scholarly journals Gradually Tunable Conductance in TiO2/Al2O3 Bilayer Resistors for Synaptic Device

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 440
Author(s):  
Hojeong Ryu ◽  
Sungjun Kim
Keyword(s):  
Resistive Switching ◽  
Strong Electric Field ◽  
Single Layer ◽  
High Resistance State ◽  
Forming Process ◽  
Initial State ◽  
Conduction Model ◽  
Bipolar Resistive Switching ◽  
Trap Assisted Tunneling ◽  
Resistance State

In this work, resistive switching and synaptic behaviors of a TiO2/Al2O3 bilayer device were studied. The deposition of Pt/Ti/TiO2/Al2O3/TiN stack was confirmed by transmission electron microscopy (TEM) and energy X-ray dispersive spectroscopy (EDS). The initial state before the forming process followed Fowler-Nordheim (FN) tunneling. A strong electric field was applied to Al2O3 with a large energy bandgap for FN tunneling, which was confirmed by the I-V fitting process. Bipolar resistive switching was conducted by the set process in a positive bias and the reset process in a negative bias. High-resistance state (HRS) followed the trap-assisted tunneling (TAT) model while low-resistance state (LRS) followed the Ohmic conduction model. Set and reset operations were verified by pulse. Moreover, potentiation and depression in the biological synapse were verified by repetitive set pulses and reset pulses. Finally, the device showed good pattern recognition accuracy (~88.8%) for a Modified National Institute of Standards and Technology (MNIST) handwritten digit database in a single layer neural network including the conductance update of the device.

Two modes of bipolar resistive switching characteristics in asymmetric TaOx-based ReRAM cells

MRS Advances ◽  
2019 ◽  
Vol 4 (48) ◽  
pp. 2601-2607
Author(s):  
Toshiki Miyatani ◽  
Yusuke Nishi ◽  
Tsunenobu Kimoto
Keyword(s):  
Resistive Switching ◽  
High Resistance State ◽  
Opposite Polarity ◽  
Electrical Characteristics ◽  
Forming Process ◽  
Initial State ◽  
Bipolar Resistive Switching ◽  
Change Mechanism ◽  
Resistance State ◽  
Switching Characteristics

ABSTRACTImpacts of a forming process on bipolar resistive switching (RS) characteristics in Pt/TaOx/Ta2O5/Pt cells were investigated. We found that the forming resulted in a transition from an initial state to a particular high resistance state (HRS) in most of the Pt/TaOx/Ta2O5/Pt cells. Evaluation of electrical characteristics after the transition to the particular HRS revealed that two modes of bipolar RS with the conventional polarity based on valence change mechanism and with the opposite polarity could be selectively obtained by adjusting the magnitude of the applied voltage. Moreover, the cell resistance decreased gradually during set processes in the bipolar RS with the opposite polarity.

scholarly journals Effects of Sm2O3 and V2O5 Film Stacking on Switching Behaviors of Resistive Random Access Memories

Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 318
Author(s):  
Lin ◽  
Wu ◽  
Chen
Keyword(s):  
Resistive Switching ◽  
Random Access ◽  
Single Layer ◽  
High Resistance State ◽  
Switching Behavior ◽  
Bipolar Resistive Switching ◽  
Compliance Behavior ◽  
Order Of Magnitude ◽  
Resistance State ◽  
Switching Characteristics

: In this work, the resistive switching characteristics of resistive random access memories (RRAMs) containing Sm2O3 and V2O5 films were investigated. All the RRAM structures made in this work showed stable resistive switching behavior. The High-Resistance State and Low-Resistance State of Resistive memory (RHRS/RLRS) ratio of the RRAM device containing a V2O5/Sm2O3 bilayer is one order of magnitude higher than that of the devices containing a single layer of V2O5 or Sm2O3. We also found that the stacking sequence of the Sm2O3 and V2O5 films in the bilayer structure can affect the switching features of the RRAM, causing them to exhibit both bipolar resistive switching (BRS) behavior and self-compliance behavior. The current conduction mechanisms of RRAM devices with different film structures were also discussed.

