The Effects of Alloying Elements on the Bonding Strength of Diamond/Carbide/Cu Interface Based on First‐Principles Calculations

The effects of different alloying elements (Ti, Zr) on the bonding strength of the diamond (111)/carbide (111)/Cu (111) interface system have been systematically investigated by means of first‐principles calculations based on density functional theory. It is found that the metal (Ti, Zr)‐terminated carbide is more likely to participate in the formation of the carbide (111)/Cu (111) and carbide (111)/diamond (111) interface. However, the C‐terminated carbide (111) interfaces have higher bonding strength compared with the metal (Ti, Zr)‐terminated carbide interfaces. In the Cu/carbide/diamond interface system, the bonding strength of carbide/Cu interface is lower than that of the carbide/diamond interface, which means the Cu/carbide/diamond interface failure first occurs in the carbide/Cu interface. According to the charge density, the stronger charge interaction between Zr and Cu causes higher bonding strength of ZrC/Cu interface compared with TiC/Cu interface. Therefore, the Cu/ZrC/diamond interface has higher bonding strength compared with the Cu/TiC/diamond interface. The C sp (carbide)–C sp (diamond) covalent bond and the metal (Ti 3d , Zr 4d )–C sp (diamond) covalent bond are formed at the diamond/carbide interface, while the Cu 3d –C sp (carbide) covalent bond and the metal (Ti 3d , Zr 4d )–Cu 3d metallic bond are formed at the Cu/carbide interface.