• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.529-530
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• 2005

A voltage driving AMOLED(Active Matrix Organic Light Emitting Diode) is useful for large-sized, high resolution OLED display. The conventional 2-TFTs, 1-CAP AMOLED circuit suffer from the threshold voltage variation of TFT. In this paper, a new AMOLED structure is proposed. It is composed of 5-TFTs and 2-capacitors. It is described that the operating principle and the characteristics of the proposed structure and is verified the performance by HSPICE simulation. The result of simulation shows that the effect of the threshold voltage variation in this circuit, is able to neglect.

• Transactions on Electrical and Electronic Materials
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• 제18권4호
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• pp.199-202
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• 2017

Silicon carbide (SiC) is being spotlighted as a next-generation power semiconductor material owing to the characteristic limitations of the existing silicon materials. SiC has a wider band gap, higher breakdown voltage, higher thermal conductivity, and higher saturation electron mobility than those of Si. When using this material to implement Schottky barrier diode (SBD) devices, SBD-state operation loss and switching loss can be greatly reduced as compared to that of traditional Si. However, actual SiC SBDs exhibit a lower dielectric breakdown voltage than the theoretical breakdown voltage that causes the electric field concentration, a phenomenon that occurs on the edge of the contact surface as in conventional power semiconductor devices. Therefore in order to obtain a high breakdown voltage, it is necessary to distribute the electric field concentration using the edge termination structure. In this paper, we designed an edge termination structure using a field plate structure through oxide etch angle control, and optimized the structure to obtain a high breakdown voltage. We designed the edge termination structure for a 650 V breakdown voltage using Sentaurus Workbench provided by IDEC. We conducted field plate experiments. under the following conditions: $15^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, and $75^{\circ}$. The experimental results indicated that the oxide etch angle was $45^{\circ}$ when the breakdown voltage characteristics of the SiC SBD were optimized and a breakdown voltage of 681 V was obtained.

• 센서학회지
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• 제32권6호
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• pp.441-446
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• 2023

Electrical and optical characteristics of the GaN-based light-emitting diode (LED) with the improved multi-quantum well (MQW) structure have been studied for light source in bio-sensing systems. Novel GaN/In_0.1GaN/In_0.2GaN/In_0.1GaN/GaN and Al_0.1GaN/GaN/In_0.2GaN/GaN/Al_0.1GaN (MQW) structures were suggested, and their radiative recombination rate, light output power, electroluminescence, and external quantum efficiency were compared with those of the conventional GaN/In_0.2GaN/GaN MQW structure using device simulation. The LED with the GaN/In_0.1GaN/In_0.2GaN/In_0.1GaN/GaN MQW structure showed an excellent recombination rate of 5.57 × 10²⁸ cm^-3·s^-1 that was more than one order improvement over that of the conventional LED. In addition, the efficiency droop was relieved by the suggested stepped MQW structure.

• 전력전자학회논문지
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• 제24권6호
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• pp.396-405
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• 2019

Single-phase full-bridge inverters have shoot-through problems. Dead time is an essential way of solving these issues, but it distorts the output voltage and current. Dual-buck inverters are designed to eliminate the abovementioned problems. However, these inverters result in switching power loss and electromagnetic interference due to the diode reverse-recovery problem. Previous studies have suggested reducing the switching power loss from diode reverse-recovery, but their proposed methods have complex circuit configurations and high system costs. To alleviate the switching power loss from diode reverse-recovery, the current work proposes a dual-buck inverter with a coupled inductor. In the structure of the proposed inverter, the current flowing into the original diode is divided into a new diode. Therefore, the switching power loss is reduced, and the efficiency of the proposed inverter is improved. Simulation waveforms and experimental results for a 1.0 kW prototype inverter are discussed to verify the performance of the proposed inverter.

• 한국산학기술학회논문지
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• 제11권2호
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• pp.485-490
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• 2010

본 논문에서는 버팅 콘택(butting contact) 구조를 갖는 DDI DRAM소자의 감지 증폭기의 입력 게이트 단의 모든 기생 성분을 포함한 등가 회로를 제안 하였다. 제안한 모델을 이용하여 기생 쇼트키 다이오드가 감지 증폭기 동작에 어떤 영향을 미치는지 분석하였다. 각각의 불량 가능성에 대해 감지 증폭기가 어떻게 동작하는지 분석하여 단측 불량 특성의 원인을 규명하였다. DDI DRAM에서 단측 불량 원인과 불량률의 온도 의존성은 감지 증폭기의 입력 게이트 단에 형성된 기생 쇼트키 다이오드 형성에 기인한 것으로 판단된다. 이러한 기생 쇼트키 다이오드는 게이트 입력에 기생 전압 강하를 야기하게 되고 결국 감지 증폭기의 노이즈 마진을 감소시켜 단측 불량률을 증가시킨다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 D
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• pp.754-757
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• 2000

