Tunnel Electroresistance in Hf0.5Zr0.5O2-Based Ferroelectric Tunnel Junctions under Hysteresis: Approach of the Point Contact Model and the Linearized Thomas–Fermi Screening

Quantum tunneling is the core phenomenological problem in the study of ferroelectric tunnel junctions. Recent advances in ultrathin film ferroelectric devices have yielded the possibility of achieving stable and switchable ferroelectric polarization P even in nanometer-thick Hf0.5Zr0.5O2 layers. In this study, the transport model of the point contact is adapted for the current density (J–V) simulation in metal–ferroelectric–metal [M1/FE/M2] and metal–dielectric–ferroelectric–dielectric–metal [M1/DE/FE/DE/M2] systems, including contributions from hysteresis. Important interfacial screening regions in metals are calculated by a simplified Thomas–Fermi model utilizing a linear approach and keeping an exact analytical solution for the electron transmission. Both systems were compared with each other and with related experimental data. The derived J–V curves are characterized by multi- and monodomain ferroelectric behaviors.