TEMPLATE FOR EPITAXIAL GROWTH AND PROCESS FOR PRODUCING SAME

摘要

A surface of a sapphire (0001) substrate is processed to form recesses and protrusions so that protrusion tops are flat and a given plane-view pattern is provided. An initial-stage AlN layer is grown on the surface of the sapphire (0001) substrate having recesses and protrusions by performing a C+ orientation control so that a C+ oriented AlN layer is grown on flat surfaces of the protrusion tops, excluding edges, in such a thickness that the recesses are not completely filled and the openings of the recesses are not closed. An Al x Ga y N(0001) layer (1 ‰¥ x > 0, x + y = 1) is epitaxially grown on the initial-stage AlN layer by a lateral overgrowth method. The recesses are covered with the Al x Ga y N(0001) layer laterally overgrown from above the protrusion tops. Thus, an template for epitaxial growth having a fine and flat surface and a reduced threading dislocation density is produced.