The surface region of sapphire was modified by implantation of Pt ions. Sin
gle crystalline alpha-Al2O3 samples were implanted at room temperature with
160 keV Pt ions to fluences from 1x10(14) to 5x10(16) Pt+/cm(2). For doses
up to 10(15) Pt+/cm(2), 80% of the implanted ions occupy substitutional si
tes in the Al sublattice. The increase in dose makes the implanted region h
ighly damaged. The amorphization is observed for doses higher than 10(16) P
t+/cm(2). During vacuum annealing at 1200 degrees C, the substitutional fra
ction of Pt decreases and most of the damage is recovered. Annealing of 5x1
0(16) Pt+/cm(2) implanted alpha-Al2O3 at the same temperature but in an oxi
dizing atmosphere allows the complete recrystallization of the amorphous re
gion and induces the formation of Pt precipitates in agreement with glancin
g incidence X-ray diffraction (GIXRD) measurements. Detailed angular scans
through the main axial and planar directions show that the metallic precipi
tates are aligned with the c-axis of the alpha-Al2O3 structure. (C) 1999 El
sevier Science B.V. All rights reserved.