Nitride semiconductor substrate and manufacturing method thereof

摘要

The present invention relates to a nitride semiconductor substrate such as gallium nitride substrate and a method for manufacturing the same. The present invention forms a plurality of trenches on a lower surface of a base substrate that are configured to absorb or reduce stresses applied larger when growing a nitride semiconductor film on the base substrate from a central portion of the base substrate towards a peripheral portion. That is, the present invention forms the trenches on the lower surface of the base substrate such that pitches get smaller or widths or depths get larger from the central portion of the base substrate towards the peripheral portion.