| abstract |
The present invention provides a transistor having excellent electrical properties and a method for manufacturing the same. The transistor includes an oxide semiconductor layer having a source region, a drain region, and a channel formation region formed on an insulating surface, a gate insulating layer formed on the oxide semiconductor layer, a gate electrode formed on the gate insulating layer, and overlapping the channel formation region, and a source region It has a source electrode in contact with and a drain region in contact with the drain region, and the source region and the drain region have a portion having a higher oxygen concentration than the channel formation region. |