Here we report the ZrO_( x )-based negative capacitance (NC) FETs with 45.06?mV/decade subthreshold swing (SS) under?±?1?V V _(GS)range, which can achieve new opportunities in future voltage-scalable NCFET applications. The ferroelectric-like behavior of the Ge/ZrO_( x )/TaN capacitors is proposed to be originated from the oxygen vacancy dipoles. The NC effect of the amorphous HfO_(2)and ZrO_( x )films devices can be proved by the sudden drop of gate leakage, the negative differential resistance (NDR) phenomenon, the enhancement of I DS and sub-60 subthreshold swing. 5?nm ZrO_( x )-based NCFETs achieve a clockwise hysteresis of 0.24?V, lower than 60?mV/decade SS and an 12% I DS enhancement compared to the control device without ZrO_( x ). The suppressed NC effect of Al_(2)O_(3)/HfO_(2)NCFET compared with ZrO_( x )NCFET is related to the partial switching of oxygen vacancy dipoles in the forward sweeping due to negative interfacial dipoles at the Al_(2)O_(3)/HfO_(2)interface.
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