Influence of SiO2 Layer on Resistive Switching Properties of SiO2/CuXO Stack Structure

2011 ◽  
Vol 687 ◽  
pp. 106-111
Author(s):  
Chih Yi Liu ◽  
Yu Chen Li ◽  
Chun Hung Lai ◽  
Shih Kun Liu
Keyword(s):  
Resistive Switching ◽  
High Resistance State ◽  
Switching Behavior ◽  
Forming Process ◽  
Dc Voltage ◽  
Si Substrates ◽  
Non Volatile Memory ◽  
Resistance State ◽  
The Difference ◽  
Switching Characteristics

CuxO and SiO2thin films were deposited using a radio-frequency magnetron sputter on Pt/Ti/SiO2/Si substrates to form SiO2/CuxO/Pt and CuxO/Pt structures. The current-voltage characteristics were measured by DC voltage sweeping using a tungsten (W) probe. The two structures needed a large voltage to initiate the first resistive switching; this sweep was called the forming process. Afterwards, the resistances of the two structures could be switched reversibly between the low-resistance-state (LRS) and high-resistance-state (HRS) by applying a DC voltage. The conduction mechanisms of the LRS and the HRS were dominated by Ohmic conduction. Structures with non-destructive readout characteristics and long retention time were suitable for use in non-volatile memory. The difference between resistive switching in W-probe/SiO2/CuxO/Pt and W-probe/CuxO/Pt structures was investigated. The additional SiO2layer decreased the switching voltages and currents; this should be due to the presence of pinholes within the SiO2layer. The influence of SiO2thickness on the resistive switching characteristics was also investigated. The switching voltages and currents, except the forming voltage, decreased as the thickness of SiO2decreased. The conducting filament model with a thermochemical reaction was suggested to best explain the resistive switching behavior that was observed.

Bipolar resistive switching characteristics of samarium oxide solid electrolyte thin films for non-volatile memory applications

2019 ◽  
Vol 12 (03) ◽  
pp. 1950023
Author(s):  
Mei Ji ◽  
Yangjiang Wu ◽  
Zhengzhong Zhang ◽  
Ya Wang ◽  
Hao Liu
Keyword(s):  
Thin Films ◽  
Solid Electrolyte ◽  
Resistive Switching ◽  
High Resistance State ◽  
High Yield ◽  
Bipolar Resistive Switching ◽  
Non Volatile Memory ◽  
Resistance State ◽  
Volatile Memory ◽  
Oxide Solid Electrolyte

In this paper, we report the bipolar resistive switching behaviors in Ag/Sm2O3/Pt structures where the Sm2O3 thin films act as solid electrolyte layer of electrochemical metallization memory (ECM) devices. The memory devices show reproducible and stable bipolar resistive switching over 1000 cycles with a resistance ratio (high-resistance state to low-resistance state) of over 4 orders of magnitude and stable retention for over 104[Formula: see text]s at room temperature. Moreover, the benefits of high yield and multilevel storage possibility make the device promising in the next generation non-volatile memory application.

scholarly journals Nonideal resistive and synaptic characteristics in Ag/ZnO/TiN device for neuromorphic system

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jongmin Park ◽  
Hojeong Ryu ◽  
Sungjun Kim
Keyword(s):  
Resistive Switching ◽  
Random Access ◽  
High Resistance State ◽  
Resistive Random Access Memory ◽  
Bipolar Resistive Switching ◽  
Applied Pulse ◽  
Negative Effect ◽  
Endurance Tests ◽  
Resistance State ◽  
The Impact

