Thermal reaction of Pt film with < 110 > GaN epilayer

Backscattering spectrometry, x-ray diffractometry, and scanning electron mi croscopy have been used to study the reaction of a thin Pt film with an epi layer of [110] GaN on [110] sapphire upon annealing at 450, 550, 650, 750, and 800 degrees C for 30 min. A Ga concentration of 2 at. % is detected by MeV He-4(++) backscattering spectrometry in the Pt layer at 550 degrees C. By x-ray diffraction, structural changes are observed already at 450 degree s C. At 650 OC, textured Ga2Pt appears as reaction product. The surface mor phology exhibits instabilities by the formation of blisters at 650 degrees C and voids at 800 degrees C. (C) 1999 American Vacuum Society. [S0734-2101 (99)10705-X].