Epitaxial crystallization of amorphous SiO2 films deposited on single-crystalline alpha-quartz

The epitaxial alpha-quartz thin film could be a promising material for fabr icating optical devices because of its unique optical and mechanical proper ties and processing advantages compared to bulk materials. This letter repo rts on the solid-phase epitaxial growth of thin amorphous SiO2 films deposi ted by electron gun evaporation on single-crystalline alpha-quartz substrat es. This was achieved by high-dose Cs+-ion implantation and subsequent ther mal annealing in air. Also, a thin amorphous layer produced by Si+-ion impl antation on alpha-quartz was epitaxially regrown, thus indicating that the epitaxy is independent of the preparation history of the amorphous layer. T he results are explained on the basis of network modifications induced by a lkali and oxygen in the SiO2 structure. (C) 1999 American Institute of Phys ics. [S0003-6951(99)02845-4].