• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.207-207
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• 2006

We investigated the effects of hydrogen addition to the growth process of SiC single crystal using sublimation physical vapor transport(PVT) techniques. Hydrogen was periodically added to an inert gas for the growth ambient during the SiC bulk growth Grown 2"-SiC single crystals were proven to be the polytype of 6H-SiC and carrier concentration levels of about $10^{17}/cm^3$ was determined from Hall measurements. As compared to the characteristics of SiC crystal grown without using hydrogen addition, the SiC crystal without definitely exhibited lower carrier concentration and lower microplpe density as well as reduced growth rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.7 no.1
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• pp.37-45
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• 1982

We have analyzed the effect of multipath cochannel interference and Gaussian noise on binary DPSK systems used in land mobile radio communications. Considering multipath channel as non-selective Rayleigh channel, we have found a gnenral equation for bit error rates (BER) deriving the probability density function (p.d.f) of output of phase detector. The numerical results are shown in graphs and discussed as functions of carrier to noise power ratio (CNR), carrier to interferer power ratio (CIR) and correlation of signal component over the pulse length.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.707-710
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• 2006

Zinc oxide (ZnO) is typically highly doped n-type semiconductor. To be used for thin-film transistor (TFT) devices, carrier concentration must be controlled precisely. We studied characteristics of ZnO grown by MOCVD at temperatures between $200^{\circ}C$ and $400^{\circ}C$. We found that hydrogen incorporated during growth plays important role in determining carrier density.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.7
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• pp.780-790
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• 1988

We have studied the hot-carrier-induced degradation caused by the high channel electric field due to the decrease of the gate length of MOSFET used in VLSI. Under DC stress, the condition in which maximum substrate current occures gave the worst degradation. Under AC dynamic stress, other conditions, the pulse shape and the falling rate, gave enormous effects on the degradation phenomena, especially at 77K. Threshold voltage, transconductance, channel conductance and gate current were measured and compared under various stress conditions. The threshold voltage was almost completely recovered by hot-injection stress as a reverse-stress. But, the transconductance was rapidly degraded under hot-hole injection and recovered by sequential hot-electron stress. The Si-SiO2 interface state density was analyzed by a charge pumping technique and the charge pumping current showed the same trend as the threshold voltage shift in degradation process.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.1
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• pp.55-62
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• 1983

The error rate performance of phase shift Keyed(PSK) signal has been evaluated in terms of carrier-to-noise ratio(CNR), carrier-to-interferer ratio(CIR), impulsive index, and the phase difference between signal and interferer in the environment of cochannel PSK inter-ference and impulsive noise. We hays derived a general equation of the probability density function (p.d.f.) of output of coherent phase detector. And the error rate of the received binary PSK(BPSK) signal has been numerically evaluated. The graphic results show us that the best case is the situation of the signal and the inter- ferer meet with orthogonal phase.

• Korean Journal of Materials Research
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• v.26 no.1
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• pp.42-46
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• 2016

The properties of zinc oxynitride semiconductors and their associated thin film transistors are studied. Reactively sputtered zinc oxynitride films exhibit n-type conduction, and nitrogen-rich compositions result in relatively high electron mobility. Nitrogen vacancies are anticipated to act as shallow electron donors, as their calculated formation energy is lowest among the possible types of point defects. The carrier density can be reduced by substituting zinc with metals such as gallium or aluminum, which form stronger bonds with nitrogen than zinc does. The electrical properties of gallium-doped zinc oxynitride thin films and their respective devices demonstrate the carrier suppression effect accordingly.

• Progress in Superconductivity
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• v.13 no.1
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• pp.47-51
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• 2011

Mono-atomic-layer graphene is an interesting system for studying the relativistic carrier transport arising from a linear energy-momentum dispersion relation. An easy control of the carrier density in graphene by applying an external gate field makes the system even more useful. In this study, we measured the Josephson current in a device consisting of mono-layer graphene sheet sandwiched between two closely spaced (~300 nm) aluminum superconducting electrodes. Gate dependence of the supercurrent in graphene Josephson junction follows the gate dependence of the normal-state conductance. The gate-tunable and relatively large supercurrent in a graphene Josephson junction would facilitate our understanding on the weak-link behavior in a superconducting-normal metal-superconducting (SNS) type Josephson junction.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.2
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• pp.223-225
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• 2016

The newly proposed analysis method using a direct-current current-voltage (DCIV) simulation is introduced for investigating leakage current composing MOS transistor. From comparing the density and location of traps using DCIV method and investigating the leakage current of gate channel transistor, we proposed the graphical analysis method to correlate the DCIV current and leakage mechanism by the traps. And, our graphical method intuitively explains that leakage current in MOS transistor is well correlated with the DCIV current of the MOS transistor arrays due to two kinds of traps created by Fowler-Nordheim (F-N) stress and Hot carrier stress, respectively.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.1
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• pp.82-87
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• 2004

The purpose of this paper is to obtain the data for manufacturing of microbe carriers as a method of FRP waste recycling technology. Since FRP waste is polymer, the experiment of the thermogravity analyzing was carried out to find thermal behavior. After that, microbe carriers were prepared from waste FRP powder, which had been decomposed, milled, and mixed with clay as a binder and CaCO3 as a flux and a loaming agent, respectively. finally it was made by filing of the sample up to 1,05$0^{\circ}C$. It was investigated how the variation of the additives and firing temperature effect apparent density, water absorption and micro structure.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.6 no.6
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• pp.23-31
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• 1992

Charged particle in the polymers is supposed to affect the electrical conduction and to lead them th dielectrical breakdown finally. So we measured the space charge distribution made by application of high electric field and evaluated the polarity of the charged particle affected on electrical conduction and space charge formed in the insulating materials by using temperature gradient thermally stimulated current measurement method(TG-TSC measurement). As a result, in the cross-linked polyethylene, A-peak was caused from dipole polarization, C-peak was caused from ionic space charge polarization and D-peak was injected trap hole. Also we found it crossible the evaluated the polarity of injected trap carrier and electron(or hole) of carrier trap in the cross-lined polyethylene. We found that ${\gamma}$-ray irradiated low density polyethylene had a relation to the electronic trap and we also could get the value of electric field distribution in the samples of which evaluation was available.