| 摘要 |
Provided is a field-effect transistor (FET) having small off-state current, which is used in a miniaturized semiconductor integrated circuit. The field-effect transistor includes a thin oxide semiconductor which is formed substantially perpendicular to an insulating surface and has a thickness of greater than or equal to 1 nm and less than or equal to 30 nm, a gate insulating film formed to cover the oxide semiconductor, and a strip-shaped gate which is formed to cover the gate insulating film and has a width of greater than or equal to 10 nm and less than or equal to 100 nm. In this structure, three surfaces of the thin oxide semiconductor are covered with the gate, so that electrons injected from a source or a drain can be effectively removed, and most of the space between the source and the drain can be a depletion region. Therefore, off-state current can be reduced. |
