Anomalous threshold voltage shifts in various devices under high-temperature rapid thermal annealing and glass reflow conditions were studied. Transient enhanced B out-diffusion and P pile-ups, as well as interface states which were generated by the degradation of thin gate oxides during rapid thermal annealing, were suggested to be the main source of this anomalous shift.

Y.K.Fang, J.C.Hsieh, C.W.Chen, C.H.Koung, N.S.Tsai, J.Y.Lee, F.C.Tseng: Applied Physics Letters, 1992, 61[4], 447-9