Semiconductor device with dram cell and method of manufacturing the same

Abstract

A semiconductor device including a semiconductor substrate a trench forming in the substrate, an insulating film forming on an inner surface of the trench so as to be rendered thicker from a substrate surface side thereof toward a trench deep side thereof, and an electrode layer forming inside the insulating film forming inside the trench so as to extend from a trench deep part side toward the surface side of the substrate. The substrate surface side of the insulating film functions as a collar insulating film retaining an insulation performance between the electrode layer and the semiconductor substrate, and the trench deep side of the insulating film functions as a capacitor insulating film composing a capacitor of a DRAM cell.

1 . A semiconductor device comprising: 
 a semiconductor substrate;    a trench formed in the substrate;    an insulating film formed on an inner surface of the trench so as to be rendered thicker from a substrate surface side thereof toward a trench deep side thereof; and    an electrode layer formed inside the insulating film formed inside the trench so as to extend from a trench deep part side toward the surface side of the substrate,    wherein the substrate surface side of the insulating film functions as a collar insulating film retaining an insulation performance between the electrode layer and the semiconductor substrate, and the trench deep side of the insulating film functions as a capacitor insulating film composing a capacitor of a DRAM cell.    
   
   
       2 . The semiconductor device according to  claim 1 , wherein the insulating film is formed so as to have a tapered section and contains a nitrogen atom.