This article was received on Thursday, September 14, 1995 and
accepted on Tuesday, January 16, 1996.
Abstract
We report the use of ScAlMgO4 as a substrate for the
epitaxial growth of wurzitic GaN. The low misfit (+1.8%) allows coherent
epitaxy of GaN, as observed by RHEED. The congruent melting of
ScAlMgO4 makes Czochralski growth possible, suggesting that large,
high quality substrates can be realized. Boules about 17mm in diameter are
reported. We have used nitrogen-plasma molecular beam epitaxy to grow GaN
epitaxial films onto ScAlMgO4 substrates. Band-gap photoluminescence
has been observed from some of these films, depending primarily on the
deposition conditions. A 3x3 superstructure has been observed by RHEED on the
GaN surfaces. Structural analysis by x-ray diffraction indicates very good
in-plane alignment of the GaN films. We also report thermal expansion
measurements for ScAlMgO4.
