Semiconductor devices and semiconductor memory devices

Abstract

This invention provides a semiconductor device and a semiconductor memory device that can be manufactured with superior semiconductor device quality. The semiconductor device of this invention comprises: an oxide semiconductor extending in a vertical direction, having an annular upper surface, a concave surface connected to the inner edge of the upper surface and facing downward, a side surface, and a contact surface located downward; an insulating film surrounding the side surface of the oxide semiconductor; a first electrode in contact with the contact surface of the oxide semiconductor; a gate electrode, separated by the insulating film and facing a portion of the side surface away from the upper surface and the contact surface; and a second electrode in contact with the upper surface and the concave surface of the oxide semiconductor.

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