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.

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.

Impact of resistive switching parameters on resistive random access memory crossbar arrays

2020 ◽  
Vol 34 (12) ◽  
pp. 2050115
Author(s):  
Liping Fu ◽  
Sikai Chen ◽  
Zewei Wu ◽  
Xiaoyan Li ◽  
Mingyang You ◽  
...  
Keyword(s):  
Resistive Switching ◽  
Random Access ◽  
High Resistance State ◽  
Resistive Random Access Memory ◽  
High Density ◽  
Access Memory ◽  
Storage Density ◽  
Crossbar Array ◽  
Resistance State ◽  
Potential Impact

Sneak current issue of RRAM-based crossbar array is one of the biggest hindrances for high-density memory application. The integration of an addition selector to each cell is one of the most familiar solutions to avoid this undesired cross-talk issue, and resistive switching parameters would affect on the storage density. This paper investigates the potential impact of different resistive switching parameters on crossbar arrays with one-diode one-resistor (1D1R) and one-selector one-resistor (1S1R) architectures. Results indicate that 1S1R architecture is a more scalable technology for high-density crossbar array than 1D1R, and the storage density of 1D1R- and 1S1R-based crossbar array shows little dependence on resistance values of high-resistance state and low-resistance state, which gives a guideline for choosing appropriate selectors for RRAM crossbar array with specific parameters.

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.

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.

scholarly journals Investigation of Conductive Mechanism of Amorphous IGO Resistive Random-Access Memory with Different Top Electrode Metal

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 504
Author(s):  
Wei-Lun Huang ◽  
Yong-Zhe Lin ◽  
Sheng-Po Chang ◽  
Shoou-Jinn Chang
Keyword(s):  
Resistive Switching ◽  
Rf Sputtering ◽  
Random Access ◽  
Random Access Memory ◽  
Resistive Random Access Memory ◽  
Access Memory ◽  
Bipolar Resistive Switching ◽  
Reset Voltage ◽  
Resistance State ◽  
Conductive Mechanism

In this paper, resistive random-access memory (RRAM) with InGaO (IGO) as an active layer was fabricated by radio-frequency (RF) sputtering system and the resistive switching mechanism with the different top electrode (TE) of Pt, Ti, and Al were investigated. The Pt/IGO/Pt/Ti RRAM exhibits typical bipolar resistive switching features with an average set voltage of 1.73 V, average reset voltage of −0.60 V, average high resistance state (HRS) of 54,954.09 Ω, and the average low resistance state (LRS) of 64.97 Ω, respectively. Ti and Al were substituted for Pt as TE, and the conductive mechanism was different from TE of Pt. When Ti and Al were deposited onto the switching layer, both TE of Ti and Al will form oxidation of TiOx and AlOx because of their high activity to oxygen. The oxidation will have different effects on the forming of filaments, which may further affect the RRAM performance. The details of different mechanisms caused by different TE will be discussed. In brief, IGO is an excellent candidate for the RRAM device and with the aids of TiOx, the set voltage, and reset voltage, HRS and LRS become much more stable.

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 Alloyed High-k-Based Resistive Switching Memory in Contact Hole Structures

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 451
Author(s):  
Byeongjeong Kim ◽  
Chandreswar Mahata ◽  
Hojeong Ryu ◽  
Muhammad Ismail ◽  
Byung-Do Yang ◽  
...  
Keyword(s):  
Resistive Switching ◽  
High Resistance ◽  
Random Access ◽  
High Resistance State ◽  
Memory Device ◽  
Resistive Random Access Memory ◽  
Long Term Memory ◽  
Pulse Input ◽  
Low Resistance ◽  
Resistance State

Resistive random-access memory (RRAM) devices are noticeable next generation memory devices. However, only few studies have been conducted regarding RRAM devices made of alloy. In this paper, we investigate the resistive switching behaviors of an Au/Ti/HfTiOx/p-Si memory device. The bipolar switching is characterized depending on compliance current under DC sweep mode. Good retention in the low-resistance state and high-resistance state is attained for nonvolatile memory and long-term memory in a synapse device. For practical switching operation, the pulse transient characteristics are studied for set and reset processes. Moreover, a synaptic weight change is achieved by a moderate pulse input for the potentiation and depression characteristics of the synaptic device. We reveal that the high-resistance state and low-resistance state are dominated by Schottky emissions.

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.

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.

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