Browsing by Author "Lin, Chun-Chieh"

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Current status of resistive nonvolatile memories
(2008-12-01)
Lin, Chih-Yang
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Liu, Chih-Yi
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Lin, Chun-Chieh
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Tseng, T. Y.
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電子工程學系及電子研究所
Several emerging nonvolatile memories (NVMs) such as ferroelectric memory, magnetoresistive rams and ovonic universal memory are being developed for possible applications. Resistive random access memory (RRAM) is another interesting competitor in the class of NVMs. The RRAM is based on a large change in electrical resistance when the memory film is exposed to voltage or current pulses, and can keep high or low resistance states without any power. The ideal RRAM Should have the superior properties of reversible switching, long retention tune, multilevel switching, simple structure, small size, and low operating voltage. Perovskite oxides, transition metal oxides, and molecular materials were found to have resistive memory properties. This presentation reviews the ongoing research and development activities on future resistance NVMs technologies incorporating these new memory materials. The possible basic mechanisms for their bistable resistance switching are described. The effect of processing, composition, and structure on the properties of resistive memory materials and consequently the devices are discussed.
Effect of thermal treatment on resistive switching characteristics in Pt/Ti/Al(2)O(3)/Pt devices
(2008-12-25)
Lin, Chih-Yang
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Lee, Dai-Ying
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Wang, Sheng-Yi
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Lin, Chun-Chieh
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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
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Lee, Dai-Ying
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Wang, Sheng-Yi
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Lin, Chun-Chieh
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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.
Effect of Top Electrode Materials on the Nonvolatile Resistive Switching Characteristics of CCTO Films
(2011-03-01)
Lin, Chun-Chieh
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Chang, Yi-Peng
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Ho, Chia-Cheng
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Shen, Yu-Shu
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Chiou, Bi-Shiou
A novel material CaCu(3)Ti(4)O(12) (CCTO) for resistive random access memory (RRAM) application was prepared by sol-gel spin-coating method. Our previous studies indicated that the CCTO possesses stable resistive switching behavior. In this work, the effects of the top electrode (TE) material on the resistive switching characteristics of CCTO films are investigated. It indicates the work function of the TE is an important factor on the resistive switching properties. Successive resistive switching was observed for electrode materials of Ni, Pd, and Pt. Furthermore, optimized consideration of the electrode material for RRAM is also studied.
Improved resistive switching properties of Ti/ZrO(2)/Pt memory devices for RRAM application
(2011-07-01)
Wang, Sheng-Yu
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Tsai, Chen-Han
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Lee, Dai-Ying
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Lin, Chih-Yang
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Lin, Chun-Chieh
In this study, we have investigated the effect of current compliance during forming process on resistive switching (RS) characteristics of the Ti/ZrO(2)/Pt device. The higher the current compliance is, the larger RS operation voltage is needed. The Ti/ZrO(2)/Pt device with high device yield can be operated over 10,000 RS cycles by sweeping dc voltage. and the on and off two memory states exhibit good stability under 0.3 V stress voltage. Moreover, the data retention of both memory states is over 10(5) s. As applying +6-V 10-ns and -3-V 10-ns voltage pulses on the device, there are operation errors observed during continuous write-read-erase-read cycles until increasing the pulse width to 50 ns. Nondestructive readout tests are also performed on the Ti/ZrO(2)/Pt device before and after 10(3) pulse cycles without any obvious degradation observed. Compared with reported ZrO(2)-based memory devices, our Ti/ZrO(2)/Pt device exhibits better RS properties and has a high potential for memory application. (C) 2011 Elsevier B.V. All rights reserved.
Improved resistive switching properties of Ti/ZrO2/Pt memory devices for RRAM application
(2011-07-01)
Wang, Sheng-Yu
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Tsai, Chen-Han
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Lee, Dai-Ying
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Lin, Chih-Yang
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Lin, Chun-Chieh
In this study, we have investigated the effect of current compliance during forming process on resistive switching (RS) characteristics of the Ti/ZrO2/Pt device. The higher the current compliance is, the larger RS operation voltage is needed. The Ti/ZrO2/Pt device with high device yield can be operated over 10,000 RS cycles by sweeping dc voltage. and the on and off two memory states exhibit good stability under 0.3 V stress voltage. Moreover, the data retention of both memory states is over 10(5) s. As applying +6-V 10-ns and -3-V 10-ns voltage pulses on the device, there are operation errors observed during continuous write-read-erase-read cycles until increasing the pulse width to 50 ns. Nondestructive readout tests are also performed on the Ti/ZrO2/Pt device before and after 10(3) pulse cycles without any obvious degradation observed. Compared with reported ZrO2-based memory devices, our Ti/ZrO2/Pt device exhibits better RS properties and has a high potential for memory application. (C) 2011 Elsevier B.V. All rights reserved.
