Nonvolatile semiconductor memory

Abstract

A nonvolatile semiconductor memory of an aspect of the present invention includes a memory cell including, a charge storage layer on a gate insulating film, a multilayer insulator on the charge storage layer, and a control gate electrode on the multilayer insulator, the gate insulating film including a first tunnel film, a first high-dielectric-constant film on the first tunnel film and offering a greater dielectric constant than the first tunnel film, and a second tunnel film on the first high-dielectric-constant film and having the same configuration as that of the first tunnel film, the multilayer insulator including a first insulating film, a second high-dielectric-constant film on the first insulating film and offering a greater dielectric constant than the first insulating film, and a second insulating film on the second high-dielectric-constant film and having the same configuration as that of the first insulating film.

1 . A nonvolatile semiconductor memory comprising:
 a memory cell including:
 an element region partitioned by isolation insulating films in a semiconductor substrate; 
 a first gate insulating film provided on the element region; 
 a charge storage layer provided on the first gate insulating film; 
 a multilayer insulator provided on the charge storage layer, the multilayer insulator including a first insulating film, a first high-dielectric-constant film provided on the first insulating film and having a greater dielectric constant than a dielectric constant of a silicon nitride film, and a second insulating film provided on the first high-dielectric-constant film; 
 a control gate electrode provided on the multilayer insulator; 
   wherein a thickness of the first gate insulating film is smaller than a thickness of the multilayer insulator,   the first gate insulating film is provided between the isolation insulating films, and   a bottom surface of the first high-dielectric-constant film is positioned higher than or equal to an upper surface of the charge storage layer.   
     
     
         2 . The nonvolatile semiconductor memory according to  claim 1 , wherein
 the first gate insulating film includes a first tunnel film, a second high-dielectric-constant film provided on the first tunnel film and having a greater dielectric constant than the first tunnel film, and a second tunnel film provided on the second high-dielectric-constant film and having a same configuration as that of the first tunnel film.   
     
     
         3 . The nonvolatile semiconductor memory according to  claim 1 , wherein
 the first gate insulating film includes a first tunnel film, a second high-dielectric-constant film contacting to the first tunnel film and having a greater dielectric constant than the first tunnel film, and a second tunnel film contacting to the second high-dielectric-constant film and having a same configuration as that of the first tunnel film.   
     
     
         4 . The nonvolatile semiconductor memory according to  claim 1 , wherein
 the first insulating film contacts to the first high-dielectric-constant film, and the first high-dielectric-constant film contacts to the second insulating film.   
     
     
         5 . The nonvolatile semiconductor memory according to  claim 3 , wherein
 the first insulating film contacts to the first high-dielectric-constant film, and the first high-dielectric-constant film contacts to the second insulating film.   
     
     
         6 . The nonvolatile semiconductor memory according to  claim 5 , wherein
 the element region contacts to the first gate insulating film, the first gate insulating film contacts to the charge storage layer, the charge storage layer contacts to the multilayer insulator, and the multilayer insulator contacts to the control gate electrode.   
     
     
         7 . The nonvolatile semiconductor memory according to  claim 6 , wherein
 the dielectric constant of the first high-dielectric-constant film is greater than that of the second high-dielectric-constant film.   
     
     
         8 . The nonvolatile semiconductor memory according to  claim 6 , wherein
 a thickness of the second tunnel film is smaller than a thickness of the second insulating film,   a thickness of the second high-dielectric-constant film is smaller than thickness of the first high-dielectric-constant film.   
     
     
         9 . The nonvolatile semiconductor memory according to  claim 1 , wherein
 the charge storage layer is an insulating film.   
     
     
         10 . The nonvolatile semiconductor memory according to  claim 1 , wherein
 both side surfaces of the first gate insulating film are contacting to the isolation insulating films.   
     
     
         11 . A nonvolatile semiconductor memory comprising:
 a plurality of memory cells, each of the memory cells including:
 an element region partitioned by an isolation insulating films in a semiconductor substrate; 
 a first gate insulating film provided on the element regions, respectively; 
 a charge storage layer provided on the first gate insulating films, respectively; 
 a multilayer insulator provided on the charge storage layer, the multilayer insulator including a first insulating film, a first high-dielectric-constant film provided on the first insulating film and having a greater dielectric constant than a dielectric constant of a silicon nitride film, and a second insulating film provided on the first high-dielectric-constant film; and 
 a control gate electrode provided on the multilayer insulator; 
   wherein a thickness of the first gate insulating film is smaller than a thickness of the multilayer insulator,   each of the first gate insulating films is provided between the isolation insulating films in a first direction, and   a bottom surface of the first high-dielectric-constant film is positioned higher than or equal to an upper surface of the charge storage layer.   
     
     
         12 . The nonvolatile semiconductor memory according to  claim 11 , wherein
 the first gate insulating film includes a first tunnel film, a second high-dielectric-constant film contacting to the first tunnel film and having a greater dielectric constant than the first tunnel film, and a second tunnel film contacting to the second high-dielectric-constant film and having a same configuration as that of the first tunnel film.   
     
     
         13 . The nonvolatile semiconductor memory according to  claim 12 , wherein
 the first insulating film contacts to the first high-dielectric-constant film, and the first high-dielectric-constant film contacts to the second insulating film.   
     
     
         14 . The nonvolatile semiconductor memory according to  claim 13 , wherein
 the element region contacts to the first gate insulating film, the first gate insulating film contacts to the charge storage layer, the charge storage layer contacts to the multilayer insulator, and the multilayer insulator contacts to the control gate electrode.   
     
     
         15 . The nonvolatile semiconductor memory according to  claim 14 , wherein
 the dielectric constant of the second high-dielectric-constant film is greater than that of the first high-dielectric-constant film.   
     
     
         16 . The nonvolatile semiconductor memory according to  claim 14 , wherein
 a thickness of the second tunnel film is smaller than a thickness of the second insulating film, and   a thickness of the second high-dielectric-constant film is smaller than the thickness of the first high-dielectric-constant film.   
     
     
         17 . The nonvolatile semiconductor memory according to  claim 11 , wherein
 the charge storage layers are an insulating film.   
     
     
         18 . The nonvolatile semiconductor memory according to  claim 11 , wherein
 both side surfaces of each of the first gate insulating film are contacting to the isolation insulating films, respectively.   
     
     
         19 . The nonvolatile semiconductor memory according to  claim 11 , wherein
 the multilayer insulator is shared adjacent to the memory cells in the first direction.