US Patent 11495690 Semiconductor device and fabrication method of semiconductor device

A semiconductor device having high on-state current and high reliability is provided. The semiconductor device includes, a first insulator; a first oxide over the first insulator; a second oxide over the first oxide; a first conductor and a second conductor over the second oxide; a third oxide over the second oxide; a second insulator over the third oxide; a third conductor located over the second insulator and overlapping with the third oxide; a third insulator in contact with a top surface of the first insulator, a side surface of the first oxide, a side surface of the second oxide, a side surface of the first conductor, a top surface of the first conductor, a side surface of the second conductor, and a top surface of the second conductor; a fourth insulator over the third insulator; a fifth insulator over the fourth insulator; and a sixth insulator over the third conductor, the second insulator, the third oxide and the fifth insulator. The sixth insulator is in contact with a top surface of each of the third conductor, the second insulator, the third oxide, and the fifth insulator.