Characteristics and mechanisms of subthreshold voltage hysteresis in 4H-SiC MOSFETs
Xi-Ming Chen(陈喜明)1,2, Bang-Bing Shi(石帮兵)2, Xuan Li(李轩)1,†, Huai-Yun Fan(范怀云)2, Chen-Zhan Li(李诚瞻)2, Xiao-Chuan Deng(邓小川)1, Hai-Hui Luo(罗海辉)2, Yu-Dong Wu(吴煜东)2, and Bo Zhang(张波)1
1 School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; 2 State Key Laboratory of Advanced Power Semiconductor Devices, Zhuzhou CRRC Times Semiconductor Company Ltd., Zhuzhou 412001, China
Abstract In order to investigate the characteristics and mechanisms of subthreshold voltage hysteresis (∆ V th, sub) of 4H-SiC metal-oxide-semiconductor field-effect transistors (MOSFETs), 4H-SiC planar and trench MOSFETs and corresponding P-type planar and trench metal-oxide-semiconductor (MOS) capacitors are fabricated and characterized. Compared with planar MOSFEF, the trench MOSFET shows hardly larger ∆ V th, sub in wide temperature range from 25 °C to 300 °C. When operating temperature range is from 25 °C to 300 °C, the off-state negative V gs of planar and trench MOSFETs should be safely above -4 V and -2 V, respectively, to alleviate the effect of ∆ V th, sub on the normal operation. With the help of P-type planar and trench MOS capacitors, it is confirmed that the obvious ∆ V th, sub of 4H-SiC MOSFET originates from the high density of the hole interface traps between intrinsic Fermi energy level (E i) and valence band (E v). The maximum ∆ V th, sub of trench MOSFET is about twelve times larger than that of planar MOSFET, owing to higher density of interface states (D it) between E i and E v. These research results will be very helpful for the application of 4H-SiC MOSFET and the improvement of ∆ V th, sub of 4H-SiC MOSFET, especially in 4H-SiC trench MOSFET.
(Composition, segregation; defects and impurities)
Fund: Project supported by the National Key Research and Development Program of China (Grant No. 2017YFB0903203), the National Natural Science Foundation of China (Grant No. 62004033), and China Postdoctoral Science Foundation (Grant No. 2020M683287).
Xi-Ming Chen(陈喜明), Bang-Bing Shi(石帮兵), Xuan Li(李轩), Huai-Yun Fan(范怀云), Chen-Zhan Li(李诚瞻), Xiao-Chuan Deng(邓小川), Hai-Hui Luo(罗海辉), Yu-Dong Wu(吴煜东), and Bo Zhang(张波) Characteristics and mechanisms of subthreshold voltage hysteresis in 4H-SiC MOSFETs 2021 Chin. Phys. B 30 048504
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