scholarly journals Bipolar and Complementary Resistive Switching Characteristics and Neuromorphic System Simulation in a Pt/ZnO/TiN Synaptic Device

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 315 ◽  
Author(s):  
Sobia Ali Khan ◽  
Geun Ho Lee ◽  
Chandreswar Mahata ◽  
Muhammad Ismail ◽  
Hyungjin Kim ◽  
...  
Keyword(s):  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
Recognition Rate ◽  
Long Term Potentiation ◽  
Memory Device ◽  
Chemical Information ◽  
Bipolar Resistive Switching ◽  
Cross Point ◽  
Pulse Input

In this work, a ZnO-based resistive switching memory device is characterized by using simplified electrical conduction models. The conventional bipolar resistive switching and complementary resistive switching modes are accomplished by tuning the bias voltage condition. The material and chemical information of the device stack including the interfacial layer of TiON is well confirmed by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analysis. The device exhibits uniform gradual bipolar resistive switching (BRS) with good endurance and self-compliance characteristics. Moreover, complementary resistive switching (CRS) is achieved by applying the compliance current at negative bias and increasing the voltage at positive bias. The synaptic behaviors such as long-term potentiation and long-term depression are emulated by applying consecutive pulse input to the device. The CRS mode has a higher array size in the cross-point array structure than the BRS mode due to more nonlinear I–V characteristics in the CRS mode. However, we reveal that the BRS mode shows a better pattern recognition rate than the CRS mode due to more uniform conductance update.

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 Demonstration of Threshold Switching and Bipolar Resistive Switching in Ag/SnOx/TiN Memory Device

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1605
Author(s):  
Jooyoung Pyo ◽  
Seungjin Woo ◽  
Kisong Lee ◽  
Sungjun Kim
Keyword(s):  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
Pulse Amplitude ◽  
Memory Device ◽  
Gradual Transition ◽  
Bipolar Resistive Switching ◽  
Memory Switching ◽  
Threshold Switching ◽  
Non Volatile Memory ◽  
Multiple Pulses

In this work, we observed the duality of threshold switching and non-volatile memory switching of Ag/SnOx/TiN memory devices by controlling the compliance current (CC) or pulse amplitude. The insulator thickness and chemical analysis of the device stack were confirmed by transmission electron microscope (TEM) images of the Ag/SnOx/TiN stack and X-ray photoelectron spectroscopy (XPS) of the SnOx film. The threshold switching was achieved at low CC (50 μA), showing volatile resistive switching. Optimal CC (5 mA) for bipolar resistive switching conditions with a gradual transition was also found. An unstable low-resistance state (LRS) and negative-set behavior were observed at CCs of 1 mA and 30 mA, respectively. We also demonstrated the pulse operation for volatile switching, set, reset processes, and negative-set behaviors by controlling pulse amplitude and polarity. Finally, the potentiation and depression characteristics were mimicked by multiple pulses, and MNIST pattern recognition was calculated using a neural network, including the conductance update for a hardware-based neuromorphic system.

scholarly journals Resistive Switching Characteristics of Li-Doped ZnO Thin Films Based on Magnetron Sputtering

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1282 ◽  
Author(s):  
Zhao ◽  
Li ◽  
Ai ◽  
Wen
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
Lattice Structure ◽  
Zno Thin Films ◽  
Bipolar Resistive Switching ◽  
X Ray ◽  
Doped Zno ◽  
Switching Characteristics

