EPITAXIAL WAFER COMPOSED OF SINGLE CRYSTAL SUBSTRATE AND GALLIUM NITRIDE-BASED COMPOUND SEMICONDUCTOR CRYSTAL GROWN THEREON

摘要

PROBLEM TO BE SOLVED: To obtain an epitaxial wafer remarkably reduced in lattice matching properties between the wafer and a single crystal substrate and markedly reduced in crystal defects in an epitaxial film by epitaxially growing a gallium nitride-based compound on a single crystal substrate having a specific structure. SOLUTION: A single crystal substrate is composed of a perovskite type tetragonal crystal containing Al and Sr in an epitaxial wafer composed of the single crystal substrate and the gallium nitride-based compound semiconductor crystal grown thereon. The single crystal substrate has the general structural formula represented in the form of A1-x Srx A1y B1-y O3 [O<=(x)<=1; 0<=(y)<=1]. The constituent element A is a rare earth element and the constituent element B is a group 5A element. In the formula, the constituent element A is preferably lanthanum(La), neodymium(Nd) or praseodymium(Pr) and the constituent element B is preferably tantalum,(Ta) or niobium(Nb).