| abstract |
A semiconductor device that can be miniaturized or highly integrated is provided. Alternatively, favorable electrical characteristics are given to a semiconductor device including an oxide semiconductor. Another object is to provide a highly reliable semiconductor device in which variation in electrical characteristics of a semiconductor device including an oxide semiconductor is suppressed. A semiconductor device is in contact with an island-shaped oxide semiconductor layer provided over an insulating surface, an insulating layer surrounding a side surface of the oxide semiconductor layer, an upper surface of the oxide semiconductor layer, and an upper surface of the insulating layer. A source electrode layer, a gate electrode layer provided to overlap with the oxide semiconductor layer, and a gate insulating layer provided between the oxide semiconductor layer and the gate electrode layer. The layer and the drain electrode layer are provided above the top surface of the oxide semiconductor layer, and the top surface of the insulating layer is planarized. [Selection] Figure 1 |