• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.343-346
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• 1998

Ultra-thin gate oxide in MOS devices are subjected to high-field stress during device operation, which degrades the oxide and exentually causes dielectric breakdown. In this paper, we investigate the electrical properties of ultra-thin nitrided oxide (NO) and reoxidized nitrided oxide(ONO) films that are considered to be promising candidates for replacing conventional silicon dioxide film in ULSI level integration. We study vriations of I-V characteristics due to F-N tunneling, and time-dependent dielectric breakdown (TDDB) of thin layer NO and ONO depending on nitridation and reoxidation condition, and compare with thermal $SiO_{2}$. From the measurement results, we find that these NO and ONO thin films are strongly depending on its condition and that optimized reoxided nitrided oxides (ONO) films show superior dielectric characteristics, and breakdown-to-change ( $Q_{bd}$ ) performance over the NO films, while maintaining a similar electric field dependence compared to NO layer.

• Journal of Magnetics
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• v.15 no.3
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• pp.132-137
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• 2010

Plasma etching of $SiO_2$ contact holes was statistically analyzed by a fractional factorial experimental design. The analysis revealed the dependence of the etch rate and DC self-bias voltage on the input factors of the magnetically enhanced reactive ion etching reactor, including gas pressure, magnetic field, and the gas flow rates of $CHF_3$, $CF_4$, and Ar. Empirical models of the DC self-bias voltage and etch rate were obtained. The DC self-bias voltage was found to be determined mainly by the operating pressure and the magnetic field, and the etch rate was related mainly to the pressure and the flow rates of Ar and $CHF_3$.

• Journal of Korea Game Society
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• v.9 no.1
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• pp.3-10
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• 2009

This paper presents the effects on logical thinking of the Korean LOGO programming used in teaching for the second grade of middle school with regard to cognitive styles and specific sub-classifications of logical thinking. In result, the LOGO programming teaching method significantly affected logical thinking and its sub-classifications.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.11a
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• pp.165-168
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• 1998

Re-oxidized nitrided oxides which have been investigated as alternative gate oxide for Metal- Oxide -Semiconductor field effect devices were grown by conventional furnace process using pure NH$_3$ and dry $O_2$ gas, and were characterized via a Fowler-Nordheim Tunneling electron injection technique. We studied Ig-Vg characteristics, leakage current, $\Delta$Vg under constant current stress from electrical characteristics point of view and TDDB from reliability point of view of MOS capacitors with SiO$_2$, NO, ONO dielectrics. Also, we studied the effect of stress temperature (25, 50, 75, 100, and 1$25^{\circ}C$). Overall, our results indicate that optimized re-oxidized nitrided oxide shows improved Ig-Vg characteristics, leakage current over the nitrided oxide and SiO$_2$. It has also been shown that re-oxidized nitrided oxide have better TDDB performance than SiO$_2$ while maintaining a similar temperature and electric field dependence. Especially, the Qbd is increased by about 1.5 times.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.355-355
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• 2010

We studied the dependence of the performance of schottky barrier metal-oxide-field effect transistors(SB MOSFETs) on the work function of source/drain metals. A strong impact of the various work functions and the light wavelengths on the transistor characteristics is found and explained using experimental data. We used an insulator of a high thickness (100nm) and back gate issues in SOI substrate, subthreshold swing was measured to 300~400[mV/dec] comparing with a ideal subthreshold swing of 60[mV/dec]. Excellent characteristics of Al/Si was demonstrated higher on/off current ratios of ${\sim}10^7$ than others. In addition, extensive photoresponse analysis has been performed using halogen and deuterium light sources(200<$\lambda$<2000nm).

