SiC/SiO2界面态电荷对SiC MOSFET短路特性影响的研究

碳化硅/二氧化硅（SiC/SiO₂）界面态电荷数量的减少有利于降低碳化硅金属-氧化物-半导体场效应晶体管（SiCMOSFET）的通态电阻和开关损耗，然而沟道电流的提升会给遭遇短路故障的SiC MOSFET带来更大的电流应力。在传统的SiCMOSFET等效电路模型的基础上建立了SiC MOSFET的短路失效模型，该模型考虑了强电流应力下器件内的泄漏电流，并引入了包含界面态电荷的沟道载流子迁移率。利用该模型讨论了SiC/SiO₂界面态电荷对SiC MOSFET短路特性的影响，结果显示界面态电荷的减少缩短了SiC MOSFET短路耐受时间。随后通过从失效电流中分离出不同产生机制下的泄漏电流分量，讨论了界面态电荷对SiC MOSFET短路特性影响的机理。

Research on the Impact of Trapped Charges at SiC/SiO2 Interface on the Short-circuit Performances of SiC MOSFET

The decrease in the trapped charges at SiC/SiO₂ interface is helpful to lower the on-state resistance and switching loss of SiC MOSFET, however, the lift of channel current brings higher current stress to SiC MOSFET during short-circuit case. On the basis of the traditional equivalent circuit model for SiC MOSFET, a short-circuit failure model of SiC MOSFET has been developed. The model introduces the leakage current across the PN junction between N-drift region and P base region of SiC MOSFET, and employs an advance carrier mobility model with the trapped charges at the SiC/SiO₂ interface. By the developed failure model, the influence brought by the interface trapped charges on the short-circuit performances has been exploited, and the result shows that the reduction of interface trapped charge shortens the time of SiC MOSFET withstanding short-circuit stress. Further, the mechanism of interface trapped charges affecting the short-circuit withstanding time has been discussed by separating the leakage current components from the failure current.