Bottom electrode of capacitor of semiconductor device and method of forming the same

Abstract

To form a bottom electrode of a capacitor of a semiconductor device, a first insulation layer pattern having a first contact hole is formed on a substrate, and a contact plug for the bottom electrode is formed in the contact hole. A second insulation layer is formed on the first insulation layer pattern and the contact plug. The second insulation layer has a second etching rate higher than a first etching rate of the first insulation layer pattern. The second insulation layer is etched to form a second insulation layer pattern having a second a contact hole exposing the contact plug. A conductive film is formed on the sidewall and the bottom face of the second contact hole. According to the difference between the first etching rate and the second etching rate, the etching of the first insulation layer pattern near the contact plug is reduced.

1 . A bottom electrode of a capacitor of a semiconductor device comprising: 
 a contact plug formed on a substrate;    a node formed on the contact plug; and    a protection layer pattern formed near the contact plug, wherein the contact plug is electrically connected to the node, and the protection layer pattern prevents an electrical connection between the contact plug and an adjacent contact plug.    
   
   
       2 . The bottom electrode of  claim 1 , wherein the protection layer pattern comprises a film chosen from the group consisting of a silicon nitride film, an aluminum oxide film, and a composite film that includes a silicon nitride film and an aluminum oxide film.  
   
   
       3 . The bottom electrode of  claim 1 , wherein the node has a cylindrical shape.  
   
   
       4 . The bottom electrode of  claim 1 , wherein the node comprises an upper node and a lower node, and wherein a critical dimension of the lower node is larger than a critical dimension of the upper node.