Comparative study of NBTI as a function of Si film orientation and thickness in SOI pMOSFETs

Negative bias temperature instability of SOI pMOSFET is investigated as a function of Si film orientation and film thickness. It is observed that NBTI induced threshold voltage shift is bigger for (1 1 0) MOSFETs in comparison to (1 0 0) MOSFETs and it decreases with the decrease of Si film thickness. The possible reason for less degradation of thinner Si film devices is explained by the small gate current due to low oxide field. The activation energy is independent on Si film orientation. The dependence of recovery behavior on the Si film orientation is studied by comparing of a conventional stress-measurement-stress technique with un-interrupted stress technique. It is also observed that the NBTI effect is underestimated and the recovery phenomenon is more profound in (1 1 0) MOSFETs.