Memory effect of RF sputtered ZrO2 thin films
(2007-12-03)
Lin, Chih-Yang
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Wu, Chung-Yi
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Wu, Chen-Yu
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Lin, Chun-Chieh
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Tseng, Tseung-Yuen
Electrical properties of RF sputtered ZrO2 Memory thin films were investigated in this study. The device with structure AI/ZrO2/Pt shows a reproducible resistive switching behavior traced over 100 times at room temperature. Moreover, by using various top electrodes, such as Pt, Cu, Ni, Ag, Ti, and even W-probe, the resistive switching phenomenon can be observed in ZrO2-based memory with Pt bottom electrode, indicating that the ZrO2 bulk dominates the resistive switching. The bias polarity dependent resistive switching behavior is demonstrated in the Ti/ZrO2/Pt device, which might be due to interface reaction between Ti and ZrO2 film. The resistance value of high conductive state in the Ti/ZrO2/Pt device decreases with increasing current compliance implying the possibility for multi-bit storage. Besides, the Ti/ZrO2/Pt device can be operated over 2000 resistive switching cycles at 85 degrees C by sweeping DC voltage, and the two memory states demonstrate good stability under read voltage stress at room temperature and 95 degrees C. The write-read-erase-read operations can be over 10(3) cycles at 85 degrees C. No data loss is found upon successive readout before and after performing 10(3) endurance cycles at 85 degrees C. According to above experimental results, the ZrO2 thin film has high potential for nonvolatile memory application. (C) 2007 Elsevier B.V. All rights reserved.
Nonpolar Bistable Resistive Switching Behaviors of Bismuth Titanate Oxide Thin Film
(2009)
Lin, Meng-Han
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Wu, Ming-Chi
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Lin, Chun-Chieh
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Tseng, Tseung-Yuen
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電子工程學系及電子研究所
Nonpolar bistable resistive switching behaviors of sol-gel derived bismuth titanate oxide (BTO) thin film are investigated in this study. The BTO thin film memory device without thermal treatment shows higher resistance ratio (similar to 10(4)) than the other annealed devices. The resistive switching behavior of the Pt/BTO/LNO/Pt device is reproducible and can be traced over 100 times. Both low resistance state (ON-state) and high resistance state (OFF-state) are stable over 10(4) s under 0.3 V voltage stress at room temperature (RT) and 85 degrees C. The retention behaviors of both memory states in the Pt/BTO/LNO/Pt device are very stable over 2 x 10(6) s at RT and 85 degrees C, showing that the BTO thin film memory device is a good candidate for nonvolatile memory application
Peroxide induced volatile and non-volatile switching behavior in ZnO-based electrochemical metallization memory cell
(2017-09-20)
Simanjuntak, Firman Mangasa
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Chandrasekaran, Sridhar
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Pattanayak, Bhaskar
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Lin, Chun-Chieh
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Tseng, Tseung-Yuen
We explore the use of cubic-zinc peroxide (ZnO2) as a switching material for electrochemical metallization memory (ECM) cell. The ZnO2 was synthesized with a simple peroxide surface treatment. Devices made without surface treatment exhibits a high leakage current due to the self-doped nature of the hexagonal-ZnO material. Thus, its switching behavior can only be observed when a very high current compliance is employed. The synthetic ZnO2 layer provides a sufficient resistivity to the Cu/ZnO2/ZnO/ITO devices. The high resistivity of ZnO2 encourages the formation of a conducting bridge to activate the switching behavior at a lower operation current. Volatile and non-volatile switching behaviors with sufficient endurance and an adequate memory window are observed in the surface-treated devices. The room temperature retention of more than 10(4) s confirms the non-volatility behavior of the devices. In addition, our proposed device structure is able to work at a lower operation current among other reported ZnO-based ECM cells.
Reproducible resistive switching behavior in sputtered CeO(2) polycrystalline films
(2008-12-25)
Lin, Chih-Yang
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Lee, Dai-Ying
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Wang, Sheng-Yi
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Lin, Chun-Chieh
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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
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Lee, Dai-Ying
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Wang, Sheng-Yi
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Lin, Chun-Chieh
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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.
Resistive switching mechanisms of V-doped SrZrO3 memory films
(2006-09-01)
Lin, Chun-Chieh
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Tu, Bing-Chung
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Lin, Chao-Cheng
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Lin, Chen-Hsi
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Tseng, Tseung-Yuen
The resistive switching behaviors of sputtered V-doped SrZrO3 (V:SZO) memory films were investigated in this letter. The current states of the memory films were switched between high current state (H-state) and low current state (L-state). The resistance ratio of the two current states was over 1000 at a read voltage. The switching mechanism from L- to H-state corresponds to the formation of current paths. However, this mechanism from H- to L-state is thought to be due to the fact that the defects present in the V:SZO film randomly trap electrons, and hence, the current paths are ruptured. The conduction mechanism of the H-state is dominated by ohmic conduction, whereas the L-state conduction is dominated by Frenkel-Poole emission. The polarity direction of the resistive switching is an intrinsic property of the SrZrO3 oxides. The V:SZO films with high uniformity and good stability are expected to be used in nonvolatile memory.
