Fabrication method of silicon carbide semiconductor element

摘要

A (000-1) C-plane of an n− type silicon carbide substrate having an off-angle θ in a <11-20> direction is defined as a principal plane, and a periphery of a portion of this principal surface layer defined as an alignment mark is selectively removed to leave the convex-shaped alignment mark. The alignment mark has a cross-like plane shape such that two rectangles having longitudinal dimensions tilted by 45 degrees relative to the <11-20> direction are orthogonal to each other. When a film thickness of a p− type epitaxial layer is Y; a width of the alignment mark parallel to the principal surface of the n− type silicon carbide substrate is X; and an off-angle of the n− type silicon carbide substrate is θ, an epitaxial layer is formed on an upper surface of the alignment mark such that Y≧X·tan θ is satisfied.

主权项

1. A fabrication method of a silicon carbide semiconductor element, the fabrication method comprising:
defining a plane of a silicon carbide substrate having a <0001> c-axis tilted by θ from a normal line direction of a principal plane of the silicon carbide substrate in a <11-20> direction as the principal plane and removing a principal surface layer of the silicon carbide substrate such that a periphery of a region in which an alignment mark is provided is surrounded so as to leave a convex-shaped alignment mark; and growing an epitaxial layer on the principal surface layer of the silicon carbide substrate to cover the alignment mark, wherein a width X of the alignment mark parallel to the principal surface of the silicon carbide substrate satisfies Y≧X·tan θ in terms of a relationship with a film thickness Y of the epitaxial layer.