A semiconductor device includes: a P+ substrate; a P− epitaxial layer over the P+ substrate; a P-well and an N− drift region in the P− epitaxial layer and laterally adjacent to each other; an N+ source region in the P-well and connected to a front-side metal via a first contact electrode; an N+ drain region in the N− drift region and connected to the front-side metal via a second contact electrode; a gate structure on the P− epitaxial layer and connected to the front-side metal via a third contact electrode; and a metal plug through the P− epitaxial layer and having one end in contact with the P+ substrate and the other end connected to the front-side metal, the metal plug being adjacent to one side of the N+ source region that is farther from the N− drift region. A method for fabricating the semiconductor device is also disclosed.