CORRELATION BETWEEN RESISTIVITY AND DIFFUSION IN THIN-FILMS

Empirical equations have been derived that relate resistivity to diffusivity and activation energies for thin films. Results for the Cr/Au structure agree with published data on the interdiffusion of Cr and Au thin films at temperatures ranging from 350 to 450-degrees-C. The following relationships were determined: DELTA-rho/rho-0C = lambda-exp(- Q/kT); DELTA-rho/rho-0C = nDt/chi-2; DELTA-rho/rho-0C = psi-exp(- chi-2/4Dt) and D = N-chi-2/t exp(- Q/kT), where N-chi-2/t = D0(cm2/s) is the frequency factor; DELTA-rho is the change in resistivity; rho-0 is the room temperature resistivity; chi is film thickness; T is temperature; t is time; C is concentration; k is Boltzman's constant; D is diffusion coefficient; and n, psi, N, and lambda are constants. Analysis of the Cr/Au resistivity data using these equations gives D0 = 1.2 x 10(-7) cm2/s and Q = 1.00 eV for Cr diffusion in Au; and D0 = 1.0 x 10(-7) cm2/s and Q = 1.06 eV for Au diffusion in Cr. These values were verified by analysis using Rutherford backscattering spectroscopy and, they are consistent with those reported for grain boundary diffusion.