Demonstration of High-speed Hysteresis-free Negative Capacitance in Ferroelectric Hf0.5Zr0.5O2

We report the experimental observation of hysteresis-free negative capacitance (NC) in thin ferroelectric Hf
_0.5
Zr
_0.5
O
₂
(HZO) films through high-speed pulsed charge-voltage measurements. Hysteretic switching is suppressed by the addition of thin Al
₂
O
₃
layers on top of the HZO to prevent the screening of the polarization. We observe an S-shaped polarization-electric field dependence without hysteresis in agreement with Landau theory, which enables direct extraction of NC modeling parameters for ferroelectric HZO. Hysteresis-free NC is demonstrated down to 100 ns pulse widths limited only by our measurement setup. These results give critical insights into the physics of ferroelectric NC and practical NC device design using ferroelectric HZO.