Synthesis of Hydrogenated Nanocrystalline Silicon Films By HW-CVD Without Hydrogen Dilution of Silane

Abstract

In this work we report synthesis and characterization of nc-Si:H films by HW-CVD method. The role of filament temperature (T fil ) in controlling the material properties has been carefully and systematically investigated. Characterization of these films with Raman spectroscopy and XRD revealed that increase in T fil endorses the growth of crystallinity in the films. Furthermore, crystallites in the films have preferential orientation in (111) direction. The hydrogen content in the films shows decreasing trend with increase in T fil but it remains < 6 at. % over the entire range of T fil studied. However, band gap remains as high as 2.1 eV. We attribute high band gap at low hydrogen content to increase in crystalline fraction with T fil . From the present study we conclude that T fil is a key process parameter in HW-CVD to induce crystallinity in Si:H films without hydrogen dilution of Silane.