Report on the growth of bulk aluminum nitride and subsequent substrate preparation

High-quality, bulk aluminum nitride crystal grains exceeding I cm in dimens ion have been obtained using a self-seeded sublimation-recondensation growt h technique at 0.9 mm/h driving rate. X-ray double crystal diffraction and topography show a full-width-at-half-maximum of around 100 arcsec and exten sive areas with a density of dislocations less than 10(4) cm(-2), respectiv ely. These substrates have been prepared by chemical mechanical polishing t echniques to obtain a surface roughness of 1.4-1.6 nm. The size, structural quality, and surface roughness prove these substrates to be adequate for I II-nitride device fabrication. (C) 2001 Elsevier Science B.V. All rights re served.