Effects of the Variation of ${V}_{\text {GS}}$ Sweep Range on the Performance of Negative Capacitance FETs

We report the first investigation of the impacts of gate voltage sweep range V
_GS,range
on the performance of negative capacitance (NC) transistors. As V
_GS,range
is reduced, NC GeSn pFETs generally exhibit an increased hysteresis or a transition from non-hysteretic to hysteretic, and show a degradation of IDS. This is due to the reduction of the ratio of remnant polarization Pr to coercive field E
_c
with the reduced voltage across the HZO. Interestingly, however, some NC devices show a negligible impact of V
_GS,range
on hysteresis and IDS. The NC transistor demonstrates a stable hysteresis in 139-149 mV range and the improved SS and IDS over the control device, with a reduced V
_GS,range
of 0.5 to -0.5 V. To obtain device performance independent of V
_GS,range
, the ratio of Pr/Ec of the HZO needs to stabilize in a very small V
_GS,range
.