AbstractIdeal resistive switching in resistive random-access memory (RRAM) should be ensured for synaptic devices in neuromorphic systems. We used an Ag/ZnO/TiN RRAM structure to investigate the effects of nonideal resistive switching, such as an unstable high-resistance state (HRS), negative set (N-set), and temporal disconnection, during the set process and the conductance saturation feature for synaptic applications. The device shows an I–V curve based on the positive set in the bipolar resistive switching mode. In 1000 endurance tests, we investigated the changes in the HRS, which displays large fluctuations compared with the stable low-resistance state, and the negative effect on the performance of the device resulting from such an instability. The impact of the N-set, which originates from the negative voltage on the top electrode, was studied through the process of intentional N-set through the repetition of 10 ON/OFF cycles. The Ag/ZnO/TiN device showed saturation characteristics in conductance modulation according to the magnitude of the applied pulse. Therefore, potentiation or depression was performed via consecutive pulses with diverse amplitudes. We also studied the spontaneous conductance decay in the saturation feature required to emulate short-term plasticity.

scholarly journals Irregular Resistive Switching Behaviors of Al2O3-Based Resistor with Cu Electrode

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 653
Author(s):  
Hojeong Ryu ◽  
Sungjun Kim
Keyword(s):  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
Complementary Metal Oxide Semiconductor ◽  
High Resistance State ◽  
Oxide Semiconductor ◽  
Bipolar Resistive Switching ◽  
Thin Film Layer ◽  
Film Layer ◽  
Resistance State ◽  
Al2o3 Thin Film

In this work, we examined the irregular resistive switching behaviors of a complementary metal–oxide–semiconductor (CMOS)-compatible Cu/Al2O3/Si resistor device. X-ray photoelectron spectroscopy (XPS) analysis confirmed the chemical and material compositions of a Al2O3 thin film layer and Si substrate. Bipolar resistive switching occurred in a more stable manner than the unipolar resistive switching in the device did. Five cells were verified over 50 endurance cycles in terms of bipolar resistive switching, and a good retention was confirmed for 10,000 s in the high-resistance state (HRS) and the low-resistance state (LRS). Both high reset current (~10 mA) and low reset current (<100 μA) coexisted in the bipolar resistive switching. We investigated nonideal resistive switching behaviors such as negative-set and current overshoot, which could lead to resistive switching failure.

Resistive switching of multiferroic BiCoO3 nanoflowers

2015 ◽  
Vol 08 (01) ◽  
pp. 1550001 ◽  
Author(s):  
Bai Sun ◽  
Qiling Li ◽  
Yonghong Liu ◽  
Peng Chen
Keyword(s):  
Resistive Switching ◽  
High Resistance ◽  
Hydrothermal Process ◽  
High Resistance State ◽  
Bipolar Resistive Switching ◽  
Low Resistance ◽  
Current Voltage ◽  
Extreme Change ◽  
Resistance State ◽  
Switching Characteristics

Multiferroic BiCoO 3 nanoflowers were synthesized by a hydrothermal process. The BiCoO 3 nanoflowers show superior bipolar resistive switching characteristics. The typical current–voltage (I–V) characteristics of the Ag / BiCoO 3/ Ag structures exhibit an extreme change in resistance between high resistance state (HRS) or "OFF" state and low resistance state (LRS) or "ON" state with ON/OFF ratio ~ 105.

High Total-Dose Proton Radiation Tolerance in TiN/HfO2/TiN ReRAM Devices

2012 ◽  
Vol 1430 ◽  
Author(s):  
Xiaoli He ◽  
Robert E. Geer
Keyword(s):  
Resistive Switching ◽  
Random Access ◽  
High Resistance State ◽  
Resistive Random Access Memory ◽  
Switching Behavior ◽  
Radiation Tolerance ◽  
Proton Radiation ◽  
Performance Parameters ◽  
Trap Assisted Tunneling ◽  
Resistance State

ABSTRACTThe resistive switching properties of CMOS compatible TiN/HfO2/TiN resistive-random-access-memory (ReRAM) devices have been investigated after exposure to 1 MeV proton radiation. The HfO2-based ReRAM devices were found to have high total-ionizing-dose (TID) radiation tolerance up to 5 Grad(Si). TiN/HfO2/TiN ReRAM performance parameters include high-resistance state (HRS) resistance, low-resistance state (LRS) resistance, set and reset voltages. HfO2-based ReRAM devices exhibited no degradation in these performance parameters following proton irradiation exposure with TID from 105 to 109 rad(Si). Furthermore, the HfO2-based ReRAM devices exhibited more uniform resistive switching behavior with increased TID. Based on this radiation response it is proposed that the resistive switching mechanism in TiN/HfO2/TiN – trap-assisted tunneling associated with Hf-rich conducting filament formation – may be reinforced through proton exposure which acts to stabilize the formation/rupture of Hf-rich filaments. The high radiation tolerance of HfO2-based ReRAM devices suggests such devices may be potentially attractive for aerospace and nuclear applications.

