Flexible Memory Device Composed of Metal-Oxide and Two-Dimensional Material (SnO2/WTe2) Exhibiting Stable Resistive Switching

Two-terminal, non-volatile memory devices are the fundamental building blocks of memory-storage devices to store the required information, but their lack of flexibility limits their potential for biological applications. After the discovery of two-dimensional (2D) materials, flexible memory devices are easy to build, because of their flexible nature. Here, we report on our flexible resistive-switching devices, composed of a bilayer tin-oxide/tungsten-ditelluride (SnO2/WTe2) heterostructure sandwiched between Ag (top) and Au (bottom) metal electrodes over a flexible PET substrate. The Ag/SnO2/WTe2/Au flexible devices exhibited highly stable resistive switching along with an excellent retention time. Triggering the device from a high-resistance state (HRS) to a low-resistance state (LRS) is attributed to Ag filament formation because of its diffusion. The conductive filament begins its development from the anode to the cathode, contrary to the formal electrochemical metallization theory. The bilayer structure of SnO2/WTe2 improved the endurance of the devices and reduced the switching voltage by up to 0.2 V compared to the single SnO2 stacked devices. These flexible and low-power-consumption features may lead to the construction of a wearable memory device for data-storage purposes.

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HfOx Thin Films for Resistive Memory Device by Use of Atomic Layer Deposition

MRS Proceedings ◽

10.1557/proc-0997-i07-04 ◽

2007 ◽

Vol 997 ◽

Cited By ~ 2

Author(s):

Pang Shiu Chen ◽

Heng-Yuan Lee ◽

Ching-Chiun Wang ◽

Ming-Jinn Tsai ◽

Kou-Chen Liu

Keyword(s):

Hafnium Oxide ◽

Random Access ◽

Chemical Vapor ◽

Atomic Layer ◽

High Resistance State ◽

Memory Device ◽

Soft Error ◽

Memory Devices ◽

Resistance State ◽

Switching Characteristics

AbstractThe materials properties and resistance switching characteristics of hafnium oxide-based binary oxide were investigated for next generation memory device application. A nonstoichometric hafnium oxide (HfOx) film with a mixture structure of monoclinic and tetragonal phase and some metallic Hf-Hf bonds on TiN/Si were prepared by atomic layer chemical vapor deposition (ALCVD). Resistance random access memory devices consisting of Pt/HfOx/TiN/Si with low power operation (< 0.4 mW) and reset current (< 100 mA) were fabricated. The resistance ratio of high resistance state to low resistance state maintains 100∼1000 and after 1000 cycles of repetitively switching. A 1-nm-thick Al2O3 film in the interface between top electrode and HfOx films, the Pt/Al2O3/HfOx/TiN/Si memory devices were found that soft-error of set and reset process often occurred. Interface states in the anode side play an important role in maintaining a stable resistive switching for HfOx-based memory devices.

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Building resistive switching memory having super-steep switching slope with in-plane boron nitride

Nanotechnology ◽

10.1088/1361-6528/ac4289 ◽

2021 ◽

Author(s):

Yisen Wang ◽

Zhifang Huang ◽

Xinyi Chen ◽

Miao Lu

Keyword(s):

Boron Nitride ◽

Metal Ions ◽

Resistive Switching ◽

Hexagonal Boron Nitride ◽

High Resistance State ◽

Two Dimensional ◽

Horizontal Structure ◽

Metal Insulator Metal ◽

Resistance State ◽

Pass Through

Abstract The two-dimensional hexagonal boron nitride (h-BN) has been used as resistive switching (RS) material for memory due to its insulation, good thermal conductivity and excellent thermal/chemical stability. A typical h-BN based RS memory employs a Metal-Insulator-Metal (MIM) vertical structure, in which metal ions pass through the h-BN layers to realize the transition from high resistance state (HRS) to low resistance state (LRS). Alternatively, just like the horizontal structure widely used in the traditional MOS capacitor based memory, the performance of in-plane h-BN memory should also be evaluated to determine its potential applications. As consequence, a horizontal structured resistive memory has been designed in this work by forming freestanding h-BN across Ag nanogap, where the two-dimensional h-BN favored in-plane transport of metal ions to emphasize the RS behavior. As a result, the memory devices showed switching slope down to 0.25 mV/dec, ON/OFF ratio up to 1E8, SET current down to pA and SET voltage down to 180 mV.