Resistive switching properties of sol-gel derived Mo-doped SrZrO3 thin films
(2007-12-15)
Lin, Chih-Yang
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Lin, Chun-Chieh
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Huang, Chun-Hsing
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Lin, Chen-Hsi
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Tseng, Tseung-Yuen
Hysteretic I-V characteristics of the SrZrO3 (SZO) thin films with various Mo-doping concentrations were investigated in the study. The 0.2 mol% Mo-doping SZO-based memory device showed excellent resistive switching characteristics, and the resistive switching can be operated over 300 times during successive operation. Both high and low conductive states were stable over 10(4) s. Multi-bit behavior was investigated by dc voltage sweeping with different spans of voltage scan for OFF-process and by various OFF-pulse voltages as well. The endurance test can be over 1000 times with no data loss found. The experimental results showed high potential for nonvolatile memory application. (c) 2007 Published by Elsevier B.V.
Resistive switching properties of SrZrO(3)-based memory films
(2007-04-01)
Lin, Chun-Chieh
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Lin, Chao-Cheng
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Tu, Bing-Chung
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Yu, Jung-Sheng
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Lin, Chen-Hsi
The resistive switching properties of the sputter-deposited SrZrO(3) (SZO) memory films were investigated in this study. The resistive switching behaviors of the SZO film can be improved by doping with vanadium oxide. The conduction mechanisms of the high and low current states of the 0.3% V-doped SZO (V:SZO) film are ohmic conduction and Frenkel-Poole emission, respectively, which implies the bulk effect of the memory film. The resistive ratio of two current states of the 0.3% V:SZO film remains 1000 times after applying 100 voltage sweeping cycles. Furthermore, the 0.3% V:SZO film shows stable resistive switching properties when measurement is performed at 100 degrees C. The band modulation of the SZO/LNO interface is proposed to explain the forming process of the SZO films. The 0.3% V:SZO memory film has excellent properties, such as high stability, good endurance, and long retention time, which make it a good candidate for next-generation nonvolatile memory application.
Role of nanorods insertion layer in ZnO-based electrochemical metallization memory cell
(2017-12-01)
Simanjuntak, Firman Mangasa
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Singh, Pragya
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Chandrasekaran, Sridhar
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Lumbantoruan, Franky Juanda
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Yang, Chih-Chieh
An engineering nanorod array in a ZnO-based electrochemical metallization device for nonvolatile memory applications was investigated. A hydrothermally synthesized nanorod layer was inserted into a Cu/ZnO/ITO device structure. Another device was fabricated without nanorods for comparison, and this device demonstrated a diode-like behavior with no switching behavior at a low current compliance (CC). The switching became clear only when the CC was increased to 75 mA. The insertion of a nanorods layer induced switching characteristics at a low operation current and improve the endurance and retention performances. The morphology of the nanorods may control the switching characteristics. A forming-free electrochemical metallization memory device having long switching cycles (> 10(4) cycles) with a sufficient memory window (10(3) times) for data storage application, good switching stability and sufficient retention was successfully fabricated by adjusting the morphology and defect concentration of the inserted nanorod layer. The nanorod layer not only contributed to inducing resistive switching characteristics but also acted as both a switching layer and a cation diffusion control layer.
SrTiO3-SiO2 oxide films for possible high-k gate dielectric applications
(2007-07-31)
Lin, Chun-Chieh
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Lai, Li-Wen
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Lin, Chih-Yang
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Tseng, Tseung-Yuen
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電子工程學系及電子研究所
Amorphous thin films of SrTiO3-SiO2 high-k dielectric oxides were deposited on p-Si substrate by sputtering from the targets made by SrTiO3 and SiO2 powder mixtures. The surface morphology, crystal structure, chemical bonding configuration, and depth profile of the composition were investigated by using scanning electron microscopy, glancing incident angle X-ray diffraction, X-ray photoelectron spectroscopy, and Auger electron spectroscopy, respectively. The capacitance-voltage (CV) and current-voltage characteristics were used for demonstrating their electrical properties. The SrTiO3-SiO2 thin films remained as amorphous structures when annealed up to 900 degrees C. The Pt/SrTiO3-SiO2/Si MOS structure 2 had a low leakage current density of similar to 2 x 10(-8) A/cm(2) measured at 100 kV/cm and dielectric constant of 24 for 700 degrees C-annealed film. The films annealed at 600 degrees C showed typical CV characteristics. However, the deformed CV curves were found for films annealed at 700 degrees C due to the diffusion of Ti species in the SrTiO3-SiO2 film into the Si substrate. (C) 2006 Elsevier B.V. All rights reserved.
