EPITAXIALLY LAMINATED III-NITRIDE SUBSTRATE

摘要

Disclosed is an epitaxially laminated III-nitride substrate in which the crystallinity of a III-nitride semiconductor can be improved without increasing the amount of deflection of the substrate. Specifically disclosed is an epitaxially laminated III-nitride substrate comprising a base substrate, a buffer formed on the base substrate, and a main laminate formed on the buffer by epitaxially growing a III-nitride layer on the buffer. The substrate is characterized in that the buffer comprises an initial film-growth layer that is in contact with the base substrate, a first superlattice laminate that is formed on the initial film-growth layer, and a second superlattice laminate that is formed on the first superlattice laminate, the first superlattice laminate is produced by laminating 5 to 20 first AlN layers that comprise an AlN material and an equal number of second GaN layers that comprise a GaN material in an alternating manner, one pair of a first AlN layer and a second GaN layer has a thickness of less than 44 nm, and the second superlattice laminate is produced by laminating a plurality of first layers comprising an AlN material or an AlGaN material and second layers comprising an AlGaN material having a different band gap from that of the first layer in an alternating manner.