Solid phase epitaxial regrowth of Si1−xGex/Si strained-layer structures amorphized by ion implantation

Strained-layer structures consisting of ∼30–35 nm Si1−xGex (x=0.16–0.29) and 33 nm Si deposited by molecular beam epitaxy on a (100)Si substrate have been amorphized by ion implantation at 40 K with 120 keV As+. Rutherford backscattering/channeling measurements using 2 MeV He+ ions have been used to measure the thickness of the amorphous layer and monitor the subsequent epitaxial regrowth occurring as a result of annealing at 560–600 °C. Angular scans across the {110} planar channels indicate that the initial crystallinity and strain was recovered for x=0.16; however, for x=0.29 crystal quality was greatly reduced and the coherency at the substrate-alloy layer interface was destroyed.