Stable resistive switching behaviors of sputter deposited V-doped SrZrO3 thin films
(2007-12-03)
Lin, Chun-Chieh
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Yu, Jung-Sheng
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Lin, Chih-Yang
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Lin, Chen-Hsi
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Tseng, Tseung-Yuen
The influences of doping concentration and element on the resistive switching properties of SZO-based memory devices are investigated in this study. The sputter-deposited LNO bottom electrode and SZO resistive layer exhibit (100)-preferred orientation, and the LNO film annealed at 600 degrees C performs smooth surface and high conductivity. The 0.3% V:SZO memory device depicts the good switching behaviors including high resistance ratio, high endurance, long retention time, and non-destructive readout property. The turn-on voltage is slightly dependent on the SZO thickness, while the turn-off voltage is almost irrelative to the thickness. Besides, the switching properties of MoO3-, MoO2-, and Cr2O3-doped SZO devices are also studied. The results demonstrate that the resistive switching is an intrinsic property of the SZO film, but proper doping concentration and element can improve and stabilize the resistive switching behaviors. (C) 2007 Elsevier B.V. All rights reserved.
Switching Failure Mechanism in Zinc Peroxide-Based Programmable Metallization Cell
(2018-10-19)
Simanjuntak, Firman Mangasa
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Chandrasekaran, Sridhar
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Lin, Chun-Chieh
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Tseng, Tseung-Yuen
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電子工程學系及電子研究所
The impact of peroxide surface treatment on the resistive switching characteristics of zinc peroxide (ZnO2)-based programmable metallization cell (PMC) devices is investigated. The peroxide treatment results in a ZnO hexagonal to ZnO2 cubic phase transformation; however, an excessive treatment results in crystalline decomposition. The chemically synthesized ZnO2 promotes the occurrence of switching behavior in Cu/ZnO2/ZnO/ITO with much lower operation current as compared to the Cu/ZnO/ITO (control device). However, the switching stability degrades as performing the peroxide treatment for a longer time. We suggest that the microstructure of the ZnO2 is responsible for this degradation behavior and fine tuning on ZnO2 properties, which is necessary to achieve proper switching characteristics in ZnO2-based PMC devices.
Voltage-polarity-independent and high-speed resistive switching properties of v-doped SrZrO3 thin films
(2007-12-01)
Lin, Chun-Chieh
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Lin, Chih-Yang
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Lin, Meng-Han
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Lin, Chen-Hsi
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Tseng, Tseung-Yuen
In this paper, nonpolar resistive switching behavior is reported for the first time in a SZO-based memory device. The electrode materials used which have different conductivities affect the resistive switching properties of the device. The A1/V:SZO-LNO/Pt device shows nonpolar switching behavior, whereas the A1/V:SZO/LNO device has bipolar switching property. The resistance ratios of these two devices are quite distinct owing to the difference between the resistance of low resistance states. The A1/V:SZO-LNO/Pt device with lower resistive switching voltages (+/- 7 V turn on and 2 V turn off) and higher resistance ratio (10(7)) is more suitable for practical applications compared to the A1/V:SZO/LNO device. The switching speed of the A1/V:SZO-LNO/Pt device is 10 ns, which is the fastest speed that has ever been reported. The conduction mechanisms, nondestructive readout property, retention time, and endurance of this device are also reported in this paper.
ZnO2/ZnO bilayer switching film for making fully transparent analog memristor devices
(2019-05-01)
Simanjuntak, Firman Mangasa
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Chandrasekaran, Sridhar
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Lin, Chun-Chieh
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Tseng, Tseung-Yuen
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電子工程學系及電子研究所
Hydrogen peroxide treatment induces the phase transformation of hexagonal ZnO to cubic ZnO2 on the surface of the ZnO switching memory film; this oxidation process effectively reduces the concentration of n-type donor defects (oxygen vacancies and zinc interstitials) in the switching film. The chemically oxidized ZnO2 layer not only lowers the operation current of the device but also can serve as an oxygen bank to improve the endurance of the memristor. The oxidation reaction of peroxide treatment can be easily controlled to achieve an analog behavior with good switching uniformity. The analog memristor device is able to perform two-bit per cell and synaptic operations. Based on the experimental synaptic data, an image processing of 7 x 9 pixels using a simulated artificial neural network comprises 63 synapses is evaluated to mimic the visual cortex function of the brain.