• Title/Summary/Keyword: Thermally-activated process

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Microstructure and Electrical Resistivity of Ink-Jet Printed Nanoparticle Silver Films under Isothermal Annealing (잉크젯 프린팅된 은(Ag) 박막의 등온 열처리에 따른 미세조직과 전기 비저항 특성 평가)

  • Choi, Soo-Hong;Jung, Jung-Kyu;Kim, In-Young;Jung, Hyun-Chul;Joung, Jae-Woo;Joo, Young-Chang
    • Korean Journal of Materials Research
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    • v.17 no.9
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    • pp.453-457
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    • 2007
  • Interest in use of ink-jet printing for pattern-on-demand fabrication of metal interconnects without complicated and wasteful etching process has been on rapid increase. However, ink-jet printing is a wet process and needs an additional thermal treatment such as an annealing process. Since a metal ink is a suspension containing metal nanoparticles and organic capping molecules to prevent aggregation of them, the microstructure of an ink-jet printed metal interconnect 'as dried' can be characterized as a stack of loosely packed nanoparticles. Therefore, during being treated thermally, an inkjet-printed interconnect is likely to evolve a characteristic microstructure, different from that of the conventionally vacuum-deposited metal films. Microstructure characteristics can significantly affect the corresponding electrical and mechanical properties. The characteristics of change in microstructure and electrical resistivity of inkjet-printed silver (Ag) films when annealed isothermally at a temperature between 170 and $240^{\circ}C$ were analyzed. The change in electrical resistivity was described using the first-order exponential decay kinetics. The corresponding activation energy of 0.44 eV was explained in terms of a thermally-activated mechanism, i.e., migration of point defects such as vacancy-oxygen pairs, rather than microstructure evolution such as grain growth or change in porosity.

Studies on Film Growth and Mechanical Properties of TiN by Chemical Vapor Deposition (화학증착에 의한 TiN 박막의 제조 및 기계적 성질에 관한 연구)

  • 김시범;김광호;천성순
    • Journal of the Korean Ceramic Society
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    • v.26 no.1
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    • pp.21-30
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    • 1989
  • Titanium Nitride (TiN) was deposited onto the SKH9 tool steels by chemical vapor deposition (CVD) using a gaseous mixture of TiCl4, N2, and H2. The effects of the deposition temperature and input gas composition on the deposition rate, microstructure, preferred orientation, microhardness and wear resistance of TiN deposits were studied. The experimental results showed that the TiN deposition is thermally activated process with an apparent activation energy of about 27Kcal/mole in the temperature range between 1200$^{\circ}$K and 1400$^{\circ}$K. As H2/N2 gas input ratio increased, the deposition rate increased, showed maximum at H2/N2 gas input ratio of 1.5 and then decreased. Mechanical properties such as microhardness and wear resistance have close relation with the microstructure and preferred orientation of TiN deposits. It is suggested that the equiaxed structure with random orientation increases the microhardness and wear resistance of TiN deposits.

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The Electrical Property of Polymer Matrix Composites Added Carbon Powder

  • Shin, Soon-Gi
    • Korean Journal of Materials Research
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    • v.25 no.12
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    • pp.678-682
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    • 2015
  • The electrical property of polymer matrix composites with added carbon powder is studied based on the temperature dependency of the conduction mechanism. The temperature coefficient of the resistance of the polymer matrix composites below the percolation threshold (x) changed from negative to positive at 0.20 < x < 0.21; this trend decreased with increasing of the percolation threshold. The temperature dependence of the electrical property(resistivity) of the polymer matrix composites below the percolation threshold can be explained by using a tunneling conduction model that incorporates the effect of the thermal expansion of the polymer matrix composites into the tunneling gap. The temperature coefficient of the resistance of the polymer matrix composites above the percolation threshold has a positive value; its absolute value increased with increasing volume fraction of carbon powder. By assuming that the electrical conduction through the percolating paths is a thermally activated process and by incorporating the effect of thermal expansion into the volume fraction of the carbon power, the temperature dependency of the resistivity above the percolation threshold can be well explained without violating the universal law of conductivity.

Measurements of Local Coercivity Distribution in Ferromagnetic Films Using Magneto-Optical Microscope Magnetometer (MOMM)

  • Choe, Sug-Bong;Shin, Sung-Chul
    • Journal of Magnetics
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    • v.5 no.3
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    • pp.81-84
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    • 2000
  • A magneto-optical microscope magnetometer (MOMM) has been developed to simultaneously measure 2-dimensional array hysteresis loops of each local area of $320\times320-nm^2$ spots on ferromagnetic films, in addition to grabbing time-resolved domain evolution patterns. Using the system, spatial distribution of local coercivity can be quantitatively generated and then, compared directly with domain patterns grabbed at precisely the same position of a sample. It is clearly demonstrated that local coercivity distribution governs domain reversal behavior via a thermally activated relaxation process.

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Noise Modeling and Performance Evaluation in Nanoscale MOSFETs (나노 MOSFETs의 노이즈 모델링 및 성능 평가)

  • Lee, Jonghwan
    • Journal of the Semiconductor & Display Technology
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    • v.19 no.3
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    • pp.82-87
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    • 2020
  • The comprehensive and physics-based compact noise models for advanced CMOS devices were presented. The models incorporate important physical effects in nanoscale MOSFETs, such as the low frequency correlation effect between the drain and the gate, the trap-related phenomena, and QM (quantum mechanical) effects in the inversion layer. The drain current noise model was improved by including the tunneling assisted-thermally activated process, the realistic trap distribution, the parasitic resistance, and mobility degradation. The expression of correlation coefficient was analytically described, enabling the overall noise performance to be evaluated. With the consideration of QM effects, the comprehensive low frequency noise performance was simulated over the entire bias range.