Si PIN diodes are subject to be damaged from the exposure of fast neutron by displacement of Si lattice structure. The defects are effective recombination centers for carriers which migrate through the base region of the PIN diode when forward voltage is applied. It causes an increase in current and a decrease in resistivity of the diode. This paper presents the development of a neutron sensor based on displacement damage effect. PIN diodes having various structures were made by micro-fabrication process, and neutron beam test was performed to identify neutron damage effect to the diode. From a result of the test, it was shown that the forward voltage drop of the diode, at a constant current, has good linearity for neutron dosage. Also it was found that the newton dosage can be measured by the pin diode neutron dosimeter with constant current power.

• 한국통신학회논문지
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• 제19권3호
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• pp.591-596
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• 1994

Gain-guided 구조를 갖는 단일양자우물 laser diode에서, stripe 폭에 따른 threshold의 변화를 복소수영역 유효굴적률방법을 이용하여 분석하였다. 분석결과 stripe 폭이 좁은 영역에서는, 측방향광집속률을 나타내기위하여 세롭게 도입된 변수 가 수직방향광집속률 가 감소함에따라 급격하게 감소하는 경향을 알아내었다. 따라서 일반적으로 매우작은 수직방향광집속률을 갖는 단일양자우물 laser diode에서는, stripe 폭의 크기에 따라서는 광집속률이 측방향은 물론 수직방향으로도 매우 나빠지게 됨으로 이득포와현상을 더욱 심하게시키게되며 경우에 따라서는 문턱전류가 비정상적으로 증가하는 현상으로 이어지게된다. 이와같은 문턱치의 stripe 폭에 대한 약간의 비정상적인 의존성을 이해하는 것은 양자우물 laser diode의 구조최적화에 있어서 매우 중요한 일이라고 판단된다.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권11호
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• pp.654-659
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• 2005

An improved power supply for APD(Avalanche Photo Diode) with a received optical power monitoring circuit allows the received optical power increase temporary without of the degradation of the electrical signal. For the cost reduction and simple fabrication, an improved power supply has been proposed that it was designed for driving a APD as a receiving device of a wireless optical transmission system. It was demonstrated that it was possible to improve a dynamic range by compensating the temperature coefficient of the APD up to 1.0 V/$^{\circ}C$ through the power supply. Also, for an efficient transmission at the receiver end, a simple structure of a single cylindrical micro-lens configuration was used in conjunction with the laser diode to partially compensate a laser beam ellipticity. For this purpose, an astigmatism introduced by the micro-lens is utilized for the additional compensation of the beam ellipticity at the receiver end. In this paper, it is demonstrated that an efficient beam shaping is realized by using the proposed configuration consisting of the single lens attached to the laser diode.

• 한국진공학회지
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• 제21권4호
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• pp.185-192
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• 2012

Light Emitting Diode (LED) 칩의 크기는 전도를 통한 열의 방출에 있어 면적의 확대로 인한 열 밀도의 감소와 칩의 외부양자효율 변화로 인하여 LED 칩의 p-n 정션 온도와 패키지의 열 저항에 영향을 미친다. 본 연구에서는 16칩 LED 패키지에서 칩의 크기가 0.6 mm와 1 mm인 두 가지 경우에 대하여 순전압(forward voltage)을 측정하였고, 순간열분석법(thermal transient analysis)을 이용하여 정션 온도와 열 저항을 평가하였으며, 이를 LED 칩의 전기적인 특성과 LED 패키지의 구조적인 특성과 연관하여 해석하였다.

• 전기학회논문지
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• 제62권11호
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• pp.1566-1570
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• 2013

In this paper, we analyzed the electric characteristics of the OLEDs device of which anode ITO has been treated with the oxygen plasma. We fabricated the basic three-layer structure (ITO / AF / $Alq_3$ / $Cs_2CO_3$ / Al) device, analyzed how the oxygen plasma treatments of the ITO surface affects to the electrical characteristics of OLEDs. We also produced a four-layer structure device (ITO / AF / TPD / $Alq_3$ / $Cs_2CO_3$ / Al) with the oxygen plasma treatment. From the comparative analysis to the devices, we confirmed following results. The three-layer structure OLEDs device with oxygen plasma treatment has better characteristics than the device without the treatments; maximum luminance, luminous efficiency, and external quantum efficiency are improved approximately 151 [%], 126 [%], and 175[%], respectively. Also, the electric characteristics of the four-layer structure device with oxygen plasma treatment are improved comparing to the characteristics of the three-layer structure device with oxygen plasma treatment; maximum luminance, luminous efficiency, and external quantum efficiency are improved approximately 144 [%], 115 [%], and 124[%], respectively.