Improved Molybdenum Dioxide Atomic Layer Deposition Process by Introducing Pre‐Reduction Agent

ABSTRACT In this study, the molybdenum dioxide (MoO ₂ ) as a promising electrode material for next‐generation semiconductor memory devices is investigated. A pre‐reduction agent is introduced into the MoO ₂ atomic layer deposition (ALD) process to prevent surface morphology degradation occurring during crystallization. The chemical changes in MoO ₂ thin films upon the application of the pre‐reduction agent are analyzed, thereby elucidating the role of the pre‐reduction agent in MoO ₂ ALD. With the use of the pre‐reduction agent, the Mo ⁶⁺ corresponding to molybdenum trioxide (MoO ₃ ) decreased, while that of Mo ⁵⁺ corresponding to MoO _x (2 < x < 3) increases in the as‐deposited state. Accordingly, the MoO _x thin film is partially reduced in the as‐deposited state, suppressing surface morphology degradation during the annealing process. The improved surface morphology of MoO ₂ , MoO ₂ /TiO ₂ thin film, enhances the electrical performance of MoO ₂ /TiO ₂ ‐based metal‐insulator‐metal (MIM) capacitors. The insights into the role and mechanism of the pre‐reduction agent contribute to the development of optimized MoO ₂ /TiO ₂ ‐based MIM capacitors, providing significant progress toward addressing the challenges and enhancing the performance of next‐generation semiconductor memory devices.