Browsing by Author "Sun, Li-Chuan"

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Abnormal High Resistive State Current Mechanism Transformation in Ti/HfO2/TiN Resistive Random Access Memory
(2020-02-01)
Zhou, Kuan-Ju
;
Chang, Ting-Chang
;
Lin, Chih-Yang
;
Chen, Chun-Kuei
;
Tseng, Yi-Ting
In this letter, the electrical characteristics of Ti/HfO2/TiN resistive random access memory (RRAM) were thoroughly investigated. An abnormal current degradation was seen in the DC sweeping cycle. Both the on-state and off-state current clearly exhibited degradation with time. Next, current fitting analysis was used to investigate the carrier transport mechanisms. The results indicate that the on-state carrier transport mechanism changed from space-charge-limited current into hopping conduction after cycle sweeping. However, the off-state current changes from Schottky thermal emission to hopping conduction. Based on comparisons of different Schottky distances and Schottky barriers, physical models were proposed to explain the abnormal current degradation behavior. Finally, COMSOL electric field simulations were used to show the electric field distribution around the conducting filament (CF), and the conducting model was subsequently verified.
Impact of electrode thermal conductivity on high resistance state level in HfO2-based RRAM
(2020-09-23)
Lin, Shih-Kai
;
Wu, Cheng-Hsien
;
Chen, Min-Chen
;
Chang, Ting-Chang
;
Lien, Chen-Hsin
This study examines the influence of different electrode thermal conductivity on switching behavior during the reset process. Electrical analysis methods and an analysis of current conduction mechanism indicate that better thermal conductivity in the electrode will require larger input power in order to induce more active oxygen ions to take part in the reset process. More active oxygen ions result in a more oxidized switching layer, and cause the effective switching gap (d(sw)) to become larger in the reset process. The effect of the electrode thermal conductivity and input power are explained by our model and clarified by electrical analysis methods.
The Effect of Humidity on Reducing Forming Voltage in Conductive-Bridge Random Access Memory With an Alloy Electrode
(2019-10-01)
Lin, Shih-Kai
;
Chen, Min-Chen
;
Chang, Ting-Chang
;
Lien, Chen-Hsin
;
Chang, Jing-Shuen
This letter investigates Au30Ag70 (alloy electrode)/SiO2/TiN conductive-bridge random access memory (CBRAM) to verify the influence of ambient conditions on forming voltage (V-F) and the location of galvanic reaction. Previous literature demonstrates that the galvanic reaction in CBRAM with an alloy electrode results in a lower V-F. In this work, a higher environmental H2O concentration results in a decrease in V-F. From this change in VF, we infer that environmental H2O concentration influences the amount of galvanic reaction. Moreover, we verify the location of the galvanic reaction by varying electrode thickness. Finally, we propose a physical model to explain our observations.