Kinetics of Contact Wearout for Silicided (TiSi2) and Non-Silicided Contacts

The failure kinetics for both titanium silicided and non-silicided contacts are discussed for Al-Si (1%) metallization. The activation energies for accumulation of silicon in silicided and non-silicided contacts as well as the depletion of silicon from non-silicided contacts were found to correspond to diffusion of silicon in aluminum, 0.8 to 0.9 eV. The dependence of the reaction rate on current was found to vary with the level of applied stress. Depletion related leakage failures for TiSi2 contacts proceed at a much slower rate than the depletion of silicon from contacts to silicon and an activation energy of 1.5 eV was observed.