Monte-Carlo simulations of 2-MeV α-particle channeling in Si1−xSnx alloy

Abstract

Monte-Carlo simulations of 2-MeV α-particle channeling in Si1−xSnx alloys with 0⩽x⩽1 have been performed. The simulations are compared with measured channeling-angular scans for strained Si0.95Sn0.05 layers grown by molecular beam epitaxy (MBE). Agreement between simulated and measured angular scans can only be achieved if we assume a deviation of the crystal structure from the ideal one. This deviation can be attributed to a mosaic structure in the films and to an atomic-scale distortion of the crystal lattice due to an expected difference in the bond lengths between the Si–Si, Si–Sn and Sn–Sn atoms (such a difference in bond lengths has been observed in the epitaxial Si1−xGex system). The contributions from both of these imperfections are estimated and discussed.