METHOD FOR PRESERVING A GALLIUM NITRIDE SUBSTRATE, PRESERVED GALLIUM NITRIDE SUBSTRATE, SEMICONDUCTOR DEVICE, AND MANUFACTURING METHOD THEREFOR

摘要

A GaN substrate storage method of storing, within an atmosphere in which the oxygen concentration is not greater than 15 vol. % and the water-vapor concentration is not greater than 20 g/m3, a GaN substrate (1) having a planar first principal face (1m), and whose plane orientation in an arbitrary point (P) along the first principal face (1m) and separated 3 mm or more from the outer edge thereof has an off-inclination angle Δα of -10° or more, 10° or less with respect to the plane orientation of an arbitrarily designated crystalline plane (1a) that is inclined 50° or more, 90° or less with respect to a plane (1c), being either the (0001) plane or the (0001) plane, through the arbitrary point. In this way a method of storing GaN substrates whose principal-face plane orientation is other than (0001) or (0001), with which semiconductor devices of favorable properties can be manufactured is made available.