Semiconductor Memory Device and Manufacturing Method Thereof

Abstract

A nonvolatile semiconductor memory device having high charge retention characteristics and capable of improving leakage characteristics of a dielectric film disposed between a charge storage layer and a control gate electrode, and manufacturing method thereof is disclosed. According to one aspect, there is provided a semiconductor memory device comprising a first electrode disposed on a first insulator on a semiconductor substrate, a second insulator disposed on the first electrode, a second electrode disposed on the second insulator, and diffusion layers disposed in the semiconductor substrate, wherein the second insulator including a silicon-rich silicon nitride film containing more silicon than that in a stoichiometric silicon nitride film, and a silicon oxide film formed on the silicon-rich silicon nitride film, and wherein the silicon-rich silicon nitride film has a ratio of a silicon concentration and a nitrogen concentration set to 1:0.9 to 1:1.2.

1 .- 6 . (canceled) 
     
     
         7 . A semiconductor memory device comprising:
 a first insulator formed on a semiconductor substrate;   a first electrode disposed on the first insulator;   a second insulator disposed on the first electrode and continuously disposed in a word line direction across a plurality of cell transistors;   a second electrode disposed on the second insulator and continuously disposed in the word line direction; and   diffusion layers disposed in the semiconductor substrate, the first and second electrodes disposed in-between,   wherein the second insulator includes:
 a low hydrogen silicon nitride film having a hydrogen concentration of 1% or less; and 
 a silicon oxide film formed on the low hydrogen silicon nitride film. 
   
     
     
         8 . The semiconductor memory device according to  claim 7 , wherein the low hydrogen silicon nitride film is a CVD film formed by using a silicon source gas not containing hydrogen and a nitrogen source gas. 
     
     
         9 . The semiconductor memory device according to  claim 7 , wherein the low hydrogen silicon nitride film has a film thickness of 3 to 5 nm. 
     
     
         10 - 20 . (canceled)