碳化硅金属-氧化物-半导体场效应晶体管（Metal Oxide Semiconductor Field Effect Transistor, MOSFET）凭借优异的性能受到电力电子工程师们的喜爱。但是，碳化硅MOSFET较差的栅氧质量引发的动态阈值漂移成为了碳化硅MOSFET稳定运行的潜在隐患，尤其是在雪崩这样的极端工况下，并联碳化硅MOSFET动态阈值漂移将会极大提高碳化硅MOSFET雪崩失效的可能性。为了研究动态阈值漂移对于碳化硅MOSFET并联雪崩的影响，本文搭建了碳化硅MOSFET双管并联雪崩测试平台，采用分离变量的方法，研究经历不同动态阈值漂移量下的碳化硅MOSFET并联雪崩分流情况。实验结果表明，当并联碳化硅MOSFET阈值电压差异较小时，并联碳化硅MOSFET雪崩电流均流度较高，但是当并联碳化硅MOSFET阈值差异超过0.5V时，并联碳化硅MOSFET雪崩电流均流度较差，无论是电流上升阶段和雪崩阶段，均是阈值较小的器件流过较大电流。分析认为，阈值电压较大的器件，由于捕获了大量的电子，导致沟道迁移率下降，从而使得雪崩分流较低。

Silicon carbide metal-oxide-semiconductor field-effect transistors (SiC MOSFETs) are favored by power electronics engineers for their excellent performance. However, the dynamic threshold voltage drift caused by the poor gate oxide quality of SiC MOSFETs poses a potential threat to their stable operation. Particularly under extreme conditions such as avalanche, the dynamic threshold voltage drift in parallel SiC MOSFETs significantly increases the likelihood of avalanche failure. To investigate the impact of dynamic threshold voltage drift on the avalanche behavior of parallel SiC MOSFETs, a dual parallel avalanche test platform was established. Using the method of separating variables, the avalanche current sharing of parallel SiC MOSFETs with different amounts of dynamic threshold voltage drift was studied. Experimental results indicate that when the threshold voltage difference between parallel SiC MOSFETs is small, the current sharing during avalanche is high. However, when the threshold voltage difference exceeds 0.5V, the current sharing during avalanche is poor, with the device having the smaller threshold voltage carrying more current during both the current rise and avalanche phases. It is believed that the device with the larger threshold voltage captures a significant amount of electrons, leading to a decrease in channel mobility and consequently lower avalanche current sharing.

TN 386