Effects of Non-killer Defects on SiC MOSFET Short-Circuit Ruggedness and Reliability

Inhalt:
The manufacturing process of Silicon Carbide (SiC) devices, from the substrate to the epitaxial growth and subsequent fabrication stages, introduces various defects. These defects are classified into killer and non-killer defects (NKDs). NKDs deviate from the perfect crystal structure and consequently impact the performance and reliability of the device [3]. This paper concentrates on the different types of NKD defects found in 900 V SiC MOSFETs, including basal plane dislocations (BPDs), stacking faults (SFs), partials and micropipes (MPs). Furthermore, a set of devices that do not contain any NKDs (considered as good) are also included for the comparison purpose. The devices undergo electrical characterization before and after being subjected to single and repetitive short-circuit (SC) testing. For the first time, this study establishes a link between the existence of non-killer defects (NKDs) in SiC devices and their influence on electrical performance, short-circuit (SC) ruggedness and reliability. The critical shortcircuit energy (E(SC)) for the specific NKDs tends to be higher on average and exhibits a narrower variation compared to the devices without NKDs. On the other hand, the group labeled as ‘SFs’ shows higher short-circuit peak currents (I(Dmax)). Additionally, there is a noticeable variability in the short-circuit withstand time (t(SCWT)) for both groups ‘SFs’ and ‘good’.