A tunneling field effect transistor is formed from a fin of semiconductor material on a support substrate. The fin of semiconductor material includes a source region, a drain region and a channel region between the source region and drain region. A gate electrode straddles over the fin at the channel region. Sidewall spacers are provided on each side of the gate electrode. The source of the transistor is made from an epitaxial germanium content source region grown from the source region of the fin and doped with a first conductivity type. The drain of the transistor is made from an epitaxial silicon content drain region grown from the drain region of the fin and doped with a second conductivity type.