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

Applied Sciences ◽

10.3390/app10103506 ◽

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.

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Resistive Switching Characteristics of a SiOxLayer with CF4Plasma Treatment

Journal of Nanomaterials ◽

10.1155/2014/703463 ◽

2014 ◽

Vol 2014 ◽

pp. 1-5 ◽

Cited By ~ 2

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.

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

Coatings ◽

10.3390/coatings11040451 ◽

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.

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Resistive Switching Characteristics in Boron Doped Zinc Oxide Films

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.764-765.87 ◽

2015 ◽

Vol 764-765 ◽

pp. 87-91

Author(s):

Fu Chien Chiu

Keyword(s):

Zinc Oxide ◽

Resistive Switching ◽

Current Density ◽

Nonvolatile Memory ◽

High Resistance State ◽

Switching Behavior ◽

Memory Devices ◽

Boron Doped ◽

Resistance State ◽

Increasing Temperature

In this work, metal/oxide/metal capacitors were fabricated and investigated using transparent boron-doped zinc oxide (ZnO:B) films for nonvolatile memory applications. Both top and bottom electrodes are tungsten. The average value of transmittance of ZnO:B films grown on silicon substrates is found to be about 91% in the visible light region. According to the relationship between transmittance and wavelength, the optical band gap of ZnO:B films is determined to be about 3.26 eV. The temperature dependent current-voltage curves show that the current density increases with increasing temperature in low-resistance state (LRS), meanwhile, the current density decreases with increasing temperature in high-resistance state (HRS). From the resistive switching behavior of the W/ZnO:B/W memory devices, the reset voltage which triggers the memory devices from an LRS to an HRS is independent of temperature. On the other hand, the set voltage which triggers the memory devices from an HRS to an LRS is increased with temperature.

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Possible application of lead sulfide quantum dot in memory device

Journal of Polymer Engineering ◽

10.1515/polyeng-2015-0115 ◽

2016 ◽

Vol 36 (3) ◽

pp. 293-297 ◽

Cited By ~ 1

Author(s):

Sweety Sarma

Keyword(s):

Resistive Switching ◽

Coulomb Blockade ◽

Conduction Mechanism ◽

Hysteresis Loops ◽

High Resistance State ◽

Memory Device ◽

Switching Behavior ◽

Resistive Switching Behavior ◽

Resistance State ◽

Unipolar Resistive Switching

Abstract Unipolar resistive switching behavior was observed in the as-fabricated Al/PVA/PbS QD/ITO device with ROFF/RON ratio of 3.15×103 with retentivity for prolonged time and repeatability of hysteresis loops. Schottky emission mechanism dominates conduction mechanism in low-resistance state and high-resistance state of the device. Unipolar resistive switching behavior observed in the device is attributed to Coulomb blockade. The observed characteristic in the device points toward possible application of PbS QDs in memory device.

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Low-Frequency 1/f Noise Characteristics of Ultra-Thin AlOx-Based Resistive Switching Memory Devices with Magneto-Resistive Responses

Electronics ◽

10.3390/electronics10202525 ◽

2021 ◽

Vol 10 (20) ◽

pp. 2525

Author(s):

Jhen-Yong Hong ◽

Chun-Yen Chen ◽

Dah-Chin Ling ◽

Isidoro Martínez ◽

César González-Ruano ◽

...