Unipolar Resistive Switching and Associated Photoresponse in Sm doped BiFeO3 Thin Film Grown by RF Sputtering

2013 ◽  
Vol 1577 ◽  
Author(s):  
Rajesh K. Katiyar ◽  
Pankaj Misra ◽  
G. L Sharma ◽  
Gerardo Morell ◽  
J. F Scott ◽  
...  
Keyword(s):  
Resistive Switching ◽  
High Resistance ◽  
Rf Sputtering ◽  
High Resistance State ◽  
Forming Process ◽  
Low Resistance ◽  
Ohmic Behavior ◽  
Conduction Behavior ◽  
Resistance State ◽  
Unipolar Resistive Switching

ABSTRACTNonvolatile unipolar resistive switching has been observed in Sm doped BFO thin films in Pt/Sm: BFO/SRO stack geometry. The initial forming voltage was found to be ∼ 11 V. After the forming process repeatable switching of the resistance of Sm:BFO film was obtained between low and high resistance states with nearly constant resistance ratio ∼ 105 and non overlapping switching voltages in the range of 0.7-1 V and 4-6 V respectively. The temperature dependent measurements of the resistance of the device indicated metallic and semiconducting conduction behavior in low and high resistance states respectively. The current conduction mechanism of the Pt/Sm:BFO/SRO device in low resistance states was found to be dominated by the Ohmic behavior while in case of high resistance state and at high voltages it deviated significantly from normal Ohmic behavior and was found to correspond the Pool-Frankel (PF) emission. The Pt/Sm:BFO/SRO structure also showed efficient photo-response in high and low resistance states with increase in photocurrent which was significantly higher in low resistance state when illuminated with white light.

scholarly journals Bipolar resistive switching on Ti/TiO2/NiCr memory cells

2017 ◽  
Vol 30 (4) ◽  
pp. 65-68
Author(s):  
Eric Hernandez Rodriguez ◽  
Alfredo Marquez Herrera ◽  
Miguel Melendez Lira ◽  
Enrique Valaguez Velazquez ◽  
Martin Zapata Torres
Keyword(s):  
Thin Films ◽  
Resistive Switching ◽  
Rf Sputtering ◽  
High Resistance State ◽  
Switching Behavior ◽  
Emission Model ◽  
Tio2 Thin Films ◽  
Bipolar Resistive Switching ◽  
Metal Insulator Metal ◽  
Resistance State

We investigated the electric-field-induced resistance-switching behavior of metal-insulator-metal (MIM) cells based on TiO2 thin films fabricated by the reactive RF-sputtering technique. MIM cells were constructed by sandwiched TiO2 thin films between a pair of electrodes; Ti thin films were employed to form an ohmic bottom contact and NiCr thin films were employed to form Schottky top electrodes obtaining Ti/TiO2/NiCr MIM cells. Schottky barrier height for the TiO2/NiCr junction was determined according to the thermionic emission model by using the Cheung´s functions. SEM and Raman analysis of the TiO2 thin films were carried out to ensure the quality of the films. Current-Voltage (I-V) sweeps obtained at room temperature by the application of dc bias showed a bipolar resistive switching behavior on the cells. Both low resistance state (ON state) and high resistance state (OFF state), of Ti/TiO2/NiCr cells are stable and reproducible during a successive resistive switching. The resistance ratio of ON and OFF state is over 103 and the retention properties of both states are very stable after 105 s with a voltage test of 0.1 V.

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