Sapphire is widely used as a substrate material for blue light emitting diode and laser diode devices, as well as for visible/ infrared window and radome applications. The ensuing component performance is highly dependent on the quality of the surface finish, and degree of subsurface damage. A novel process has been developed which has the potential to replace the final stage chemical and mechanical polishing steps currently necessary to achieve the requisite surface finish. The process entails deposition of a thin film of Al on the (0 0 0 1) sapphire substrate, followed by an oxidation anneal. The final step is grain growth of the underlying substrate, which leads to complete single crystal conversion. The influence of heat treatment conditions on the final surface finish was investigated. Microstructural and topographical development of the surface layer was studied using scanning electron microscopy, orientation image microscopy, and atomic force microscopy.