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

Abstract

Abstract 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 HfO2 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 Al2O3/HfO2 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 Al2O3/HfO2 interface.

Keywords

• Amorphous ZrO x
• Ferroelectric
• FET
• Subthreshold swing
• Negative capacitance