Browsing by Author "Wu, Chung-Wei"

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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
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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.
Incorporation of Resistive Random Access Memory into Low-Temperature Polysilicon Transistor with Fin-Like Structure as 1T1R Device
(1970-01-01)
Huang, Wei-Chen
;
Zheng, Hao-Xuan
;
Chen, Po-Hsun
;
Chang, Ting-Chang
;
Tan, Yung-Fang
In this study, a one transistor one resistor (1T1R) structure combining a fin-like low-temperature polycrystalline-silicon (LTPS) transistor and a resistive random access memory (RRAM) is successfully fabricated. For the fin-like LTPS transistor, both n-type and p-types show excellent electrical output characteristics. Fin-like structure produces more stable output characteristics. Also, the forming and current-voltage (I-V) characteristics are measured in this study, and the RRAM exhibits a forming voltage of about -1.9 V. As for the I-V switching property, the devices are stable and show excellent performance, with the set and reset voltages showing only minimal change over 100 cycles. Moreover, combining the fin-like LTPS transistor and RRAM into a 1T1R structure results in favorable operation over 100 cycles, with excellent retention and endurance. According to these results, RRAM can be successfully combined with a fin-like LTPS transistor for application in current integrated circuit processes without difficulty.
Investigation of the forming process under UV illumination in HfO2-based resistance random access memory with a transparent electrode
(2020-01-09)
Huang, Wei-Chen
;
Huang, Shin-Ping
;
Chen, Po-Hsun
;
Chen, Min-Chen
;
Chang, Ting-Chang
Traditionally, metal is used for the top electrode (TE) in HfO2-based resistance random access memory. When transparent indium-tin-oxide (ITO) is used as the TE, different forming processes, including lower forming voltages and higher forming currents, are exhibited. This work investigates the forming process with such a transparent TE under UV illumination. In addition, different TE thicknesses and device cell sizes are also investigated to confirm the results. Finally, a possible conduction model is provided to explain the mechanisms under UV-light illumination for the transparent TE during the forming process.