In this study, the structural and electrical characteristics of the Al/Al₂O₃/SiO₂/n-Si Metal-Oxide-Semiconductor (MOS) structure were investigated. Al₂O₃ films were deposited on the n-type Si wafer by RF magnetron sputtering after the growth of SiO₂ by dry oxidation. The fabricated Al₂O₃/SiO₂/n-Si structures were annealed at 250^oC, 450^oC, and 750^oC in a N₂ ambient. XRD and AFM measurements were conducted in order to examine the crystallinity and the surface topography of the Al₂O₃/SiO₂/n-Si structure. Aluminum (Al) front and back contacts were then deposited by RF magnetron sputtering. C-V and G/w-V measurements were performed at low and high frequencies with the aim of analyzing the electrical characteristics. The discrepancy in the C-V curves for different frequencies stemmed from the defects and dangling bonds at the interfaces and in the oxide layers

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