Improved Intrinsic Nonlinear Characteristics of Ta2O5/Al2O3-Based Resistive Random-Access Memory for High-Density Memory Applications

Abstract

The major hindrance for high-density application of two-terminal resistive random-access memory (RRAM) array design is unintentional sneak path leakage through adjacent cells. Herein, we propose a bilayer structure of Ta2O5/Al2O3-based bipolar type RRAM by evaluating the intrinsic nonlinear characteristics without integration with an additional transistor and selector device. We conducted X-ray photoelectron spectroscopy (XPS) analysis with different etching times to verify Ta2O5/Al(2)O(3)layers deposited on the TiN bottom electrode. The optimized nonlinear properties with current suppression are obtained by varying Al(2)O(3)thickness. The maximum nonlinearity (similar to 71) is achieved in a Ta2O5/Al2O3(3 nm) sample. Furthermore, we estimated the comparative read margin based on the I-V characteristics with different thicknesses of Al(2)O(3)film for the crossbar array applications. We expect that this study about the effect of the Al(2)O(3)tunnel barrier thickness on Ta2O5-based memristors could provide a guideline for developing a selector-less RRAM application.