A kind of devices Pt/Ag/ZnO:Li/Pt/Ti with high resistive switching behaviors were prepared on a SiO2/Si substrate by using magnetron sputtering method and mask technology, composed of a bottom electrode (BE) of Pt/Ti, a resistive switching layer of ZnO:Li thin film and a top electrode (TE) of Pt/Ag. To determine the crystal lattice structure and the Li-doped concentration in the resulted ZnO thin films, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) tests were carried out. Resistive switching behaviors of the devices with different thicknesses of Li-doped ZnO thin films were studied at different set and reset voltages based on analog and digital resistive switching characteristics. At room temperature, the fabricated devices represent stable bipolar resistive switching behaviors with a low set voltage, a high switching current ratio and a long retention up to 104 s. In addition, the device can sustain an excellent endurance more than 103 cycles at an applied pulse voltage. The mechanism on how the thicknesses of the Li-doped ZnO thin films affect the resistive switching behaviors was investigated by installing conduction mechanism models. This study provides a new strategy for fabricating the resistive random access memory (ReRAM) device used in practice.

A new opportunity for the emerging tellurium semiconductor: resistive switching device implementation

2021 ◽  
Author(s):  
Yifei Yang ◽  
Mingkun Xu ◽  
Lujie Xu ◽  
Xinxin Wang ◽  
Huan Liu ◽  
...  
Keyword(s):  
Data Storage ◽  
Resistive Switching ◽  
High Performance ◽  
Visual Recognition ◽  
Stimulus Frequency ◽  
Dielectric Materials ◽  
Cross Point ◽  
Electrochemically Active ◽  
Event Based

Abstract The electrochemical (EC) resistive switching (RS) cross-point arrays, composed of nonvolatile RS (NV-RS) memories and volatile RS (V-RS) selectors, hold promise for high-density data storage, in-memory computing and neuromorphic computing. However, the conventional EC-RS devices based on metallic filaments suffer from the notorious current-volatility dilemma that the low and high current requirements for NV-RS memories and V-RS selectors, respectively, cannot be satisfied simultaneously, due to the dominant EC nature of the RS. In this work, we demonstrate electrochemically active, low thermal-conductivity and low melting-temperature semiconducting tellurium filament-based RS devices that solve this dilemma, enabling NV-RS memories to operate under lower currents than do V-RS selectors. This novel phenomenon arises as the consequence of the adversarial EC and Joule heating (JH) effects. The devices also show unusual stimulus frequency dependent long-term plasticity (LTP)-to-short-term plasticity (STP) transition. Devices with this property can be generically utilized as spatial-temporal filters in spiking neural networks (SNNs) for high-performance event-based visual recognition tasks, as illustrated in our noise filtering simulations. By regulating the EC-JH relationship using dielectric materials with decreasing thermal conductivities, full functional-range tunable Te filament-based devices, from always-NV RS, to NV-to-V transitionable RS, and to always-V RS, are also demonstrated. The tellurium filament-based RS devices are promising enablers for functional cross-point arrays.

scholarly journals Improved Stability and Controllability in ZrN-Based Resistive Memory Device by Inserting TiO2 Layer

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 905
Author(s):  
Junhyeok Choi ◽  
Sungjun Kim
Keyword(s):  
Data Storage ◽  
Resistive Switching ◽  
Memory Device ◽  
Comparison Study ◽  
Tio2 Layer ◽  
Bipolar Resistive Switching ◽  
Resistive Switching Memory ◽  
Current Voltage ◽  
Improved Stability ◽  
Switching Characteristics

In this work, the enhanced resistive switching of ZrN-based resistive switching memory is demonstrated by embedding TiO2 layer between Ag top electrode and ZrN switching layer. The Ag/ZrN/n-Si device exhibits unstable resistive switching as a result of the uncontrollable Ag migration. Both unipolar and bipolar resistive switching with high RESET current were observed. Negative-SET behavior in the Ag/ZrN/n-Si device makes set-stuck, causing permanent resistive switching failure. On the other hand, the analogue switching in the Ag/TiO2/ZrN/n-Si device, which could be adopted for the multi-bit data storage applications, is obtained. The gradual switching in Ag/TiO2/ZrN/n-Si device is achieved, possibly due to the suppressed Ag diffusion caused by TiO2 inserting layer. The current–voltage (I–V) switching characteristics of Ag/ZrN/n-Si and Ag/TiO2/ZrN/n-Si devices can be well verified by pulse transient. Finally, we established that the Ag/TiO2/ZrN/n-Si device is suitable for neuromorphic application through a comparison study of conductance update. This paper paves the way for neuromorphic application in nitride-based memristor devices.

