High-Conductance, Ohmic-like HfZrO$_4$ Ferroelectric Memristor

TL;DR

This paper reports on a high-conductance, Ohmic-like ferroelectric memristor based on ultra-thin HfZrO$_4$ with stable, low-voltage operation and no fatigue, suitable for neuromorphic computing.

Contribution

The study demonstrates a novel HfZrO$_4$ ferroelectric memristor with record current density, linear I-V behavior, and stable resistive states achieved through atomic layer deposition and interface engineering.

Findings

Achieved 0.01 A/cm$^2$ current density at 80 mV

Operates at voltages below 3.5 V with low energy consumption

Shows no wake-up or fatigue effects after repeated switching

Abstract

The persistent and switchable polarization of ferroelectric materials based on HfO$_2$-based ferroelectric compounds, compatible with large-scale integration, are attractive synaptic elements for neuromorphic computing. To achieve a record current density of 0.01 A/cm$^2$ (at a read voltage of 80 mV) as well as ideal memristive behavior (linear current-voltage relation and analog resistive switching), devices based on an ultra-thin (2.7 nm thick), polycrystalline HfZrO$_4$ ferroelectric layer are fabricated by Atomic Layer Deposition. The use of a semiconducting oxide interlayer (WO$_{x<3}$) at one of the interfaces, induces an asymmetric energy profile upon ferroelectric polarization reversal and thus the long-term potentiation / depression (conductance increase / decrease) of interest. Moreover, it favors the stable retention of both the low and the high resistive states. Thanks to the low operating voltage (<3.5 V), programming requires less than 10${^-12}$ J for 20 ns long pulses. Remarkably, the memristors show no wake-up or fatigue effect.