Substrate temperature and hydrogen dilution: parameters for amorphous to microcrystalline phase transition in silicon thin films

Amorphous to microcrystalline phase transition in hydrogenated silicon (Si:H) is realized separately with the variations of substrate temperature and hydrogen dilution. The Raman spectroscopy reveals structural transformations and marks the transition. It occurs at ∼450°C with 10% silane concentration, whereas that is noted at 250°C with a silane concentration of 4.5%. The material evolved in the transition region is a well-developed amorphous matrix containing a small fraction (∼12%) of crystallites. A uniform distribution of small (∼100 Å) crystallites in the films is observed by transmission electron microscopy. The transition material is photosensitive.