Method of manufacturing a capacitor in a semiconductor device

Abstract

The present invention relates to a method of manufacturing a capacitor in a semiconductor device. It is designed to solve the problem due to oxidization of the surface of the underlying tungsten electrode during thermal process performed after depositing Ta 2 O 5 to form a dielectric film in a Ta 2 O 5 capacitor of a MIM (Metal Insulator Metal) structure using tungsten (W) as an underlying electrode. Thus, the present invention includes forming a good thin WO 3 film by processing the surface of the underlying tungsten electrode by low oxidization process before forming a Ta 2 O 5 dielectric film and then performing deposition and thermal process of Ta 2 O 5 to form a Ta 2 O 5 dielectric film. As a good WO 3 film is formed on the surface of the underlying tungsten electrode before forming a Ta 2 O 5 dielectric film, the grain boundary of the tungsten film is filled with oxygen atoms, thus preventing diffusion of oxygen atoms from the Ta 2 O 5 dielectric film during a subsequent thermal process. Also, as a further oxidization of the surface of the underlying tungsten electrode by the WO 3 film could be prevented, thereby improving the characteristic of the leak current of the Ta 2 O 5 capacitor.

What is claimed is:  
     
         1 . A semiconductor device having a capacitor comprising: 
 a substrate containing an underlying structure;    a tungsten electrode formed on the substrate;    a WO 3  film formed on the surface of the tungsten;    a dielectric film formed on the WO 3  film; and    a upper electrode formed on the dielectric film,    wherein, the WO 3  film prevents the diffusion of oxygen atoms from the dielectric film into the tungsten film.    
     
     
         2 . A capacitor comprising: 
 a tungsten electrode supported by a substrate;    a WO 3  film formed on the surface of the tungsten;    a dielectric film formed on the WO 3  film; and    a upper electrode formed on the dielectric film,    wherein, the WO 3  film prevents the diffusion of oxygen atoms from the dielectric film into the tungsten film.