The present invention relates to a semiconductor device and a method of manufacture thereof, particularly, to a semiconductor device including a vertical type gate and a method of forming the same. According to the present invention, a semiconductor device includes a vertical pillar which is protruded from a semiconductor substrate, has a vertical channel, and has a first width; an insulating layer which has a second width smaller than the first width, provided in both sides of the vertical pillar which is adjacent in a first direction; and a nitride film provided in a side wall of the insulating layer.