CAPACITOR AND ITS MANUFACTURE

PURPOSE: To enhance capacitance ratio by forming a multilevel dielectric after formation of a polysilicon layer, etching a via therein reaching the lower electrode of polysilicon and then depositing a capacitor dielectric. CONSTITUTION: After depositing a field oxide 8 on a substrate 4 and forming patterned polysilicon layers 10, 12 thereon, a diffused part 6 is formed by ion implantation. The diffused part 6 and the polysilicon layers 10, 12 are then coated with a silicate 14 to form a multilevel dielectric 16 and a via reaching the polysilicon layer 10 serving as a lower electrode plate is made therein. Subsequently, a silicon dioxide 20 and a silicon nitride 22 of capacitor dielectric are deposited and contact to the diffusion layer 6 and the polysilicon structure 12 are formed by etching. Finally, a metal layer 24 is formed and patterned thus forming the metal layers 24, 30 of an upper electrode plate of a capacitor 2 on the silicon dioxide layer 20 and the silicon nitride layer 22.