Patent ID: 6989561

Claim:
A trench capacitor having a large capacitor surface area, comprising: a buried diffusion plate doped in a substrate and encompassing a bottle-shaped lower portion of said trench capacitor, said buried diffusion plate being electrically connected to an upwardly extending cylindrical center electrode via a bottom contact surface of said bottle-shaped lower portion, wherein said buried diffusion plate and said upwardly extending cylindrical center electrode serve as a first electrode of said trench capacitor; a first insulation layer disposed on interior surface of said bottle-shaped lower portion of said trench capacitor except for said bottom contact surface; an outer electrode layer situated on said first insulation layer and encircling said cylindrical center electrode; a second insulation layer disposed between said outer electrode layer and said cylindrical center electrode; a central pillar electrode downwardly extending along the length of said cylindrical center electrode and encompassed by said cylindrical center electrode; a third insulation layer disposed between said central pillar electrode and said cylindrical center electrode; and a collar electrode layer located on said central pillar electrode and on said outer electrode layer, said collar electrode layer being electrically connected to said central pillar electrode and said outer electrode layer, wherein said collar electrode layer, said central pillar electrode and said outer electrode layer constitute a second electrode of said trench capacitor.