• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.207-209
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• 2004

Currently, for satisfying the needs of scaled MOSFET's a high quality thin oxide dielectric is desired because the properties of conventional $SiO_2$ film are not acceptable for these very small sized transistors. As an alternative gate dielectric have drawn considerable alternation due to their superior performance and reliability properties over conventional $SiO_2$, to obtain the superior characteristics of ultra thin dielectric films, $N_2O$ grown thin oxynitride has been proposed as a dielectric growtuanneal ambient. In this study the authors observed process characteristics of $N_2O$ grown thin dielectric. In view points of the process characteristics of MOS capacitor, the sheet resistance of 4.07$[\Omega/sq.]$, the film stress of $1.009e^{10}[dyne/cm^2]$, the threshold voltage$(V_t)$ of 0.39[V], the breakdown voltage(BV[V]) of 11.45[V] was measured in PMOS. I could achieve improved electrical characteristics and reliability for deep submicron MOSFET devices with $N_2O$ thin oxide.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.196-197
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• 2010

NAND형 charge trap flash (CTF) non-volatile memory (NVM) 소자가 30nm node 이하로 고집적화 되면서, 기존의 SONOS형 CTF NVM의 tunnel barrier로 쓰이는 SiO2는 direct tunneling과 stress induced leakage current (SILC)등의 효과로 인해 data retention의 감소 등 물리적인 한계에 이르렀다. 이에 따라 개선된 retention과 빠른 쓰기/지우기 속도를 만족시키기 위해서 tunnel barrier engineering (TBE)가 제안되었다. TBE NVM은 tunnel layer의 전위장벽을 엔지니어드함으로써 낮은 전압에서 전계의 민감도를 향상 시켜 동일한 두께의 단일 SiO2 터널베리어 보다 빠른 쓰기/지우기 속도를 확보할 수 있다. 또한 최근에 각광받는 high-k 물질을 TBE NVM에 적용시키는 연구가 활발히 진행 중이다. 본 연구에서는 Si3N4와 HfAlO (HfO2 : Al2O3 = 1:3)을 적층시켜 staggered의 새로운 구조의 tunnel barrier Capacitor를 제작하여 전기적 특성을 후속 열처리 온도와 방법에 따라 평가하였다. 실험은 n-type Si (100) wafer를 RCA 클리닝 실시한 후 Low pressure chemical vapor deposition (LPCVD)를 이용하여 Si3N4 3 nm 증착 후, Atomic layer deposition (ALD)를 이용하여 HfAlO를 3 nm 증착하였다. 게이트 전극은 e-beam evaporation을 이용하여 Al를 150 nm 증착하였다. 후속 열처리는 수소가 2% 함유된 질소 분위기에서 $300^{\circ}C$와 $450^{\circ}C$에서 Forming gas annealing (FGA) 실시하였고 질소 분위기에서 $600^{\circ}C{\sim}1000^{\circ}C$까지 Rapid thermal annealing (RTA)을 각각 실시하였다. 전기적 특성 분석은 후속 열처리 공정의 온도와 열처리 방법에 따라 Current-voltage와 Capacitance-voltage 특성을 조사하였다.

• Journal of Power Electronics
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• 제19권2호
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• pp.363-379
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• 2019

Resonant converters have attracted a lot of attention because of their high efficiency due to the soft-switching performance. An isolated high step-up converter with secondary-side resonant loops is proposed and analyzed in this paper. By placing the resonant loops on the secondary side, the current stress for the resonant capacitors is greatly reduced. The power loss caused by the equivalent series resistance of the resonant capacitor is also decreased. Clamp diodes in parallel with the resonant capacitors ensure a unique discontinuous current mode in the converter. Under this mode, the active switches can realize soft-switching during both turn-on and turn-off transitions. Meanwhile, the reverse-recovery problems of diodes are also alleviated by the leakage inductor. The converter is essentially a step-up converter. Therefore, it is helpful for decreasing the transformer turn-ratio when it is applied as a high step-up converter. The steady-state operation principle is analyzed in detail and design considerations are presented in this paper. Theoretical conclusions are verified by experimental results obtained from a 500W prototype with a 35V-42V input and a 400V output.

