Plated trench capacitor structures
A method and structure is directed to eDRAM cells with high-conductance electrodes. The method includes forming upper layers on a semiconductor substrate and forming an opening in the upper layers. The method further includes forming a trench in the semiconductor substrate, aligned with the opening. The method further includes forming a metal plate on all exposed surface in the trench by applying a metallic aqueous solution with an electrical bias to a backside of the semiconductor substrate.
1. A structure, comprising:
a semiconductor substrate;
a trench in the semiconductor substrate and in alignment with an opening in a plurality of upper layers covering the semiconductor substrate;
a conformal metal plate lining exposed surfaces of the trench;
a dielectric liner on the conformal metal plate;
a metal inner electrode on the dielectric liner;
a contact in contact with the metal inner electrode; and
an oxide cap within the opening and on any exposed top surfaces of the conformal metal plate, the dielectric liner, and the metal inner electrode,
wherein the contact extends through the oxide cap and into contact with at least a portion of the metal inner electrode.
2. The structure of claim 1 , wherein the semiconductor substrate is a single uniformly doped layer of silicon substrate.
3. The structure of claim 1 , wherein the upper layers comprise:
an insulator layer on the semiconductor substrate;
a semiconductor layer on the insulator layer; and
a pad layer on the semiconductor layer.
4. The structure of claim 1 , wherein the conformal metal plate is lining all exposed surfaces of the trench.
5. The structure of claim 1 , wherein the conformal metal plate is comprised of platinum or gold.
6. The structure of claim 5 , wherein the dielectric liner is comprised of a high-k material.
7. The structure of claim 6 , wherein the metal inner electrode is comprised of a polysilicon film.
8. The structure of claim 7 , wherein the contact is in contact with an upper surface of the metal inner electrode.
9. The structure of claim 1 , further comprising a hardmask material lining exposed surfaces of the upper layers in the opening to isolate the exposed surfaces of the upper layers.