A semiconductor device includes: a first active region defined by a recess contained in a device isolation film of a semiconductor substrate belonging to a first region and a second region, in a peripheral region including the first region, the second region, and a third region; a second active region defined by the device isolation film contained in the semiconductor substrate of the third region; a buried metal layer buried in the recess; a first conductive layer formed over the semiconductor substrate of the first region; and a second conductive layer formed over the semiconductor substrate of the second region, wherein the first conductive layer or the second conductive layer is formed over the semiconductor substrate of the third region. A three-dimensional dual gate is formed in a peripheral region, such that performance or throughput of transistors is maximized even in the peripheral region.