Patent ID: 11588014

Abstract:
An epitaxial structure includes a substrate, a nucleation layer on the substrate, a buffer layer on the nucleation layer, and a nitride layer on the buffer layer. The nucleation layer consists of regions in a thickness direction, wherein a chemical composition of the regions is Al(1−x)InxN, where 0≤x≤1. A maximum value of the x value in the regions decreases along the thickness direction, and the x value in the chemical composition of each two regions consists of a fixed region and a gradient region, wherein a gradient slope of the gradient regions is −0.1%/nm to −50%/nm, and a stepwise slope of the fixed regions is −0.1%/loop to −50%/loop. A thickness of the nucleation layer is less than that of the buffer layer. A surface roughness of the nucleation layer in contact with the buffer layer is greater than that of the buffer layer in contact with the nitride layer.