A Self-Rectifying Resistive Switching Device Based on HfO2/TaO<inline-formula> <tex-math notation="LaTeX">$_{{x}}$ </tex-math> </inline-formula> Bilayer Structure

Abstract

To effectively solve the crosstalk issue in highdensity crossbar array (CBA), high rectifying characteristics should be introduced in the resistance random-access memory (ReRAM) device, and in-depth understanding of the affecting factors on rectifying properties is essential for the large-scale application of ReRAM. In this paper, a highperformance self-rectifying device with CMOS compatible Pd/HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /TaO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> /Ta structure was demonstrated in a 1-kb CBA. Forming-free, self-compliance, and high uniformity characteristics were successfully achieved. By modulating the thickness of the HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> rectifying layer, the rectifying ratio of device could be achieved as high as ~2 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> under ±3 V at low-resistance state (LRS). It was also experimentally confirmed that the selected unit cell in high-resistance state (logically the “OFF” state) was stably readable when it was surrounded by unselected LRS (logically the “ON” state) cells, in an array of up to 32 × 32 cells. Furthermore, a model based on interfacial barrier modulation and defects trapping/detrappingwas proposed to elucidatethe impact of the dielectric thickness on the self-rectifying characteristics of the device. The results presented in this paper provide a great potential for selector-free high-density memory applications.