Browsing by Author "Wang, Sheng-Yi"

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Effect of thermal treatment on resistive switching characteristics in Pt/Ti/Al(2)O(3)/Pt devices
(2008-12-25)
Lin, Chih-Yang
;
Lee, Dai-Ying
;
Wang, Sheng-Yi
;
Lin, Chun-Chieh
;
Tseng, Tseung-Yuen
Resistive switching characteristics of Pt/Ti/Al(2)O(3)/Pt memory devices annealed at various temperatures including 400 degrees C, 500 degrees C and 600 degrees C for 1 h under ambient condition were investigated in the study. The Al(2)O(3) thin films annealed at up to 600 degrees C for 1 h remain amorphous phase based on the X-ray diffraction (XRD) analyses. As increasing annealing temperature, the forming voltage (activating the pristine device) of the memory device decreases in contrast to the rising trend of the turn-on voltage (switching from high to low resistance state). However, the turn-off voltage (switching from low to high resistance state) is almost uninfluenced by thermal annealing. These phenomena might be attributed to the interdiffusion between Ti and Al(2)O(3), based on the analyzed results of secondary ion mass spectroscopy (SIMS) and high resolution transmission electron microscope (HR-TEM). Moreover, the thermal annealing process eventually creates high conducting paths with a high density of oxygen vacancies between the two electrodes. (c) 2008 Elsevier B.V. All rights reserved.
Effect of thermal treatment on resistive switching characteristics in Pt/Ti/Al2O3/Pt devices
(2008-12-25)
Lin, Chih-Yang
;
Lee, Dai-Ying
;
Wang, Sheng-Yi
;
Lin, Chun-Chieh
;
Tseng, Tseung-Yuen
Resistive switching characteristics of Pt/Ti/Al2O3/Pt memory devices annealed at various temperatures including 400 degrees C, 500 degrees C and 600 degrees C for 1 h under ambient condition were investigated in the study. The Al2O3 thin films annealed at up to 600 degrees C for 1 h remain amorphous phase based on the X-ray diffraction (XRD) analyses. As increasing annealing temperature, the forming voltage (activating the pristine device) of the memory device decreases in contrast to the rising trend of the turn-on voltage (switching from high to low resistance state). However, the turn-off voltage (switching from low to high resistance state) is almost uninfluenced by thermal annealing. These phenomena might be attributed to the interdiffusion between Ti and Al2O3, based on the analyzed results of secondary ion mass spectroscopy (SIMS) and high resolution transmission electron microscope (HR-TEM). Moreover, the thermal annealing process eventually creates high conducting paths with a high density of oxygen vacancies between the two electrodes. (c) 2008 Elsevier B.V. All rights reserved.
Electrical properties and fatigue behaviors of ZrO(2) resistive switching thin films
(2008-01-01)
Lin, Chih-Yang
;
Wang, Sheng-Yi
;
Lee, Dai-Ying
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
The resistive switching mechanisms of ZrO(2) memory films are proposed to explain why resistive switching characteristics of Ti/ZrO(2)/Pt device are more stable than those of Pt/ZrO(2)/Pt and Al/ZrO(2)/Pt devices in this study. Different from the Pt/ZrO(2)/Pt and the Al/ZrO(2)/Pt devices, the carrier conduction mechanisms in the Ti/ZrO(2)/Pt device obey space charge limited current theory, which may be caused by the formation of the interface layer between Ti and ZrO(2). Moreover, the resistive switching mechanisms are proposed to be related to the filament formation/rupture theory and oxygen ion migration. The location where filament formation/rupture takes place should be confined near the interface between Ti and ZrO(2), leading to the stable resistive switching characteristics and a better endurance performance. During successive resistive cycles at room temperature and 150 degrees C, the fatigue behaviors are observed due to the degradation of both two memory states, which might be related to the transformation of the interface layers between Ti and ZrO(2) and the coalescence of ZrO(x) clusters. (C) 2008 The Electrochemical Society.
Electrical properties and fatigue behaviors of ZrO2 resistive switching thin films
(2008-01-01)
Lin, Chih-Yang
;
Wang, Sheng-Yi
;
Lee, Dai-Ying
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
The resistive switching mechanisms of ZrO2 memory films are proposed to explain why resistive switching characteristics of Ti/ZrO2/Pt device are more stable than those of Pt/ZrO2/Pt and Al/ZrO2/Pt devices in this study. Different from the Pt/ZrO2/Pt and the Al/ZrO2/Pt devices, the carrier conduction mechanisms in the Ti/ZrO2/Pt device obey space charge limited current theory, which may be caused by the formation of the interface layer between Ti and ZrO2. Moreover, the resistive switching mechanisms are proposed to be related to the filament formation/rupture theory and oxygen ion migration. The location where filament formation/rupture takes place should be confined near the interface between Ti and ZrO2, leading to the stable resistive switching characteristics and a better endurance performance. During successive resistive cycles at room temperature and 150 degrees C, the fatigue behaviors are observed due to the degradation of both two memory states, which might be related to the transformation of the interface layers between Ti and ZrO2 and the coalescence of ZrOx clusters. (C) 2008 The Electrochemical Society.
Reproducible resistive switching behavior in sputtered CeO(2) polycrystalline films
(2008-12-25)
Lin, Chih-Yang
;
Lee, Dai-Ying
;
Wang, Sheng-Yi
;
Lin, Chun-Chieh
;
Tseng, Tseung-Yuen
Sputter-deposited CeO(2) film in the metal-insulator-metal structure exhibits repeatable resistive switching behavior under voltage sweep. Based on the X-ray diffraction patterns and the cross-sectional scanning electron microscope image, the CeO(2) film is polycrystalline with columnar grains perpendicular to the bottom electrode. Moreover, due to the symmetric device structure of Pt/CeO(2)/Pt, the resistive switching behavior is independent of bias polarity so that both positive and negative voltages can switch the device from high conducting state (ON-state) into low conducting state (OFF-state) and then back to ON-state, which is named non-polar resistive switching. The resistance ratio between two memory states is about five orders of magnitude, which is stable over 10(4) S at 0.3 V stress. in addition, the resistance ratio decreases with increasing the current compliance during forming process. The stability of ON-state, OFF-state, and as-deposited film state (the state before performing forming process) against temperature is also investigated in this study, showing that the OFF-state is less stable. (C) 2008 Elsevier B.V. All rights reserved.
Reproducible resistive switching behavior in sputtered CeO2 polycrystalline films
(2008-12-25)
Lin, Chih-Yang
;
Lee, Dai-Ying
;
Wang, Sheng-Yi
;
Lin, Chun-Chieh
;
Tseng, Tseung-Yuen
Sputter-deposited CeO2 film in the metal-insulator-metal structure exhibits repeatable resistive switching behavior under voltage sweep. Based on the X-ray diffraction patterns and the cross-sectional scanning electron microscope image, the CeO2 film is polycrystalline with columnar grains perpendicular to the bottom electrode. Moreover, due to the symmetric device structure of Pt/CeO2/Pt, the resistive switching behavior is independent of bias polarity so that both positive and negative voltages can switch the device from high conducting state (ON-state) into low conducting state (OFF-state) and then back to ON-state, which is named non-polar resistive switching. The resistance ratio between two memory states is about five orders of magnitude, which is stable over 10(4) S at 0.3 V stress. in addition, the resistance ratio decreases with increasing the current compliance during forming process. The stability of ON-state, OFF-state, and as-deposited film state (the state before performing forming process) against temperature is also investigated in this study, showing that the OFF-state is less stable. (C) 2008 Elsevier B.V. All rights reserved.