Patent ID: 8642426

Claim:
A method of producing the semiconductor device comprising: providing a semiconductor device including: an island-shaped silicon layer; a first gate dielectric film surrounding the island-shaped silicon layer; a gate electrode surrounding the first gate dielectric film; a second gate dielectric film surrounding the gate electrode; a tubular silicon layer surrounding the second gate dielectric film; a first n+-type diffusion layer disposed on a top of the island-shaped silicon layer; a second n+-type diffusion layer disposed underneath the island-shaped silicon layer; a first p+-type diffusion layer disposed on a top of the tubular silicon layer; a second p+-type diffusion layer disposed underneath the tubular silicon layer and directly contacting the second n+-type diffusion layer; a third n+-type diffusion layer directly contacting a bottom of the second n+-type diffusion layer and a bottom of the second p+-type diffusion layer; and a silicon-metal compound layer directly contacting a part where the second p+-type diffusion layer contacts the third n+-type diffusion layer, the method further comprising etching single-crystal silicon to form the island-shaped silicon layer and the tubular silicon layer.