Floating gate nitridation

Abstract

The floating gate, or the oxide between the floating and control gates, or both are nitrided before the control gate layer is deposited.

1 . A method for manufacturing an integrated circuit comprising a nonvolatile memory, the method comprising: 
 forming a first layer comprising silicon, the first layer being to provide one or more floating gates for the nonvolatile memory;    nitriding a surface of the first layer to incorporate nitrogen atoms into said surface;    forming a first dielectric at the nitrided surface, wherein forming the first dielectric comprises forming silicon oxide at the nitrided surface;    forming a conductive layer separated from the nitrided surface by the first dielectric, the conductive layer providing one or more control gates for the nonvolatile memory.    
     
     
         2 . The method of  claim 1  wherein forming the silicon oxide at the nitrided surface comprises forming the silicon oxide by thermal oxidation.  
     
     
         3 . The method of  claim 1  wherein the surface of the first layer is a polysilicon surface.  
     
     
         4 . An integrated circuit manufactured by the method of  claim 1 .  
     
     
         5 . An integrated circuit comprising a nonvolatile memory cell: 
 a channel region;    a first dielectric on a surface of the channel region;    a conductive floating gate on the first dielectric, the floating gate having a surface which has silicon and nitrogen atoms therein;    silicon oxide formed at said surface of the floating gate;    a conductive control gate opposite to said surface of the floating gate.    
     
     
         6 . The integrated circuit of  claim 5  further comprising a second dielectric between said surface of the floating gate and the control gate.  
     
     
         7 . A method for manufacturing an integrated circuit comprising a nonvolatile memory, the method comprising: 
 forming a first layer to provide one or more floating gates for the nonvolatile memory;    forming a first dielectric on a surface of the first layer, wherein the first dielectric comprises a first surface comprising silicon oxide;    nitriding the first surface of the first dielectric to incorporate nitrogen atoms into the first surface;    forming a conductive layer on the nitrided first surface of the first dielectric, the conductive layer providing one or more control gates for the nonvolatile memory.    
     
     
         8 . An integrated circuit manufactured by the method of  claim 7 .  
     
     
         9 . An integrated circuit comprising a nonvolatile memory cell comprising: 
 a channel region;    a first dielectric on a surface of the channel region;    a conductive floating gate on the first dielectric;    a second dielectric on a surface of the floating gate; and    a conductive control gate separated from the floating gate by the second dielectric;    wherein the second dielectric comprises a layer of silicon oxide having a surface having nitrogen atoms embedded therein; and    the control gate contacts said silicon oxide surface with nitrogen atoms.