US Patent 10032672 Method of fabricating a semiconductor device having contact structures

A method for fabricating a semiconductor device includes the following steps: providing a semiconductor substrate having a first fin; forming a first set of gate structures on the first fin, where the gate structures are surrounded by an interlayer dielectric; forming a first contact hole in the interlayer dielectric between two adjacent gate structures; forming a first dopant source layer on the bottom of the first contact hole, where the dopant source layer comprise dopants with a first conductivity type; and annealing the first dopant source layer to diffuse the dopants out of the first dopant source layer.