Estimation of Influence on Carbon Vacancy Regarding 4H-SiC Substrate Grown by HTCVD Method

In order to increase productivity and reduce the cost of wafers, we have developed a high temperature chemical vapor deposition (HTCVD) method that can realize the high-speed growth of 4H-SiC crystals. Tokuda et al. reported an interesting study in which the carrier lifetime of a substrate grown by HTCVD (HTCVD substrate) was considerably shorter than that of the substrate grown by physical vapor transport (PVT); moreover, bipolar degradation was highly suppressed when the HTCVD substrate was applied to PiN diodes [1]. Herein, we demonstrate that the short carrier lifetime of the HTCVD substrate is mainly attributable to the carbon vacancy (V C ) and that V C particularly diffuses from the HTCVD substrate to the epitaxial layer.