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In this letter, we demonstrate the differing influences of a nitrogen buffering effect in both the switching layer and the indium-tin-oxide (ITO) electrode layer of resistive random access memory (RRAM) which has undergone an NH3 treatment. The nitrogen buffering effect in the switching layer cannot counteract the electric field force, leading to similar $I$ – $V$ characteristics compared with the ITO/Hf:SiO2/TiN control structure RRAM. The nitrogen in the ITO electrode layer, however, works as an oxygen buffer and makes it easier for the redox reaction to occur, leading to improvements in performance, such as concentrated voltages and better endurance. [ABSTRACT FROM PUBLISHER]

The instability of the gate bias and drain bias stresses is observed at high temperature in amorphous InGaZnO thin-film transistors (a-IGZO TFTs). The transfer characteristics of a-IGZO TFTs at different temperatures are also investigated in this paper. The transfer curve exhibits an apparent subthreshold current stretchout phenomenon at high temperature. The stretchout phenomenon becomes more serious with the increase of the temperature. In addition, thermally induced holes are accumulated by the negative gate voltage and get trapped in the gate dielectric or at the dielectric/channel interface at high temperature. The negative threshold voltage shifts with stress time and this is because the trapped holes induce more electrons. For drain bias stress at high temperature, the transfer curve exhibits an apparent shift during drain bias stress at high temperature compared with the same at room temperature. At high temperature, thermally induced holes are trapped in the gate insulator, especially near the drain region. Capacitance-voltage measurements have been used to prove the nonuniform hole-trapping phenomenon. Furthermore, the simulation of the capacitance-voltage and current-voltage curves also have been applied to confirm the hole-trapping distribution. The obtained results clarify that the instability is caused by nonuniform hole-trapping phenomenon. [ABSTRACT FROM AUTHOR]

In this letter, a triple-ion redox reaction has been proposed and investigated in GeSO-based resistance random access memory. Continuous multiresistance states can be obtained by applying a series of increasing cutoff voltages in both set and reset processes. Using data retention tests, these multistates in the set and reset processes were confirmed to be stable. The conduction mechanism gradually changed during reset process from space charge limited current to Schottky emission. A triple-ion reaction model has been proposed to reveal the chemical reaction properties in the resistive switching process. [ABSTRACT FROM AUTHOR]

We have previously investigated the automatic current compliance property for indium tin oxide (ITO) resistance random access memory (RRAM). Traditionally, for the purpose of protecting RRAM, it is necessary to set equipment current compliance during the set and forming processes of RRAM devices. ITO RRAM devices, however, have an intrinsic capability to limit their current. This letter examines this ITO RRAM current compliance in depth by applying a varied stop-voltage measurement method, where different negative stop voltages were adopted to manipulate oxygen ions. Combined with material analysis and conduction current fitting, a model was established. [ABSTRACT FROM AUTHOR]

In this letter, we report the oxygen accumulation effect and its influence on resistive switching for gadolinium-doped silicon dioxide (Gd:SiO2) resistance random access memory (RRAM). We find that oxygen absorbance by indium-tin-oxide electrode affects the conduction current mechanism, and remarkably modifies the device performance of RRAM devices. By current fitting, Schottky emission can be observed in both low and high resistance states, from which conduction model is proposed to clarify the oxygen accumulation phenomenon. Reliability tests, including endurance and high temperature retention are further carried out, evaluating the significance of oxygen accumulation effect in redox reaction for RRAM devices. [ABSTRACT FROM AUTHOR]

In this letter, dual ion effect induced reset process of lithium silicate resistance random access memory (RRAM) devices is studied and discussed. Unlike the traditional silicon oxide-based RRAM, lithium ions also participate in the resistive switching process except for the oxygen ions. Owing to the twofold chemical reaction, the high resistance states are randomly distributed in a wide range. Schottky emission can be obtained through conduction current fitting, and a reaction model is established to demonstrate the special behaviors of the two types of ions, which also clarifies the gradual change of current fitting results. [ABSTRACT FROM AUTHOR]

