Browsing by Author "Chen, Hsin-Lu"

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An Electronic Synapse Device Based on Solid Electrolyte Resistive Random Access Memory
(2015-08-01)
Zhang, Wei
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Hu, Ying
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Chang, Ting-Chang
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Chang, Kuan-Chang
;
Tsai, Tsung-Ming
The multilevel capability of solid electrolyte resistive random access memory (RRAM) with a Pt/GeSO/TiN structure was explored for potential use as a synapse device. By varying the cutoff voltage during the dc I-V cycles or the ac pulse programming voltage amplitudes, continuous multilevel conductance states were obtained. The reference Pt/GeO/TiN RRAM was fabricated to certify the multilevel capability and was due to the character of the GeS solid electrolyte. Finally, the property of gradual conductance states was exploited to demonstrate spike-timing-dependent plasticity learning, which suggests device\'s potential for use as an electronic synapse device for neuromorphic systems.
Characterization of Oxygen Accumulation in Indium-Tin-Oxide for Resistance Random Access Memory
(2014-06-01)
Zhang, Rui
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Chang, Kuan-Chang
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Chang, Ting-Chang
;
Tsai, Tsung-Ming
;
Huang, Syuan-Yong
In this letter, we report the oxygen accumulation effect and its influence on resistive switching for gadolinium-doped silicon dioxide (Gd:SiO2) resistance random access memory (RRAM). We find that oxygen absorbance by indium-tin-oxide electrode affects the conduction current mechanism, and remarkably modifies the device performance of RRAM devices. By current fitting, Schottky emission can be observed in both low and high resistance states, from which conduction model is proposed to clarify the oxygen accumulation phenomenon. Reliability tests, including endurance and high temperature retention are further carried out, evaluating the significance of oxygen accumulation effect in redox reaction for RRAM devices.
Mechanism of power consumption inhibitive multi-layer Zn:SiO2/SiO2 structure resistance random access memory
(2013-12-21)
Zhang, Rui
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Tsai, Tsung-Ming
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Chang, Ting-Chang
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Chang, Kuan-Chang
;
Chen, Kai-Huang
In this paper, multi-layer Zn:SiO2/SiO2 structure is introduced to reduce the operation power consumption of resistive random access memory (RRAM) device by modifying the filament formation process. And the configuration of multi-layer Zn:SiO2/SiO2 structure is confirmed and demonstrated by auger electron spectrum. Material analysis together with conduction current fitting is applied to qualitatively evaluate the carrier conduction mechanism on both low resistance state and high resistance state. Finally, single layer and multilayer conduction models are proposed, respectively, to clarify the corresponding conduction characteristics of two types of RRAM devices. (C) 2013 AIP Publishing LLC.
Mechanism of Triple Ions Effect in GeSO Resistance Random Access Memory
(2015-06-01)
Zhang, Wei
;
Hu, Ying
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Chang, Ting-Chang
;
Tsai, Tsung-Ming
;
Chang, Kuan-Chang
In this letter, a triple-ion redox reaction has been proposed and investigated in GeSO-based resistance random access memory. Continuous multiresistance states can be obtained by applying a series of increasing cutoff voltages in both set and reset processes. Using data retention tests, these multistates in the set and reset processes were confirmed to be stable. The conduction mechanism gradually changed during reset process from space charge limited current to Schottky emission. A triple-ion reaction model has been proposed to reveal the chemical reaction properties in the resistive switching process.
Suppression of endurance degradation by applying constant voltage stress in one-transistor and one-resistor resistive random access memory
(2017-01-01)
Su, Yu-Ting
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Chang, Ting-Chang
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Tsai, Tsung-Ming
;
Chang, Kuan-Chang
;
Chu, Tian-Jian
In this letter we demonstrate an operation method that effectively suppresses endurance degradation. After many operations, the off-state of resistance random access memory (RRAM) degrades. This degradation is caused by reduction of active oxygen ions participating in the set process, as determined by current fitting of current-voltage (I-V) curves obtained from the endurance test between the interval of seventy to one hundred million operations. To address this problem, we propose the application of constant voltage stress after every five million operations during the endurance test. The experimental result shows that this method can maintain oxygen ions at the proper depth in the electrode and improve RRAM reliability. (c) 2017 The Japan Society of Applied Physics
The effect of high/low permittivity in bilayer HfO2/BN resistance random access memory
(2013-05-20)
Huang, Jen-Wei
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Zhang, Rui
;
Chang, Ting-Chang
;
Tsai, Tsung-Ming
;
Chang, Kuan-Chang
This letter investigated the electrical characteristics of resistance random access memory (RRAM) with HfO2/BN bilayer structures. By adopting the high/low permittivity structure, we obtained the excellent device characteristics such as uniform distribution of switching voltage and more stable resistance switching properties of RRAM. The current conduction mechanism of low resistance state in the HfO2/BN device was transferred to space-charge-limited current conduction from Ohmic conduction owing to space electric effect concentrated by the high/low permittivity bilayer structures. The electric field in the bilayer can be verified by COMSOL simulation software. (C) 2013 AIP Publishing LLC.
Tri-Resistive Switching Behavior of Hydrogen Induced Resistance Random Access Memory
(2014-02-01)
Chu, Tian-Jian
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Tsai, Tsung-Ming
;
Chang, Ting-Chang
;
Chang, Kuan-Chang
;
Zhang, Rui
In this letter, the special role of hydrogen ions in hafnium doped silicon oxide resistive random access memory (RRAM) is presented. In addition to the more typical oxygen ion-dominated resistive switching, hydrogen ions were also observed to trigger a resistance transformation phenomenon, producing a tri-resistive device. Unlike a normal RRAM device, a hydrogen plasma-treated device is operated with a reversed voltage polarity, and the direction of hydrogen ion migration results in the chemical bonds breaking and repairing. By changing the voltage polarity and stop voltage, this tri-resistive behavior can be achieved. This particular hydrogen-induced switching behavior suggests a different RRAM switching mechanism and is finally explained by our model.