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In this paper, multi-layer Zn:SiO2/SiO2 structure is introduced to reduce the operation power consumption of resistive random access memory (RRAM) device by modifying the filament formation process. And the configuration of multi-layer Zn:SiO2/SiO2 structure is confirmed and demonstrated by auger electron spectrum. Material analysis together with conduction current fitting is applied to qualitatively evaluate the carrier conduction mechanism on both low resistance state and high resistance state. Finally, single layer and multilayer conduction models are proposed, respectively, to clarify the corresponding conduction characteristics of two types of RRAM devices. [ABSTRACT FROM AUTHOR]

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]

Bipolar switching properties and electrical conduction mechanism in Sn:SiO thin-film RRAM devices were investigated and discussed. To complete the resistive switching properties of the stannum doped into silicon oxide thin films, the RTA-treated Sn:SiO thin-film RRAM devices were investigated and discussed. In addition, the improvement qualities and electrical switching properties of the RTA-treated Sn:SiO thin-film RRAM devices were carried out XPS, FT-IR, and IV measurement. The ohmic conduction with metal-like behavior and hopping conduction dependent activation energy properties by the Arrhenius plot equation in LRS of the Sn:SiO thin films was investigated. The activation energy and hopping distance for the RTA-treated thin films were found to be 0.018 eV and 1.1 nm, respectively. For the compatibility with the IC processes, the RTA treatment was a promising method for the Sn:SiO thin-film RRAM nonvolatile memory applications. [ABSTRACT FROM AUTHOR]

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]

A bilayer resistive switching memory device with an inserted porous silicon oxide layer is investigated in this letter. Compared with single Zr:SiOx layer structure, Zr:SiOx/porous SiOx structure outperforms from various aspects, including low operating voltages, tighter distributions of set voltage, higher stability of both low resistance state and high resistance state, and satisfactory endurance characteristics. Electric field simulation by comsolTM Multiphysics is applied, which corroborates that intensive electric field around the pore in porous SiOx layer guides the conduction of electrons. The constraint of conduction path leads to better stabilization and prominent performance of bilayer resistive switching devices. [ABSTRACT FROM AUTHOR]

In this study, we have observed dynamic switching behaviors in a memristive device. There are only a few atoms in the resistive switching reaction which enables the high-speed resistive switching characteristics, which was analyzed dynamically by real-time analyzing tools. From fundamental conductance considerations, the resistance of the conductive path in HfOx memristor is found to be due to barriers which are atomically incremented during the RESET process. Simultaneously, we have demonstrated the quantized switching phenomena at ultra-cryogenic temperature (4 K), which are attributed to the atomic-level reaction in metallic filament. [ABSTRACT FROM AUTHOR]

The tin-doped can supply conduction path to induce resistance switching behavior. However, the defect of tin-doped silicon oxide (Sn:SiOx) increased the extra leakage path lead to power consumption and joule heating degradation. In the study, supercritical CO2 fluids treatment was used to improve resistive switching property. The current conduction of high resistant state in post-treated Sn:SiOx film was transferred to Schottky emission from Frenkel-Poole due to the passivation effect. The molecular reaction model is proposed that the defect was passivated through dehydroxyl effect of supercritical fluid technology, verified by material analyses of x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. [ABSTRACT FROM AUTHOR]

The switching layer with Si interfusion is investigated to improve the electrical characteristics of WOX resistance random access memory (RRAM). The WOX has attracted extensive attention for RRAM because it can form by converting the surface of the W-plug with a current complementary metal oxide semiconductor (CMOS) compatible thermal oxidation process. In general, the resistance switching behavior of WOX-RRAM devices is unstable because the diverse oxidation state provided the stochastic conduction paths. In this research, the Si interfusion can effectively localize the filament conduction path in WOX resistance switching layer because the tungsten filament path is limited by SiOX in the WSiOX film during the forming process. [ABSTRACT FROM AUTHOR]

In the study, we reduced the operation current of resistance random access memory (RRAM) by supercritical CO2 (SCCO2) fluids treatment. The power consumption and joule heating degradation of RRAM device can be improved greatly by SCCO2 treatment. The defect of nickel-doped silicon oxide (Ni:SiOx) was passivated effectively by the supercritical fluid technology. The current conduction of high resistant state in post-treated Ni:SiOx film was transferred to Schottky emission from Frenkel-Pool due to the passivation effect. Additionally, we can demonstrate the passivation mechanism of SCCO2 for Ni:SiOx by material analyses of x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. [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]