In this letter, the special role of hydrogen ions in hafnium doped silicon oxide resistive random access memory (RRAM) is presented. In addition to the more typical oxygen ion-dominated resistive switching, hydrogen ions were also observed to trigger a resistance transformation phenomenon, producing a tri-resistive device. Unlike a normal RRAM device, a hydrogen plasma-treated device is operated with a reversed voltage polarity, and the direction of hydrogen ion migration results in the chemical bonds breaking and repairing. By changing the voltage polarity and stop voltage, this tri-resistive behavior can be achieved. This particular hydrogen-induced switching behavior suggests a different RRAM switching mechanism and is finally explained by our model. [ABSTRACT FROM PUBLISHER]

Incorporation of nitrogen as an oxygen-confining layer in the resistance switching reaction region is investigated to improve the reliability of resistance random access memory (RRAM). The switching mechanism can be attributed to the formation and rupture of conduction filaments. A compatible WSiON (around 5 nm) layer is introduced at the interface of tungsten silicon oxide (WSiOx) and TiN electrode to prevent the randomly diffusing oxygen ions surpassing the storage region of the WSiON layer. The double-layer WSiOx/\rm WSiON memory structure would enhance the endurance over 100 times so as to better confirm the WSiOx RRAM application of nonvolatile memory. [ABSTRACT FROM PUBLISHER]

In this letter, we introduced hydrogen ions into titanium metal doped into SiO2 thin film as the insulator of resistive random access memory (RRAM) by supercritical carbon dioxide (SCCO)2 fluid treatment. After treatment, low resistance state split in to two states, we find the insert RRAM, which means it has an operating polarity opposite from normal RRAM. The difference of the insert RRAM is owing to the resistive switching dominated by hydrogen ions, dissociated from OH bond, which was not by oxygen ions as usual. The current conduction mechanism of insert RRAM was hopping conduction due to the metal titanium reduction reaction through SCCO2. [ABSTRACT FROM PUBLISHER]

In this letter, a double-active-layer (Zr:SiOx/C:SiOx) resistive switching memory device with a high on/off resistance ratio and small working current (0.02 mA), is presented. Through the analysis of Raman and Fourier transform infrared spectroscopy spectra, we find that graphene oxide exists in the C:SiOx layer. It can be observed that Zr:SiOx/C:SiOx structure has superior switching performance and higher stability compared with the single-active-layer (Zr:SiOx) structure, which is attributed to the existence of graphene oxide flakes formed during the sputter process. I-V characteristics under a series of increasing temperature were analyzed to testify the carrier hopping distance variation, which is further verified by our graphene oxide redox reaction model. [ABSTRACT FROM PUBLISHER]

To improve the resistive switching properties of the resistive random access memory (RRAM), the supercritical carbon dioxide (SCCO2) fluid is used as a low temperature treatment. In this letter, the Zn:SiOx thin films are treated by SCCO2 fluid mixed with pure water. After SCCO2 fluid treatment, the resistive switching qualities of the Zn:SiOx thin films are carried out by XPS, fourier transform infrared spectroscopy, and IV measurement. We believe that the SCCO2-treated Zn:SiOx thin film is a promising material for RRAM applications due to its compatibility with portable flat panel display. [ABSTRACT FROM PUBLISHER]

In this letter, we presented that the charge quantity is the critical factor for forming process. Forming is a pivotal process in resistance random access memory to activate the resistance switching behavior. However, overforming would lead to device damage. In general, the overshoot current has been considered as a degradation reason during the forming process. In this letter, the quantity of charge through the switching layer has been proven as the key element in the formation of the conduction path. Ultrafast pulse forming can form a discontinuous conduction path to reduce the operation power. [ABSTRACT FROM PUBLISHER]

