Strength of Cu-TiN and Al-TiN interfaces from first-principles

TL;DR

This study uses first-principles calculations to compare the mechanical strength and stability of Cu/TiN and Al/TiN interfaces, revealing differences in orientation preferences and strength relative to bulk materials.

Contribution

It provides the first detailed comparison of the thermodynamic stability and mechanical strengths of Cu/TiN and Al/TiN interfaces using DFT calculations.

Findings

Al/TiN interface prefers a specific orientation relation.

Cu/TiN interface has lower tensile and shear strengths than bulk materials.

Al/TiN interface strengths are comparable to bulk constituents.

Abstract

Using density functional theory (DFT) based first principles calculations, we show that the preferred interfacial plane orientation relationship is determined by the strength of bonding at the interface. The thermodynamic stability, and the ideal tensile and shear strengths of Cu/TiN and Al/TiN interfaces are calculated. While there is a strong orientation relation (OR) preference for Al/TiN interface, there is no OR preference for Cu/TiN interface. Both the ideal tensile and shear strengths of Cu/TiN interfaces are lower than those of bulk Cu and TiN, suggesting such interfaces are weaker than their bulk components. By comparison, the ideal strengths of Al/TiN interface are comparable to the constituents in the bulk form. Such contrasting interfaces can be a test-bed for studying the role of interfaces in determining the mechanical behavior of the nanolayered structures.