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收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作,涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

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  • Item type:Item,
    Solving the Scaling Issue of Increasing Forming Voltage in Resistive Random Access Memory Using High-k Spacer Structure
    (2017-09-01)
    Tseng, Yi-Ting
    ;
    Chen, Po-Hsun
    ;
    Chang, Ting-Chang
    ;
    Chang, Kuan-Chang
    ;
    Tsai, Tsung-Ming
    In this study, the rising forming voltage issue during device cell scale-down in resistance random access memory (RRAM) is solved by introducing new high-permittivity (high-k) material as the side-wall spacer structure, unlike the normally used low-permittivity (low-k) material. Simulated electrical fields based on COMSOL Multiphysics software results suggest a RRAM device with a high-k spacer effectively confines the electric field. The effects of this confined electric field are notable, especially when the device cell is scaled down. The device fabrication process is modified to incorporate the high-k sidewall. Cross-sectional transmission electron microscopy imaging confirms the existence of SiO2 and HfO2 as the spacer structures in two different devices. Electrical measurements of forming voltages ranging from 1 to 0.16 mu m(2) are conducted to verify the effects. Statistical measurements confirm that the forming voltages of the devices with high-k material as sidewall do not increase with a reduction in device cell size. Moreover, reliability tests, including endurance and retention for the high-k sidewall device, also exhibit very stable resistance switching characteristics. As a result, the structure that is proposed successfully solves the forming voltage issues within small device cells in RRAM without any cost to device reliability.
  • Item type:Item,
    Obtaining Lower Forming Voltage and Self-Compliance Current by Using a Nitride Gas/Indium-Tin Oxide Insulator in Resistive Random Access Memory
    (2016-12)
    Chen, Po-Hsun
    ;
    Chang, Ting-Chang
    ;
    Chang, Kuan-Chang
    ;
    Tsai, Tsung-Ming
    ;
    Pan, Chih-Hung
    This paper investigates the characteristics of applying indium-tin oxide (ITO) with and without nitride gas (N-2) as the insulator in resistive random access memory (RRAM). After cosputtering an ITO target with N-2 as the insulator and capping the same ITO material as the top electrode, the device exhibits rectifier and resistance switching characteristics before and after the forming process, respectively. The Schottky diodelike rectifier mechanism was also verified by various temperature measurements. Furthermore, robust resistance switching at a positive forming voltage, smaller than that required during negative bias forming, can be achieved. Both positive and negative forming processes are examined with current fitting results, which show different dominant mechanisms when using positive or negative biases. All these mechanisms have also been verified by temperature effect experiments, which confirmed the dominant conduction mechanisms. This, in combination with the fact that the positive forming voltage itself is smaller than the negative forming voltage, and decreases with device scale down, provides two highly beneficial results. This good performance achieved by using ITO with N-2 suggests significant progress of RRAM and remarkable potential applications.
  • Item type:Item,
    Resistance Switching Characteristics Induced by O-2 Plasma Treatment of an Indium Tin Oxide Film for Use as an Insulator in Resistive Random Access Memory
    (2017-01-25)
    Chen, Po-Hsun
    ;
    Chang, Ting-Chang
    ;
    Chang, Kuan-Chang
    ;
    Tsai, Tsung-Ming
    ;
    Pan, Chih-Hung
    In this study, an O-2 inductively coupled plasma (ICP) treatment was developed in order to modify the characteristics of indium tin oxide (ITO) film for use as an insulator in resistive random access memory (RRAM). After the O-2 plasma treatment, the previously conductive ITO film is oxidized and becomes less conductive. In addition, after capping the same ITO material for use as a top electrode, we found that the ITO/ITO (O-2 plasma)/TiN device exhibits very stable and robust resistive switching characteristics. On the contrary, the nontreated ITO film for use as an insulator in the ITO/ ITO/TiN device cannot perform resistance switching behaviors. The material analysis initially investigated the ITO film characteristics with and without O-2 plasma treatment. The surface was less rough after O-2 plasma treatment. However, the molar concentration of each element and measured sheet resistance results for the O-2-plasma-treated ITO film were dramatically modified. Next, electrical measurements were carried out to examine the resistance switching stability under continuous DC and AC operation in this ITO/ITO(O-2 plasma)/TiN device. Reliability tests, including endurance and retention, also proved its capability for use in data storage applications. In addition to these electrical measurements, current fitting method experiments at different temperatures were performed to examine and confirm the resistance switching mechanisms. This easily fabricated device, using a simple material combination, achieves excellent performance by using ITO with an O-2 plasma treatment and can further the abilities of RRAM for use in remarkable potential applications.
  • Item type:Item,
    Modifying Indium-Tin-Oxide by Gas Cosputtering for Use as an Insulator in Resistive Random Access Memory
    (2016-11)
    Chen, Po-Hsun
    ;
    Chang, Kuan-Chang
    ;
    Chang, Ting-Chang
    ;
    Tsai, Tsung-Ming
    ;
    Pan, Chih-Hung
    In this paper, indium-tin-oxide (ITO) was used to act as both insulator and top electrode in resistive random access memory (RRAM) on identical bottom substrates. This is achieved by cosputtering an ITO target with nitride (N-2) or oxygen (O-2) gas as the insulator; then capping by an ITO electrode, such that both the rectifier and RRAM characteristics can be achieved before and after a forming process, respectively. In contrast, using pure ITO as an insulator does not exhibit RRAM behavior. To verify the rectifier and RRAM characteristics, material analyses and electrical measurements at various temperatures were conducted. Reliability tests including retention and endurance were also applied to verify the resistance switching stability. Finally, the rectifier and RRAM conduction models were proposed to examine the resistance switching behaviors. By applying the ITO material as both electrode and insulator, the resistance switching characteristic with high reliability is thus obtained.
  • Item type:Item,
    Hopping Effect of Hydrogen-Doped Silicon Oxide Insert RRAM by Supercritical CO2 Fluid Treatment
    (2013-05-01)
    Chang, Kuan-Chang
    ;
    Pan, Chih-Hung
    ;
    Chang, Ting-Chang
    ;
    Tsai, Tsung-Ming
    ;
    Zhang, Rui
    In this letter, we introduced hydrogen ions into titanium metal doped into SiO2 thin film as the insulator of resistive random access memory (RRAM) by supercritical carbon dioxide (SCCO)(2) fluid treatment. After treatment, low resistance state split in to two states, we find the insert RRAM, which means it has an operating polarity opposite from normal RRAM. The difference of the insert RRAM is owing to the resistive switching dominated by hydrogen ions, dissociated from OH bond, which was not by oxygen ions as usual. The current conduction mechanism of insert RRAM was hopping conduction due to the metal titanium reduction reaction through SCCO2.