Electromigration in thin films of aluminium and aluminium alloys is shown to lead to stepwise increases of the electrical 1/f noise. These are attributed to the generation of highly mobile defect configurations by a nucleation-and-growth process. It is conjectured that among them may be the defects that are responsible for the eventual failure of VLSI electronic devices by electromigration damage. 1/f noise promises to be an early indicator of this damage.

The paper reports on the recovery of irradiation‐induced defects in thin aluminium films as studied by measurements of the electrical 1/f noise. The defects are produced by irradiation with 1 MeV electrons at 10 K, which results in a strong increase of the noise. Subsequent isochronal annealing at progressively higher temperatures causes the 1/f noise measured at 10 K to recover in discrete steps which occur at the same temperatures as the well‐known recovery stages of the irradiation‐induced electrical resistivity increase. In the noise measurements at 40 K, however, an additional recovery step without analogue in the recovery spectrum of the electrical resistivity is observed at 70 K. The temperature dependence and annealing behaviour of the 1/f noise may be understood in terms of thermally activated motion of defects in a distorted lattice potential. A microscopic explanation of the present observation as well as of earlier measurements on Cu by Pelz and Clarke within the framework of the two‐interstitial model of radiation damage of metals is presented.

Thin polycrystalline aluminum films were investigated by high-resolution ac noisemeasurements before and after damaging by high direct current. Immediately after the interruption of the dc-stress a transient noise component was observed that was inversely proportional to the square of the frequency f (1/f 2 -noise). It was caused by discrete jumps in the resistance presumably due to the relaxation of mechanical stress. The second component of noise was stable and in all cases approximately proportional to 1/f. The spectral density of 1/f-noise showed characteristic discrete steps as a function of damaging time, in contrast to the resistance which increased almost continuously up to the failure of the film. This indicates that nucleation-and-growth processes of mobile defects were observed in the noise measurements. Thus noise measurements might help to understand the microscopic process of electromigration.

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