Semiconductor device and method for fabricating the same

Abstract

A semiconductor device is disclosed, in which a capacitor lower electrode is formed of doped polysilicon and a capacitor upper electrode is formed of metal material to improve voltage coefficient characteristic. The semiconductor device includes a semiconductor substrate in which an active region and a field region are defined, a gate electrode and source and drain regions formed in the active region of the semiconductor substrate, a field oxide film formed in the field region of the semiconductor substrate, a capacitor lower electrode and a resistor formed of a doped polysilicon on the field oxide film, a capacitor dielectric film formed in a predetermined region on the capacitor lower electrode, and a capacitor upper electrode formed of metal material on the capacitor dielectric film.

What is claimed is:  
     
         1 . A semiconductor device comprising: 
 a semiconductor substrate in which an active region and a field region are defined;    a gate electrode and source and drain regions formed in the active region of the semiconductor substrate;    a field oxide film formed in the field region of the semiconductor substrate;    a capacitor lower electrode and a resistor formed of a doped polysilicon on the field oxide film;    a capacitor dielectric film formed in a predetermined region on the capacitor lower electrode; and    a capacitor upper electrode formed of metal material on the capacitor dielectric film.    
     
     
         2 . The semiconductor device as claimed in    claim 1   , wherein the capacitor dielectric film is used as an insulating film for prevention of silicide.  
     
     
         3 . The semiconductor device as claimed in    claim 1   , further comprising a silicide film on the gate electrode and the source and drain regions, the capacitor lower electrode in which the capacitor dielectric film is not formed, and the resistor in which the insulating film for prevention of silicide is not formed.  
     
     
         4 . The semiconductor device as claimed in    claim 1   , wherein the silicide film is connected with a metal line through a plug.  
     
     
         5 . The semiconductor device as claimed in    claim 4   , wherein the plug is formed of metal material in the same manner as the capacitor upper electrode.  
     
     
         6 . The semiconductor device as claimed in    claim 1   , wherein the gate electrode is formed of doped polysilicon in the same manner as the capacitor lower electrode and the resistor.  
     
     
         7 . A method for fabricating a semiconductor device comprising the steps of: 
 forming a gate electrode and source and drain regions in an active region of a semiconductor substrate in which a field oxide film is formed;    forming a capacitor lower electrode and a resistor on the field oxide film;    forming an insulating film for prevention of silicide in a predetermined region on the resistor and the capacitor lower electrode;    forming a silicide film on the gate electrode, the source and drain regions, and the resistor and the capacitor lower electrode on which the insulating film for prevention of silicide is not formed; and    forming a capacitor upper electrode of metal material on the insulating film formed on the capacitor lower electrode.    
     
     
         8 . The method as claimed in    claim 7   , wherein the gate electrode, the capacitor lower electrode, and the resistor are formed of doped polysilicon.  
     
     
         9 . The semiconductor device as claimed in    claim 8   , wherein the steps of forming the gate electrode, the capacitor lower electrode and the resistor include the steps of: 
 forming a field oxide film in the field region of the semiconductor substrate to define an active region;    implanting ions for adjustment of a threshold voltage into the active region of the semiconductor substrate;    forming a gate insulating film on the semiconductor substrate;    depositing a doped polysilicon on the entire surface of the semiconductor substrate including the field oxide film; and    selectively removing the doped polysilicon to form the gate electrode on the active region of the semiconductor substrate and to form the capacitor lower electrode and the resistor on the field oxide film.    
     
     
         10 . The method as claimed in    claim 7   , wherein insulating film for prevention of silicide is used as a dielectric film between the capacitor lower electrode and the capacitor upper electrode.  
     
     
         11 . The method as claimed in    claim 7   , wherein the step of forming the capacitor upper electrode includes the steps of: 
 forming an insulating film for IMP on an entire surface of the semiconductor substrate in which the silicide film is formed;    selectively removing the insulating film for IMP to expose the insulating film for prevention of silicide formed on the capacitor lower electrode and the silicide film and forming a contact hole; and    plugging a metal material in the contact hole to form a plug and the capacitor upper electrode.