Crystallization, Diffusion and Phase Separation in Sapphire Amorphised by Indium Ion Implantation

Abstract

ABSTRACTIndium implantation into a-axis sapphire to peak concentrations of 8–45 mol % In produces amorphous surface layers.Migration of In during isothermal annealing at 600°C shows a strong ion dose dependence. For a dose of 6×1016In/cm2, two distinct types of In migration are seen - a) rapid diffusion of In within amorphous Al2O3 and b) diffusion of In into crystalline Al2O3 underlying the amorphous layer. For doses lower than 3×1016In/cm2 , no such migration of In is seen under identical anneal conditions. However, In undergoes phase separation into crystalline In2O3 particles embedded in amorphous Al2O3 at all doses.