• 한국자기학회:학술대회 개요집
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• 한국자기학회 2003년도 하계학술연구발표회 및 한.일 공동심포지엄
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• pp.160-161
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• 2003

• The Korean Journal of Ceramics
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• 제3권3호
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• pp.159-162
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• 1997

Diamond was uniformly nucleated on large area Si(001) substrate (3cm$\times$4cm) using the low pressure magnetoactive microwave plasma chemical vapor deposition. $CH_4/He$ gas mixture was used as source gas in order to obtain high radical density in the nucleation enhancement step. $CH_3$radical density was measured by means of infrared laser absorption spectroscopy. The effect of substrate bias voltage on diamond nucleation was examined. The results showed that a suitable positive bias voltage appled to the substrate with respect to the chamber could enhance diamond nucleation while a negative bias voltages leaded to deposition of only non-diamond phase carbon.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.461-464
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• 1999

This study has been investigated that traps generated inside of the oxide and at the oxide interfaces by the stress bias voltage. The traps are charged near the cathode with negative charge and charged near the anode with positive charge. The charge state of the traps can easily be changed by application of low voltages after the stress high voltage. These trap generation involve either electron impact ionization processes or high field generation processes. It determined to the relative traps locations inside the oxides ranges from 113.4$\AA$ to 814$\AA$ with capacitor areas of 10$^{-3}$ $\textrm{cm}^2$ . The oxide charge state of traps generated by the stress high voltage contain either a positive or a negative charge.

• 한국진공학회지
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• 제13권4호
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• pp.150-156
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• 2004

Si(100) 기판 위에 RF UBM 스퍼터링 (Unbalanced Magnetron Sputtering) 방법을 이용하여 BN 박막을 증착하였다. 이온 충돌 에너지에 영향을 주는 증착 압력과 기판 바이어스 전압을 변화시켜, 증착된 BN박막의 미세구조와 압축응력의 변화를 살펴보았다. 높은 증착 압력에서는 hBN laminate의 정렬도가 기판 바이어스 전압이 증가함에 따라 선형적으로 증가한 반면, 낮은 증착 압력에서는 낮은 기판 바이어스 전압에서 hBN laminate의 정렬도가 높게 나타났다. hBN 박막의 응력 변화와 표면 형상은 hBN laminate의 정렬도와 밀접한 관계가 있는 것으로 관찰되었는데, 이의 적절한 조절에 의해 압축응력의 증가 없이도 hBN 박막 위에 cBN 상의 핵 형성이 일어날 수 있었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(2)
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• pp.395-398
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• 2004

High-linearity voltage-controlled current sources (VCCSs) circuits for wide voltage-controlled oscillator and automatic gun control were proposed. The VCCS consists of emitter follower for voltage input, two common-base amplifier which their emitter connected for current output, and current mirror which connected the two amplifier for large output current. The VCCS used only five transistors and a resistor without an extra bias circuit. Simulation results show that the VCCS has current output range from 0mA to 300mA over the control voltage range from 1V to 4.8V at supply voltage 5V. The linearity error of output current has less than $1.4\%$ over the current range from 0A to 300mA.

• 한국재료학회지
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• 제10권3호
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• pp.179-183
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• 2000

$BCI_3/H_2/Ar$ ICP(Inductively Coupled Plasma)를 이용한 GaN이 건식식각에 있어서 공정변수들이 식각 특성에 미치는 영향을 분석하고 적정조건을 도출하였다. 연구 결과 식각속도와 측벽수직도 공히 ICP 전력, bias 전압과 $BCI_3$ 조성의 증가, 공정압력의 감소에 의해 현저히 증가하며, 온도의 증가에 따라 다소간 증가하였고, 온도의 증가에 따라 다소간 증가하였고, $BCI_3$조성이 가장 큰 영향을 미쳤다. 표면거칠기는 bias 전압 증가에 의해 크게 향상, $BCI_3$ 조성의 감소에 따라 향상되었으며 다른 변수는 큰 영향을 미치지 않았다. 결과적으로 ICP 전력 900W, bias 전압 400V, $BCI_3$ 조성 60%, 공정압력 4mTorr의 조건에서 175nm/min 정도의 $CI_2$ 사용 시와 유사한 높은 식각속도와 평탄한 표면이 얻어졌다. Bias 전압이 낮은 경우 식각 후 시료 표면에 $GaC_x$로 추정되는 식각부산물이 관찰되었다.

