Evaluation of residual stresses in Cu/Mo, Cu/Nb nanomultilayers with a strong fiber texture

Residual stresses are one of the key factors for tuning the properties, microstructure, and reliability of thin films and nanomultilayers, but their measurement and evaluation are challenging. Residual stresses in nanomultilayers with {1 1 0} out-of-plane texture exhibit a dependence on the in-plane crystal orientation, which complicates their evaluation using X-ray diffraction. The texture and residual stresses were investigated for two representative nanomultilayers of immiscible materials with fcc/bcc structure: Cu/Mo and Cu/Nb grown on Si substrate with an amorphous silicon nitride layer. Both multilayered structures exhibited Cu {111} // Mo, respectively Nb {1 1 0} out-of-plane fiber texture, and showed compressive stress. A modified crystallite group method for {110}, {111} fiber texture was used to determine residual stresses in the nanomultilayers. The method was proven to be a good tool to extract the residual stress in nanomultilayers with a strong fiber texture.