ZrO(x) Negative Capacitance Field-Effect Transistor with Sub-60 Subthreshold Swing Behavior

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 IDS 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% IDS 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.