Patent ID: 8174068

Claim:
A semiconductor device comprising: a semiconductor substrate having a main surface; a silicon pillar having first and second side surfaces that are substantially perpendicular to the main surface of the semiconductor substrate; a gate dielectric film that covers the first side surface of the silicon pillar; an insulator pillar that covers the second side surface of the silicon pillar; a gate electrode having a first portion that covers the first side surface of the silicon pillar via the gate dielectric film and a second portion that covers the insulator pillar; an interlayer dielectric film provided above the silicon pillar, the gate dielectric film, the insulator pillar, and the gate electrode; and a gate contact plug that is embedded in a first contact hole provided in the interlayer dielectric film and is in contact with the second portion of the gate electrode, wherein a film thickness of the insulator pillar in a direction parallel to the main surface of the semiconductor substrate is thicker than a film thickness of the gate dielectric film in the direction.