Amorphous 10nm-thick layers were found to be effective diffusion barriers between Cu and thermal silicon dioxide. The films were evaluated electrically by using TaSiN/Cu/TaSiN-oxide capacitors and bias thermal stress treatments. The capacitors were stressed at 300C by using electric fields of more than 1MV/cm for up to 80h. High-frequency capacitance-voltage characteristics were monitored at room temperature, before and after the bias thermal stress treatment. On the basis of a comparison of the C-V curves, it was concluded that barrier failure did not occur.

M.S.Angyal, Y.Shacham-Diamand, J.S.Reid, M.A.Nicolet: Applied Physics Letters, 1995, 67[15], 2152-4