Formation of microcrystalline structure in a-Si:H films prepared by RF sputtering

Formation of microcrystalline structure in a-Si:H films prepared by RF sputtering has been investigated by TEM and FT-IR. The Films deposited in pure H₂ have grain-like structure and tend to crystallize with increasing the gas pressure, while the films deposited in Ar containing 10 % H₂ usually become amorphous. With increasing input power and the gas pressure, however, the latter films tend to have amorphous-microcrystalline mixed structure, and corresponding to this structural change, shift of optical absorption edge to lower energy and decreases of resistivity and activation energy of its temperature dependence are observed.