Comparison and Analysis of Short Circuit Performance of 1200V SiC MOSFETs

Abstract

The short-circuit capability of Silicon Carbide (SiC) MOSFETs is much worse than the Si IGBT counterparts. There are two kinds of commercially available SiC MOSFET devices (trench MOSFETs and planar MOSFETs), and their short-circuit capability is not exactly the same. At present, there is a lack of comparative study on the short-circuit capability of these two kinds of devices. To solve this problem, this paper carries out a comparative study of the short-circuit capability of the two devices. Experiment results show that in the case of short circuit tests, it takes more time for planar MOSFETs to reach their peak currents because of their lower channel mobility and higher trap density. The DC voltage has little impact on the peak current which is mainly affected by the gate voltage. At the low DC voltage, such as 400V, 500V and 600V, planar MOSFETs have better short-circuit indexes no matter the short circuit withstand time (SCWT) or the short-circuit energy. However, at 800V DC voltage, trench MOSFETs have a better performance in short-circuit tests. Considering the factor of different areas, the short-circuit energy density of trench MOSFETs is higher than that of planar devices, especially under the condition of 800V high DC voltage.