Eradicating negative-Set behavior of TiO₂-based devices by inserting an oxygen vacancy rich zirconium oxide layer for data storage applications

Abstract

Memristors, with low energy consumption, long data storage and fast switching speed, are considered to be promising for applications such as terabit data storage memory and hardware based neurocomputation applications. However, unexpected negative-Set behavior is a serious issue that causes deterioration of reliability and uniformity of switching parameters. In this work, negative-Set behavior of TiO 2 -based RRAM is successfully eradicated by inserting a thin oxygen vacancy rich ZrO 2−x layer. In addition, oxygen vacancy rich ZrO 2−x layer is also responsible for the enhancement of resistive switching characteristics in terms of excellent endurance performance (2000 DC cycles), good data retention upto 10 4 s and uniformity in Set/Reset voltages. Experimental results and density functional theory (DFT) analysis confirm that an interface layer TiO x has formed between highly reactive electrode (Ti) and ZrO 2 interlayer. This interface layer is serving as a low series resistance layer and oxygen ion reservoir in Set-process and oxygen ions supplier in Reset-process to generate/refill the oxygen vacancies in the formation and rupture of conductive filaments. Comparing with the single layer Ti/TiO 2 /Pt device, it is noteworthy that the switching process in the bilayer (BL) Ti/ZrO 2−x /TiO 2 /Pt memristor device is not affected even at high Reset-voltages, but the negative-Set behavior has been eradicated effectively. This work demonstrates that the insertion of a thin oxygen vacancy rich ZrO 2−x interlayer into TiO 2 -based devices is a feasible approach to solve unpredicted negative-Set behavior of RRAM devices.

Unveiling the Potential of HfO2/WS2 Bilayer Films: Robust Analog Switching and Synaptic Emulation for Advanced Memory and Neuromorphic Computing

“…The reason for this is the uncontrolled migration of titanium (Ti) into the WS 2 dielectric that leads to irreversible failure of the memristive device. A similar behavior was observed in our previous study . These results indicate that the Pt/TiN/HfO 2 /WS 2 /Pt memristive device exhibits high stability and reliable switching characteristics, unlike the Pt/TiN/WS 2 /Pt memristive devices.…”

“…A similar behavior was observed in our previous study. 65 These results indicate that the Pt/TiN/HfO 2 /WS 2 /Pt memristive device exhibits high stability and reliable switching characteristics, unlike the Pt/ TiN/WS 2 /Pt memristive devices. As a result, the Pt/TiN/ HfO 2 /WS 2 /Pt memristive devices are highly suitable for storing multiple levels of data, which is crucial for applications in neuromorphic systems.…”

Highly Reliable Synaptic Cell Array Based on Organic–Inorganic Hybrid Bilayer Stack toward Precise Offline Learning

“…As previously discussed, Joule heating, which causes abrupt filament rupture, especially during RESET, can determine the quality of the switching layer films (pV3D3), resulting in aggravation of long‐term stability [31a,33] . According to Joule's equation of electrical heating, the degree of heating in conductors is proportional to the square of its current and the product of its resistance ( P α I 2 R ).…”

To the Issue of the Memristor’s HRS and LRS States Degradation and Data Retention Time

“…In addition, the dependence of the heat capacity, density, and thermal conductivity on the film thickness leads to a change in the heating of the filament with a variation in the thickness, and, therefore, strongly affects the diffusion, drift, and creation/recombination of vacancies [21]. In the works [12,13,27,[107][108][109][110][111][112][113][114][115][116][117], an increase in the stability of devices with a two-layer dielectric, such as AlO It was found in [118] that Ti/TiO 2 /Pt breaks down during the RESET, which results in an LRS with extremely low resistance, which confirms the overgrowth of the conductive filaments. However, the addition of a vacancy-rich-2 nm ZrO 2-x layer on the Ti/TiO 2 boundary increased the retention time (>10 4 s) without any apparent degradation of the HRS and LRS resistances.…”