High-temperature growth of thick AlN layers on sapphire (0001) substrates by solid source halide vapor-phase epitaxy

High-temperature growth of thick AlN layers was performed by solid source halide vapor-phase epitaxy (HVPE) with local heating system. it was found that crystalline quality of AlN layers grown on sapphire (0 0 0 1) substrates improved with increase of growth temperature until 1500 degrees C. Degradation of crystalline quality occurred over 1550 degrees C, which is thought to be due to the decomposition of AlN crystal or sapphire substrate during the epitaxial growth. The full-width at half-maximum (FWHM) values of (0 0 0 2) and (10 10) diffraction from the AlN layer grown at 1500 degrees C were 103 and 828 arcsec, respectively. Secondary ion mass spectrometry (SIMS) measurement showed a high concentration of oxygen incorporated into the AlN layer through the interface between sapphire and AlN at 1550 degrees C. The near band-edge emission peaking at 208.2 nm was also observed by cathodoluminescence measurement at room temperature. (c) 2008 Elsevier B.V. All rights reserved.