• Journal of Mechanical Science and Technology
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• v.17 no.1
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• pp.157-167
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• 2003

The exciplex fluorescence technique with the TMPD (tetamethyl-Ρ-phenylene-diamine) / naphthalene dopant system was applied in a combustion-type constant-volume spray chamber. A detailed set of calibration experiments has been performed in order to quantify the TMPD fluorescence signal. It has been demonstrated that the TMPD fluorescence intensity was directly proportional to concentration, was independent of the chamber pressure, and was not sensitive to quenching by either water vapor or carbon dioxide. Using a dual heated-jet experiment, the temperature dependence of TMPD fluorescence up to 1000 K was measured. The temperature field in the spray images was determined using a simple mixing model, and an iterative solution method was used to determine the concentration and temperature field including the additional effects of the laser sheet extinction. The integrated fuel vapor concentration compared favorably with the measured amount of injected fuel when all of the liquid fuel had evaporated.

• 한국가시화정보학회:학술대회논문집
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• 2007.11a
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• pp.51-54
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• 2007

The induced-charge electroosmosis (ICEO) is a kind of electroosmotic flow which is generated by the electrical charge induced by an externally-applied electric field. That kind of electrokinetic phenomenon provides a nonmechanical technique to handle microscale flows and particles. In this work, we report that the ICEO-like flow is observed around two kinds of circular-cylindrical rod submerged in a dielectric liquid. The conductivity of the solution is varied by adding a surfactant. The flow field is visualized by the PIV method, and average flow speed shows a remarkable dependence on electrical input frequency. Interestingly, the characteristics of the flow are quite different from the conventional ICEO with respect to the flow direction and the locations of center of vortices.

• Wind and Structures
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• v.19 no.5
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• pp.541-563
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• 2014

This paper investigates the topographic effects on wind characteristics over hilly terrain, based on wind data recorded at a number of meteorological stations in or near complex terrain. The multiply data sources allow a more detailed investigation of the flow field than is normally possible. Vertical profiles of mean and turbulent wind components from a Sodar profiler were presented and then modeled as functions of height and wind speed. The correlations between longitudinal and vertical wind components were discussed. The phenomena of flow separation and generation of vortices were observed. The distance-dependence of the topographic effects on gust factors was revealed subsequently. Furthermore, the canyon effect was identified and discussed based on the observations of wind at a saddle point between two mountain peaks. This study aims to further understanding of the characteristics of surface wind over rugged terrain. The presented results are expected to be useful for structural design, prevention of pollutant dispersion, and validation of CFD (computational fluid dynamics) models or techniques over complex terrains.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.37-40
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• 2001

The semiconductor's design rule becomes more stringent, hence the silicon-dioxide etching technique is important issue. In this work we compared the etching characteristics of different three types of Plasma source, Normal ICP, magnetized ICP and E-IC $P^{TM}$. The E-IC $P^{TM}$ source shows higher etch rate at lower pressure and this is advantageous for the fine pattern process. The etching characteristics were varied with external magnetic field frequency at I-lCP and this is examined with Nanospe $c^{TM}$ and SEM. We designed Langmuir probe system for time resolved diagnosis. ion density of E-ICP is varying periodically with the applied external magnetic field frequencyquency

• Journal of Magnetics
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• v.6 no.1
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• pp.9-12
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• 2001

The dependence of the magnetoimpedance effect (MI) on magnetic properties has been investigated in mumetal thin films prepared by rf magnetron sputtering. Coercivity of thin films prepared at 400 W was about 0.4 Oe, and the magnetic anisotropy field of films deposited under a uniaxial magnetic field decreased with increasing film thickness. The saturation magnetization of mumetal films increased with rising input power and thickness and was smaller than that of permalloy films. Transverse incremental Permeability (TPR) of films of 1$\mu m$ thick increased with increasing effective permeability. The magneto impedance ratio (MIR) was proportional to TPR in films 1$\mu m$ thick but in spite of lower effective permeability at higher thicknesses, MIR increased due to skin effect. The height of the double peaks in the MIR curves decreased with decreasing anisotropy and thickness. The maximum MIR value for a 4$\mu m$ thick 75% at 36.5 MHz.