US Patent 9893182 FinFET and method for forming the same

The present disclosure provides a method for forming a field-effect fin transistor (FinFET) structure. The method includes providing a substrate with fin structures; forming a gate structures across the fin structures; and forming ion implantation regions in the fin structures at both sides of the gate structure. The method also includes removing top portions of the fin structures at both sides of the gate structure to form remaining portions of the fin structures; forming a first semiconductor material layer on the remaining portions of the fin structures; and forming a second semiconductor material layer on the first semiconductor material layer, the second semiconductor material being doped with barrier-lowering ions. The method further includes forming a metal layer on the second semiconductor material layer, and performing an annealing process on the metal layer to form a contact-resistance-reducing layer.