| abstract |
The invention provides a transistor with a large current when it is turned on (on). One aspect of the present invention is a semiconductor device including a first insulator containing excess oxygen; a first oxide semiconductor on the first insulator; a second oxide semiconductor on the first oxide semiconductor; and a second oxide semiconductor First and second conductors disposed at a distance from each other; side surfaces of the first oxide semiconductor, top surfaces and sides of the second oxide semiconductor, top surfaces of the first conductor, and top surfaces of the second conductor A third oxide semiconductor in contact; a second insulator on the third oxide semiconductor; a third conductor facing the top and side surfaces of the second oxide semiconductor via the second insulator and the third oxide semiconductor, wherein, The first oxide semiconductor has higher oxygen permeability than the third oxide semiconductor. |