Browsing by Author "Tsai, Ming-Jinn"

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A carbon nanotube field effect transistor with tunable conduction-type by electrostatic effects
(2006-07-01)
Chen, Bae-Horng
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Wei, Jeng-Hua
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Lo, Po-Yuan
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Wang, Hung-Hsiang
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Lai, Ming-Jinn
In this paper, we report a conduction-type-tunable carbon nanotube field effect transistor (CNT-FET) with double-gate structure (DG CNT-FET). In this study, a specially designed narrow top-gate is created to modulate the energy band in the middle region of a single CNT. In the proposed DG device structure, the top-gate and bottom-gate biases exhibit independent modulation behaviors. Depending on whether a positive or negative bias is applied to the top-gate, the CNT-FET can be operated in either n- or p-type conduction. Energy band diagram conducive to the physical mechanisms of the proposed DG CNT-FET device structure is proposed. Based on the proposed hypothesis, ambipolar CNT-FETs can indeed be converted to n- or p-type-like behaviors. (c) 2006 Elsevier Ltd. All rights reserved.
A process for high yield and high performance carbon nanotube field effect transistors
(2010-05-01)
Lee, Tseng-Chin
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Tsui, Bing-Yue
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Tzeng, Pei-Jer
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Wang, Ching-Chiun
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Tsai, Ming-Jinn
Carbon nanotube field effect transistors (CNTFETs) have been considered as one of the potential candidates for nanoelectronics beyond Si CMOS. However, it is not easy to have high performance CNTFETs with high yield currently. In this work, we proposed a local bottom-gate (LBG) CNTFETs combined with a novel device concept and optimized process technologies. High performance of CNTFET with low subthreshold swing of 139 mV/dec, high transconductance of 1.27 mu S, and high I(on)/I(off) ratio of 10(6) can be easily obtained with Ti source/drain contact after a post annealing process. Record high yield of 74% has been demonstrated. On the basis of the proposed process, lots of high performance CNTFETs can be obtained easily for advanced study on the electrical characteristics of CNTFETs in the future. (C) 2010 Elsevier Ltd. All rights reserved.
Asymmetric Carrier Conduction Mechanism by Tip Electric Field in WSiOX Resistance Switching Device
(2012-03-01)
Syu, Yong-En
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Chang, Ting-Chang
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Tsai, Tsung-Ming
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Chang, Geng-Wei
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Chang, Kuan-Chang
Resistance random access memory (RRAM) is a great potential candidate for next-generation nonvolatile memory due to the outstanding memory characteristic. However, the resistance switching mechanism is still a riddle nowadays. In this letter, the switching mechanism is investigated by current-voltage (I-V) curve fitting in the TiN/WSiOX/Pt RRAM device. The asymmetric phenomenon of the carrier conduction behavior is explained at the high-resistance state in high electric field. The switching behavior is regarded to tip electric field by localizing the filament between the interface of top electrode and insulator.
Atomic-level quantized reaction of HfOx memristor
(2013-04-29)
Syu, Yong-En
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Chang, Ting-Chang
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Lou, Jyun-Hao
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Tsai, Tsung-Ming
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Chang, Kuan-Chang
In this study, we have observed dynamic switching behaviors in a memristive device. There are only a few atoms in the resistive switching reaction which enables the high-speed resistive switching characteristics, which was analyzed dynamically by real-time analyzing tools. From fundamental conductance considerations, the resistance of the conductive path in HfOx memristor is found to be due to barriers which are atomically incremented during the RESET process. Simultaneously, we have demonstrated the quantized switching phenomena at ultra-cryogenic temperature (4 K), which are attributed to the atomic-level reaction in metallic filament. (C) 2013 AIP Publishing LLC.
Bipolar Resistive RAM Characteristics Induced by Nickel Incorporated Into Silicon Oxide Dielectrics for IC Applications
(2012-12-01)
Tsai, Tsung-Ming
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Chang, Kuan-Chang
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Chang, Ting-Chang
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Syu, Yong-En
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Chuang, Siang-Lan
In this letter, we successfully produced resistive switching behaviors by nickel doped into silicon oxide at room temperature. The nickel element was doped into silicon oxide, which is a useful dielectric material in integrated circuit (IC) industries by cosputtering technology. Based on the proposed method, satisfactory reliability of the resistance switching device can be demonstrated by endurance and retention evaluation. We believe that the silicon oxide doped with nickel at room temperature is a promising method for resistive random access memory nonvolatile memory applications due to its compatibility with the IC processes.
