First-principles study of Cu/TiN and Al/TiN interfaces: weak versus strong interfaces

Abstract

Using density functional theory 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(1 1 1)/TiN(1 1 1) and Al(1 1 1)/TiN(1 1 1) interfaces are calculated. While there is a strong orientation relation preference for the Al/TiN interface, there is no orientation relation preference for the 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 the 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.

Suppression of material transfer at contacting surfaces: the effect of adsorbates on Al/TiN and Cu/diamond interfaces from first-principles calculations

“…These geometric parameters are consistent with previous investigations. [36,50,52,55,85]. the strong colors mark atoms that were allowed to relax.…”

Microwave evaluation of electromigration susceptibility in advanced interconnects

“…The S21 losses in the low-frequency domain, are attributed primarily to signal scattering due to molecular polarization events occurring within the dielectric and ceramic cladding (i.e., dangling bond rotations within SiO 2 and TiN layers surrounding the copper), 16 and the eddy currents within about 1000 nm of the skin of the copper TSV fill. Since the copper and the claddings are adhered to each other albeit weakly, 25–27 we discuss the observations at an integrated system level.…”

“…32,33 Thus, while the resistive heating from the forced current may not alter the bulk material properties of the cladding dielectrics, 31 it could change the nature of the Cu-TiN interface from the changing hydrostatic stress of the copper fill because the Cu/TiN interface is extraordinarily “weak” in shear, and significantly weaker than either the bulk form TiN or Cu. 25 …”

Ab initio modeling of zincblende AlN layer in Al-AlN-TiN multilayers

“…Similar methodology has been applied to our earlier metal/nitride interface calculations. 22,33,34 During growth and later under indentations, AlN may experience various types of stress.…”

“…In normal growth conditions, nitrogen atoms are expected to be the terminating species at the interface, as suggested in our earlier works. 33 Fig. 4 We first studied various possible interfaces between Al/AlN.…”