Keyword(s):

Resistive Switching ◽

Empirical Relation ◽

Low Frequency ◽

High Resistance State ◽

Noise Power ◽

Memory Devices ◽

Noise Power Spectral Density ◽

Noise Characteristics ◽

Wide Range ◽

Resistance State

Low-frequency 1/f voltage noise has been employed to probe stochastic charge dynamics in AlOx-based non-volatile resistive memory devices exhibiting both resistive switching (RS) and magneto-resistive (MR) effects. A 1/fγ noise power spectral density is observed in a wide range of applied voltage biases. By analyzing the experimental data within the framework of Hooge’s empirical relation, we found that the Hooge’s parameter α and the exponent γ exhibit a distinct variation upon the resistance transition from the low resistance state (LRS) to the high resistance state (HRS), providing strong evidence that the electron trapping/de-trapping process, along with the electric field-driven oxygen vacancy migration in the AlOx barrier, plays an essential role in the charge transport dynamics of AlOx-based RS memory devices.

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Functional Gradient Transparent Conducting Oxide Nanowire Arrays as Monophasic Schottky-Barrier Free Memristors for Bipolar Linear Switching

10.26434/chemrxiv.11866062.v1 ◽

2020 ◽

Author(s):

Thomas Herzog ◽

Naomi Weitzel ◽

Sebastian Polarz

Keyword(s):

Schottky Barrier ◽

Data Storage ◽

Tin Oxide ◽

Transparent Conducting Oxide ◽

Electrical Potential ◽

High Resistance State ◽

Nanowire Arrays ◽

Metal Metal ◽

Resistance State ◽

Barrier Free

<div><div><div><p>One of the fascinating properties of metal-semiconductor Schottky-barriers, which has been observed for some material combinations, is memristive behavior. Memristors are smart, since they can reversibly switch between a low resistance state and a high resistance state. The devices offer a great potential for advanced computing and data storage, including neuromorphic networks and resistive random-access memory. However, as for many other cases, the presence of a real interface (metal - metal oxide) has numerous disadvantages. The realization of interface-free, respectively Schottky-barrier free memristors is highly desirable. The aim of the current paper is the generation of nanowire arrays with each nanorod possessing the same crystal phase (Rutile) and segments only differing in composition. The electric conductivity is realized by segments made of highly-doped antimony tin oxide (ATO) transitioning into pure tin oxide (TO). Complex nanoarchitectures are presented, which include ATO-TO, ATO-TO-ATO nanowires either with a stepwise distribution of antimony or as a graded functional material. The electrical characterization of the materials reveals that the introduction of memristive properties in such structures is possible. The special features observed in voltage-current (IV) curves are correlated to the behavior of mobile oxygen vacancies (VO..) at different values of applied electrical potential.</p></div></div></div>

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Gradually Modified Conductance in the Self-Compliance Region of an Atomic-Layer-Deposited Pt/TiO2/HfAlOx/TiN RRAM Device

Metals ◽

10.3390/met11081199 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1199

Author(s):

Hojeong Ryu ◽

Sungjun Kim

Keyword(s):

Photoelectron Spectroscopy ◽

Depth Profiling ◽

Atomic Layer ◽

High Resistance State ◽

Long Term Potentiation ◽

Memory Device ◽

Bipolar Resistive Switching ◽

Term Potentiation ◽

Resistance State ◽

Neuromorphic System

This study presents conductance modulation in a Pt/TiO2/HfAlOx/TiN resistive memory device in the compliance region for neuromorphic system applications. First, the chemical and material characteristics of the atomic-layer-deposited films were verified by X-ray photoelectron spectroscopy depth profiling. The low-resistance state was effectively controlled by the compliance current, and the high-resistance state was adjusted by the reset stop voltage. Stable endurance and retention in bipolar resistive switching were achieved. When a compliance current of 1 mA was imposed, only gradual switching was observed in the reset process. Self-compliance was used after an abrupt set transition to achieve a gradual set process. Finally, 10 cycles of long-term potentiation and depression were obtained in the compliance current region for neuromorphic system applications.

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