Semiconductor device and semiconductor memory device

Abstract

This invention provides a semiconductor device with excellent transistor characteristics. The semiconductor device of the embodiment includes: a first electrode, a second electrode, an oxide semiconductor layer between the first electrode and the second electrode, a gate electrode, a first insulating layer between the first electrode and the gate electrode, a second insulating layer between the gate electrode and the second electrode, and a gate insulating layer between the gate electrode, the first insulating layer, the second insulating layer, and the oxide semiconductor layer. When the thickness of the gate insulating layer between the first insulating layer and the oxide semiconductor layer is set as a first thickness, the thickness of the gate insulating layer between the second insulating layer and the oxide semiconductor layer is set as a second thickness, the thickness of the gate insulating layer between the first end of the gate electrode on the first electrode side and the oxide semiconductor layer is set as a third thickness, and the thickness of the gate insulating layer between the second end of the gate electrode on the second electrode side and the oxide semiconductor layer is set as a fourth thickness, the second thickness is thicker than the first thickness, or the fourth thickness is thicker than the third thickness.