A semiconductor device is provided. The semiconductor device includes a substrate; an epitaxial layer disposed over the substrate; a gate electrode disposed over the epitaxial layer; a source region and a drain region disposed in the epitaxial layer at opposite sides of the gate electrode; a trench extending from a top surface of the epitaxial layer through the source region into the epitaxial layer, wherein the trench has a slanted side and a bottom surface; and a first conductive-type linking region having the first conductive type, wherein the first conductive-type linking region surrounds the slanted side of the trench and contacts the bottom surface of the trench, wherein the first conductive-type linking region electrically connects the source region and the substrate. The present disclosure also provides a method for manufacturing this semiconductor device.