| abstract |
Provided is a semiconductor device with excellent properties. This semiconductor device comprises a transistor. The transistor comprises a first oxide, a second oxide above the first oxide, an insulator above the second oxide, and an electric conductor above the insulator. The first oxide comprises a channel forming region, and a first region and a second region positioned so as to sandwich the channel forming region. The second oxide is provided in such a manner as to be in contact with the channel forming region, a portion of the first region, and a portion of the second region. The oxygen concentrations in the first region and in the second region are lower than in the channel forming region. |