Growth and characterization of thin Si80C20 films based upon Si4C building blocks

Abstract

The growth of thin ${\mathrm{Si}}_{\mathrm{80}}{\mathrm{C}}_{\mathrm{20}}$ diamond-structured material on (100)Si has been achieved using the novel C–H free, carbon source tetrasilyl methane, ${\mathrm{C(SiH}}_{\mathrm{3}}{\mathrm{)}}_{\mathrm{4}}.$ The precursor decomposes at temperatures in the range 600–700 °C to give thin amorphous layers with a composition of ${\mathrm{Si}}_{\mathrm{0.80}}{\mathrm{C}}_{\mathrm{0.20}},$ which corresponds to the same relative concentrations of Si and C as in the precursor. The amorphous material is crystallized via solid-phase epitaxy by annealing at 825 °C to yield a potentially ordered structure in which ${\mathrm{Si}}_{\mathrm{4}}\mathrm{C}$ tetrahedra are linked together in a three-dimensional diamond-cubic framework. Measured lattice parameters are larger than expected from Vegards’ Law, a discrepancy which is attributed to steric repulsions causing bond elongation.