Structural properties of polycrystalline silicon films having varied textures fabricated with intentional control of surface reactions using SiF4/H2/SiH4 mixing gas

Abstract Polycrystalline silicon (poly-Si) films were fabricated from SiF 4 and H 2 gas mixtures by very high frequency (100 MHz) plasma enhanced chemical vapor deposition. The relationship between the deposition condition and film orientation was studied over a wide range of growth temperatures and SiF 4 /H 2 gas flows. We found that (4 0 0) oriented films were obtained at the larger SiF 4 /H 2 ratios and at temperatures higher than 150°C while (2 2 0) oriented films were obtained at other SiF 4 /H 2 flow ratios. The optimized SiF 4 /H 2 ratio for (4 0 0) oriented growth shifts to smaller ratios as the growth temperature decreases. (2 2 0) preferential growth is observed at high temperatures independent of the SiF 4 /H 2 flow ratio. A phenomenological explanation is proposed for these preferential growths. We conclude that (2 2 0) growth requires larger thermal energy compared to those of (4 0 0) and randomly oriented growths. Also, the larger high H 2 mixing inhibits the (4 0 0) growth.