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,O,to form a dielectric film in a Ta,O,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,film by processing the surface of the underlying tungsten electrode by low oxidization process before forming a Ta,O,dielectric film and then performing deposition and thermal process of Ta,O,to form a Ta,O,dielectric film. As a good WO,film is formed on the surface of the underlying tungsten electrode before forming a Ta,O,dielectric film, the grain boundary of the tungsten film is filled with oxygen atoms, thus preventing diffusion of oxygen atoms from the Ta,O,dielectric film during a subsequent thermal process. Also, as a further oxidization of the surface of the underlying tungsten electrode by the WO,film could be prevented, thereby improving the characteristic of the leak current of the Ta,O,capacitor.