A Self-Rectifying Resistive Switching Device Based on HfO2/TaO $_{{x}}$ Bilayer Structure

To effectively solve the crosstalk issue in high-density 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 high-performance self-rectifying device with CMOS compatible Pd/HfO
₂
/TaO
_x
/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
₂
rectifying layer, the rectifying ratio of device could be achieved as high as
$\sim 2\times 10^{\textsf {3}}$
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
$32 \times 32$
cells. Furthermore, a model based on interfacial barrier modulation and defects trapping/detrapping was proposed to elucidate the 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.