Method of manufacturing a capacitor in a semiconductor device

摘要

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 Ta2O5 to form a dielectric film in a Ta2O5 capacitor of a MIM (Metal Insulator Metal) structure using tungsten (W) as an underlying electrode. Thus, the present invention includes forming a good thin WO3 film by processing the surface of the underlying tungsten electrode by low oxidization process before forming a Ta2O5 dielectric film and then performing deposition and thermal process of Ta2O5 to form a Ta2O5 dielectric film. As a good WO3 film is formed on the surface of the underlying tungsten electrode before forming a Ta2O5 dielectric film, the grain boundary of the tungsten film is filled with oxygen atoms, thus preventing diffusion of oxygen atoms from the Ta2O5 dielectric film during a subsequent thermal process. Also, as a further oxidization of the surface of the underlying tungsten electrode by the WO3 film could be prevented, thereby improving the characteristic of the leak current of the Ta2O5 capacitor.