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

Sapphire single crystal [alpha-Al(2)O(3)(0 0 0 1)] samples were treated by irradiation with Ti(+) ions in the energy range 0.5-7.0 keV at 25 degrees C and 750 degrees C under UHV conditions for total doses of 10(16) Ti(+)/cm(2). These Ti treated sapphire samples were studied by ex situ X-ray photoelectron spectroscopy (XPS) depth profiling and by atomic force microscopy (AFM). Aluminum in the oxidation states Al(0,3+,x+), where 0 < x < 3, and titanium in the oxidation states Ti(0.2+,3+,4+) were found to coexist throughout the implanted region, with variation of their relative amounts along the depth distribution. The AFM measurements showed that there was minimal change in surface morphology following implantation at all conditions, indicating that the sapphire surface has enough resiliency to retain its original surface morphology despite the keV ion impacts. (C) 1999 Elsevier Science B.V. All rights reserved.