Stress voltages on time-dependent breakdown characteristics of GaN MIS-HEMTs during negative gate bias stress (with VGS < 0, VD = VS = 0) and off-state stress (VG < VTh, VDS > 0, VS = 0) are investigated. For...Stress voltages on time-dependent breakdown characteristics of GaN MIS-HEMTs during negative gate bias stress (with VGS < 0, VD = VS = 0) and off-state stress (VG < VTh, VDS > 0, VS = 0) are investigated. For negative bias stress, the breakdown time distribution (β) decreases with the increasing negative gate voltage, while β is larger for higher drain voltage at off-state stress. Two humps in the time-dependent gate leakage occurred under both breakdown conditions, which can be ascribed to the dielectric breakdown triggered earlier and followed by the GaN layer breakdown. Combining the electric distribution from simulation and long-term monitoring of electric parameter, the peak electric fields under the gate edges at source and drain sides are confirmed as the main formation locations for per-location paths during negative gate voltage stress and off-state stress, respectively.展开更多
The effect of high overdrive voltage on the positive bias temperature instability(PBTI)trapping behavior is investigated for GaN metal–insulator–semiconductor high electron mobility transistor(MIS-HEMT)with LPCVD-Si...The effect of high overdrive voltage on the positive bias temperature instability(PBTI)trapping behavior is investigated for GaN metal–insulator–semiconductor high electron mobility transistor(MIS-HEMT)with LPCVD-SiNx gate dielectric.A higher overdrive voltage is more effective to accelerate the electrons trapping process,resulting in a unique trapping behavior,i.e.,a larger threshold voltage shift with a weaker time dependence and a weaker temperature dependence.Combining the degradation of electrical parameters with the frequency–conductance measurements,the unique trapping behavior is ascribed to the defect energy profile inside the gate dielectric changing with stress time,new interface/border traps with a broad distribution above the channel Fermi level are introduced by high overdrive voltage.展开更多
The strong polarization effect of GaN-based materials is widely used in high-performance devices such as white-lightemitting diodes(white LEDs),high electron mobility transistors(HEMTs),and GaN polarization superjunct...The strong polarization effect of GaN-based materials is widely used in high-performance devices such as white-lightemitting diodes(white LEDs),high electron mobility transistors(HEMTs),and GaN polarization superjunctions.However,the current researches on the polarization mechanism of GaN-based materials are not sufficient.In this paper,we studied the influence of polarization on electric field and energy band characteristics of Ga-face GaN bulk materials by using a combination of theoretical analysis and semiconductor technology computer-aided design(TCAD) simulation.The selfscreening effect in Ga-face bulk GaN under ideal and non-ideal conditions is studied respectively.We believe that the formation of high-density two-dimensional electron gas(2 DEG) in GaN is the accumulation of screening charges.We also clarify the source and accumulation of the screening charges caused by the GaN self-screening effect in this paper and aim to guide the design and optimization of high-performance GaN-based devices.展开更多
We experimentally evaluated the interface state density of GaN MIS-HEMTs during time-dependent dielectric breakdown(TDDB).Under a high forward gate bias stress,newly increased traps generate both at the SiNx/AlGaN int...We experimentally evaluated the interface state density of GaN MIS-HEMTs during time-dependent dielectric breakdown(TDDB).Under a high forward gate bias stress,newly increased traps generate both at the SiNx/AlGaN interface and the SiNx bulk,resulting in the voltage shift and the increase of the voltage hysteresis.When prolonging the stress duration,the defects density generated in the SiNx dielectric becomes dominating,which drastically increases the gate leakage current and causes the catastrophic failure.After recovery by UV light illumination,the negative shift in threshold voltage(compared with the fresh one)confirms the accumulation of positive charge at the SiNx/AlGaN interface and/or in SiNx bulk,which is possibly ascribed to the broken bonds after long-term stress.These results experimentally confirm the role of defects in the TDDB of GaN-based MIS-HEMTs.展开更多
基金Project supported by the National Key Research and Development Program,China(Grant No.2017YFB0402800)the Key Research and Development Program of Guangdong Province,China(Grant Nos.2019B010128002 and 2020B010173001)+4 种基金the National Natural Science Foundation of China(Grant No.U1601210)the Natural Science Foundation of Guangdong Province,China(Grant No.2015A030312011)the Open Project of Key Laboratory of Microelectronic Devices and Integrated Technology(Grant No.202006)the Science and Technology Plan of Guangdong Province,China(Grant No.2017B010112002)the China Postdoctoral Science Foundation(Grant No.2019M663233).
