Characterization of structure and role of different textures in polycrystalline Si films

Plasma enhanced chemical vapor deposited polycrystalline Si films were prepared at 300 °C, with varying SiF4 and/or H2 flow rates under otherwise fixed conditions. The changes in the SiF4 and/or H2 flow rates caused changes in the structural properties, defects, and the surface morphology of the Si films. The occurrence of a dominant 〈1 1 0〉 texture for film with [H2] = 0 sccm and under high SiF4 flow rate corresponded with low hydrogen coverage. While with an increase in the hydrogen flow rate the 〈3 1 1〉 texture becomes a predominant plan for grains growth, suggesting a reduction in the grain size for 〈1 1 0〉 texture and an increase in the nucleation rate for 〈3 1 1〉 texture. The film surface roughness investigation shows that it greatly affected the grains orientation. Finally we found that the degree of preferred orientation is an important factor in controlling the oxidation of the film and its stability.