ZrO2 Negtive Capacitance Field-Effect Transistor with Sub-60 Subthreshold Swing Behavior

Abstract

Here we report the ZrO2 - 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 furture voltage-scalable NCFET applications. The ferroelectric-like behavior of the Ge/ZrO2/TaN capacitors is proposed to be originated from the oxygen vacancy dipoles. The NC effect of the amorphous HfO2 and ZrO2 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 ZrO2 - based NCFETs achieve a clockwise hysteresis of of 0.24 V, lower than 60 mV/decade SS and an 12% I DS enhancement compared to the control device without ZrO2 . The suppressed NC effect of Al2O3/HfO2 NCFET compared with ZrO2 NCFET is related to the partical swiching of oxygen vacancy dipoles in the forward sweeping due to negative interfical dipoles at the Al2O3 /HfO2 interface.