• 한국표면공학회지
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• 제44권5호
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• pp.213-219
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• 2011

Recently aspheric lenses are widely used for superpricision optical instruments, such as cellular phone camera modules, digital cameras and optical communication modules. The aspherical lenses are processed using mold core under high temperature compressive forming pressure. It is imperative to develop superhard protective films for the life extension of lens forming mold core. Especially ta-C films with higher $sp^3$ fractions receive attentions for the life extension of lens forming mold and, in turn, the cost reduction of lenses due to their suprior high temperature stability, high hardness and smooth surfaces. In this study ta-C films were processed on WC mold as a function of substrate bias voltage using FVA (Filtered Vacuum Arc) method. The processed films were characterized by Raman spectroscopy and nano-indentation to investigate bonding nature and hardness, respectively. The film with maximun 87% of $sp^3$ fraction was obtained at the substrate bias voltage of -60 V, which was closest to ta-C film. ta-C films showed better high temperature stability by sustaining relatively high fraction of $sp^3$ bonding even after 2,000 glass lens forming applications.

• 한국세라믹학회지
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• 제23권1호
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• pp.44-50
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• 1986

Si-ZnO n-n heterojunction diodes were prespared by r.f diode sputtering of the sintered ZnO target on n-type Si single crystal wafers and their structures and electrical properties were studied. The films were grown orientedly with the c-axis of crystallites perpendicular to the substrate surface at low r.f. powder and grown to polycrystalline films with random orientation at high r. f. powder. The crystallite size increased with the increasing substrate temperture The oriented texture films only were used to prepare the photovoltaic diodes and these didoes showed the photovoltaic effect veing positive of the ZnO side for the photons in the wavelength range of 380-1450nm. The sign reversal of phootovoltage which is the property os isotype heterojunction was not observed because of the degeneration of the ZnO films. The diode showed the forward rectification when it was biased with the ZnO side positive. The current-voltage characteristics exhibited the thermal-current type relationship J∝exp(qV/nkT) with n=1.23 at the low forward bias voltage and the tunnelling-current type relationship J∝exp($\alpha$V) where $\alpha$ was constant independent of temperature at the high forward bias voltage. The crystallite size of ZnO films were influenced largely on the photovoltaic properties of diodes ; The diodes with the films of the larger crystallites showed the poor photovoltaic properties. This reason may be cosidered that the ZnO films with the large crystallites could not grow to the electrically continuous films because the thickness of films was so thin in this experiment.

• Transactions on Electrical and Electronic Materials
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• 제3권1호
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• pp.38-41
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• 2002

We have investigated current-voltage-luminance characteristics of organic light-emitting diodes based on TPD/Alq$_3$organics depending on the application of forward-backward bias voltage. Luminance-voltage characteristics and luminous efficiency were measured at the same time when the current-voltage characteristics were measured. We have observed that the current-voltage characteristics shows a reversible current maxima at low voltage, which is possibly not related to the emission from Alq$_3$. Current-voltage-luminance characteristics imply that the conduction luminance mechanism at low voltage is different from that of high voltage one.

• Transactions on Electrical and Electronic Materials
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• 제17권2호
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• pp.113-117
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• 2016

Temperature dependent reverse-bias current-voltage (I-V) characteristics in Cu Schottky contacts to oxygen plasma treated n-InP were investigated. For untreated sample, current transport mechanisms at low and high temperatures were explained by thermionic emission (TE) and TE combined with barrier lowering, respectively. For plasma treated sample, experimental I-V data were explained by TE or TE combined with barrier lowering models at low and high temperatures. However, the current transport was explained by a thermionic field emission (TFE) model at intermediate temperatures. From X-ray photoemission spectroscopy (XPS) measurements, phosphorus vacancies (VP) were suggested to be generated after oxygen plasma treatment. V_P possibly involves defects contributing to the current transport at intermediate temperatures. Therefore, minimizing the generation of these defects after oxygen plasma treatment is required to reduce the reverse-bias leakage current.