Method of manufacturing silicon carbide semiconductor device

摘要

A first impurity region is formed by ion implantation through a first opening formed in a mask layer. By depositing a spacer layer on an etching stop layer on which the mask layer has been provided, a mask portion having the mask layer and the spacer layer is formed. By anisotropically etching the spacer layer, a second opening surrounded by a second sidewall is formed in the mask portion. A second impurity region is formed by ion implantation through the second opening. An angle of the second sidewall with respect to a surface is 90°±10° across a height as great as a second depth. Thus, accuracy in extension of an impurity region can be enhanced.

主权项

1. A method of manufacturing a silicon carbide semiconductor device, comprising the steps of:
preparing a silicon carbide substrate having a surface; forming an etching stop layer on said surface of said silicon carbide substrate; depositing a mask layer on said etching stop layer; forming a first opening surrounded by a first sidewall in said mask layer; forming a first impurity region having a first conductivity type from said surface to a first depth in said silicon carbide substrate by ion implantation through said first opening; forming a mask portion having said mask layer and a spacer layer by depositing said spacer layer on said etching stop layer on which said mask layer has been provided, after said step of forming a first impurity region, said spacer layer covering said first sidewall and said etching stop layer in said first opening; forming a second opening surrounded by a second sidewall in said mask portion by anisotropically etching said spacer layer in said first opening; and forming a second impurity region having a second conductivity type different from said first conductivity type from said surface to a second depth smaller than said first depth in said silicon carbide substrate, by ion implantation through said second opening, said second sidewall having a substantially uniform thickness across a height as great as said second depth.