Fabrication of high-quality strain relaxed SiGe(1Â 1Â 0) films by controlling defects via ion implantation

We investigate effects of ion implantation on strain relaxation of SiGe(1 1 0) layers grown on Si(1 1 0) substrates. Ar+ or Si+ ion implantation is carried out before or after the SiGe growth. It is found that the strain relaxation of the SiGe(1 1 0) film is largely enhanced due to implantation-induced defects both for Ar and Si implantation. Particularly, the sample with Si implantation after the SiGe growth allows large strain relaxation and smaller surface roughness than Ar implantation. As a result, a 50-nm-thick Si0.79Ge0.21 or Si0.77Ge0.23(1 1 0) buffer layer with almost full relaxation and rms surface roughness below 0.5 nm was obtained. It is, therefore, expected that high-mobility strained Si/Ge(1 1 0) channels can be realized on the SiGe(1 1 0) relaxed buffer layers fabricated by Si implantation. It is also demonstrated that the local introduction of the implantation defects allows controlling of lateral strain states and dislocation generation, opening new concepts of engineering of both strain and surface orientation.