Large thickness-dependent improvement of crystallographic texture of CVD silicon films on R-sapphire

Thin (80-800 nm) epitaxial silicon films on sapphire substrates were deposited via CVD technique and studied with XRD, SEM, EDS, EBSD, HRTEM and AFM methods. Increase of grain size, reduction of microtwin concentration and strong sharpening of crystallographic texture with increasing film thickness was observed. To our knowledge, XRD texture analysis in relation to film thickness of silicon on sapphire samples was performed for the first time. Thickness-dependent behavior of texture quality and film microstructure can be explained by the model of evolutionary selection and disclination formation.