Patent ID: 7524725

Claim:
A method for forming a vertical transistor of a semiconductor device, the method comprising: etching a semiconductor substrate to form a silicon fin; performing an angled ion implant process to form a source region in the semiconductor substrate below a lower portion of the silicon fin, wherein the angled ion implant process is performed in four directions with a tilt angle ranging from 30° to 45°; performing a channel ion implant process to form a channel region in a sidewall of the silicon fin; performing an ion implant process to form a drain region in an upper portion of the silicon fin; forming a gate oxide film on a surface of the semiconductor substrate and the sidewall of the silicon fin; forming a first gate electrode on a first sidewall of the silicon fin, wherein the first gate electrode comprises a first gate polysilicon layer and a first gate metal layer; and forming a second gate electrode on a second sidewall of the silicon fin, wherein the second gate electrode comprises a second gate polysilicon layer and a second gate metal layer.