Patent ID: 7504299

Claim:
A method of forming a capacitor in a substrate comprising the steps of: etching a trench in said substrate; forming a first capacitor plate by diffusing a dopant into said substrate; depositing a first conformal dielectric layer on an interior surface of said trench; depositing a first conductive storage plate on an interior surface of said first dielectric layer; depositing a second conformal dielectric layer on an interior surface of said first conductive storage plate; etching directionally through said second dielectric layer and said first storage plate to expose a substrate contact surface of said first capacitor plate whereby upper and lower edges of said first storage plate are exposed; forming an insulator covering said exposed upper and lower edges of said first storage plate; depositing a second capacitor plate on an interior surface of said second dielectric layer, to make electrical contact with said substrate contact surface; forming a third dielectric layer on exposed interior surfaces of said second capacitor plate; removing said insulator covering said exposed upper edge of said first storage layer, thereby exposing said upper edge of said first storage plate; and depositing a second conductive storage plate abutting said third dielectric layer, thereby establishing electrical contact between said first and second conductive storage plates, which are separated from said first and second capacitor plates by said first, second and third dielectric layers.