Fast Growth of Polycrystalline Film in SiCl₄/H₂ Plasma

We report the discovery of fast growth of polycrystalline silicon films under low temperature of 200-300°C from SiCl₄/H₂ mixture gases by plasma enhanced chemical vapour deposition technique. The deposition rate strongly depends not only on the rf power and the flow ratio of H₂/SiCl₄, but also on the substrate temperature, while the crystalline fraction is mainly affected by both the rf power and the flow ratio of H₂/SiCl₄. The high film-growth rate is due to the enhancement of the gas-phase reaction in SiCl₄/H₂ plasma. By means of adjusting the matching relation between the flow ratio of H₂/SiCl₄ and rf power, and optimizing the substrate temperature, we obtain the polycrystalline silicon films deposited at a higher deposition rate over 3.5Å/s, with a crystalline fraction of 75% and an average crystallite size of 400-500 nm in diameter.