Bipolar resistive switching of chromium oxide for resistive random access memory
(2011-08-01)
Chen, Shih-Cheng
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Chang, Ting-Chang
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Chen, Shih-Yang
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Chen, Chi-Wen
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Chen, Shih-Ching
This study investigates the resistance switching characteristics of Cr(2)O(3)-based resistance random access memory (RRAM) with Pt/Cr(2)O(3)/TiN and Pt/Cr(2)O(3)/Pt structures. Only devices with Pt/Cr(2)O(3)/TiN structure exhibit bipolar switching behavior after the forming process because TiN was able to work as an effective oxygen reservoir but Pt was not. Oxygen migration between Cr(2)O(3) and TiN was observed clearly before and after resistance switching from Auger electron spectroscopy (AES) analysis. Both low resistance state, ON state, and high resistance state, OFF state, of Pt/Cr(2)O(3)/TiN structures are stable and reproducible during a successive resistive switching. The resistance ratio of ON and OFF state is over 10(2), on top of that, the retention properties of both states are very stable after 10(4) s with a voltage of -0.2 V. (C) 2010 Elsevier Ltd. All rights reserved.
Cerium oxide nanocrystals for nonvolatile memory applications
(2007-12-24)
Yang, Shao-Ming
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Chien, Chao-Hsin
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Huang, Jiun-Jia
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Lei, Tan-Fu
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Tsai, Ming-Jinn
The characteristics of silicon-oxide-nitride-oxide-silicon-type memories embedded with cerium oxide nanocrystals were demonstrated. They were fabricated by depositing a thin CeO(2) film on the SiO(2) tunneling layer and subsequently rapid-thermal annealing process. The mean size and aerial density of the CeO(2) nanocrystals embedded in SiO(2) are estimated to be about 8-10 nm and (3-7)x10(11)/cm(-2) after a high-temperature annealing with different ambients on 900 degrees C. The program/erase behaviors and data retention characteristics were described to demonstrate its advantages for nonvolatile memory device applications. (c) 2007 American Institute of Physics.
Effect of ITO electrode with different oxygen contents on the electrical characteristics of HfOx RRAM devices
(2013-09-01)
Zhong, Chia-Wen
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Tzeng, Wen-Hsien
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Liu, Kou-Chen
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Lin, Horng-Chih
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Chang, Kow-Ming
In this study, the influence of indium tin oxide (ITO) top electrodes with different oxygen contents on the resistive switching characteristics of HfOx/TiN capacitor structure is investigated. Switching parameters, including set and reset voltage values, and high and low resistance values are highly related to the properties of ITO thin films. Higher resistance values in both states can be obtained when ITO thin films with higher oxygen contents are used as top electrodes; such values are accompanied by larger set voltages and fluctuating transient currents during the reset process. Based on the proposed filament model, we suggest that the switching mechanism of HfOx/TiN structure is attributed to the formation and rupture of conducting filamentary paths near the anodic side, which is highly correlated with the properties of the top electrode. The top electrode must be well determined to obtain reliable switching properties. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.
Effect of oxygen absorption on contact resistance between metal and carbon nano tubes (CNTs)
(2006)
Tsui, Bing-Yue
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Weng, Chien-Li
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Chang, Chih-Lien
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Wei, Jeng-Hua
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Tsai, Ming-Jinn
Contact resistance (R-c) between metal and carbon nanotubes (CNTs) is studied extensively. Metal oxide formation at interface due to oxygen absorption plays very important role. Chemically inert metals such as Pt and Au results in the lowest R-c. Adding Ta into Pt can solve the adhesion issue while keeps low R-c. Those metals can break metal oxide and form metal carbide are also preferred.
