A semiconductor device with a large storage capacity per unit area is provided.
A semiconductor device includes a memory cell. The memory cell includes a first conductor; a first insulator over the first conductor; a first oxide over the first insulator and including a first region, a second region, and a third region positioned between the first region and the second region; a second insulator over the first oxide; a second conductor over the second insulator; a third insulator positioned in contact with a side surface of the first region; and a second oxide positioned on the side surface of the first region, with the third insulator therebetween. The first region includes a region overlapping the first conductor. The third region includes a region overlapped by the second conductor. The first region and the second region have a lower resistance than the third region.