Group iii nitride epitaxial substrate and method for manufacturing the same

Abstract

Provided is a Group III nitride epitaxial substrate that can suppress the occurrence of breakage during a device formation process and a method for manufacturing the same. A Group III nitride epitaxial substrate according to the present invention includes a Si substrate, an initial layer in contact with the Si substrate, and a superlattice laminate, formed on the initial layer, including a plurality of sets of laminates, each of the laminates including, in order, a first layer made of AlGaN with an Al composition ratio greater than 0.5 and 1 or less and a second layer made of AlGaN with an Al composition ratio greater than 0 and 0.5 or less. The Al composition ratio of the second layer progressively decreases with distance from the substrate.

Dependencies are inferred from the claim text.