A re-interpretation of the existence of a spectrum of activation energies for the microstructural changes in Al 1% Si lines

Abstract

During the first thermal treatment after deposition and/or passivation of Al-based interconnects, a marked decrease in the electrical resistance can be observed. This resistance decrease cannot be described in terms of a single rate constant. Precipitation of the alloyed elements is probably the responsible atomic process. In a previous article, a spectrum of activation energies was extracted in order to characterize this decay. Recent research has shown that the presence of an activation energy spectrum is, mathematically, completely equivalent with a spectrum of pre-exponential factors. Since for precipitation-dissolution, the pre-exponential factor is a function of the distribution and geometry of the precipitates, the use of a spectrum of pre-exponential factors is for this specific case probably physically more relevant. The technique introduced for the determination of the spectrum of activation energies is still valid in case of the presence of a spectrum of pre-exponential factors. (C) 1996 American Institute of Physics.