Method for forming a tungsten upper electrode of a capacitor

Abstract

There is provided a method for forming a capacitor of a semiconductor device capable of preventing a dielectric layer from being damaged in forming a tungsten upper electrode on a dielectic layer, and preventing tungsten siliside from being formed on a tungsten film in the following processes. In the present invention, for protecting a dielectric layer, a polisilicon layer is formed on a dielectric layer as a sacrifical reduction layer. Then, a tungsten seed layer is formed on the dielectric layer by reducing WF6 with the polysilicon layer. After that, a tungsten film to be an upper electrode is formed by subsequently carrying out a deposition process using the reaction of WF6 and H2 or SiH4 Then, for preventing tungsten silicide film from being formed in following thermal process, a thermal process is performed in ammonia(NH3) cointaining ambient, or a plasma process using a nitrogen gas or an ammonia gas is performed to nitrize the surface of the tungsten film.

Dependencies are inferred from the claim text.