• 조명전기설비학회논문지
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• 제27권7호
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• pp.8-16
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• 2013

This paper investigates the electrical characteristics of popular power converters such as a half-bridge rectifier, a full-bridge rectifier, a buck converter, and an inverter when the arc is occurred at the input and the output of each converter. In order to generate an artificial arc, the arc generator has been implemented according to the design guideline suggested in UL1699. After that, the trend of the input and output voltage variation and the switching stress of the devices are analyzed. From the analysis, it has been confirmed that the generated arc causes an uncertain operation to the power converters. To reduce the unexpected disturbance effect of the arc, the capacitor adjustment method has been proposed, and its superiority has been experimentally verified.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.397-398
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• 2010

본 논문에서는 고전력 밀도 및 저가형으로 구현 가능한 새로운 구조의 계통 연계형 태양광 인버터 시스템을 제안한다. 제안된 시스템은 링크 캐피시터와 배터리를 직렬 연결하여 링크 캐패시터의 전압 스트레스를 저감하였고, 이를 통하여 기존 대비 1/2의 캐패시터 사용이 가능하다. 제안 시스템의 우수성을 검증하기 위하여 1.5kW급 시작품을 제작하였고 이를 바탕으로 제안된 시스템의 타당성을 검증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.328-331
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• 1990

A new quasi-resonant do link inverter is suggested, which can operate at the constant peak do link voltage irrespective of the magnitude of load current. The inverter is analyzed by using the topological analogy between the proposed inverter and the resonant DC/DC converter. Based on the analysis, an appropriate current controller is developed, which results in low current stress to the resonant capacitor and also enjoys the inherent capability of the current initialization of resonant inductor. For the purpose of confirming the inverter characteristics, some simulation results are presented.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 추계학술대회 논문집
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• pp.121-124
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• 2002

The conventional three-level high frequency phase-shifted dc/dc converter has a disadvantage that a circulating current flows through transformer and switching devices during the freewheeling interval. Due In this circulating current and RMS current stress, conduction losses of transformer and switching devices increases. To alleviate these problems, we propose an improved three-level Zero Voltage and Zero Current Switching (ZVZCS) dc/dc converter using a tapped inductor, a snubber capacitor and two snubber diodes attached at the secondary side of transformer The proposed ZVZCS converter is verified on a 7kW, 30kHz experimental prototype.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.689-693
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• 2001

The conventional three-level high frequency phase-shifted dc/dc converter has a disadvantage that a circulating current flows through transformer and switching devices during the freewheeling interval. Due to this circulating current and RMS current stress, conduction losses of transformer and switching devices increases. To alleviate these problems, we propose an improved three-level Zero Voltage and Zero Current Switching (ZVZCS) dc/dc converter using a tapped inductor, a snubber capacitor and two snubber diodes attached at the secondary side of transformer. The proposed ZVZCS converter is verified on a 10 kW, 30kHz experimental prototype.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.335-336
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• 2007

A new current-programmed pixel circuit for activematrix organic light emitting diodes (AMOLEDs), based on Organic TFTs (OTFTs), is proposed and verified by SPICE simulations. The simulation results show that the proposed pixel circuit, which is a current mirror structure consisting of five Organic TFTs and one capacitor, has reliable linear characteristics between input current and output OLED current. Also, the threshold voltage degradation of Organic TFTs due to long time operation stress is well compensated to reliable values.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 추계학술대회 논문집
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• pp.133-136
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• 2008

This paper presents a novel soft switching topology with resonant DC-DC converter and inverter. The resonant DC-DC converter consists of the auxiliary switch, resonant capacitor and inductor. All switches in the proposed topology is turn on at ZCS and turn off at ZVS operation. The proposed soft switching technology can be obtained the reduced switching losses and voltage and current stress of the power devices. Therefore, the resonant converter efficiency is higher than conventional boost converter. Simulation results on a 1kW soft switching converter are presented.