Strain compensation in Si 1− x− yGe xC y layers prepared by ion implantation and excimer laser annealing

Abstract

Si 1− x Ge x , Si 1− y C y and Si 1− x− y Ge x C y layers, about 200 nm thick, with x≈0.1 and y≈0.01, have been synthesized by multiple energy ion implantation and liquid-phase epitaxy regrowth using excimer laser pulses around 1 J cm −2. Secondary ion mass spectrometry and Rutherford backscattering depth profilings and Fourier transform infrared (FTIR) absorption show that, using selected conditions, both SiC precipitation and carbon diffusion can be avoided, while germanium is uniformly redistributed over the molten layer. Raman spectroscopy and FTIR confirm that C atoms are located in substitutional lattice sites. However, estimations of the tetragonal expansion using Raman scattering and channeling angular scans in oblique incidence, reveal an incomplete incorporation of carbon in substitutional positions and, consequently, a partial strain compensation in the ternary alloy.