Crystallization, diffusion and phase separation in sapphire amorphised by indium ion implantation

This paper discusses how indium implantation into a-axis sapphire to peak concentration of 8-45 mol % In produces amorphous surface layers. Migration of In during isothermal annealing at 6000C shows a strong ion dose dependence. For a dose of 6X1016In/cm2, two distinct types of In migration are seen: rapid diffusion of In within amorphous Al2O3 and diffusion of In into crystalline Al2O3 underlying the amorphous layer. For doses lower than 3X1016In/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