Network modification and epitaxial recrystallisation of ion-implanted alpha-quartz

We have investigated the thermally induced epitaxial recrystallisation of ion-implanted alpha-quartz. The samples were irradiated with different ions (Cs+, Si+, O+, Xe+) and subsequently annealed between 775 and 1275 K in air or in vacuum. Before and after annealing, the thickness of the disordered layer was monitored by means of Rutherford Backscattering Spectroscopy in channeling geometry. After Cs-implantation and subsequent annealing in air, complete recovery of the crystallinity was achieved at 1150 K. Only partial regrowth took place when heating the Cs-irradiated samples under vacuum. After the implantation of stoichiometric amounts of Si- and O-ions or of Xe-ions epitaxial recrystallisation did not occur up to 1175 K. The dependence of the recrystallisation rate on the Cs fluence was determined. The epitaxial recrystallisability after annealing in air can be explained by the topological alterations of the [SiO4]-tetrahedral network due to the dissolution of alkali-oxide. (C) 1999 Elsevier Science B.V. All rights reserved.