Microvoids in amorphous Si1−<i>x</i>C<i>x</i>:H alloys studied by small-angle x-ray scattering

Abstract

The microstructure of hydrogenated amorphous silicon-carbon alloys has been analyzed by small-angle x-ray scattering, infrared absorption, and density measurements. Decreasing density with C incorporation is due to microvoids about 0.6 nm in average radius, which are either approximately spherical in shape or randomly oriented nonspheres. The microvoid number density increases from about 5×1019/cm3 for a-Si:H to about 4×1020/cm3 for a-Si0.7 C0.3 :H. The CH3 species probably causes the enhanced microvoid formation in these alloys. A large fraction of the microvoid surfaces is not hydrogenated.