Activation energies associated with current noise of thin metal films

Abstract

Current noise measurements of thin metal films may be used as a valuable tool for studying their material properties. The noise voltage spectra are sensitive to microscopic processes which affect conduction and govern effects such as electromigration. This paper reviews methods for determining activation energies associated with the 1/f and I/f ² current noise components in thin metal films. The activation energies are close to those reported in the literature for grain boundary diffusion. Although the 1/f noise increases dramatically with the structural damage caused by electromigration damage, the 1/f ² noise component is more directly related to the electromigration process. Direct activation energy measurements based on the 1/f ² noise component’s temperature dependence yield 0.59 eV, 0.69 eV and 0.74 eV for Al(99.999%), Al-Si(2%) and Al-Cu(2%), respectively. Possible generation mechanisms of current noise and its relation to the electromigration process will be discussed.