Enhancement of the stability of resistive switching characteristics by conduction path reconstruction
(2013-07-22)
Huang, Jheng-Jie
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Chang, Ting-Chang
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Yu, Chih-Cheng
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Huang, Hui-Chun
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Chen, Yu-Ting
In this study, a Pt/BiFeO3/TiN device was fabricated and the resistance switching characteristics were investigated. After the first forming process, the conduction path was formed and exhibited unstable bipolar switching characteristics. Subsequently, the original conduction path was destroyed thoroughly by high negative bias. By reconstructing the conduction path after a second forming process (re-forming process), the device exhibits stable bipolar switching characteristics. Transmission electron microscopy analysis indicates that the stability of switching behavior was enhanced because of the joule heating effect, and is an easy way to improve the resistance switching characteristics. (C) 2013 AIP Publishing LLC.
Forming-free HfO2 Bipolar RRAM Device with Improved Endurance and High Speed Operation
(2009)
Chen, Yu-Sheng
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Wu, Tai-Yuan
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Tzeng, Pei-Jer
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Chen, Pang-Shiu
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Lee, Heng-Yuan
High charge storage characteristics of CeO2 nanocrystals for novolatile memory applications
(2008)
Yang, Shao-Ming
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Huang, Jiun-Jia
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Chien, Chao-Hsin
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Taeng, Pei-Jer
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Lee, Lurng-Shehng
This paper presents the formation of CeO2 nanocrystals on SiO2 tunneling layer and its annealing effect to the nonvolatile memory device. The characteristics including the program/erase behaviors, data retention, and endurance of Silicon-Oxide-Nitride-Oxide-Silicon type memories embedded with cerium oxide (CeO2) nanocrystals were studieded to demonstrate its advantages as a nonvolatile memory device.
Impact of Electroforming Current on Self-Compliance Resistive Switching in an ITO/Gd:SiOx/TiN Structure
(2013-07-01)
Tseng, Hsueh-Chih
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Chang, Ting-Chang
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Wu, Yi-Chun
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Wu, Sei-Wei
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Huang, Jheng-Jie
This letter investigates self-compliance behavior for nonvolatile resistance random access memory using the indium tin oxide (ITO)/Gd:SiOx/TiN structure. Different current compliances in the electroforming process results in different trends in the set process, including a different self-compliance scale and one-or two-step set behaviors. The oxygen ions generated during the electroforming and set process drift to ITO, inducing a semiconductor-like ITO interface formation, which can be regarded as a self-built series resistor.
Improving Resistance Switching Characteristics with SiGeO(x)/SiGeON Double Layer for Nonvolatile Memory Applications
(2011-01-01)
Syu, Yong-En
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Chang, Ting-Chang
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Tsai, Chih-Tsung
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Chang, Geng-Wei
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Tsai, Tsung-Ming
The switching layer with SiGeO(x)/SiGeON structure is investigated to improve the electrical characteristics of resistive nonvolatile memory. A bipolar resistance switching behavior owning inferior stability was observed in Pt/SiGeO(x)/TiN memory cells. To obtain practical memory, a convenient and compatible SiGeON (similar to 5 nm) is introduced at SiGeO(x)/anode interface to stabilize the disruption length of filaments near anode electrode. Compared with Pt/SiGeO(x)/TiN memory cells, the proposed Pt/SiGeO(x)/SiGeON/TiN cells is effective at minimizing the dispersions of memory switching parameters. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3615823] All rights reserved.
Improving Resistance Switching Characteristics with SiGeOx/SiGeON Double Layer for Nonvolatile Memory Applications
(2011-01-01)
Syu, Yong-En
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Chang, Ting-Chang
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Tsai, Chih-Tsung
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Chang, Geng-Wei
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Tsai, Tsung-Ming
The switching layer with SiGeOx/SiGeON structure is investigated to improve the electrical characteristics of resistive nonvolatile memory. A bipolar resistance switching behavior owning inferior stability was observed in Pt/SiGeOx/TiN memory cells. To obtain practical memory, a convenient and compatible SiGeON (similar to 5 nm) is introduced at SiGeOx/anode interface to stabilize the disruption length of filaments near anode electrode. Compared with Pt/SiGeOx/TiN memory cells, the proposed Pt/SiGeOx/SiGeON/TiN cells is effective at minimizing the dispersions of memory switching parameters. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3615823] All rights reserved.
