Strain distributions in carbon-doped silicon nanowires along [110] and [100] investigated by X-ray diffraction

Abstract

Abstract Carbon-doped Si films formed on Si substrates have a large tensile strain, and the strain is relaxed by microfabrication into nanowires. We investigated the effects of crystalline orientation, width and carbon concentration on lattice relaxation using reciprocal space mapping (RSM) with X-ray diffraction. RSM profiles of 400–480 periodically aligned C-doped Si nanowires on Si substrates indicate that lattice relaxation of Si0.9917C0.0083 nanowires along the [100] direction was larger than that of [110] nanowires. The effect of crystalline orientation of nanowires is considered to increase as lattice mismatch to the substrate increases, since no difference was observed in residual strains between [100] and [110] Si0.9940C0.0060 nanowires with a smaller lattice mismatch to the Si substrate. It has also been revealed that the strains of C-doped Si nanowires became more relaxed as the nanowire width decreased.