A method for fabricating a gate-all-around field-effect-transistor device includes forming a plurality of first stacked structures, each including a first sacrificial layer and a first semiconductor layer; forming a first dummy gate structure across the first stacked structures and partially covering the top and the sidewall surfaces of each first stacked structure, and a first sidewall spacer on each sidewall surface of the first dummy gate structures; forming a first source/drain doped layer, and a dielectric structure exposing the top surfaces of the first dummy gate structure and each first sidewall spacer; removing the first dummy gate structure to form a first trench; removing a portion of the first sacrificial layer to form a first via which partially exposes the first source/drain doped layer; forming a first barrier layer on the first source/drain doped layer; and forming a first gate structure to fill the first trench and the first via.