TiAl sub 3 formation kinetic in sputtered Ti/AlCu0.5% thin films

Sputtered aluminum on titanium double layers are widely used in conventional interconnection schemes of integrated circuits (IC); one known phenomenon is the formation of intermetallic compounds. In this work, the kinetic of the TiAl sub 3 reaction is studied by collecting the sheet resistance increase of 400 nm AlCu0.5% on 10 nm titanium sputtered samples, in situ annealed at three different temperatures (450, 480 and 500 deg C). The observed resistance drift is correlated to the expected aluminum consumption and the TEM observed TiAl sub 3 grain morphology; by adopting an exponential fit of observed resistance curves, the activation energy of the TiAl sub 3 formation is found out to be 1.75 plus /minus 0.25 eV.