Study son Short-Circuit Failure Model of GaN/SiC Cascode Devices

A Cascode Junction Field Effect Transistor (JFET) is a combination structure that uses a low-voltage MOSFET as an auxiliary switch to convert a high-voltage normally-on JFET into a normally-off device. In this paper, a failure circuit model of GaN/SiC Cascode with a new structure is established, and the failure mechanism of GaN/SiC Cascode under short-circuit conditions is discussed. The failure model introduces additional leakage current based on the traditional circuit model. Among them, GaN HEMT introduces leakage current at the gate and drain levels, and SiC JFET introduces leakage current at the drain and source levels. At the same time, in GaN HEMT, the relationship between drain-source voltage and failure is explored, and in SiC JFET, the relationship between temperature and failure is explored. Finally, the accuracy of the established GaN/SiC Cascode model is verified by switching circuit and short circuit experiments.