PROCESS FOR FABRICATING TRENCH MOS TYPE SILICON CARBIDE SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a process for fabricating a trench MOS type silicon carbide semiconductor device in which dielectric breakdown strength can be enhanced by making an SiO2film on the footprint of a trench thick without utilizing a crystal face of high oxidation rate or a damage on the crystal face caused by an ion beam. SOLUTION: The process for fabricating a trench MOS type silicon carbide semiconductor device comprises a step for forming a trench 6 reaching a first n-type epitaxial silicon carbide thin film by using an Al film mask 5 after forming first n-type epitaxial silicon carbide thin film 2 and p-type epitaxial silicon carbide thin film 3 and a second n-type epitaxial silicon carbide thin film 4 in this order on an n-type silicon carbide semiconductor substrate 1 having an Si face as a major surface and then forming recesses and protrusions 8 on the bottom of the trench by using an Al film mask 7 formed again, and a subsequent thermal oxidation step. The step for forming protrusions and recesses is a step for processing into a recessed and protruding shape having such an interval of protrusions as the protrusions transformed into an oxide film by the subsequent thermal oxidation step touch each other. COPYRIGHT: (C)2008,JPO&INPIT