Patent ID: 7619271

Claim:
A deep trench device, comprising: a trench capacitor structure disposed in a bottom portion of a trench in a substrate, wherein the substrate has a drain region adjacent to the trench; a collar insulator formed on a sidewall of the trench and surrounding a portion of the trench capacitor structure, the collar insulator having a tapered height with regard to an outer peripheral sidewall of the trench, wherein a lowermost height of the collar insulator exposes a portion of the sidewall of the trench and an uppermost height of the collar insulator fully covers a portion of the sidewall of the trench; a connecting structure disposed in the trench and on top of the trench capacitor structure to electrically connect the trench capacitor structure to the drain region, wherein the connecting structure comprises: a connecting member formed on top of the trench capacitor structure so as to electrically connect to the trench capacitor structure; and an epitaxial silicon layer connected with the portion of the sidewall of the trench, where the lowermost portion of the collar insulator exposes and being adjacent to the connecting member; and a cap layer disposed on the connecting structure.