A method for fabricating a semiconductor device includes providing a semiconductor structure including a semiconductor substrate, a plurality of semiconductor fin structures, and a plurality of dummy gate structures, each including a dummy insulating layer and a dummy gate electrode; forming a covering layer including a first portion on side surfaces of each dummy gate structure and a second portion on semiconductor fin structures; forming a sacrificial layer on side surfaces of the first portion of the covering layer; forming a first trench and a second trench on two opposite sides of each dummy gate structure; forming a source electrode in each first trench and a drain electrode in each second trench; forming an interlayer dielectric layer; performing a planarization process to expose dummy gate structures; and removing each dummy gate electrode and a portion of the dummy insulating layer to form a trench to expose the semiconductor fin structure.