Semiconductor device and method for manufacturing semiconductor device

Abstract

A semiconductor device having favorable electrical characteristics is provided. The semiconductor device includes a conductor, a first insulator in contact with a side surface of the conductor, a second insulator in contact with a top surface of the conductor and a top surface of the first insulator, and an oxide over the second insulator. The oxide includes a region that overlaps with the conductor with the second insulator interposed therebetween. The maximum height of a roughness curve (Rz) of the top surface of the conductor is 6.0 nm or smaller. The region includes crystals, and c-axes of the crystals are aligned in the normal direction of the top surface of the conductor.

1 . A semiconductor device comprising:
 a conductor;   a first insulator in contact with a side surface of the conductor;   a second insulator in contact with a top surface of the conductor and a top surface of the first insulator; and   an oxide over the second insulator,   wherein the oxide includes a region that overlaps with the conductor with the second insulator interposed therebetween,   wherein the maximum height of a roughness curve (Rz) of the top surface of the conductor is 6.0 nm or smaller,   wherein the region includes crystals, and   wherein c-axes of the crystals are aligned in the normal direction of the top surface of the conductor.