Semiconductor thin film, method and apparatus for producing the same, and semiconductor device and method of producing the same

The present invention relates to a semiconductor film for use in thin film transistors (TFTs) used in liquid crystal displays, photosensors such as linear sensors, photovoltaic devices such as solar cells, memory LSIs for SRAMs (static random access memories) and the like. The invention also relates to a method and an apparatus for producing the semiconductor film. More particularly, the semiconductor film is a crystalline semiconductor thin film formed on, for example, a glass substrate or the like, by laser annealing an amorphous material or the like. The invention further relates to semiconductor device using the semiconductor thin film and a method of producing the device. In a polycrystalline silicon thin film transistor, a semiconductor device having a high field effect mobility is achieved by increasing a grain size of a silicon thin film. First, an insulation layer having a two-layer structure is formed on a transparent insulated substrate . In the insulation layer, a lower insulation layer , which is in contact with the transparent insulating substrate , is made to have a higher thermal conductivity than an upper insulation layer . Thereafter, the upper insulation layer is patterned so that a plurality of stripes are formed thereon. Subsequently, an amorphous silicon thin film is formed on the patterned insulation layer, and the insulation layer is irradiated with a laser light scanning in a direction parallel to the stripe pattern on the upper insulation layer . Thus, the amorphous silicon thin film is formed into a polycrystalline silicon thin film