Effect of interlayer on resistive switching properties of SnO2-based memristor for synaptic application

2020

Nanomaterials

Self Cite

In this work, we propose three types of resistive switching behaviors by controlling operation conditions. We confirmed well-known filamentary switching in Al2O3-based resistive switching memory using the conventional device working operation with a forming process. Here, filamentary switching can be classified into two types depending on the compliance current. On top of that, the homogeneous switching is obtained by using a negative differential resistance effect before the forming or setting process in a negative bias. The variations of the low-resistance and high-resistance states in the homogeneous switching are comparable to the filamentary switching cases. However, the drift characteristics of the low-resistance and high-resistance states in the homogeneous switching are unstable with time. Therefore, the short-term plasticity effects, such as the current decay in repeated pulses and paired pulses facilitation, are demonstrated when using the resistance drift characteristics. Finally, the conductance can be increased and decreased by 50 consecutive potentiation pulses and 50 consecutive depression pulses, respectively. The linear conductance update in homogeneous switching is achieved compared to the filamentary switching, which ensures the high pattern-recognition accuracy.

Section: Resultsmentioning

confidence: 99%

Synaptic Characteristics from Homogeneous Resistive Switching in Pt/Al2O3/TiN Stack

Ryu

2020

Nanomaterials

Self Cite

“…The peak binding energies of Ti 2p 3/2 and Ti 2p 1/2 are located at approximately 458.94 eV and 464.5 eV for Ti-O bonds [30]. However, the peak binding energies of Ti 2p 3/2 and Ti 2p 1/2 are found at approximately 454.92 eV and 460.93 eV for Ti-N bonds [31]. Figure 1d shows the Hf 4f spectra at an etch level of 9.…”

Section: Resultsmentioning

confidence: 98%

Gradually Modified Conductance in Self-Compliance Region of Atomic-Layer-Deposited Pt/TiO2/HfAlO x /TiN RRAM Device

Ryu

2021

Preprint

Self Cite

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.

“…This switching occurs because of the formation and rupture of a localized conducting filament. The TiN electrode as a reactive metal can form a TiON interfacial layer, which provides better resistive switching when a positive bias is applied on the TiN electrode [43]. On the other hand, a gradual resistance change is seen in the TiN/TiO 2 /WO x /Pt devices without electroforming in Figure 2.…”

Section: Resultsmentioning

confidence: 99%

Enhancing Short-Term Plasticity by Inserting a Thin TiO2 Layer in WOx-Based Resistive Switching Memory

Cho

2020

Coatings

Self Cite

In this work, we emulate biological synaptic properties such as long-term plasticity (LTP) and short-term plasticity (STP) in an artificial synaptic device with a TiN/TiO2/WOx/Pt structure. The graded WOx layer with oxygen vacancies is confirmed via X-ray photoelectron spectroscopy (XPS) analysis. The control TiN/WOx/Pt device shows filamentary switching with abrupt set and gradual reset processes in DC sweep mode. The TiN/WOx/Pt device is vulnerable to set stuck because of negative set behavior, as verified by both DC sweep and pulse modes. The TiN/WOx/Pt device has good retention and can mimic long-term memory (LTM), including potentiation and depression, given repeated pulses. On the other hand, TiN/TiO2/WOx/Pt devices show non-filamentary type switching that is suitable for fine conductance modulation. Potentiation and depression are demonstrated in the TiN/TiO2 (2 nm)/WOx/Pt device with moderate conductance decay by application of identical repeated pulses. Short-term memory (STM) is demonstrated by varying the interval time of pulse inputs for the TiN/TiO2 (6 nm)/WOx/Pt device with a quick decay in conductance.