REACTIONS OF TRIMETHYLALUMINUM AND AMMONIA ON ALUMINA AT 600-K - SURFACE CHEMICAL ASPECTS OF ALN THIN-FILM GROWTH

The reactions of trimethylaluminum (TMAl) and ammonia (NH3) on gamma-a lumina at 600 K were studied by Fourier-transform infrared spectroscop y (FTIR) and X-ray photoelectron spectroscopy (XPS) to explore fundame ntal issues of AlN film growth. FTIR and XPS assignments for surface s pecies present after the deposition process have been directly correla ted from measurements taken in the same instrument. Sequential exposur e of TMAl and NH3 leads to self-limiting adsorption of TMAl and site-s elective reaction with NH3 to form a thin layer of AlN along with dini trogen and NH2 species. The coexposure of TMAl and NH3 leads to contin uous deposition resulting in a thick film of AlN with NH2 and dinitrog en species present at the AlN/alumina interface and NH terminating the AlN/vacuum interface. These processes are discussed in terms of AlN t hin film growth strategies.