METHOD FOR MANUFACTURING INSULATED GATE SWITCHING ELEMENT INCLUDING TRENCH GATE ELECTRODE

摘要

PROBLEM TO BE SOLVED: To provide a technique capable of further flattening a side surface of a trench of a trench gate electrode.SOLUTION: A method for manufacturing an insulated gate switching element including a trench gate electrode comprises a trench forming step, a protective film forming step, a thermal processing step, a gate insulating film forming step, and a gate electrode forming step. The trench forming step forms a trench whose side surface extends along an m surface on a surface (c surface) of the SiC substrate. The protective film forming step forms a protective film containing carbon and covering at least a part of the surface. The thermal processing step thermally processes the SiC substrate in the state in which at least a part of the surface is covered by the protective film and the side surface is exposed. The gate insulating film forming step forms a gate insulating film on the side surface after the thermal processing. The gate electrode forming step forms a gate in the trench.SELECTED DRAWING: Figure 4