Intrinsic Nature of Negative Capacitance in Multidomain Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub>‐Based Ferroelectric/Dielectric Heterostructures
Michael Hoffmann, Mengcheng Gui, Stefan Slesazeck, Riccardo Fontanini, Mattia Segatto, David Esseni, Thomas Mikolajick
Abstract
Abstract Harnessing ferroelectric negative capacitance in Hf 0.5 Zr 0.5 O 2 ‐based thin films is promising for applications in nanoscale electronic devices with ultralow power dissipation, due to their ultimate scalability and semiconductor process compatibility. However, so far, it has been unclear if negative capacitance is an intrinsic material property of ferroelectric Hf 0.5 Zr 0.5 O 2 , or if it is an extrinsic effect caused by specific domain configurations and lateral domain wall motion as seen in perovskite ferroelectrics. Here, symmetric and asymmetric Hf 0.5 Zr 0.5 O 2 /Al 2 O 3 ‐based ferroelectric/dielectric heterostructures are investigated to understand the relationship among depolarization, interfacial charge, domain formation, and negative capacitance. To achieve this, detailed electrical characterization is combined with structural data, analytical modeling, and numerical simulations. The findings suggest that negative capacitance in these ferroelectric/dielectric heterostructures is an intrinsic property of the Hf 0.5 Zr 0.5 O 2 layer, which has important implications for potential applications. Furthermore, it is experimentally observed that the energy barrier for polarization switching in Hf 0.5 Zr 0.5 O 2 is largely independent of the domain configuration and layer thickness, which confirms recent predictions by first principles calculations.