A method for fabricating complimentary metal-oxide-semiconductor field-effect transistor is disclosed. The method includes the steps of: (A) forming a first gate structure and a second gate structure on a substrate; (B) performing a first co-implantation process to define a first type source/drain extension region depth profile in the substrate adjacent to two sides of the first gate structure; (C) forming a first source/drain extension region in the substrate adjacent to the first gate structure; (D) performing a second co-implantation process to define a first pocket region depth profile in the substrate adjacent to two sides of the second gate structure; (E) performing a first pocket implantation process to form a first pocket region adjacent to two sides of the second gate structure.