The use of  in situ  depth-resolved positron annihilation spectroscopy revealed the dynamic formation of vacancies in 1 x 1 lines of Al-0.5wt%Cu under a current flow. It was shown that the number of vacancies in these lines increased when a direct current of 80000A/cm2 was applied. This increase in the vacancy concentration was considerably greater (4 x 1018/cm3) than that (3 x 1017/cm3) due to thermal vacancy generation alone. Isothermal measurements, in the absence of a current flow, yielded a vacancy formation energy of 0.60eV. The results showed that positron annihilation spectroscopy could be used to study the initial stages of interconnect damage, due to electromigration. Detection of Current-Induced Vacancies in Thin Aluminum–Copper Lines using Positrons. P.Asoka-Kumar, K.O’Brien, K.G.Lynn, P.J.Simpson, K.P.Rodbell: Applied Physics Letters, 1996, 68[3], 406-8