In this study, the electrical conduction mechanism of Zn:SiOx resistance random access memory (RRAM) treated with supercritical CO2 fluid (SCCO2) process was investigated by low temperature measurement. The current of low resistance state for current-voltage curves in SCCO2-treated and untreated Zn:SiOx RRAM were measured and compared under a low temperature range from 100 K to 298 K. The electrical conduction mechanisms of hopping conduction and metal-like behaviors in SCCO2-treated and untreated Zn:SiOx RRAM were discussed, respectively. Finally, the electrical conduction mechanism was analyzed and verified by the chemical composition and bonding intensity of XPS analyses. [ABSTRACT FROM AUTHOR]

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]

This letter investigated the electrical characteristics of resistance random access memory (RRAM) with HfO2/BN bilayer structures. By adopting the high/low permittivity structure, we obtained the excellent device characteristics such as uniform distribution of switching voltage and more stable resistance switching properties of RRAM. The current conduction mechanism of low resistance state in the HfO2/BN device was transferred to space-charge-limited current conduction from Ohmic conduction owing to space electric effect concentrated by the high/low permittivity bilayer structures. The electric field in the bilayer can be verified by comsol simulation software. [ABSTRACT FROM AUTHOR]

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]

An abnormal subthreshold leakage current is observed at high temperature, which causes a notable stretch-out phenomenon in amorphous InGaZnO thin film transistors (a-IGZO TFTs). This is due to trap-induced thermal-generated holes accumulating at the source region, which leads to barrier lowering on the source side and causes an apparent subthreshold leakage current. In order to obtain superior thermal stability performance of a-IGZO TFTs, conducting N2O plasma treatment on active layer was expected to avert defects generation during SiO2 deposition process. Reducing defects generation not only suppresses subthreshold current stretch-out phenomenon but also significantly improves the bias stress stability in a-IGZO TFTs at high temperature. [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]

In this Letter, the characteristics of set process of hafnium oxide based resistance random access memory are investigated by different set processes with increasing compliance current. Through current fitting, carrier conduction mechanism of low resistance state changes from hopping to surface scattering and finally to ohmic conduction with the increase of setting compliance current. Experimental data of current-voltage measurement under successive increasing temperature confirms the conduction mechanism transition. A model of filament growth is eventually proposed in a way by merging discrete metal precipitates and electrical field simulation by comsol Multiphysics further clarifies the properties of filament growth process. [ABSTRACT FROM AUTHOR]

In this study, the hopping conduction distance variation of Zn:SiO2 resistance random access memory (RRAM) devices with different operating compliance currents was discussed and verified. To investigate and determine the hopping conduction distance dependent activation energy characteristics, the Arrhenius plot of low resistance state of Zn:SiO2 RRAM devices was applied, from which we proposed carrier conduction model. With the increase of current compliance, more metal ions would accumulate to form precipitates with larger diameter, which in turn resulted in the shortening of hopping distance. Because of shorter hopping distance, activation energy for carrier hopping would decrease. [ABSTRACT FROM AUTHOR]

Highlights: [•] The supercritical fluid treatment can efficiently reduce the operation current of resistance random access memory. [•] The dangling bonds of Sn:SiO x thin film were cross linking by the hydration–dehydration reaction by supercritical fluid treatment. [•] The current conduction mechanism of low resistance state in post-treated RRAM device was dominated by hopping conduction. [•] The current conduction mechanism of high resistance state in post-treated RRAM device was dominated by Schottky emission. [ABSTRACT FROM AUTHOR]

Abstract: N2O plasma treatment suppressed the temperature-dependent sub-threshold leakage current of amorphous indium–gallium–zinc-oxide thin film transistors (a-IGZO TFTs). For untreated devices, the transfer curve exhibited abnormal electrical properties at high temperature. The abnormal electrical properties are explained by the energy band diagrams for both forward and reverse sweep. Above 400K, holes can be generated from trap-assisted transition, and drift to the source side which induces source barrier lowering. The source side barrier lowering enhances electron injection from the source to channel and causes an apparent sub-threshold leakage current. This phenomenon, which is experimentally verified, only appears in the device without N2O plasma treatment, but not in the device with N2O plasma treatment. The results suggested that the density of states for a-IGZO with N2O plasma treatment is much lower than that without plasma treatment. [Copyright &y& Elsevier]