Speaker
Description
Silicon carbide (SiC) is a wide-band semiconductor with exceptional properties for applications in power electronics. It outperforms Si as a semiconductor in terms of electric breakdown field, saturation carrier velocities and thermal conductivities. Especially the latter makes SiC also more attractive compared to other wide band semiconductors such as GaN. In general, crystal defects play a central role for electric and optical properties and deep atomistic insights are still missing.
In this talk we present calculations including densitiy functional theory and interatomic potentials to explore the properties of crystal defects in SiC. We focus on the energetics of polytypes, point defects, dopants, dislocations, grain boundaries and surfaces. With respect to dislocations we show the core structure of SiC and explore the formation of hollow micropipes as a function of Burgers vector size. We find that commonly observed inner radii are smaller in theory compared to experiments and discuss the possible reasons for the discrepancy. Furthermore, we discuss point defects in SiC that are relevant for quantum sensing applications. We investigate the relevant defect levels and study their properties in different crystallographic environments. Finally we also present out activities to develop machine learning interatomic potentials that can be used to explore deposition phenomena of crystal growth that are relevant crystal growth to understand how the quality of SiC crystals can be improved during the physical vapor transport process.