文摘Stress voltages on time-dependent breakdown characteristics of GaN MIS-HEMTs during negative gate bias stress (with VGS < 0, VD = VS = 0) and off-state stress (VG < VTh, VDS > 0, VS = 0) are investigated. For negative bias stress, the breakdown time distribution (β) decreases with the increasing negative gate voltage, while β is larger for higher drain voltage at off-state stress. Two humps in the time-dependent gate leakage occurred under both breakdown conditions, which can be ascribed to the dielectric breakdown triggered earlier and followed by the GaN layer breakdown. Combining the electric distribution from simulation and long-term monitoring of electric parameter, the peak electric fields under the gate edges at source and drain sides are confirmed as the main formation locations for per-location paths during negative gate voltage stress and off-state stress, respectively.
基金Project supported by the National Key Research and Development Program,China(Grant No.2017YFB0402800)the Key Research and Development Program of Guangdong Province,China(Grant No.2019B010128002)+1 种基金the National Natural Science Foundation of China(Grant No.U1601210)the Natural Science Foundation of Guangdong Province,China(Grant No.2015A030312011)。
文摘The effect of high overdrive voltage on the positive bias temperature instability(PBTI)trapping behavior is investigated for GaN metal–insulator–semiconductor high electron mobility transistor(MIS-HEMT)with LPCVD-SiNx gate dielectric.A higher overdrive voltage is more effective to accelerate the electrons trapping process,resulting in a unique trapping behavior,i.e.,a larger threshold voltage shift with a weaker time dependence and a weaker temperature dependence.Combining the degradation of electrical parameters with the frequency–conductance measurements,the unique trapping behavior is ascribed to the defect energy profile inside the gate dielectric changing with stress time,new interface/border traps with a broad distribution above the channel Fermi level are introduced by high overdrive voltage.
基金Project supported by the Key Research and Development Program of Guangdong Province,China(Grant No.2020B010174003)。
文摘The strong polarization effect of GaN-based materials is widely used in high-performance devices such as white-lightemitting diodes(white LEDs),high electron mobility transistors(HEMTs),and GaN polarization superjunctions.However,the current researches on the polarization mechanism of GaN-based materials are not sufficient.In this paper,we studied the influence of polarization on electric field and energy band characteristics of Ga-face GaN bulk materials by using a combination of theoretical analysis and semiconductor technology computer-aided design(TCAD) simulation.The selfscreening effect in Ga-face bulk GaN under ideal and non-ideal conditions is studied respectively.We believe that the formation of high-density two-dimensional electron gas(2 DEG) in GaN is the accumulation of screening charges.We also clarify the source and accumulation of the screening charges caused by the GaN self-screening effect in this paper and aim to guide the design and optimization of high-performance GaN-based devices.
基金National Key Research and Development Program of China(Grant No.2017YFB0402800)the Key Research and Development Program of Guangdong Province,China(Grant Nos.2019B010128002 and 2020B010173001)+2 种基金the National Natural Science Foundation of China(Grant Nos.U1601210 and 61904207)the Natural Science Foundation of Guangdong Province of China(Grant No.2015A030312011)the China Postdoctoral Science Foundation(Grant No.2019M663233).
文摘We experimentally evaluated the interface state density of GaN MIS-HEMTs during time-dependent dielectric breakdown(TDDB).Under a high forward gate bias stress,newly increased traps generate both at the SiNx/AlGaN interface and the SiNx bulk,resulting in the voltage shift and the increase of the voltage hysteresis.When prolonging the stress duration,the defects density generated in the SiNx dielectric becomes dominating,which drastically increases the gate leakage current and causes the catastrophic failure.After recovery by UV light illumination,the negative shift in threshold voltage(compared with the fresh one)confirms the accumulation of positive charge at the SiNx/AlGaN interface and/or in SiNx bulk,which is possibly ascribed to the broken bonds after long-term stress.These results experimentally confirm the role of defects in the TDDB of GaN-based MIS-HEMTs.