A semiconductor-insulator-silicide (SIS) capacitor is formed by depositing a thin silicon containing layer on a salicide mask dielectric layer, followed by lithographic patterning of the stack and metallization of the thin silicon containing layer and other exposed semiconductor portions of a semiconductor substrate. The thin silicon containing layer is fully reacted during metallization and consequently converted to a silicide alloy layer, which is a first electrode of a capacitor. The salicide mask dielectric layer is the capacitor dielectric. The second electrode of the capacitor may be a doped polycrystalline silicon containing layer, a doped single crystalline semiconductor region, or another doped polycrystalline silicon containing layer disposed on the doped polycrystalline silicon containing layer. The SIS insulator may further comprise other dielectric layers and conductive layers to increase capacitance per area.