A semiconductor device includes: an isolation region formed in a semiconductor substrate; active regions surrounded by the isolation region and including p-type and n-type regions, respectively; an NMOS transistor formed in the active region including the p-type region and including an n-type gate electrode; a PMOS transistor formed in the active region including the n-type region and including a p-type gate electrode; and a p-type resistor formed on the isolation region. The p-type resistor has an internal stress greater than that of the p-type gate electrode.