Structure character of fast growth polycrystalline silicon film from SiCl4/H2

The polycrystalline silicon films with the deposition rate over 4.5 Å/s prepared at low temperature of 250 ° were obtained from the hydrogen dilution of tetrachlorine silicon using PECVD technique. The results show that the growing surface of film contains a large amount of silicon crystalline grains with 30-100 nm in diameter. The crystalline fraction and the crystalline grain size strongly depend on the RF power and the hydrogen dilution ratio. The optimum RF power and the optimum hydrogen dilution ratio for the best crystalline character are related to the deposition rate. On the other hand, the crystalline fraction and the crystalline grain size are almost independent on the substrate temperature. It is considered that the space reaction processes and the Cl element play an important role in the initial stage of the crystalline formation and in the crystalline grain growth for the low-temperature crystallization of the films.