The semiconductor device includes: a first conductive-type first well and a second conductive-type second well configured over a substrate to contact each other; a second conductive-type anti-diffusion region configured in an interface where the first conductive-type first well contacts the second conductive-type second well over the substrate; and a gate electrode configured to simultaneously cross the first conductive-type first well, the second conductive-type anti-diffusion region, and the second conductive-type second well over the substrate.