Fast electromigration crack in nanoscale aluminum film

Abstract

The current-induced breakage of 20 nm thin aluminum layers deposited onto capacitor grade polypropylene (PP) films is experimentally studied. Biexponential current pulses of different amplitude (10–15 A) and duration (0.1–1 μs) were applied to the samples. Breakage occurred after fast development of electromigrating ∼200 nm-wide cracks with initial propagation velocity of ∼1 m/s under a high current density of ∼1012 A/m2. The cracks stopped when their lengths reached 250–450 μm. This behavior is explained by the balance of electromigration and stress-induced atomic fluxes.