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.

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

Metals ◽  
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.

scholarly journals Effects of top electrode material in hafnium-oxide-based memristive systems on highly-doped Si

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sueda Saylan ◽  
Haila M. Aldosari ◽  
Khaled Humood ◽  
Maguy Abi Jaoude ◽  
Florent Ravaux ◽  
...  
Keyword(s):  
Resistive Switching ◽  
Hafnium Oxide ◽  
Complementary Metal Oxide Semiconductor ◽  
Differential Resistance ◽  
Oxide Semiconductor ◽  
Bipolar Resistive Switching ◽  
Current Voltage ◽  
Device Structures ◽  
Memristive Systems ◽  
P Type

Abstract This work provides useful insights into the development of HfO2-based memristive systems with a p-type silicon bottom electrode that are compatible with the complementary metal–oxide–semiconductor technology. The results obtained reveal the importance of the top electrode selection to achieve unique device characteristics. The Ag/HfO2/Si devices have exhibited a larger memory window and self-compliance characteristics. On the other hand, the Au/HfO2/Si devices have displayed substantial cycle-to-cycle variation in the ON-state conductance. These device characteristics can be used as an indicator for the design of resistive-switching devices in various scenes such as, memory, security, and sensing. The current–voltage (I–V) characteristics of Ag/HfO2/Si and Au/HfO2/Si devices under positive and negative bias conditions have provided valuable information on the ON and OFF states of the devices and the underlying resistive switching mechanisms. Repeatable, low-power, and forming-free bipolar resistive switching is obtained with both device structures, with the Au/HfO2/Si devices displaying a poorer device-to-device reproducibility. Furthermore, the Au/HfO2/Si devices have exhibited N-type negative differential resistance (NDR), suggesting Joule-heating activated migration of oxygen vacancies to be responsible for the SET process in the unstable unipolar mode.

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.

scholarly journals Resistive Switching Characteristics of HfO2 Thin Films on Mica Substrates Prepared by Sol-Gel Process

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1124 ◽  
Author(s):  
Chao-Feng Liu ◽  
Xin-Gui Tang ◽  
Lun-Quan Wang ◽  
Hui Tang ◽  
Yan-Ping Jiang ◽  
...  
Keyword(s):  
Thin Films ◽  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Random Access ◽  
High Resistance State ◽  
X Ray ◽  
Low Resistance ◽  
Sol Gel Process ◽  
Resistance State

The resistive switching (RS) characteristics of flexible films deposited on mica substrates have rarely been reported upon, especially flexible HfO2 films. A novel flexible Au/HfO2/Pt/mica resistive random access memory device was prepared by a sol-gel process, and a Au/HfO2/Pt/Ti/SiO2/Si (100) device was also prepared for comparison. The HfO2 thin films were grown into the monoclinic phase by the proper annealing process at 700 °C, demonstrated by grazing-incidence X-ray diffraction patterns. The ratio of high/low resistance (off/on) reached 1000 and 50 for the two devices, respectively, being relatively stable for the former but not for the latter. The great difference in ratios for the two devices may have been caused by different concentrations of the oxygen defect obtained by the X-ray photoelectron spectroscopy spectra indicating composition and chemical state of the HfO2 thin films. The conduction mechanism was dominated by Ohm’s law in the low resistance state, while in high resistance state, Ohmic conduction, space charge limited conduction (SCLC), and trap-filled SCLC conducted together.

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 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 Switching Characteristics and Mechanism Using Al2O3 Interfacial Layer in Al/Cu/GdOx/Al2O3/TiN Memristor

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1466
Author(s):  
Chiao-Fan Chiu ◽  
Sreekanth Ginnaram ◽  
Asim Senapati ◽  
Yi-Pin Chen ◽  
Siddheswar Maikap
Keyword(s):  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
Interfacial Layer ◽  
Stable State ◽  
Schematic Model ◽  
Bipolar Resistive Switching ◽  
Al2o3 Layer ◽  
X Ray ◽  
Resistance State ◽  
Switching Characteristics

Resistive switching characteristics by using the Al2O3 interfacial layer in an Al/Cu/GdOx/Al2O3/TiN memristor have been enhanced as compared to the Al/Cu/GdOx/TiN structure owing to the insertion of Al2O3 layer for the first time. Polycrystalline grain, chemical composition, and surface roughness of defective GdOx film have been investigated by transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and atomic force microscopy (AFM). For bipolar resistive switching (BRS) characteristics, the conduction mechanism of high resistance state (HRS) is a space-charge limited current for the Al/Cu/GdOx/TiN device while the Al/Cu/GdOx/Al2O3/TiN device shows Schottky emission. However, both devices show Ohmic at a low resistance state (LRS). After the device has been SET, the Cu filament evidences by both TEM and elemental mapping. Oxygen-rich at the Cu/GdOx interface and Al2O3 layer are confirmed by energy dispersive X-ray spectroscopy (EDS) line profile. The Al/Cu/GdOx/Al2O3/TiN memristor has lower RESET current, higher speed operation of 100 ns, long read pulse endurance of >109 cycles, good data retention, and the memristor with a large resistance ratio of >105 is operated at a low current of 1.5 µA. The complementary resistive switching (CRS) characteristics of the Al/Cu/GdOx/Al2O3/TiN memristor show also a low current operation as compared to the Al/Cu/GdOx/TiN device (300 µA vs. 3.1 mA). The transport mechanism is the Cu ion migration and it shows Ohmic at low field and hopping at high field regions. A larger hopping distance of 1.82 nm at the Cu/GdOx interface is obtained as compared to a hopping distance of 1.14 nm in the Al2O3 layer owing to a larger Cu filament length at the Cu/GdOx interface than the Al2O3 layer. Similarly, the CRS mechanism is explained by using the schematic model. The CRS characteristics show a stable state with long endurance of >1000 cycles at a pulse width of 1 µs owing to the insertion of Al2O3 interfacial layer in the Al/Cu/GdOx/Al2O3/TiN structure.

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 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.

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