A method for fabricating a semiconductor structure is provided in the present invention. The method includes the steps of forming a plurality of fins in a first region, a second region and a dummy region, forming a first solid-state dopant source layer and a first insulating buffer layer in the first region, forming a second solid-state dopant source layer and a second insulating buffer layer in the second region and the dummy region, and performing an etch process to cut the fin in the dummy region.