US Patent 7608525 Method for manufacturing nitride semiconductor substrate

A method for manufacturing a nitride semiconductor substrate comprises the steps of: growing a first nitride semiconductor on a substrate, patterning the first nitride semiconductor to obtain a pattern surrounded by a plane equivalent to the (11-20) plane and having at least two concave portions that are similar in their planar shape, and growing a second nitride semiconductor layer, using a plane equivalent to the (11-20) plane in the first nitride semiconductor pattern as a growth nucleus.