Performance improvement of resistive switching memory achieved by enhancing local-electric-field near electromigrated Ag-nanoclusters

Abstract

By introducing Ag nanoclusters (NCs), ZnO-based resistive switching memory devices offer improved performance, including improved uniformity of switching parameters, and increased switching speed with excellent reliability. These Ag NCs are formed between the top-electrode (cathode) and the switching layer by an electromigration process in the initial several switching cycles. The electric field can be enhanced around Ag NCs due to their high surface curvature. The enhanced local-electric-field (LEF) results in (1) the localization of the switching site near Ag NCs, where oxygen-vacancy-based conducting filaments have a simple structure, and tend to connect Ag NCs along the LEF direction; (2) an increase in migration and recombination rates of oxygen ions and oxygen vacancies. These factors are responsible for the improvement in device performance.

Memristive behavior of Al2O3 film with bottom electrode surface modified by Ag nanoparticles

“…The intense electric field results in the increasing of the oxygen ion drift velocity, thus effectively promote the filament formation and decrease the switching voltages and the low resistance. The local enhanced electric field can also increase recombination probability between the oxygen ions and oxygen vacancies, so the rupture will preferentially occur in the small local region near the Ag NPs [32,33]. During the next set and reset processes, the conducting filament will be prior formed and ruptured at this certain region, which stabilizes the switching characteristics and improves the sweep endurance.…”

“…The conduction mechanism of Ag NPs-induced local enhanced electric field is different from the highly mobile Ag ions under electric field [21,32]. Because the Ag NPs have a stable lattice structure and the strong electrons trap ability, it is harder to be oxidized into Ag ions, implying that the effects of Ag ion on switching behavior is weak, and the mobile Ag ions resulting from Ag NPs can be negligible.…”

Oxygen-concentration effect on p-type CuAlOx resistive switching behaviors and the nature of conducting filaments

“…Many chemical and physical models have been proposed to explain the RS events, and one model involving the rupture and formation of conducting filaments (CFs) within an insulator has been generally accepted. [4][5][6] For the RRAMs based on n-type oxides (e.g., ZnO, TiO 2 ), the composition of CFs is usually attributed to the oxygen-deficient states. 4,6 In contrast, the RS mechanism of p-type oxide RRAMs has received less attention.…”

Nonpolar resistive switching in Cu/SiC/Au non-volatile resistive memory devices

“…These results also discard the possibility of any oxygen vacancy conduction as its temperature coefficient should be at least an order of magnitude smaller than metal filaments. 23 Figure 3(b) shows the HRS I-V characteristics of all the four switching modes which can be explained by Schottky Emission mechanism following:…”