Patent ID: 8466512

Claim:
A semiconductor device comprising: a substrate; a planar semiconductor layer on the substrate; a columnar semiconductor layer on the planar semiconductor layer; a first source or drain region at a bottom of the columnar semiconductor layer; a second drain or source region in an upper part of the columnar semiconductor layer; a gate insulating film around the columnar semiconductor layer; a gate electrode on the gate insulating film so as to surround the columnar semiconductor layer; a first contact layer on the second drain or source region; a second contact layer on the first source or drain region; and a third contact layer on a gate wire extending from the gate electrode, wherein a side surface of the second contact layer is nearly perpendicular to the substrate, and an average inclination of a side surface of the first contact layer is larger than an average inclination of the side surface of the second contact layer, such that projections of an upper end of the first contact layer onto the substrate are larger than a circumference of a top part of the columnar semiconductor layer.