A synaptic device built in one diode–one resistor (1D–1R) architecture with intrinsic SiOx-based resistive switching memory

2016 ◽  
Vol 1 (4) ◽  
Author(s):  
Yao-Feng Chang ◽  
Burt Fowler ◽  
Ying-Chen Chen ◽  
Fei Zhou ◽  
Chih-Hung Pan ◽  
...  
Keyword(s):  
Resistive Switching ◽  
Silicon Oxide ◽  
Complementary Metal Oxide Semiconductor ◽  
Long Term Potentiation ◽  
Spike Timing ◽  
Oxide Semiconductor ◽  
Resistive Switching Memory ◽  
Term Potentiation ◽  
Switching Memory

Abstract We realize a device with biological synaptic behaviors by integrating silicon oxide (SiOx) resistive switching memory with Si diodes to further minimize total synaptic power consumption due to sneak-path currents and demonstrate the capability for spike-induced synaptic behaviors, representing critical milestones for the use of SiO2-based materials in future neuromorphic computing applications. Biological synaptic behaviors such as long-term potentiation, long-term depression, and spike-timing dependent plasticity are demonstrated systemically with comprehensive investigation of spike waveform analyses and represent a potential application for SiOx-based resistive switching materials. The resistive switching SET transition is modeled as hydrogen (proton) release from the (SiH)2 defect to generate the hydrogenbridge defect, and the RESET transition is modeled as an electrochemical reaction (proton capture) that re-forms (SiH)2. The experimental results suggest a simple, robust approach to realize programmable neuromorphic chips compatible with largescale complementary metal-oxide semiconductor manufacturing technology.

Zinc Oxide and IGZO Bi-layer Synaptic Device with Highly Linear Long-term Potentiation and Depression Characteristics

2021 ◽  
Author(s):  
Hyun-Woong Choi ◽  
Ki-Woo Song ◽  
Seong-Hyun Kim ◽  
Nguyen Kim Thanh ◽  
Sunil Babu Eadi ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Electrical Properties ◽  
Oxygen Vacancy ◽  
Photoelectron Spectroscopy ◽  
Long Term Potentiation ◽  
Switching Behavior ◽  
Reset Voltage ◽  
Term Potentiation ◽  
Resistance State

Abstract The electrical properties, resistive switching behavior, and long-term potentiation/depression (LTP/LTD) in a single indium-gallium-zinc-oxide (IGZO) and bi-layer IGZO/ZnO memristors were investigated for synapse application. The use of oxide bi-layer memristor, in particular, improved electrical properties such as stability, reliability of memristors, and increase in the synaptic weight states. Bi-layer IGZO/ZnO memristors had a set voltage of 0.9 V, and reset voltage around -0.7 V, resulting in low-power consumption for neuromorphic systems. The oxygen vacancies in X-ray photoelectron spectroscopy analysis played a role in the modulation of the high-resistance state (HRS) (oxygen-deficient) and the low-resistance state (oxygen-rich) region. The VRESET of bi-layer IGZO/ZnO memristors was lower than that of a single IGZO, which implied that oxygen vacancy filaments could be easily ruptured due to the higher oxygen vacancy peak HRS layer. The nonlinearity of LTP and LTD characteristics in a bi-layer IGZO/ZnO memristor was 6.77% and 11.49%, respectively, compared to those of 20.03% and 51.1% in a single IGZO memristor, respectively. Therefore, the extra ZnO layer in the bi-layer memristor with IGZO was potentially significant and essential to achieve a small set voltage and a reset voltage, and the switching behavior to form the conductive path.

Sign in / Sign up

Export Citation Format

Share Document