US Patent 7129550 Fin-shaped semiconductor device

A semiconductor layer in which a primary part of a FinFET is formed, i.e., a fin has a shape which is long in a direction x and short in a direction y. A width of the fin in the direction y changes on three stages. First, in a channel area between gate electrodes each having a gate length Lg, the width of the fin in the direction y is Wch. Further, the width of the fin in the direction y in a source/drain extension area adjacent to the channel area in the direction x is Wext (>Wch). Furthermore, the width of the fin in the direction y in a source/drain area adjacent to the source/drain extension area in the direction x is Wsd (>Wext).