Microstructure of poly-Si thin films prepared at low temperatures

Microstructures of hydrogenated polycrystalline silicon (poly-Si) and microcrystalline silicon (μc-Si:H) thin films prepared by hot wire chemical vapor deposition (HWCVD) with hydrogen dilution of silane have been studied. The columnar crystal growth of the film was clearly visible starting from substrate. The transmission electron diffraction (TED) showed the typical polycrystalline material with small crystals. The (1 1 1) preferential grain was observed in poly-Si films. The 2100 cm−1 stretching vibration mode splits into two modes centered at around 2082 and 2098 cm−1 which are suggested to be the Si–H modes at the nanocrystalline Si (1 11) and (1 1 0) surfaces, respectively.