Oxidation Reduction in Nanocrystalline Silicon Grown by Hydrogen-Profiling Technique
The deposition of a compact amorphous silicon/nano-crystalline silicon material is demonstrated by hot-wire chemical vapour deposition using a sequential hydrogen profiling technique at low hydrogen dilutions. Nano-crystallite nucleation occurs at the substrate interface that develops into a uniform, porous crystalline structure as the growth progresses. A further reduction in the H-dilution results in the onset of a dense amorphous silicon layer. The average crystalline volume fraction and nano-crystallite size in the sample bulk amounts to 30% and 6 nm, respectively, as probed by Raman spectroscopy using the 647 nm excitation. The change in hydrogen dilution is accompanied by a graded hydrogen concentration depth-profile, where the hydrogen concentration decreases as the growth progresses. The level of post-deposition oxidation is considerably reduced, as inferred from infrared spectroscopy. The presence of oxygen is mainly confined to the substrate interface as a result of thermal oxidation during thin film growth.
C. J. Arendse et al., "Oxidation Reduction in Nanocrystalline Silicon Grown by Hydrogen-Profiling Technique", Journal of Nano Research, Vol. 41, pp. 9-17, 2016