Highly uniform, electroforming-free, and self-rectifying resistive memory in the Pt/Ta₂O₅/HfO_2-x/TiN structure

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 Ta₂O ₅ 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. HfO ₂ 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.