NITRIDE SEMICONDUCTOR SUBSTRATE AND METHOD FOR MANUFACTURING THE SAME, AND NITRIDE SEMICONDUCTOR DEVICE USING NITRIDE SEMICONDUCTOR SUBSTRATE

摘要

The invention relates to a nitride semiconductor substrate and a method of manufacturing the same. A nitride semiconductor substrate in accordance with the invention comprises a supporting substrate formed by growing an over layer made of nitride semiconductor over the entire surface of a substrate made of different material; a first nitride semiconductor layer having periodically arranged T-shaped cross sections formed by laterally growing nitride semiconductor films starting at portions formed in any one of a periodical stripe, grid or island configuration provided on the surface of said supporting substrate and stopping the lateral growth before said nitride semiconductor films join together; and a second nitride semiconductor layer which is grown laterally from the top surface or the top and side surfaces of said T-shaped cross sections of said first nitride semiconductor layer to cover the entire surface of said supporting substrate, wherein cavities are formed below respective joints of said second nitride semiconductor layer, and V-shaped grooves are formed on the surface of said over layer.