Shallow implantation of Ti+ ions in sapphire [alpha-Al2O3(0001)]

Sapphire single crystal [alpha-Al2O3(0 0 0 1)] samples were treated by irra diation with Ti+ ions in the energy range 0.5-7.0 keV at 25 degrees C and 7 50 degrees C under UHV conditions for total doses of 10(16) Ti+/cm(2). Thes e Ti treated sapphire samples were studied by ex situ X-ray photoelectron s pectroscopy (XPS) depth profiling and by atomic force microscopy (AFM). Alu minum in the oxidation states Al-0,Al-3+,Al-x+, where 0 < x < 3, and titani um in the oxidation states Ti-0.2+,Ti-3+,Ti-4+ were found to coexist throug hout the implanted region, with variation of their relative amounts along t he depth distribution. The AFM measurements showed that there was minimal c hange in surface morphology following implantation at all conditions, indic ating that the sapphire surface has enough resiliency to retain its origina l surface morphology despite the keV ion impacts. (C) 1999 Elsevier Science B.V. All rights reserved.