17th International Conference on Insultating Films on Semiconductors Grenoble, FRANCE, JUN 21-24, 2011
The negative bias temperature instability (NBTI) of nanoscaled Si0.45Ge0.55 pFETs with different thicknesses of the Si passivation layer (cap) is studied. Individual discharge events are detected in the measured threshold voltage shift (Delta V-th) relaxation traces, with exponentially distributed step heights. The use of a thinner Si cap is shown to reduce both the average number of charge/discharge events and the average Delta V-th step height. To qualitatively explain the experimental observations, a simple model including a defect band in the dielectric is proposed. (C) 2011 Elsevier B.V. All rights reserved.