On the Luminescence and Driving Force of Stacking Faults in 4H-SiC

Abstract

Since it was determined that the formation and expansion of intrinsic stacking faults (SFs) induced a drift in the forward voltage (Vf) in 4H-SiC bipolar devices, significant effort has been made to understand the driving force causing SF motion as well as the various associated luminescence processes. The observation that annealing of faulted SiC devices and epilayers induced SF contraction and a recovery of the Vf drift enabled the studying of the impact of various parameters such as temperature, injection level and operation time upon SF motion, the Vf drift and luminescence within the same device. However, these observations in many cases contradicted the previously reported driving force models. Here we report on a basic driving force model explaining SF expansion in hexagonal SiC as well as discuss the observation of green luminescence from C-core partial dislocations bounding the SFs that may indicate an enhanced mobility of point defects within forward biased SiC pin diodes.