| abstract |
PROBLEM TO BE SOLVED: To provide a transistor using an oxide semiconductor having good operating characteristics. Further, by using the transistor, a semiconductor device having improved operating characteristics is provided. SOLUTION: In a plan view, one of a source electrode and a drain electrode of a transistor is surrounded by an annular gate electrode. Alternatively, in a plan view, one of the source electrode and the drain electrode of the transistor is surrounded by a channel forming region. As a result, the source electrode and the drain electrode are not electrically connected via the parasitic channel generated at the end of the island-shaped oxide semiconductor layer. [Selection diagram] Fig. 1 |