Oxygen migration during epitaxial regrowth in Cs+-irradiated alpha-quartz investigated by means of nuclear reaction analysis

The migration of oxygen in ion-beam-amorphized c-SiO2 (alpha-quartz) was in vestigated by means of nuclear reaction analysis using the resonant reactio n O-18(p,alpha)N-15 for oxygen depth profiling. Only very small amounts of oxygen were observed to diffuse in crystalline or in Xe+-ion beam-amorphize d alpha-quartz after high-temperature annealing. However, a dramatic migrat ion of oxygen occurs in Cs+-implanted alpha-quartz in the same temperature range (600-900 degrees C), where Cs diffuses out of the amorphized layer an d epitaxial recrystallization occurs. These results point out to a strong c orrelation of all these processes. A mechanism to explain the observed indi ffusion of O-18 is proposed and is related to the Cs migration and the topo logical modification to achieve epitaxial regrowth of the SiO2 matrix. (C) 2000 American Institute of Physics. [S0003-6951(00)02325-1].