Evaluation of silicon carbide Schottky barrier diode within guard ring by multifunctional scanning probe microscopy

Abstract

An evaluation method based on multifunctional scanning probe microscopy enables the nanoscale observation of power semiconductor devices. Herein, we report the results of the evaluation of a power device performed by frequency-modulation atomic force microscopy, Kelvin probe force microscopy (KPFM), and scanning capacitance force microscopy (SCFM). The evaluation sample is a commercially available silicon carbide Schottky barrier diode (SiC-SBD) with a breakdown voltage of 1200 V. In this study, we focus on the termination structure of the SiC-SBD. The termination structure such as guard ring can improve the breakdown voltage of SBD. In particular, we measured the dopant distribution and surface potential by SCFM and KPFM, respectively. We report the first observation results of the p-layer of the guard ring and the first evaluation of the relaxation effect of the electric field by the p-layer.