Investigation structural heterogeneities in hydrogenated nanocrystalline silicon thin films from argon-diluted silane dusty plasma PECVD

This study presents a novel approach for achieving a high deposition rate of nanocrystalline hydrogenated silicon (nc-Si:H) thin films using dusty plasma, eliminating the need for hydrogen dilution. Contrary to conventional beliefs, the research demonstrates that crystalline seeds can nucleate directly from the plasma environment itself. The investigation explores the relationship between plasma parameters and the degree of crystallinity in the deposited films, along with the characterization of structural inhomogeneities throughout the film's thickness. Raman spectroscopy, X-ray diffraction, and Transmission Electron Microscopy (TEM) are utilized for detailed analysis. The results reveal intriguing variations in crystallinity along the film's thickness, with higher crystallinity observed near the surface compared to regions closer to the substrate interface. In-depth analysis of grain size variation reveals that the average crystallite size decreases near the surface and increases in the bulk volume of the material. Additionally, deposition parameters, specifically power and pressure, are found to influence grain sizes, with higher values promoting larger grain growth. Notably, the observation of conical growth in layers deposited from dusty plasma presents a promising avenue for achieving controlled and desirable microstructures. This study sheds light on the critical influence of deposition parameters on film properties and the potential of dusty plasma for achieving desirable microstructures in nc-Si:H thin films. The findings offer valuable insights for tailoring thin film properties in diverse technological applications.