HIGH-ENERGY COIMPLANTATION OF TI AND O IONS INTO SAPPHIRE

Optical and structural changes of sapphire(0001) substrates implanted with Ti ions or with Ti and O ions and subjected to thermal annealing, are examined by optical absorption, RBS-channeling and XRD measuremen ts. The transmittance of the co-implanted sample was larger than that of the Ti-implanted sample. After annealing at 1000 degrees C, rutile- type TiO2 microcrystals with (200) orientation were formed in the coim planted sample of Ti and O ions. Furthermore, a broad optical absorpti on at 220-340 nm in the co-implanted sample was increased after the an nealing. This was possibly due to the formation of TiO2 microcrystals in the sapphire substrate. In contrast to this result, no evidence of the formation of titanium oxide in a crystal structure was obtained fo r the Ti-implanted sample after the annealing. (C) 1998 Elsevier Scien ce S.A. All rights reserved.