Hot-wire CVD-grown microcrystalline silicon films with and without an initial growing layer modification by using an inductively coupled plasma

Macrocrystalline Si (μc-Si) films have been deposited by using hot-wire chemical vapor deposition (HWCVD) with five W wire filaments of 0.5 mm in diameter. We compared the HWCVD-grown films with the film exposed to an inductively coupled plasma system for modification of the seed layer. The W-wire filament temperature was maintained below 1600°C to avoid metal contamination by thermal evaporation of the filament. The deposition conditions were varied, including the H ₂ dilution ratio, with and without a plasma treatment. From the Raman analysis, we observed that the film crystallinity was strongly influenced by the H ₂ dilution ratio and was weakly affected by the distance between the wire and the substrate. We were able to achieve a crystalline volume fraction of about 70 % with a SiH ₄/H ₂ ratio of 1.3 %, a wire temperature of 1514°C, a substrate distance of 4 cm, and a chamber pressure of 38 mTorr. We investigated the influence of a μc-Si seed layer by using plasma treatment. This article also deals with the influence of the H ₂ dilution ratio in crystallinity modification.