Disclosed herein is a device that includes: a semiconductor substrate including an active region having a semiconductor pillar, the semiconductor pillar having first and second side surfaces substantially perpendicular to a main surface of the semiconductor substrate; an element isolation region surrounding the active region, the element isolation region including a first insulating pillar that is in contact with the first side surface of the semiconductor pillar; a gate electrode that covers the second side surface of the semiconductor pillar with an intervention of a gate insulating film; a first impurity diffusion layer formed on an upper surface of the semiconductor pillar; a second impurity diffusion layer formed in the active region located below the semiconductor pillar; and an etching protection wall that is arranged to surround the semiconductor pillar.