Patent ID: 8242023

Claim:
A method of producing a semiconductor device, the method comprising: a masking step of forming a mask being open partially on the main face of a first conductive type semiconductor substrate; an etching step of forming trenches by etching the semiconductor portions of the first conductive type semiconductor substrate exposed to the opening portions in the mask; an exposing step of widening the width of each opening portion in the mask, and exposing the semiconductor portions on the surface of the first conductive type semiconductor substrate, remaining without being etched after the etching step; and a layer forming step of epitaxially growing a second conductive type semiconductor layer in the trenches to fill the trenches completely and the semiconductor portions of the first conductive type semiconductor substrate exposed in the exposing step, wherein the layer forming step form grows the second conductive type semiconductor layer so that an upper surface of the second conductive type semiconductor layer is situated higher than an upper surface of the first conductive type semiconductor substrate but lower than an upper surface of the mask.