Semiconductor device and method of manufacturing thereof

Abstract

This semiconductor device manufacturing method comprises the steps of: forming a thick gate oxide film (thick oxide film) in a first region of a substrate, forming a thin gate oxide film (thin oxide layer) in a second region, and then, applying oxynitridation to these gate oxide films; forming gate electrodes to 1 d on these gate oxide films; and implanting an ion that contains nitrogen or nitrogen atoms into at least one part of an interface between the hick gate oxide film (thick oxide film) and the substrate before or after the step of forming the gate electrodes, thereby forming a highly oxy-nitrided region. In this manner, in a semiconductor device in which there coexist a MISFET having a thin gate insulation film and a MISFET having a thick gate insulation film, hot carrier reliability of the MISFET having the thick gate insulation film is improved.

What is claimed is:  
     
         1 . A semiconductor device comprising: 
 a first MISFET having a first gate insulation film; and a second MISFET having a second gate insulation film that is thicker than the first MISFET, wherein nitrogen is contained in at least one part of an interface between the second gate insulation film and a semiconductor substrate, said nitrogen being contained in amount equal to or greater than that determined by a reverse ratio of film thickness as compared with an amount that exists on an interface between the first gate insulation film and the semiconductor substrate.    
     
     
         2 . A semiconductor device comprising: 
 a first MISFET having a first gate insulation film; and a second MISFET having a second gate insulation film that is thicker than the first MISFET, wherein nitrogen is contained in at least one part of an interface between a gate insulation film and a semiconductor substrate at an n-channel section of the second MISFET, said nitrogen being contained in amount equal to or greater than that existing in a p-channel section.    
     
     
         3 . A semiconductor device where an n-channel type MISFET that configures a memory cell of a dynamic random access memory is formed in a first region of a main face of a semiconductor substrate, and an n-channel type MISFET and a p-channel type MISFET, each of which configures a peripheral circuit or a logic LSI of the dynamic random access memory, is formed in a second region of a main face of the semiconductor substrate, wherein nitrogen is contained in at least one part of a gate insulation film of the n-channel type MISFET that configures the memory cell, and a gate electrode of the n-channel type MISFET that configures the memory cell is formed of a conducting material having a work function greater than that of an n-type polycrystal silicon.  
     
     
         4 . A semiconductor device where an n-channel type MISFET that configures a memory cell of a dynamic random access memory is formed in a first region of a main face of a semiconductor substrate, and an n-channel type MISFET and a p-channel type MISFET, each of which configures a peripheral circuit or a logic LSI of the dynamic random access memory, is formed in a second region of a main face of the semiconductor substrate, wherein nitrogen is contained in at least one part of an interface between a gate insulation film of an n-channel type MISFET and a p-channel type MISFET, each of which configures a peripheral circuit or a logic LSI of the dynamic random access memory.  
     
     
         5 . A method of manufacturing a semiconductor comprising the steps of: 
 (a) forming a first gate insulation film in a first region of a main face of a semiconductor substrate, followed by forming a second gate insulation film that is thicker than the first gate insulation film in a second region of a main face of the semiconductor substrate;    (b) applying oxynitridation to the first and second gate insulation film;    (c) forming a first gate electrode of a first MISFET on top of the first gate insulation film, followed by forming a second gate electrode of a second MISFET on top of the second insulation film; and    (d) implanting an ion that contains nitrogen or nitrogen atoms in at least one part of an interface between the second gate insulation film and the semiconductor substrate before or after the step (a) or before or after the step (c).    
     
     
         6 . A method of manufacturing a semiconductor device comprising the steps of: 
 (a) forming a second gate insulation film on a main face of a semiconductor substrate;    (b) applying oxynitridation to the second gate insulation film;    (c) removing the second gate insulation film in a first region of the semiconductor substrate, followed by leaving the second gate insulation film in a second region of the semiconductor substrate;    (d) oxidizing the semiconductor substrate, thereby forming a first gate insulation film that is thinner than the second gate insulation film in the first region of the semiconductor substrate;    (e) applying second oxynitridation to the first and second gate insulation films; and    (f) forming a first gate electrode of a first MISFET on top of the first gate insulation film, followed by forming a second gate electrode of a second MISFET on top of the second gate insulation film.