A semiconductor device includes a capacitor with reduced oxygen defects at an interface between a dielectric layer and an electrode of the capacitor. The semiconductor device includes a lower metal layer; a dielectric layer on the lower metal layer and containing a first metal; a sacrificial layer on the dielectric layer and containing a second metal; and an upper metal layer on the sacrificial layer. An electronegativity of the second metal in the sacrificial layer is greater than an electronegativity of the first metal in the dielectric layer.