Fig. 4. Role for NC in MOSFETs as a voltage-loss saver.
a With a simple |CNC| = COX matching, SS can be restored to 60 mV per decade in short-channel MOSFETs, and S in near- and above- threshold regimes can be reduced to the transport limit (STP). Here Ctrap and Cdep are neglected, since they have been greatly suppressed in state-of-the-art MOSFETs. Thereby, b NC layer can help suppress the short-channel effect induced subthreshold voltage loss (∆Vsub-Vth), and inversion charge screening induced overdrive voltage loss (∆Voverdrive). It is difficult for NC to help obtain hysteresis-free steep-slope turn-on characteristics. c Simulated Id–Vg and d S versus Id curve of a Si SOI NC-FET in which |CNC| is matched to COX. Lower NC non-linearity (quantified by the factor of β) is desired, in terms of restoring S back to STP.