Adsorption of Specific Organics in Water on GAC and Regeneration of GAC by Countercurrent Oxidative Reaction

  • Ryoo, Keon-Sang;Kim, Tae-Dong;Kim, Yoo-Hang
    • Bulletin of the Korean Chemical Society
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    • v.23 no.6
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    • pp.817-824
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    • 2002
  • Granular activated carbon(GAC) is highly effective in removing organic compounds which are resistant to biological disintegration in wastewater treatment. However, GAC has reached its full adsorptive capacity, GAC needs to be regenerated before it can be used for a further adsorption cycle. Countercurrent oxidative reaction (COR) technique has been developed and evaluated for the regeneration of spent GAC. Various parameters such as flame temperature, the loss of carbon, destruction and removal efficiency (DRE) of organic compounds, surface area, surface structure, adsorptive capacity, etc. were examined to determine the performance of COR. The results of these tests showed that adosorptive capacity of regenerated GAC was completely recovered, the loss of carbon was controllable, flame temperature was high enough to insure complete destruction and removal $(\geq99.9999%)$ of specific organics of interest, polychlorinated biphenyls (PCBs), that are thermally stable, and on formation of toxic byproducts such as polychlorinated dibenzo-p-dioxins (PCDDs) or polychlorinated dibenzofurans (PCDFs) were detected during the regeneration process. The COR technique is environmentally benign, easy to use and less copital intensive than other available regeneration technologies.

SUBMICRON-RESOLUTION DOMAIN REVERSAL STUDY OF Co-BASED MULTILAYERS USING MAGNETO-OPTICAL MICROSCOPE MAGNETOMETER (MOMM)

  • Shin, Sung-Chul;Choe, Sug-Bong
    • Proceedings of the Korean Magnestics Society Conference
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    • 2000.09a
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    • pp.121-146
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    • 2000
  • A novel system of magneto-optical microscope magnetometer (MOMM), capable of simultaneous local problems of magnetic properties as well as real-time magnetic domain evolution imaging of ferromagnetic thin films with 400-nm spatial resolution, New findings in domain reveral dynamics of Co-based multilayers: The reversal ratio of V/R is a governing physical parameter. The activation volumes of wall-motion and nucleation processes are generally unequal. Submicron-scale local coercivity variation determines domain reversal dynamics. A thermally activated relaxation process during domain reversal is existed on the submicron-scale in realistic films. Local variation of magnetic properties should be considered for a realistic simulation. The fantastic capabilities of the MOMM can open many possibilities to broaden and deepen our understanding of domain reversal phenomena in ferromagnetic thin films.

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Measurement of activation magnetic moment in ferromagnetic thin films

  • Choe, Sug-Bong;Shin, Sung-Chul
    • Proceedings of the Korean Magnestics Society Conference
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    • 2000.09a
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    • pp.200-206
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    • 2000
  • We have investigated the activation magnetic moment, which characterizes the basis magnetic moment acting as a single magnetic particle during magnetization reversal. The activation magnetic moment was measured from each local area on continuous ferromagnetic thin films, by analyzing the magnetic field dependence of magnetization reversal of the corresponding local area based on a thermally activated relaxation process. It was found that the activation magnetic moment was nonuniform on submicrometer scale; the fluctuation increased with increasing the number of layers in Co/Pd multilayers. The distribution could be well analyzed by exp($\delta$m$\^$3/2/), where $\delta$m is the deviation of the activation magnetic moment from the mean value.

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Measurement of Activation Magnetic Moment in Ferromagnetic Thin Films

  • Choe, Sug-Bong;Shin, Sung-Chul
    • Journal of Magnetics
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    • v.6 no.2
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    • pp.70-72
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    • 2001
  • We have investigated the activation magnetic moment, which characterizes the basic magnetic moment acting as a single magnetic particle during magnetization reversal. The activation magnetic moment was measured from each local area on continuous ferromagnetic thin films, by analyzing the magnetic field dependence of magnetization reversal of the corresponding local area, based on a thermally activated relaxation process. It was found that the activation magnetic moment was nonuniform on a submicrometer scale; the fluctuation increased with increasing the number of layers in Co/Pd multilayers. The distribution could be well described by exp($\delta m^{3/2}$), where $\delta$m is the deviation of the activation magnetic moment from the mean value.

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Unequal Activation Volumes of Wall-motion and Nucleation Process in Co/Pt Multilayers

  • Cho, Yoon-Chul;Choe, Sug-Bong;Shin, Sung-Chul
    • Journal of Magnetics
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    • v.5 no.4
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    • pp.116-119
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    • 2000
  • Magnetic field dependence of magnetization reversal in Co/Pt multilayers was quantitatively investigated. Serial samples of Co/Pt multilayers were prepared by dc-magnetron sputtering under various Ar pressures. Magnetization reversal was monitored by magnetization viscosity measurement and direct domain observation using a magneto-optical microscope system, and the wall-motion speed V and the nucleation rate R were determined using a domain reversal model based on time-resolved domain reversal patterns. Both V and R were found to be exponentially dependent on the applied reversing field. From the exponential dependencies, the activation volumes for wall motion and nucleation could be determined, based on a thermally activated relaxation model, and the wall-motion activation volume was found to be slightly larger than the nucleation activation volume.

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