Traditionally, a large number of silicon oxide materials are extensively used as various dielectrics for semiconductor industries. In general, silicon oxide cannot be used as resistance random access memory (RRAM) due to its insulating electrical properties. In this letter, we have successfully produced resistive switching and forming-free behaviors by zinc doped into silicon oxide. The current–voltage fitting data show that current transport mechanism is governed by Poole–Frenkel behavior in high-resistance state and Ohm's law in low-resistance state, consisting with filament theory. Additionally, good endurance and retention reliabilities are exhibited in the zinc-doped silicon oxide RRAM. [ABSTRACT FROM AUTHOR]

In this letter, we investigate the origin of hopping conduction in the low-resistance state (LRS) of a resistive random access memory device with supercritical \CO2 fluid treatment. The dangling bonds of a tin-doped silicon oxide ( \Sn:SiOx) thin film were cross linked by the hydration–dehydration reaction through supercritical fluid technology. The current conduction mechanism of the LRS in the posttreated \Sn:SiOx thin film was transferred to hopping conduction from Ohmic conduction, owing to isolation of metal tin in the \Sn:SiOx thin film by hydration–dehydration reaction. The phenomena can be verified by our proposed reaction model, which is speculated by the X-ray photoelectron spectroscopy analyses. [ABSTRACT FROM AUTHOR]

In this letter, we successfully produced resistive switching behaviors by nickel doped into silicon oxide at room temperature. The nickel element was doped into silicon oxide, which is a useful dielectric material in integrated circuit (IC) industries by cosputtering technology. Based on the proposed method, satisfactory reliability of the resistance switching device can be demonstrated by endurance and retention evaluation. We believe that the silicon oxide doped with nickel at room temperature is a promising method for resistive random access memory nonvolatile memory applications due to its compatibility with the IC processes. [ABSTRACT FROM AUTHOR]

Abnormal subthreshold leakage current is observed at high temperature in amorphous InGaZnO thin-film transistors. The transfer curve exhibits an apparent subthreshold current stretch-out phenomenon that becomes more serious with increasing temperatures. The negative bias temperature instability experiment has been used to prove high-temperature-induced hole generation. Furthermore, the transfer characteristics with different drain voltages have been also used to confirm the status of hole accumulation. These pieces of evidence clearly defined the stretch-out phenomenon, which is caused by thermal-induced hole generation and accumulation at the source region that leads to source-side barrier lowering. [ABSTRACT FROM AUTHOR]

Resistance random access memory (RRAM) is a great potential candidate for next-generation nonvolatile memory due to the outstanding memory characteristic. However, the resistance switching mechanism is still a riddle nowadays. In this letter, the switching mechanism is investigated by current–voltage ( I–V) curve fitting in the \TiN/WSiOX\/Pt RRAM device. The asymmetric phenomenon of the carrier conduction behavior is explained at the high-resistance state in high electric field. The switching behavior is regarded to tip electric field by localizing the filament between the interface of top electrode and insulator. [ABSTRACT FROM AUTHOR]

The on-current decrease phenomenon is observed after erasing operation in the silicon–oxide–nitride–oxide–silicon thin-film transistors (TFTs) with lightly doped drain (LDD) structure. As nonvolatile memory, when the TFT is programmed again, the on-current decrease phenomenon can be recovered. The on-current decrease and recovery are explained by the energy band diagrams at different drain biases. The explanation implies that this phenomenon only appears in the device with LDD structure, but not in the device without LDD structure, which is experimentally verified. [ABSTRACT FROM AUTHOR]

This letter investigates the resistive random access memory device characteristics and the physical mechanism of a device with a \TiN/CoSiOX\/\Pt structure. In general, the mechanism is regarded as a redox reaction in the dielectric interface between the Ti electrode and the conductive filament. Furthermore, the switching voltage is correlated only with redox reaction potential. A designed circuit is used to accurately observe the resistance switching process with a pulse generator and an oscilloscope, which reveals that the switching process is related to both time and voltage. The constant switching energy demonstrates that the switching mechanism is the redox reaction. [ABSTRACT FROM AUTHOR]