Highly Uniform, Electroforming-Free, and Self-Rectifying Resistive Memory in the Pt/Ta2O5/HfO2-x/TiN Structure

• Published in: Advanced functional materials Vol. 24; no. 32; pp. 5086 - 5095
• Main Authors: Yoon, Jung Ho, Song, Seul Ji, Yoo, Il-Hyuk, Seok, Jun Yeong, Yoon, Kyung Jean, Kwon, Dae Eun, Park, Tae Hyung, Hwang, Cheol Seong
• Format: Journal Article
• Language: English
• Published: Blackwell Publishing Ltd 27.08.2014
• Subjects: electroforming-free; high uniformity; resistive switching; self-rectification
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201400064

The development of a resistance switching (RS) memory cell that contains rectification functionality in itself, highly reproducible RS performance, and electroforming‐free characteristics is an impending task for the development of resistance switching random access memory. In this work, a two‐layered dielectric structure consisting of HfO2 and Ta2O5 layers, which are in contact with the TiN and Pt electrode, is presented for achieving these tasks simultaneously in one sample configuration. The HfO2 layer works as the resistance switching layer by trapping or detrapping of electronic carriers, whereas the Ta2O5 layer remains intact during the whole switching cycle, which provides the rectification. With the optimized structure and operation conditions for the given materials, excellent RS uniformity, electroforming‐free, and self‐rectifying functionality could be simultaneously achieved from the Pt/Ta2O5/HfO2/TiN structure. A feasible method is reported for achieving a highly uniform, electroforming‐free, and self‐rectifying RS memory cell with a two‐layered dielectric structure. HfO2 works as the resistance switching layer by trapping and detrapping the deep 1.0 eV trap sites, whereas Ta2O5 layer remains intact during the switching and forms a high Schottky barrier with a high‐work‐function Pt to constitute the rectifying functionality.