Semiconductor device and method of manufacturing the same

Abstract

Disclosed is a semiconductor device comprising a semiconductor substrate, a gate electrode, a first insulating film formed between the semiconductor substrate and the gate electrode, and a second insulating film formed along a top surface or a side surface of the gate electrode and including a lower silicon nitride film containing nitrogen, silicon and hydrogen and an upper silicon nitride film formed on the lower silicon nitride film and containing nitrogen, silicon and hydrogen, and wherein a composition ratio N/Si of nitrogen (N) to silicon (Si) in the lower silicon nitride film is higher than that in the upper silicon nitride film.

1 - 26 . (canceled)  
   
   
       27 . A semiconductor device comprising: 
 a plurality of memory cells connected in series and each comprising:    a semiconductor substrate including a source region, a drain region, and a channel region sandwiched between the source region and the drain region;    a first insulating film formed on the semiconductor substrate;    a second insulating film formed on the first insulating film and storing charges injected from the semiconductor substrate through the first insulating film, the second insulating film including a lower silicon nitride film having a thickness of at least 1 nm and at most 4 nm and an upper silicon nitride film formed on the lower silicon nitride film;    a third insulating film formed on the second insulating film; and    a control gate electrode formed on the third insulating film.    
   
   
       28 . The semiconductor device according to  claim 27 , wherein during a read, a voltage higher than an upper limit of a threshold voltage for a write is applied to the control gate electrode.  
   
   
       29 . The semiconductor device according to  claim 27 , wherein a concentration of oxygen at an interface between the lower silicon nitride film and the upper silicon nitride film is lower than 1×10 22 /cm 3 .  
   
   
       30 . The semiconductor device according to  claim 27 , wherein a ratio of the number of deuterium atoms to the number of hydrogen atoms contained in the lower and upper silicon nitride films is at least 0.01.  
   
   
       31 . A semiconductor device comprising: 
 a semiconductor substrate including a source region, a drain region and a channel region sandwiched between the source region and the drain region;    a first insulating film formed on the semiconductor substrate;    a second insulating film formed on the first insulating film and storing charges injected from the semiconductor substrate through the first insulating film, the second insulating film including a lower silicon nitride film having a thickness of at least 1 nm and at most 4 nm and an upper silicon nitride film formed on the lower silicon nitride film;    a third insulating film formed on the second insulating film; and    a control gate electrode formed on the third insulating film; and    wherein the second insulating film has a first region located near the source region and a second region located near the drain region, and charges are to be stored independently in the first region and in the second area.    
   
   
       32 . The semiconductor device according to  claim 31 , wherein during a read, a voltage higher than an upper limit of a threshold voltage for a write is applied to the control gate electrode.  
   
   
       33 . The semiconductor device according to  claim 31 , wherein a concentration of oxygen at an interface between the lower silicon nitride film and the upper silicon nitride film is lower than 1×10 22 /cm 3 .  
   
   
       34 . The semiconductor device according to  claim 31 , wherein a ratio of the number of deuterium atoms to the number of hydrogen atoms contained in the lower and upper silicon nitride films is at least 0.01.  
   
   
       35 - 52 . (canceled)