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This study investigates an improvement in memory characteristics through depositing an In2O3 layer as an oxygen ion reservoir in the switching layer (SL) of resistive random access memory (RRAM). The deposition of In2O3, denoted as Pt/HfO2/In2O3/TiN device, provides better memory characteristics including lower forming voltage (VF), set/reset voltage (VSET/VRESET), larger memory window, and higher resistances with higher uniformity at low resistance state (LRS) and high resistance state (HRS), compared to the devices without the In2O3 deposition, denoted as Pt/HfO2/TiN device. The conduction mechanisms, verified through fitting current–voltage (I - V) curves, are consistent with the results of a varied temperature I - V experiment. Finally, a physical model is proposed to explain our observations. [ABSTRACT FROM AUTHOR]

HfZrOx (HZO)-based materials have received much attention due to their special film characteristics in recent years. Ferroelectric random access memory (FeRAM) based on this HZO material also has promising potential as a next generation memory due to its non-volatile characteristics, excellent endurance, and low power consumption. Previous research has mainly focused on the material properties of HZO-based FeRAM. However, an in-depth investigation of the electrical properties of HZO-based FeRAM is necessary to better understand its transporting mechanism. In this contribution, this study aims to investigate the mechanism of an HZO-based metal–ferroelectric-metal capacitor using comprehensive experimental results, including current–voltage, capacitance–voltage, and polarization–voltage measurements. Experiments at various temperatures are also conducted to help verify the transport mechanism. The low current transport by the Fowler–Nordheim tunneling mechanism does not change with temperature, whereas the high current transport via the Schottky mechanism increases with increasing temperature. We found that the orientation of the dipole plays an important role. Finally, we also propose a band model to explain the electron transport in this HZO-based FeRAM. [ABSTRACT FROM AUTHOR]

This article explains the difference in the reset processes between single RRAM and 1T1R RRAM structures. In the single RRAM, as the reset voltage increases, the off-state resistance increases. This is a normal RRAM operation. However, in the 1T1R structure, the reset voltage increases while the OFF-state resistance does not increase. This may be caused by either current or voltage being insufficient to switch the RRAM to its higher resistance state. The measurements of real voltage indicate that the insufficient voltage is in fact the main cause. For the 1T1R RRAM structure, if it is to be reset to a higher resistance state, it is best done by increasing the gate voltage to increase the OFF-state resistance. Therefore, we provide a method to reduce the misjudgment in the array, and it would be beneficial for the development of high-density memory. [ABSTRACT FROM AUTHOR]

In this paper, vanadium oxide (VOx) was chosen for the resistive switching layer in a typical resistive random access memory (RRAM) structure. During negative forming bias, we found an initial selector property. This indicates the presence of metal–insulator-transition characteristics in the VOx layer even without an annealing process. In order to study this phenomenon, material analyses were conducted, with results indicating that there are V-O stretching bonds and an oxide/vanadium ratio of nearly 2.2 (${O}/{V} = {2.2}$). In addition, the experimental results of the dc sweeping test indicated that off-state current gradually decreased after each cycle, meaning that the selectivity characteristics in the VOx selector could be improved. Endurance performance of our experimental devices reached 108, sufficient for integration with RRAM devices in a 1S1R array. To further investigate this special phenomenon, current fitting analysis and simulation analyses were conducted. The results of the fitting analysis indicated that the conduction mechanism for off-state current was Schottky emission and the Schottky distance increased with increasing numbers of cycles. In other words, oxide ions migrate toward the filament at low negative voltage during dc sweeping, causing the formation of VOx. Furthermore, the results of thermal field simulation analysis indicated that there is a thermal concentration effect in and around the filament. Thus, oxide ions more easily migrate toward the vanadium filament when a stronger electrical field is present around the filament during dc sweeping cycles. Finally, stable vanadium selector characteristics are obtained and a conduction filament behavior model is proposed. [ABSTRACT FROM AUTHOR]

In this study, an Ag-Cu alloy was chosen as the electrode in conductive bridging random access memory (CBRAM), with results indicating a significant decrease in forming voltage. In addition, resistive switching characteristics as well as a retention test indicated better stability and a resistive switching window of at least an order. The switching time of the Ag-Cu alloy CBRAM is shorter than that of both Ag and Cu electrode CBRAMs under fast current-voltage (fast I-V). The experimental result indicated that the mechanism was dominated by the galvanic effect. Active atoms (Ag) captured electrons of inactive atoms (Cu) and generated metallic ions (Cu ions) in the alloy electrode. Cu ions drifted into the insulator and generated a conductive path when applying voltage bias. The use of this alloy as an electrode in CBRAM can significantly decrease forming voltage and enhance CBRAM characteristics. [ABSTRACT FROM AUTHOR]

A technique was proposed to concentrate the distribution of set voltages. After a plasma treatment, the stability of the high-resistive state (HRS) increased, and the distribution of set voltages was more concentrated at 0.8 V, with a sufficient HRS/LRS resistive ratio (∼100x). In addition, the surface of the TiN electrode became rougher, causing oxygen to enter the TiN electrode and form a TiON layer, which acts as an oxygen reservoir. The reservoir is confirmed and the conduction model is supported by both electrical and material analyses. We propose that the observed improvement is due to the difference in the TiN electrode surface. Image 1 • Applied the plasma treatment on electrode to stabilize set voltage. • Construct the physical model to explain abnormal current conduction. • Complete electrical and material analysis were performed in this work. [ABSTRACT FROM AUTHOR]

This study proposes the design of conductive bridge random access memory (CBRAM) using an indium electrode, which diffuses into hafnium oxide. The device is found to exhibit good operating characteristics, maintaining a large operation window, low set and reset voltages, and advantageous operation speed, thereby reducing operating power consumption. Electrical experiments, transmission electron microscopy, and energy‐dispersive spectroscopy confirm that the device exhibits the characteristics of a CBRAM device. In addition, due to the large operation window of this In electrode device, a combination of two of these CBRAM can act as a complementary resistive switching (CRS) device with a large memory window. [ABSTRACT FROM AUTHOR]