Microstructure and initial growth characteristics of nanocrystalline silicon films fabricated by very high frequency plasma enhanced chemical vapor deposition with highly H2 dilution of SiH4

Nanocrystalline silicon (nc-Si:H) film deposited on silicon oxide in a very high frequency plasma enhanced chemical vapor deposition with highly H-2 dilution of SiH4 has been investigated by Raman spectroscopy and high resolution transmission electron microscopy. It is found that at early growth stage the initial amorphous incubation layer in nc-Si:H growth on silicon oxide can be almost eliminated and crystallites with diameter of about 6 to 10 nm are directly formed on the silicon oxide. Nearly parallel columnar structures with complex microstructure are found from cross-sectional transmission electron microscopy images of the film. It is considered that highly H-2 dilution and higher excitation frequency are the main reason for eliminating the initial amorphous incubation layer in nc-Si:H growth on silicon oxide. (C) 2010 American Institute of Physics. [doi:10.1063/1.3445876]