Methods for forming ferroelectric capacitors having a bottom electrode with decreased leakage current

Abstract

Provided are methods for ferroelectric capacitors using a film of ruthenium dioxide as a bottom electrode. The method according to the invention includes the steps of: forming a first electrode of ruthenium dioxide over a lower layer including a conductive plug, the electrode being connected to the conductive plug; forming a film of strontium on the first electrode of ruthenium dioxide; forming a film of strontium ruthenium oxide by performing thermal treatment of the strontium film under oxygen atmosphere in order to prevent the diffusion of oxygen to the electrode of ruthenium dioxide; forming a thin film of crystallized ferroelectric material on the film of strontium ruthenium oxide; forming a second film of ruthenium dioxide on the ferroelectric film. The capacitor fabricated by the method according to the invention is enhanced in the characteristics about leakage current by the presence of the film of strontium ruthenium oxide as an oxygen diffusion barrier between the film of ruthenium dioxide as a bottom electrode and the ferroelectric film. The film of strontium ruthenium oxide prevents the diffusion of oxygen to the film of ruthenium dioxide when the ferroelectric film is crystallized by thermal treatment at high temperature under oxygen atmosphere.

Dependencies are inferred from the claim text.