Substrate dependence of initial growth of microcrystalline silicon in plasma-enhanced chemical vapor deposition

Very thin microcrystalline silicon films have been deposited by plasma-enhanced chemical vapor deposition (CVD) from hydrogen diluted SiH4 gas in order to study its initial growth mechanism. The dependence of the crystallinity and the Si-H bonding configuration on electrical and chemical properties of substrates have been studied using a high sensitivity Raman spectrometer. It is found that conductive and oxygen free substrates provide good crystallinity in the initial stage. The origin of the substrate dependence is explained in terms of the ion bombardment from the plasma and the chemical nature of the substrate surface.