Localization of He induced nanovoids in buried Si1-xGex thin films

The localization of voids in thin Si1-xGex layers after He+ implantation and thermal annealing is reported. A Si/Si1-xGex multilayer grown onto (001) Si was implanted with He+ in the 10-30 keV range, with fluences from 7 X 10(15) up to 1 X 10(16) cm(-2) h. Samples were analyzed by transmission electron microscopy, showing void formation only within the two layers containing Ge or at the film/substrate interface. Our results support the idea that the compressive strain in the Si1-xGex layers induces the nucleation of small cavities and the growth of voids by a mechanism where vacancies are stabilized by He. (c) 2008 American Institute of Physics.