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

• Published in: Materials Vol. 13; no. 18; p. 4201
• Main Authors: Ryu, Ji-Ho, Kim, Sungjun
• Format: Journal Article
• Language: English
• Published: MDPI 21-09-2020; MDPI AG
• Subjects: conduction mechanism; F–N tunneling; memristor; nonlinearity; read margin; RRAM
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma13184201

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/Al2O3 layers deposited on the TiN bottom electrode. The optimized nonlinear properties with current suppression are obtained by varying Al2O3 thickness. The maximum nonlinearity (~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 Al2O3 film for the crossbar array applications. We expect that this study about the effect of the Al2O3 tunnel barrier thickness on Ta2O5-based memristors could provide a guideline for developing a selector-less RRAM application.