Antimony diffusion in fine scale copper

Antimony diffusion in fine scale copper - thin films of Sb (50 nm) and Cu (200 nm) were deposited using thermal evaporation technique onto Si-substrate in high vacuum chamber. Both bulk and grain boundary (GB) diffusion coefficients were determined within the temperature range 160 200 OC and calculated to be D=6.04.10(-5).exp(1.06 eV/kT), cm(2)/s and k delta D-b=7.2.10(-10).exp(1.05eV/kT), cm(3)/s. The copper nanocrystalline powders were produced by gas condensation technique and were compacted to the 75 % of theoretical density. The mean grain size was approximately 50 nm. Sb diffusion was studied for temperature range from 50 to 100 degrees C. Based on the metallographic data diffusion cluster model was proposed. According to this model diffusion occurs along cluster boundaries following by nanograins boundaries diffusion. Both grain and cluster boundaries diffusion coefficients of Sb in n-Cu were calculated from this model. Obtained activation energy values for Sb diffusion along nanograin (0.33 eV) and cluster (0.41 eV) boundaries are close to each other and more probably describe surface mass transport than grain boundary diffusion.