Semiconductor device and method of manufacturing the same

Abstract

According to an aspect of the invention, there is provided a semiconductor device comprising a semiconductor substrate, a first insulating layer formed on the semiconductor substrate, a first conductive layer formed as a floating gate on the first insulating layer, a second insulating layer formed as an interelectrode insulating film on the first conductive layer, and comprising three layers of a first film mainly including silicon and oxygen, a second film mainly including silicon and nitrogen, and a third film mainly including silicon and oxygen, wherein a silicon and nitrogen composition ratio of the second film is in a state in which the silicon is in excess of a stoichiometric composition, and a second conductive layer formed as a control gate on the second insulating film.

1 . A semiconductor device comprising:
 a semiconductor substrate;   a first insulating layer formed on the semiconductor substrate;   a first conductive layer formed as a floating gate on the first insulating layer;   a second insulating layer formed as an interelectrode insulating film on the first conductive layer, and comprising three layers of a first film mainly including silicon and oxygen, a second film mainly including silicon and nitrogen, and a third film mainly including silicon and oxygen, wherein a silicon and nitrogen composition ratio of the second film is in a state in which the silicon is in excess of a stoichiometric composition;   a second conductive layer formed as a control gate on the second insulating film;   a trench for isolation which is formed in the semiconductor substrate, the first insulating layer, the first conductive layer, and the second insulating layer; and   a third insulating layer within the trench, a surface of the third insulating layer being lower than an upper surface of the first conductive layer but higher than a lower surface of the first conductive layer.   
     
     
         2 . The semiconductor device according to  claim 1 , wherein the second insulating layer comprises a film mainly including silicon and nitrogen and formed in at least one of an interface with the first conductive layer and an interface with the second conductive layer. 
     
     
         3 . The semiconductor device according to  claim 1 , wherein the second film of the second insulating layer has a composition ratio of nitrogen to silicon smaller than 1.30. 
     
     
         4 . The semiconductor device according to  claim 1 , wherein the second film of the second insulating layer has a composition ratio of nitrogen to silicon larger than 1.10. 
     
     
         5 . The semiconductor device according to  claim 1 , wherein the second film of the second insulating layer has a thickness of 1 to 8 nm. 
     
     
         6 . The semiconductor device according to  claim 1 , wherein the second film of the second insulating layer includes 1×10 19  cm −3  or more of chlorine. 
     
     
         7 .- 14 . (canceled)