The Cu concentration profile in SiO2 during bias temperature stress tests was simulated while considering the driving forces of both concentration gradient and electric field. In particular, the variation of electric field as a result of the diffused Cu ions in SiO2 was considered. The simulation results demonstrated that, while the driving force which

resulted from the concentration gradient was negligible in typical bias temperature stress condition, it became important in the low electric fields where devices normally operates. It means that the lifetime of device straightforwardly deduced from the stressed condition could possibly be overestimated if the effect of concentration gradient was neglected.

Simulation of the Copper Diffusion Profile in SiO2 during Bias Temperature Stress Test. J.Y.Kwon, K.S.Kim, Y.C.Joo, K.B.Kim: Japanese Journal of Applied Physics - 2, 2002, 41[2], L99-101