SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

摘要

A transistor or the like having high field-effect mobility is provided. A transistor or the like having stable electrical characteristics is provided. A semiconductor device including a first oxide semiconductor layer, a second oxide semiconductor layer, a gate insulating film, and a gate electrode which partly overlap with one another is provided. The second oxide semiconductor layer is positioned between the first oxide semiconductor layer and the gate insulating film. The gate insulating film is positioned between the second oxide semiconductor layer and the gate electrode. The first oxide semiconductor layer has fewer oxygen losses than those of the second oxide semiconductor layer.