Investigation of defect microstructures responsible for NBTI degradation using effective dipole moment extraction

The identification of the microstructure defects responsible of metal-oxide-silicon field effect transistor (MOSFET) reliability problems is important to understand, the physical mechanisms behind these problems. In this paper, the effective dipole moment of bond precursors that contribute to negative bias temperature instability (NBTI) permanent components is investigated, using the conventional charge pumping method (CCP). In addition, the contribution of the several precursors to the extracted effective dipole moment is modelled. The model is in agreement with the experimental data. The results show that the effective dipole moments responsible of NBTI permanent component correspond to Si-H and stretched Si-O bonds. The Si-H bond dipole moment clearly dominates at low stress electric field (Eox) and when their density is higher than that Si-O bond. While, the effective dipole moment of Si-O bonds is obviously observable at high stress electric field even with low density. However, for intermediate stress electric field, both effective dipole moments contribute and lead an inaccurate extraction. Moreover, the profiling of the effective dipole moment along the transistor channel, shows that Si-H and stretched Si-O bonds are mostly located in the vicinity of the LDD region.