Characterization of process-induced defects in SiC MOSFETs by cross-sectional cathodoluminescence

Abstract

Cross-sectional cathodoluminescence (CL) and scanning capacitance microscopy (SCM) measurements were carried out for silicon carbide (SiC) metal–oxide–semiconductor field-effect transistors (MOSFETs) to investigate process-induced defects. The DI defect-related line at 426 nm and a broad luminescence at approximately around 430–470 nm, which were produced by ion implantation, were observed in addition to the near-band-edge emission. CL images showed that the densities of nonradiative recombination and DI centers were high near the source region. Moreover, DI centers existed even in the n-drift region located 10 µm from the surface. These results indicate that many types of defects diffuse and interact with each other during annealing even in the area where dopant atoms are not implanted. The annealing process not only activates dopant atoms but also induces the diffusion of unstable native defects and transforms their structure into more thermally stable defects such as DI centers.