METHOD FOR MANUFACTURING SUBSTRATE FOR SEMICONDUCTOR DEVICE, AND SUBSTRATE FOR SEMICONDUCTOR DEVICE AND SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To obtain a substrate for a semiconductor device which exhibits low density of defects over a wide range. SOLUTION: A GaN film 2 and a first GaN layer 3 are stacked in sequence on a base substrate 1. An SiO2 film 10 and a Cr film 11 are formed on the first GaN layer 3 and are subjected to patterning for forming a lattice Cr film 11 having several square holes. The SiO2 film 10 is etched, by using the Cr film 11 as a mask and the GaN layer 3 is further etched for forming several holes 3b in the GaN layer 3. After that, the Cr film 11 and the SiO2 film are removed, and a second GaN layer 5 is grown on the first GaN layer 3 with the several holes 3b in its top until its surface is planarized through its growth in the lateral direction.