The intrinsic atomic-level surface roughness mobility limit of 4H-SiC

Presently, models to describe surface roughness scattering combine intrinsic and extrinsic effects, where extrinsic effects include process-induced interactions and intrinsic effects are due to inherent atomic structure. In this work, we present a general method for extracting the intrinsic surface roughness scattering rate of a material interface from the atomic structure, using Density Functional Theory and Fermi's Golden Rule. We find for the case of the 4H-SiC/SiO2 interface, intrinsic surface roughness mobility is several orders of magnitude greater than the extrinsic mobility which depends on process induced nonidealities. This result suggests that a path forward for higher mobility SiC devices may be the reduction of extrinsic miscut roughness.