High Density of Si Nanocrystals Fabricated in a VHF-PECVD System for Light-Emitting Devices

High-quality nanocrystalline silicon films were fabricated in plasma enhanced chemical vapor deposition system by using a high excitation frequency (40.68 MHz) at low temperatures. It is found that the nanocrystalline Si films with high crystallinity of 89% can be obtained by using SiH₄ highly diluted with H₂. Furthermore, the area density of the nanocrystalline Si is as high as 4.4×10¹¹/cm². The Fourier transform infrared spectroscopy and transmission spectroscopy manifest that the nanocrystalline Si film possesses small microstructure factor, low hydrogen content and wide optical band gap.