Microstructure evolution in carbon-ion implanted sapphire

Abstract

Carbon ions of MeV energy were implanted into sapphire to fluences of 1× 1017 or 2× 1017 cm-2 and thermally annealed in forming gas (4% H in Ar) for 1 h. Secondary ion mass spectroscopy results obtained from the lower dose implant showed retention of implanted carbon and accumulation of H near the end of range in the C implanted and annealed sample. Three distinct regions were identified by transmission electron microscopy of the implanted region in the higher dose implant. First, in the near surface region, was a low damage region (L1) composed of crystalline sapphire and a high density of plateletlike defects. Underneath this was a thin, highly damaged and amorphized region (L2) near the e..