the same time.Notably,this work demonstrates a common-emitter current gain(β)value of 1,384 with a nanowatt power consumption at room temperature,which is a record high value among the all 2D based hot-electron transistors.Furthermore,the temperature dependent performance is investigated,and theβvalue of 1,613 is obtained at 150 K.Therefore,this work presents the potential of 2D based transistors for high-performance applications.
基金Project supported by the National Natural Science Foundation of China(Nos.61306093,61401075)
文摘A novel 4H-SiC BJT of high current gain with a suppressing surface traps effect has been proposed. It is effective to improve the current gain due to the lower electrons density in the surface region by extending the emitter metal to overlap the passivation layer on the extrinsic base surface. The electrons trapped in the extrinsic base surface induce the degeneration of Si C BJTs device performance. By modulating the electron recombination rate, the novel structure can increase the current gain to 63.2% compared with conventional ones with the compatible process technology. Optimized sizes are an overlapped metal length of 4 m, as well as an oxide layer thickness of 50 nm.
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.
