Oxygen Impurity-Tuned Structure and Adhesion Properties of the Cu/SiO₂ Interface

The properties of the Cu/SiO₂ interface usually deteriorate in the complex atmospheric environment, which may limit its performance and application in the engineering. Using the reactive molecular dynamics method, we investigate how the mechanical behaviors of the Cu/SiO₂ interface change as it interacts with oxygen impurities. The interfacial oxidation degree could be enhanced as O₂ penetrates into the interface area. This makes the interfacial structure disordered and is not conducive to the survival of Cu-O-Si bondings, which reduces the tensile and shear strengths of the interface. To improve the abrupt bonding property change at the interface and modify the interfacial adhesion properties, O impurities are introduced at the Cu interstitial sites near the interface. By doing so, the interface strength can be significantly enhanced due to the production of typical O-Cu-O bondings while the regular interfacial structure is retained. Meanwhile, the interfacial oxidation also changes the tensile failure site and shearing sliding mode of the interface, i.e., from inside the oxide to between oxide and Cu. The findings of this work may not only advance the understanding of interaction mechanism between oxygen impurities and the Cu/SiO₂ interface but also provide new insights into optimizing the bonding properties of the metal/oxide interface.