| abstract |
Provided is a semiconductor device having excellent reliability. A semiconductor device having a first oxide, a second oxide, a first conductor, a second conductor, a third conductor, a first insulator, and a second insulator, wherein: the first conductor is provided in contact with the upper surface of the first oxide; the second conductor is provided in contact with the upper surface of the first oxide; the first insulator is disposed on the first conductor and the second conductor; the second oxide is provided in contact with the upper surface of the first oxide; the second insulator is disposed on the second oxide; the third conductor is disposed on the second insulator; the first insulator has a function for suppressing oxygen dispersion; the first oxide has indium, an element M (where M is gallium, yttrium or tin), and zinc; the first oxide has a first region that overlaps with the third conductor; and the area of the first region in contact with the second oxide is an area where the ratio of the number of atoms of aluminum (Al) with respect to that of the element M is less than 0.1. |