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.

Resistive Switching Characteristics in TiO2 ReRAM with Top Electrode of Co Selectively Formed on SAMs Printed Patterns

2007 ◽  
Vol 124-126 ◽  
pp. 603-606
Author(s):  
Sang Hee Won ◽  
Seung Hee Go ◽  
Jae Gab Lee
Keyword(s):  
Resistive Switching ◽  
Random Access ◽  
Atomic Layer ◽  
High Resistance State ◽  
Resistive Random Access Memory ◽  
Tio2 Thin Films ◽  
Selective Deposition ◽  
Precise Control ◽  
Resistance State ◽  
Switching Characteristics

Simple process for the fabrication of Co/TiO2/Pt resistive random access memory, called ReRAM, has been developed by selective deposition of Co on micro-contact printed (μ-CP) self assembled monolayers (SAMs) patterns. Atomic Layer Deposition (ALD) was used to deposit TiO2 thin films, showing its ability of precise control over the thickness of TiO2, which is crucial to obtain proper resistive switching properties of TiO2 ReRAM. The fabrication process for Co/TiO2/Pt ReRAM involves the ALD of TiO2 on sputter-deposited Pt bottom electrode, followed by μ-CP with SAMs and then selective deposition of Co. This results in the Co/TiO2/Pt structure ReRAM. For comparison, Pt/TiO2/Pt ReRAM was produced and revealing the similar switching characteristics as that of Co/TiO2/Pt, thus indicating the feasibility of Co replacement with Pt top electrode. The ratios between the high-resistance state (Off state) and the low-resistance state (On state) were larger than 102. Consequently, the selective deposition of Co with μ-CP, newly developed in this study, can simplify the process and thus implemented into the fabrication of ReRAM.

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.

Annealing Effect of Al2O3 Tunnel Barriers in HfO2-Based ReRAM Devices on Nonlinear Resistive Switching Characteristics

2015 ◽  
Vol 15 (10) ◽  
pp. 7569-7572 ◽  
Author(s):  
Sukhyung Park ◽  
Kyoungah Cho ◽  
Jungwoo Jung ◽  
Sangsig Kim
Keyword(s):  
Resistive Switching ◽  
Conduction Mechanism ◽  
Random Access ◽  
High Resistance State ◽  
Resistive Random Access Memory ◽  
Tunnel Barrier ◽  
Tunnel Barriers ◽  
Retention Characteristics ◽  
Resistance State ◽  
Switching Characteristics

In this study, we demonstrate the enhancement of the nonlinear resistive switching characteristics of HfO2-based resistive random access memory (ReRAM) devices by carrying out thermal annealing of Al2O3 tunnel barriers. The nonlinearity of ReRAM device with an annealed Al2O3 tunnel barrier is determined to be 10.1, which is larger than that of the ReRAM device with an as-deposited Al2O3 tunnel barrier. From the electrical characteristics of the ReRAM devices with as-deposited and annealed Al2O3 tunnel barriers, it reveals that there is a trade-off relationship between nonlinearity in low-resistance state (LRS) current and the ratio of the high-resistance state (HRS) and the LRS. The enhancement of nonlinearity is attributed to a change in the conduction mechanism in the LRS of the ReRAM after the annealing. While the conduction mechanism before the annealing follows Ohmic conduction, the conduction of the ReRAM after the annealing is controlled by a trap-controlled space charge limited conduction mechanism. Additionally, the annealing of the Al2O3 tunnel barriers is also shown to improve the endurance and retention characteristics.

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.

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.

scholarly journals Multilevel Bipolar Electroforming-Free Resistive Switching Memory Based on Silicon Oxynitride

2020 ◽  
Vol 10 (10) ◽  
pp. 3506
Author(s):  
Nayan C. Das ◽  
Se-I Oh ◽  
Jarnardhanan R. Rani ◽  
Sung-Min Hong ◽  
Jae-Hyung Jang
Keyword(s):  
Resistive Switching ◽  
Random Access ◽  
Charge Trapping ◽  
High Resistance State ◽  
Memory Device ◽  
Resistive Random Access Memory ◽  
Silicon Oxynitride ◽  
Set Switching ◽  
Resistance State ◽  
Switching Characteristics

Resistive random-access memory (RRAM) devices are fabricated by utilizing silicon oxynitride (SiOxNy) thin film as a resistive switching layer. A SiOxNy layer is deposited on a p+-Si substrate and capped with a top electrode consisting of Au/Ni. The SiOxNy-based memory device demonstrates bipolar multilevel operation. It can switch interchangeably between all resistance states, including direct SET switching from a high-resistance state (HRS) to an intermediate-resistance state (IRS) or low-resistance state (LRS), direct RESET switching process from LRS to IRS or HRS, and SET/RESET switching from IRS to LRS or HRS by controlling the magnitude of the applied write voltage signal. The device also shows electroforming-free ternary nonvolatile resistive switching characteristics having RHRS/RIRS > 10, RIRS/RLRS > 5, RHRS/RLRS > 103, and retention over 1.8 × 104 s. The resistive switching mechanism in the devices is found to be combinatory processes of hopping conduction by charge trapping/detrapping in the bulk SiOxNy layer and filamentary switching mode at the interface between the SiOxNy and Ni layers.

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 Resistive Switching Characteristics of a SiOxLayer with CF4Plasma Treatment

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Chih-Yi Liu ◽  
Yueh-Ying Tsai ◽  
Wen-Tsung Fang ◽  
Hung-Yu Wang
Keyword(s):  
Resistive Switching ◽  
High Resistance State ◽  
Memory Device ◽  
Switching Behavior ◽  
Operating Voltage ◽  
Radio Frequency Sputtering ◽  
Treated Sample ◽  
Resistance State ◽  
Switching Characteristics ◽  
20 Nm

A 20 nm SiOxlayer is deposited using radio-frequency sputtering to form the resistive switching layer of a Cu/SiOx/Pt memory device. The SiOx-based device demonstrates the resistive switching characteristics with an electrochemical reaction. CF4plasma treatment was used to modify the SiOxlayer and incorporate fluorine atoms into theSiOxlayer. The bombardment damage and fluorine incorporation caused the SiOxfilm to form a stack-like structure. This reduced the operating voltage and improved switching dispersion. The fluorine repaired the Cu/SiOxinterface, thus increasing the barrier height of the Cu/SiOxinterface and the resistance of the high resistance state. A statistical analysis of the conducting filament formation was performed in order to evaluate the number of formation/rupture sites. The resistive switching of the CF4-treated sample had higher possibility to use the same filament sites; thus, the CF4-treated sample had stable resistive switching behavior.

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.

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