Void evolution in silicon under inert and dry oxidizing ambient annealing and the role of a Si1−xGex epilayer cap

Voids were formed in silicon (Si) and silicon germanium/silicon (Si1−xGex/Si) samples containing 5% or 9% Ge (at. %) by 30 keV, 5 × 1016 cm−2 helium (He+) implantation followed by annealing in nitrogen (N2) or dry oxygen (O2) atmospheres in the temperature range 960–1110 °C. Si1−xGex thicknesses were 60 nm and 20 nm for 5% and 9% Ge, respectively. He+ implantation energy was set such that in Si1−xGex/Si samples voids were formed inside the Si …