Abstract This work focuses on the positive bias temperature instability of SiC-based MOSFETs under different stress voltages and temperatures. Stress experiments demonstrate that the threshold voltage shift (∆Vth) does not follow a conventional power law for long stress time, but exhibits a saturating log- time dependence attributed to the charge trapping in the pre-existing defects at the SiC/SiO2 interface or in the SiO2 layer. The maximum Vth shift (∆Vmax), which is a function of the total trap density, increases with the stress voltage (Vstress) and decreases for temperatures higher than 50 °C. The time constant of the traps (τ0) also shows an uptrend with Vstress with a maximum value of around 50 °C. Moreover, the trap energy distribution (γ) slightly increases with temperature. The recovery analysis shows that an empiric universal relaxation function well describes the data with a dispersion parameter (β) that follows the Arrhenius law. Finally, the Vth recovery, after the same Vstress, is enhanced with temperature and also depicts a linear behavior on the Arrhenius plot. This indicates that the charge de-trapping process is thermally activated and explains the low degradation observed at high temperatures during the stress phase.

中文翻译：

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碳化硅功率 MOSFET 中的 BTI 饱和和普遍弛豫

摘要 这项工作的重点是在不同应力电压和温度下 SiC 基 MOSFET 的正偏置温度不稳定性。应力实验表明，阈值电压偏移 (ΔVth) 在长时间应力时间内不遵循传统的幂律，但表现出饱和的对数时间依赖性，这归因于 SiC/SiO2 界面处预先存在的缺陷中的电荷俘获或在 SiO2 层。最大 Vth 偏移 (ΔVmax) 是总陷阱密度的函数，随应力电压 (Vstress) 的增加而增加，温度高于 50 °C 时会降低。陷阱的时间常数 (τ0) 也显示出随 Vstress 的上升趋势，最大值约为 50 °C。此外，陷阱能量分布 (γ) 随温度略有增加。恢复分析表明，经验通用松弛函数很好地描述了具有遵循 Arrhenius 定律的色散参数 (β) 的数据。最后，在相同 Vstress 之后，Vth 恢复随温度而增强，并且还在 Arrhenius 图中描绘了线性行为。这表明电荷去俘获过程是热激活的，并解释了在应力阶段在高温下观察到的低降解。