Electrical breakdown measurements of semicontinuous metal films

Abstract
The breakdown current Ic of a percolating system is measured on real materials. We find that IcBx, B is the weakly nonlinear response determined by third-harmonic generation. A new criterion for Ic is suggested, defined as the current at which a hot spot reaches the melting temperature of the metallic grains, Tm. This criterion remains valid in the presence of nonlinear effects. It is also consistent with the experimental observations: At Ic the resistance either increases to infinity or decreases, i.e., the local geometry is changed at Tm. Modeling the breakdown by hot spots yields the above power law with 0.5≥x≥0.36, in excellent agreement with the measured data: x=0.48 and 0.41 for Ag and Au films.