Epitaxial recrystallization of alkali-ion implanted alpha-quartz

This paper reports on solid phase epitaxial growth (SPEG) of Cs+, Na+- and Li+-ion beam amorphized alpha-quartz samples induced by thermal annealing i n an oxygen rich atmosphere. The evolution of the amorphous layer was monit ored by means of Rutherford backscattering spectrometry in channeling geome try (RBS-C), while the migration of the implants was measured via RES tin t he case of Cs) and time-of-flight elastic recoil detection analysis (TOF-ER DA) (in the case of Li). For all three systems, complete SPEG was observed to occur at 600-900 degrees C, with a tendency of decreasing recrystallizat ion temperature for decreasing mass of the implanted alkali (Cs: 875 degree s C, Na: 800 degrees C, Li: 650-700 degrees C. The oxygen in-diffusion into Li-irradiated samples during annealing in a O-18 atmosphere was studied us ing TOF-ERDA. At 700 degrees C almost 25% of the O-16 content within the mo dified SiO2 layer was exchanged by O-18. Th, strong oxygen in-diffusion fav ours the dissolution of alkali-oxide in the amorphous structure providing t he topological freedom necessary for the epitaxial regrowth. (C) 2000 Elsev ier Science B.V. All rights reserved.