Early stages of grain growth in ion-irradiated amorphous silicon

Transmission-electron-microscopy observations of silicon layers obtained by chemical vapor deposition at 540 °C onto ${\mathrm{SiO}}_2$ substrates reveal the presence of nanometer-diameter crystal seeds. Ion bombardment with 600-keV Kr ions at a temperature in the range 330–450 °C produces the growth of a fraction of these seeds that increases with the irradiation temperature. The interpretation of the results implies that phase stability is still controllled by the thermodynamic transition scheme even in the presence of the large density of defects generated during each collision cascade.