Method for making an isolated sidewall capacitor having a compound plate electrode

A method for making a capacitor structure, comprising the steps of:

• forming a layer of disposable material on a substrate having at least one layer of dielectric material thereon;
• patterning said layer of disposable material to leave a disposable plug;
• forming a layer of conductive material over said disposable plug and said substrate;
• forming a layer of dielectric material over said layer of conductive material, said layer of dielectric material being thick enough to fill and completely cover the conductive layer;
• planarizing said layer of dielectric material to expose a horizontal portion of the conductor material which overlies the disposable plug;
• removing the horizontal portion of the conductor material which overlies the disposable plug;
• removing the disposable plug to leave a dielectric-filled conductive structure which has an opening formed therein exposing a conductive sidewall;
• reducing the height of the conductive sidewall to bring it below the level of the dielectric fill;
• forming a non-conductive sidewall spacer on the conductive sidewall, the non-conductive sidewall having an opening formed therein;
• and
• forming a conductor in the non-conductive sidewall opening.