| 摘要 |
PURPOSE:To enhance the cutoff frequency of a transistor and to obtain a large current, by heating an amorphous silicon film or a polycrystalline silicon film by the conduction of heat, which is obtained by heating a gate electrode film, performing crystallization of the film, and forming an active region. CONSTITUTION:A gate electrode 2 comprising a polycrystalline film is formed on a transparent insulating substrate 1. The polycrystalline silicon film undergoes thermal oxidation and a gate insulating film 3 is formed thereon. Then, an amorphous silicon film 4 is formed by a glow discharge method. Optical energy 5 is projected on the silicon film 4, and annealing is performed. In general, the silicon film 4 and the insulating film 3 are thin. Therefore, the optical energy is easy to transmit through the films. Then, the gate electrode 2 comprising the thick polycrystalline film is heated. By the conduction of said heat, the silicon film 4 at the upper part is heated and crystallized. Thus the stability of the transistor, especially the stability of the threshold voltage value is improved. |
