Semiconductor material, method of making the same, and semiconductor device

摘要

A semiconductor material is provided comprising: a composition graded layer, formed on a Si substrate or an interlayer formed thereon, comprising a composition of AlXGa1-XN graded such that a content ratio of Al in the composition decreases continuously or discontinuously in a crystal growing direction; a superlattice composite layer, formed on the composition graded layer, comprising a high Al-containing layer comprising a composition of AlYGa1-YN and a low Al-containing layer comprising a composition of AlZGa1-ZN that are laminated alternately; and a nitride semiconductor layer formed on the superlattice composite layer.