A FinFET semiconductor device has an active region formed of a semiconductor substrate and projecting from a surface of the substrate. A fin having a first projection and a second projection composed of the active region are arranged in parallel and at each side of a central trench formed in a central portion of the active region. Upper surfaces and side surfaces of the first projection and the second projection comprise a channel region. A channel ion implantation layer is provided at a bottom of the central trench and at a lower portion of the fin. A gate oxide layer is provided on the fin. A gate electrode is provided on the gate oxide layer. A source region and a drain region are provided in the active region at sides of the gate electrode. A method of forming such a device is also provided.