High-k Capacitor Stack With Leakage-Blocking Interface Layers

The patent employs a composite dielectric structure consisting of a high-k dielectric layer (such as hafnium oxide or zirconium oxide) combined with a leakage blocking layer (such as aluminum oxide or silicon oxide). This composite structure enables the capacitor to achieve high capacitance through the high-k material while the blocking layer suppresses leakage current by preventing electron tunneling and ion migration, thus resolving the contradiction between increasing capacitance and reducing leakage.

The patent applies different material properties to different regions of the dielectric structure. The high-k dielectric layer is positioned to maximize capacitance where electric field strength is highest, while the leakage blocking layer is strategically placed at interfaces and regions prone to electron injection and ion migration to locally suppress leakage pathways. This spatial differentiation of material functions resolves the contradiction by optimizing each region for its specific purpose.

The patent forms the leakage blocking layer before depositing the top electrode in the reducing atmosphere. This preliminary action creates a protective barrier that prevents oxygen loss from the high-k dielectric layer during subsequent reducing atmosphere processing. The blocking layer is specifically designed to be stable under reducing conditions while protecting the oxygen-sensitive high-k material, thus enabling easy electrode formation without compromising dielectric quality.

The leakage blocking layer acts as an intermediary between the top electrode and the high-k dielectric layer. During electrode formation in reducing atmosphere, this intermediate layer absorbs or prevents the harmful effects of the reducing environment (such as oxygen removal) from reaching the high-k dielectric layer, thereby mediating between the manufacturing process requirements and the dielectric layer stability requirements.