| 摘要 |
PURPOSE: To increase the ratio of an on-state current to an off-sate current in a thin film transistor without increasing the two-dimensional occupation area of the thin-film transistor and at the same time, to make it possible to control electrically the function of the active gate of the transistor. CONSTITUTION: A heavily doped region 42, 43 and low-concentration regions 44 are formed in a polycrystalline Si film 36 covering a polycrystalline Si film 33 via an SiO2 film 35 and a source region 52, drain regions 53 and a channel regions 54 are formed in a polycrystalline Si film 46 convering the film 36 via an SiO2 film 45. Thereby, a channel length of a thin film transistor can be made long by making high the film 33 and it is possible to control electrically the work function of the film 36 by the film 33. |
