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This paper investigates the effect of oxygen flow rates on the performance of the resistive random access memory (RRAM) of indium-tin-oxide (ITO)/ITO(O2)/TiN configuration. By using a co-sputtering deposition system with oxygen gas at different flow rates, oxygen-rich ITO thin films, such as the RRAM switching layer, can be realized. The relationship between oxygen flow rates and electrical characteristics is provided in this research. Further, the material analyses indicate that the oxygen exhibits different bonding characteristics. As a result, the device with the lower oxygen flow rate has better electrical characteristics and reliability. In addition, to explain the experimental results, the Schottky emission conduction mechanism for the high-resistance state and the Ohmic conduction mechanism for the low-resistance state are determined through the current fitting results, and appropriate models are proposed. [ABSTRACT FROM AUTHOR]

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]

This research investigates one of the process or element doping methods used to enhance the reliability of resistive random access memory (RRAM). A supercritical fluid process combines the advantages of the high permeability of gas with the solubility of liquids, and this novel process introduces water molecules into the supercritical fluid for oxidation in order to improve the resistance of random storage. In terms of reliability of the memory, while previous research has used an oxygen plasma treatment to improve RRAM device performance, this work performed a comparison of the two methods and found that the supercritical oxidation treatment can reduce the forming voltage by 25% and produce superior electrical operation, with an endurance test exhibiting an increase to 108 cycles and an improvement of 102. The material analysis confirmed that, during the resistance switching process, the switching layer was more oxidized after this novel supercritical oxidation, resulting in the reduction of operating current and improved reliability compared with the plasma oxidation device. [ABSTRACT FROM AUTHOR]

In this experiment, the electrical performance of zinc oxide based-resistive random access memory (RRAM) is successfully improved by using annealing in ammonia hydroxide solution at low-temperature and high pressure to complete ammonium-doped ZnO based-RRAM. The results of material analysis indicate that using CO2 as ammonia hydroxide carrier during the annealing process leads to the reduction in dangling bond density. This can be clearly observed in the decrease in breakdown voltage during the forming process and a lower operating current during operation. Furthermore, in this ammonium-doped ZnO based-RRAM, we study the molecular doping of NH3 in ZnO, where the endurance and retention properties are improved as well. These improvements can be attributed to the higher concentration of nitrogen in the switching layer, which can effectively control the active oxygen ions during the operation process. [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]

In this paper, we investigate two different resistive switching mechanisms in sputtered nickel oxide thin film which result from using the forming compliances of 15 μA and 15 mA. X-ray photoelectron spectroscopy material analysis results verify the nickel and oxygen chemical shifts, while energy-dispersive X-ray spectroscopy results confirm oxygen content changes after the forming process. Moreover, two markedly different resistive switching mechanisms, those of unipolar and bipolar, are accomplished in a single nickel oxide thin film. To clarify the two resistance switching mechanisms in the Pt/NiO/TiN device, a size effect measurement was conducted to determine the filament-type conduction. Moreover, the device capability to act as a memory device utilizing these two switching behaviors was determined, and a retention test for reliability was also carried out over 125 °C. Finally, the switching mechanism was confirmed by current fitting and sampling reset methods, and an appropriate physical model is presented. We anticipate this model can provide an insight into further future applications of RRAM devices. • We have examined the unipolar and bipolar resistive switching (RS) characteristics using different forming compliance. • The physical mechanisms were confirmed by current fitting and constant voltage sampling results. • The physical models were established to explain two switching 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]