Single-Wafer Wet Chemical Oxide Formation for Pre-ALD High-k Deposition on 300 mm Wafer

摘要

High-k materials are being introduced at the gate stack to decrease EOT (Equivalent Oxide Thickness). As published already in some reports, direct high-k deposition on bare Si results in decreased electron mobility. Wet chemical oxide formation prior to high-k deposition is one of the commonly used methods to prevent these problems. Dilute (10 ppm) ozonated water (DIO_3) can make a uniform and saturated thin oxide film on a Si surface very easily: however, in the case of a sub-saturated thin oxide film, further optimization is required to provide a uniform layer across the wafer surface. In this study, single-wafer cleaning was applied to pre-high-k cleaning. Several developments enabled the formation of a uniform oxide film. High-k deposition and capacitor lot were investigated about the formed thin oxide surface. Since recent new devices, FinFET, require device fabrication on a Si<110> surface, this study also incorporated studies about High-k deposition on Si<110> surface.