Forming-Free, Low-Voltage, and High-Speed Resistive Switching in Ag/Oxygen-Deficient Vanadium Oxide(VO x )/Pt Device through Two-Step Resistance Change by Ag Filament Formation

• Published in: ACS applied materials & interfaces 2024-05, Vol.16 (20), p.26450-26459
• Main Authors: Ryu, Jiyeon, Park, Kitae, Sahu, Dwipak Prasad, Yoon, Tae-Sik
• Format: Article
• Language: English
• Subjects: Functional Inorganic Materials and Devices
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.4c04874

Forming-free, low-voltage, and high-speed resistive switching is demonstrated in an Ag/oxygen-deficient vanadium oxide (VO x )/Pt device via the facilitated formation and rupture of Ag filaments. Direct current (DC) voltage sweep measurements exhibit forming-free switching from a high-resistance state (HRS) to a low-resistance state (LRS), called SET, at an average VSET of +0.23 V. The reverse RESET transition occurs at an average VRESET of −0.07 V with a low RESET current of 103 during repeated measurements for thousands of cycles. In pulse measurements, switching occurs within 100 ns at an amplitude of +1.5 V. Notably, a two-step resistance change is observed in the SET operation, where the resistance first partially decreases due to Ag+ ion accumulation in VO x and then further decreases to the LRS after hundreds of nanoseconds upon complete filament formation. The VO x layer deposited to be mostly amorphous with oxygen deficiency from V2O5 has abundant vacancies and expedites Ag+ ion migration, thus realizing forming-free, high-speed, and low-voltage switching. These characteristics of the facilitated Ag filament formation using the substoichiometric VO x layer are highly beneficial for use as stand-alone nonvolatile memory and in-memory computing elements.