Constant-voltage time-dependent dielectric breakdown (TDDB) measurements are performed on recently manufactured commercial 1.2 kV 4H-SiC power metal-oxide-semiconductor (MOS) field-effect transistors (MOSFETs) from three vendors. Abrupt changes of the electric field acceleration parameters ( γ) are observed at oxide electric fields ( Eox) around 8.5 MV/cm to 9 MV/cm for all commercial MOSFETs. Gate leakage currents and threshold voltage shifts are also monitored under different oxide fields ( Eox = 8 MV/cm and 10 MV/cm). The results suggest the failure mode under high oxide electric field is modified by impact ionization or Anode Hole Injection (AHI) induced hole trapping. This observation agrees with previously published oxide reliability studies on SiC MOSFETs and suggests that constant-voltage TDDB measurements need to be carefully performed under low oxide fields to avoid lifetime overestimation caused by hole trapping. The extrapolated t63% lifetimes (times to 63% failures) from TDDB measurements performed at Eox <; 8.5 MV/cm are longer than 108 hours at 150°C for all vendors. The predicted lifetimes at Eox = 4 MV/cm demonstrate more than 105 times increases than the oxide lifetimes reported a decade ago, showing promising progress in SiC technology.

中文翻译：

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商用 1.2 kV 4H-SiC 功率 MOSFET 的时间相关介电击穿


对三个供应商最近制造的商用 1.2 kV 4H-SiC 功率金属氧化物半导体 (MOS) 场效应晶体管 (MOSFET) 进行恒压瞬态电介质击穿 (TDDB) 测量。对于所有商用 MOSFET，在氧化物电场 (Eox) 约为 8.5 MV/cm 至 9 MV/cm 时观察到电场加速参数 (γ) 的突然变化。还在不同的氧化场（Eox = 8 MV/cm 和 10 MV/cm）下监测栅极漏电流和阈值电压偏移。结果表明，高氧化物电场下的失效模式可以通过碰撞电离或阳极孔注入（AHI）诱导空穴捕获来改变。这一观察结果与之前发表的 SiC MOSFET 氧化物可靠性研究一致，并表明需要在低氧化物场下仔细执行恒压 TDDB 测量，以避免因空穴捕获而导致寿命高估。根据 Eox < 处执行的 TDDB 测量推断出 t63% 寿命（63% 故障的时间）；对于所有供应商而言，8.5 MV/cm 在 150°C 下的使用寿命都超过 108 小时。 Eox = 4 MV/cm 时的预测寿命比十年前报告的氧化物寿命增加了 105 倍以上，这表明 SiC 技术取得了有希望的进展。