Deep trench capacitor

Abstract

A deep trench capacitor disposed in a deep trench in a substrate is provided. The deep trench capacitor includes a bottom electrode disposed in the substrate surrounding a bottom of the deep trench; a first conductive layer disposed in the deep trench; a capacitor dielectric layer disposed between a lower surface of the deep trench and the first conductive layer; a second conductive layer disposed in the deep trench and above the first conductive layer; a collar oxide layer disposed between an upper surface of the deep trench and the second conductive layer; a third conductive layer disposed in the deep trench and above the second conductive layer; an isolation structure disposed in parts of the third conductive layer, the second conductive layer and the substrate; and an isolation layer disposed below the isolation structure and in parts of the second conductive layer and the substrate.

1 . A deep trench capacitor, disposed in a deep trench in a substrate, the deep trench capacitor comprising: 
 a bottom electrode, disposed in the substrate surrounding a bottom of the deep trench;    a first conductive layer, disposed in the deep trench;    a capacitor dielectric layer, disposed between a lower surface of the deep trench and the first conductive layer;    a second conductive layer, disposed in the deep trench and above the first conductive layer;    a collar oxide layer, disposed between an upper surface of the deep trench and the second conductive layer;    a third conductive layer, disposed in the deep trench and above the second conductive layer;    an isolation structure, disposed in parts of the third conductive layer, the second conductive layer and the substrate; and    an isolation layer, disposed below the isolation structure and in parts of the second conductive layer and the substrate.    
   
   
       2 . The capacitor of  claim 1 , further comprising a dielectric layer disposed between a sidewall of the deep trench and the third conductive layer.  
   
   
       3 . The capacitor of  claim 1 , wherein a bottom of the isolation layer is about 3500 angstroms to about 4000 angstroms below an upper surface of the substrate.  
   
   
       4 . The capacitor of  claim 1 , wherein the isolation layer comprises a silicon oxide material.