Al2O3 interfacial layer derived hybrid conductive filament for the reliability enhancement of Ta2O5-based resistive random access memory

Abstract

This study used an Al2O3 interfacial layer to improve the reliability characteristics of Ag/Ta2O5/Au resistive random access memory (RRAM), such as endurance and retention. The Ag/Ta2O5/Au device without the Al2O3 interfacial layer exhibited a high on/off ratio, low endurance, and poor retention. In Ag/Ta2O5/Au devices, it is difficult to precisely control the formation and rupture of conductive filaments (CFs) owing to the high diffusion coefficient of Ag cations. However, in the RS mechanism of Ag/Ta2O5/Au with an Al2O3 interfacial layer, a hybrid CF composed of Ag cations in Ta2O5 and oxygen vacancies in the Al2O3 layer was formed during the set process. During the reset process, the hybrid CF was stably ruptured by the recombination of oxygen vacancies and oxygen ions at the Al2O3 interfacial layer. This RS mechanism induces stable switching characteristics, improving endurance and retention. Therefore, Ag/Ta2O5/Au with an Al2O3 interfacial layer exhibits relatively high endurance (up to 700 cycles) and excellent retention (up to 1.0 × 104 s) while maintaining a high on/off ratio (>106) compared to those of the Ag/Ta2O5/Au device.