There are contained first and second conductive plugs formed in first insulating layer, an island-like oxygen-barrier metal layer for covering the first conductive plug, an oxidation-preventing insulating layer formed on the first insulating layer to cover side surfaces of the oxygen-barrier metal layer, a capacitor having a lower electrode formed on the oxygen-barrier metal layer and the oxidation-preventing insulating layer, a dielectric layer formed on the lower electrode, and an upper electrode formed on the dielectric layer, a second insulating layer for covering the capacitor and the oxidation-preventing insulating layer, a third hole formed in respective layers from the second insulating layer to the oxidation-preventing insulating layer on the second conductive plug, and a third conductive plug formed in the third hole and connected to the second conductive plug.