Improvement of electromigration reliability and diffusion of Cu films using coherent Cu(1 1 1)/Cr2O3(0 0 0 1) interfaces

Atomic structures and electronic properties of Cu(1 1 1)/Cr2O3(0 0 0 1) interfaces with different interfacial configurations have been investigated using the first-principles calculations. It has been demonstrated that the Cu–O interfaces are much stronger than the Cu–Cu interlayers, and the most stable structure is Cu(1 1 1)/Cr2O3(0 0 0 1) interface with O-termination, where one Cu atom occupies the empty Cr site and the other three ones are on the bridge sites between the top and second O layers. As a result, the interfacial bonding strength is greatly enhanced and the Cu atoms can hardly diffuse into the Cr2O3 layer via the Cr vacancies, indicating that the Cr2O3 is an excellent candidate for improving the electromigration reliability and as the diffusion barrier material.