Hits:

Indexed by:期刊论文

Date of Publication:2017-07-15

Journal:SURFACE & COATINGS TECHNOLOGY

Included Journals:SCIE、EI、Scopus

Volume:321

Page Number:328-335

ISSN No.:0257-8972

Key Words:Strong interaction; Stability; Film; Magnetron sputtering

Abstract:In order to apply solid solution Cu(Ge) film to a barrierless structure for Cu interconnection, a binary Cu(Ge) solid solution film was prepared on the single-crystal Si(100) substrate by magnetron sputtering, followed by vacuum annealing. It was found that the individual addition of Ge led to serious interfacial diffusion promoting Cu-Si reaction. Therefore, Fe (or Sn) was chosen as the third element to prepare Cu(Ge-Fe(or Sn)) ternary films. The strong interactions from the negative mixing enthalpy between Ge-Fe(or Sn) stabilizes Ge in the Cu lattice, improving the thermal stability of the film. After 400 degrees C/1 h annealing, the Cu99.19Ge0.73Fe0.08 and CU99.22Ge0.69Fe0.09 films with the largest lattice distortion remained stable with the resistivity as low as 2.54-2.80 mu Omega cm. For Cu(Ge-Sn) films, the Cu-Si reaction did not occur in the Cu99.01Ge0.90Sn0.09 films with the largest lattice distortion, and the resistivity was maintained at 2.51 mu Omega cm. The results proved that strong interaction elements Fe and Sn could prevent the diffusion of Ge and enhance the stability of Cu alloy films. The addition of small atomic radius element Fe, which has large diffusion activation energy and small diffusion coefficient in Cu, could inhibit diffusion for a wide range of composition. (C) 2017 Elsevier B.V. All rights reserved.