| 摘要 |
<p>The present invention implements a normally-off switching device by controlling a threshold voltage of electrical characteristics of a transistor which uses an oxide semiconductor in a channel forming region. The transistor includes a first insulation film; an oxide semiconductor layer formed on the first insulation film and including the channel forming region; a second insulation film formed to cover the oxide semiconductor layer and a source drain and a drain electrode electrically connected to the oxide semiconductor layer. The transistor further includes a first gate electrode layer formed to overlap the channel forming region by interposing the first insulation film therebetween; a second gate electrode layer formed to overlap the channel forming region by interposing the second insulation film therebetween; and a third gate electrode layer formed to overlap a side surface in a channel width direction of the oxide semiconductor layer by interposing the second insulation film therebetween.</p> |
