X-RAY PHOTOELECTRON-SPECTROSCOPY AND X-RAY-DIFFRACTION STUDY OF THE THERMAL OXIDE ON GALLIUM NITRIDE

The oxidation of single crystal gallium nitride in dry air has been in vestigated. X-ray photoelectron spectroscopy (XPS) revealed minimal ox ide growth at 450 and 750 degrees C for up to 25 h. However, at 900 de grees C the growth of an oxide approximately 5000 Angstrom thick was o bserved after 25 h. This oxide was determined to be the monoclinic bet a-Ga2O3 using glancing angle x-ray diffraction. XPS spectra of the Ga 3d and Ga 2p core levels indicated peak shifts of 1.2 and 1.3 eV, resp ectively, from Ga-O to Ga-N bonding. The Ga L3M45M45 core level bindin g energy was also investigated and beta-Ga2O3 and GaN each presented a characteristic peak shape. (C) 1997 American Institute of Physics.