PRETREATMENT METHOD FOR BASE SUBSTRATE, AND METHOD FOR MANUFACTURING LAMINATE USING PRETREATED BASE SUBSTRATE

摘要

Provided is a method for pretreatment of a group III nitride single crystal substrate having a high Al composition ratio, for manufacturing a high-quality group III nitride thin film. The method includes heating the base substrate at a temperature range of 1000 to 1250°C for no less than 5 minutes under a first mixed gas atmosphere before a layer of a second group III nitride single crystal is grown, wherein the first mixed gas includes hydrogen gas and nitrogen gas; the base substrate includes a layer of a first group III nitride single crystal at least on a surface of the base substrate; the first group III nitride single crystal is represented by a composition formula of Al A Ga B In C N; and the layer of the second group III nitride single crystal is to be grown on the layer of the first group III nitride single crystal.