Influence of electrode material on the resistive memory switching property of indium gallium zinc oxide thin films
(2010-06-28)
Chen, Min-Chen
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Chang, Ting-Chang
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Tsai, Chih-Tsung
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Huang, Sheng-Yao
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Chen, Shih-Ching
The InGaZnO taken as switching layer in resistive nonvolatile memory is proposed in this paper. The memory cells composed of Ti/InGaZnO/TiN reveal the bipolar switching behavior that keeps stable resistance ratio of 10(2) with switching responses over 100 cycles. The resistance switching is ascribed to the formation/disruption of conducting filaments upon electrochemical reaction near/at the bias-applied electrode. The influence of electrode material on resistance switching is investigated through Pt/InGaZnO/TiN devices, which perform the unipolar and bipolar behavior as applying bias on Pt and TiN electrode, respectively. Experimental results demonstrate that the switching behavior is selective by the electrode. (C) 2010 American Institute of Physics. [doi:10.1063/1.3456379]
Influence of forming process on resistance switching characteristics of In2O3/SiO2 bi-layer
(2013-01-15)
Huang, Jheng-Jie
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Chang, Ting-Chang
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Yang, Po-Chun
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Chen, Yu-Ting
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Tseng, Hsueh-Chih
In this study, we fabricated and analyzed resistance switching characteristics for resistance random access memory (RRAM) in a Pt/In2O3/SiO2/TiN structure. By applying opposing electric fields to performa soft breakdown of the In2O3/SiO2 insulating bi-layer, different switching behaviors are exhibited. When positive forming voltage was applied to the TiN electrode to soft breakdown the device, the resistance switching behavior was dominated by the bipolar mode. However, the negative voltage forming process exhibited both unipolar switching characteristics in addition to a bipolar switch mode. In order to analyze the composition of the conduction path and resistance switching mechanism, resistance value trends versus temperature was extracted and showed that the conduction paths of bipolar and unipolar modes are dominated by oxygen vacancies and metallic filament, respectively. Hence, metallic filament was considered to be formed by the migration of indium ions because the unipolar characteristic was only present during negative bias forming condition. (c) 2012 Elsevier B.V. All rights reserved.
Influence of molybdenum doping on the switching characteristic in silicon oxide-based resistive switching memory
(2013-01-28)
Chen, Yu-Ting
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Chang, Ting-Chang
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Huang, Jheng-Jie
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Tseng, Hsueh-Chih
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Yang, Po-Chun
This report compares Mo-doped and undoped SiO2 thin films of a similar thickness as well as MoOx. The Mo-doped SiO2 film exhibited switching behavior after the forming process, unlike the undoped SiO2 film. Through material analyses, a self-assembled layer is observed in the Mo-doped SiO2 film. Due to the formation of this layer, the thickness required to be broken down is effectively reduced. Subsequently, the occurrence of the switching behavior in the thinner SiO2 film further confirmed the supposition. A comparison of the two switching behaviors shows that SiO2 dominates the switching characteristic of the Mo-doped SiO2. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4790277]
Influence of Oxygen Concentration on Resistance Switching Characteristics of Gallium Oxide
(2012-10-01)
Huang, Jheng-Jie
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Chang, Ting-Chang
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Yang, Jyun-Bao
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Chen, Shih-Ching
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Yang, Po-Chun
In this letter, we fabricated resistance random access memory in a Pt/GaOx/TiN structure with a bipolar resistance switching characteristic and a bistable resistance ratio of about two orders by I-V sweeping. In order to increase the oxygen ion quantity in the gallium oxide layer, the proposed sample was sputtered in a mixed ambient of Ar and oxygen, and the resistance ratio was enhanced by 2.5 orders. In addition to the resistance ratio, set voltage distribution statistics show that the stability of gallium oxide sputtered in mixed Ar and oxygen gas was better than standard Ar-only sample.
Influence of Oxygen Concentration on Self-Compliance RRAM in Indium Oxide Film
(2014-09-01)
Yang, Jyun-Bao
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Chang, Ting-Chang
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Huang, Jheng-Jie
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Chen, Yu-Ting
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Tseng, Hsueh-Chih
This letter investigates various oxygen concentrations in indium oxide films which induce different resistance switching behaviors, including two self-compliance behaviors and a two-step set process. The accumulated oxygen ions produce an oxygen-rich indium oxide film, which can be considered as a variable series resistor after the forming process. Analyses indicate that the lower self-compliance current can be attributed to this larger variable series resistor from the additional oxygen ions. The more significant oxidation reaction decreases the current of the high resistance state. Hence, power consumption can be reduced effectively.