Influence of rf power on the properties of nanostructured silicon-carbon films deposited by PECVD

Nanostructured films composed of silicon crystallites embedded in an hydrogenated amorphous silicon carbon matrix have been deposited by plasma enhanced chemical vapour deposition from silane methane mixture diluted in hydrogen varying the rf power from 30 to 80 W. The films have been investigated in their structural, optical and electrical properties. The increase of rf power appears to be an effective deposition parameter to increase the incorporation of carbon in the amorphous matrix and to facilitate the reduction of the crystallite size. The dark conductivity of the studied films decreases from 1.4 × 10-3 to 3.5 × 10-9 Ω-1cm-1 while the photo conductivity decreases from to 3.2 × 10-3 to 3.5 × 10-7 Ω-1cm-1 as a function of rf power. The photosensitivity is about 100 in 40-80 W range.