Thin film transistor, thin film transistor substrate, electronic apparatus and process for producing polycrystalline semiconductor thin film

The present invention provides a TFT characteristics easily realized a low threshold voltage, high carrier mobility and low leakage current, and the like. TFT polycrystalline Si film having a small heat capacity and large heat capacity part of the portion, at least part of a small heat capacity is used as a channel portion. Further, the film grain of the polycrystalline Si film by laser annealing to form a structure, the energy density of the laser annealing has a small heat capacity part of the heat capacity is completely melted portion is not completely melted size. Since constituting the channel portion of coarse grains small heat capacity part and a large heat capacity part of the interface of the growth, it is possible to use general laser annealing apparatus easily realized a low threshold voltage, high carrier mobility and low leakage current characteristics.