A semiconductor device includes: a substrate; at least one hybrid channel structure formed on the substrate and including at least one 1st channel structure extended in 1st and 2nd directions in parallel with an upper surface of the substrate without directly contacting the substrate, and a 2nd channel structure connected to and intersecting the at least one 1st channel structure in a 3rd direction perpendicular to the 1st or 2nd direction; a gate structure surrounding the hybrid channel structure; and source/drain regions respectively formed at two opposite ends of the at least one hybrid channel structure in the 1st direction.