Method for producing aluminum nitride substrate, aluminum nitride substrate, and method for suppressing introduction of dislocation into aluminum nitride growth layer

A method for manufacturing an aluminum nitride substrate comprising:

• a processing step of removing a part of a silicon carbide substrate to form a pattern with a minor angle;
• and a crystal growth step of forming an aluminum nitride growth layer on the silicon carbide substrate on which the pattern is formed, wherein the pattern includes a 4n-gonal shape, including a reference figure which is a regular n-gonal shape including n vertices included in vertices of the pattern, a first line segment extending from each of the n vertices and a second line segment adjacent to the first line segment without extending from any of the n vertices, the n is a natural number larger than 2, and an angle formed by two adjacent first line segments in the pattern is constant and is equal to an angle formed by two adjacent second line segments in the pattern.

A method for suppressing introduction of dislocations into an aluminum nitride growth layer, the method comprising:

• a processing step of removing a part of a silicon carbide substrate before forming the aluminum nitride growth layer on the silicon carbide substrate to form a pattern with a minor angle,
• wherein the processing step includes a through hole formation step of removing a part of the silicon carbide substrate to form through holes.