Preparation of Sapphire for High Quality III-Nitride Growth
J. Cui, A. Sun, M. Reshichkov, F. Yun, A. Baski, H. Morkoç
Virginia Commonwealth University,Department of Electrical Engineering and Physics Department
This article was received on Friday, June 2, 2000 and
accepted on Friday, July 21, 2000. Abstract
We developed a unique preparation technique to eliminate
surface damage on the c-plane of sapphire and render it atomically flat. AFM
images of c-plane sapphire annealed at 1380 °C for 1hour show
terrace-like features with about 0.2 µm long terraces. The GaN layers grown
by MBE on annealed sapphire have [0 0 2] symmetric and [1 0 4] asymmetric full
width at half maximum (FWHM) of about 60 and 132 arcsec, respectively. This
compares with 408 and 600 arcsec, respectively, for GaN grown on sapphire
having gone through conventional chemical cleaning.
