The failure mechanism of these bilayers, as diffusion barriers between Cu and n+Si, was investigated. The bilayers were formed by annealing TiN(50nm)/Si layers, using various rapid thermal processes, or by reactively sputtering TiN(50nm) onto TiSi2. Leakage current measurements revealed no deterioration of n+-p diode junctions during annealing at up to 475C for 0.5h in N2. At a sintering temperature of 500C, the leakage current increased abruptly and secondary ion mass spectrometry profiles revealed that a large amount of Cu diffused into the junctions of n+-p diodes.

Thermal Stability Study of TiN/TiSi2 Diffusion Barrier between Cu and n+Si. T.S.Chang, W.C.Wang, L.P.Wang, J.C.Hwang, F.S.Huang: Journal of Applied Physics, 1994, 75[12], 7847-51