Thickness dependence of resistive switching characteristics of the sol–gel processed Y₂O₃ RRAM devices

Abstract

In this study, yttrium oxide (Y2O3)-based resistive random-access memory (RRAM) devices were fabricated using the sol-gel method. The fabricated Y2O3 RRAM devices exhibited conventional bipolar RRAM device characteristics and did not require a forming process. The Y2O3 film thickness was controlled by varying the liquid-phase precursor concentration. As the concentration increased, thicker Y2O3 films were formed. In addition, the concentration of oxygen vacancies increased. The RRAM device properties were not observed for thin Y2O3 films, which had the lowest oxygen vacancy concentration. Moreover, RRAM devices, which consisted of the thickest Y2O3 films with the largest oxygen vacancy concentration, showed poor non-volatile properties. The optimized Y2O3-based RRAM devices with a thickness of 37 nm showed conventional bipolar RRAM device characteristics, which did not require an initial forming process. The fabricated RRAM devices showed a high resistance state to low resistance state ratio of over 104, less than +1.5 V of SET voltage, and –15. V of RESET voltage. The RRAM devices also showed promising non-volatile memory properties, without significant degradation after 10^3 s retention and 10^2 cycle endurance tests.

Sol–Gel-Processed Y2O3 Multilevel Resistive Random-Access Memory Cells for Neural Networks

“…To increase this ratio, the leakage current should be suppressed under HRS conditions. The leakage current is affected by the film phase, defect concentration, or energy barrier conditions [10,11,18,32]. More investigation is needed.…”

“…Numerous metal oxide materials, including ZrO 2 , HfO 2 , TiO 2 , and Y 2 O 3 , have been utilized as active channel layers in RRAM devices [8][9][10][11][12][13][14][15][16][17][18]. Among them, Y 2 O 3 stands out due to its high dielectric constant and large optical band gap, making it a promising highk candidate for replacing SiO 2 in complementary metal-oxide-semiconductor processes in the industry.…”

Effect of Electrochemically Active Top Electrode Materials on Nanoionic Conductive Bridge Y2O3 Random-Access Memory

“…Its high refractive index (n = 2.1) can make it a waveguide in solid state lasers [ 15 , 16 ]. Particularly for RRAM devices, Y 2 O 3 has high defect chains along preferred orientations, which is helpful for easily forming the conductive filament, and leads to forming process-free RRAM devices [ 17 , 18 ]. There are two types of RRAM corresponding to conductive filaments between two electrodes: oxygen vacancy-based conductive filament-based OxRRAM and conductive-metal-bridge-filament-based conductive bridging random access memory (CBRAM) [ 19 , 20 , 21 ].…”

Sol–Gel-Processed Y2O3–Al2O3 Mixed Oxide-Based Resistive Random-Access-Memory Devices

“…To realize RRAM devices, many metal oxides (such as ZrO 2 , HfO 2 , TiO 2 , and Y 2 O 3 ) have been studied for use in the active channel layers of RRAM devices [8][9][10][11][12][13][14][15][16][17][18]. Y 2 O 3 has been investigated to replace the low-k SiO 2 dielectric layers with high-k ones during CMOS processes in industries.…”