The interface characteristics of TiN(100)/MgO(100) multilayer on oxidized Si(100) substrate via first-principle calculations and experimental investigation

Titanium nitride (TiN) buffer is generally applied to improve the epitaxial growth quality of MgO(100) on Si(100) substrate, despite lacking integral and comprehensive description of the mechanism in theoretical explanation and experimental illustration. The interfacial structures and bond nature of Si(SiO₂)(100)/TiN(100) and TiN(100)/MgO(100) were calculated and analyzed by the first-principles. MgO(100) thin film was also deposited with and without a TiN transition layer in order to characterize the differences on surface morphology, roughness and bonding energy. Cation–anion configuration is steady for TiN(100)/MgO(100) interface due to Mg-N ionic bonds. However, in Si(SiO₂)(100)/TiN(100) model, Ti-Si covalent bonds play the dominant part in the formation of the stable structure. The introduction of TiN mid-layer can effectively enhance the bonding strength and reduce the roughness of the upper layer. In conclusion, TiN transition layer acts as an adhesive joint, which may also offer a possibility for the epitaxial growth of other metallic oxide or even ceramic coatings on Si(100) matrix.