Improving AlN crystalline quality by high-temperature ammonia-free microwave plasma chemical vapor deposition

Abstract Microwave plasma chemical vapor deposition (MPCVD) offers us a new option to realize high-temperature epitaxy. In this work, AlN films were deposited on 6H-SiC substrates by MPCVD. The epitaxy was carried out without the participation of ammonia. The results reveal that workable temperature for AlN epitaxy is from 1300 °C–1450 °C. X-ray rocking curves and X-ray photoelectron spectroscopy confirm the improved crystalline quality of AlN grown at higher temperatures. The narrowest FWHM of X-ray rocking curves for AlN (0002) and (10–12) are 142 and 350 arcsec at 1450 °C, respectively. Possible growth mechanisms are suggested.