Ion beam doping and epitaxial regrowth of alpha-quartz

Thermally induced epitaxial crystallization of thin a-SiO2 films represents a promising procedure for removing the ion-beam damage induced during the fabrication of integrated optical devices. In this paper we report on the c rystallization of a-SiO2 films deposited on single crystalline alpha -quart z substrates, investigated by means of Rutherford backscattering spectromet ry in channeling geometry (RBS-C). The epitaxial crystallization was achiev ed by means of a novel three-step procedure which uses high-fluence Cs+-ion doping of the films and subsequent annealing in air at 800-900 degreesC. S imilarly, amorphous SiO2 layers, created by the ion irradiation of alpha -q uartz samples, were epitaxially regrown after alkali post-implantation and annealing, thus demonstrating that the regrowth is independent of the produ ction history of the amorphous film. Optical spectroscopy in the range 300- 1100 nm showed the good optical properties of the regrown layer. (C) 2001 E lsevier Science B.V. All rights reserved.