Patent ID: 7683436

Claim:
A semiconductor device, comprising: a square pole-shaped channel portion made from a first semiconductor layer formed on a substrate, and surrounded with four side faces, the first semiconductor layer being made of a Si crystal; a gate electrode formed on a first side face of the channel portion, and a second side face of the channel portion opposite to the first side face through respective gate insulating films; a source region having a conductivity type different from that of the channel portion and being formed on a third side face of the channel portion, the source region including a second semiconductor layer having a lattice constant larger than that of the first semiconductor layer and being formed directly on the substrate, the second semiconductor layer being made of a SiGe crystal; and a drain region having a conductivity type different from that of the channel portion and being formed on a fourth side face of the channel portion opposite to the third side face, the drain region including the second semiconductor layer being formed directly on the substrate.