• 센서학회지
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• 제19권4호
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• pp.328-335
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• 2010

We have designed and fabricated an active pixel sensor(APS) using an optimized n-well/gate-tied p-channel metal oxide semiconductor field effect transistor(PMOSFET)-type photodetector with a built-in transfer gate. This photodetector has a floating gate connected to n-well and a built-in transfer gate. The photodetector has been optimized by changing the length of the transfer gate. The APS has been fabricated using a 0.35 ${\mu}m$ standard complementary metal oxide semiconductor(CMOS) process. It was confirmed that the proposed APS has a wider dynamic range than the APS using the previously proposed photodetector and a higher sensitivity than the conventional APS using a p-n junction photodiode.

• ETRI Journal
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• 제45권1호
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• pp.171-179
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• 2023

We have developed an InAlAs/InGaAs metamorphic high electron mobility transistor device fabrication process where the gate length can be tuned within the range of 0.13㎛-0.16㎛ to suit the intended application. The core processes are a two-step electron-beam lithography process using a three-layer resist and gate recess etching process using citric acid. An electron-beam lithography process was developed to fabricate a T-shaped gate electrode with a fine gate foot and a relatively large gate head. This was realized through the use of three-layered resist and two-step electron beam exposure and development. Citric acid-based gate recess etching is a wet etching, so it is very important to secure etching uniformity and process reproducibility. The device layout was designed by considering the electrochemical reaction involved in recess etching, and a reproducible gate recess etching process was developed by finding optimized etching conditions. Using the developed gate electrode process technology, we were able to successfully manufacture various monolithic microwave integrated circuits, including low noise amplifiers that can be used in the 28 GHz to 94 GHz frequency range.

• Journal of information and communication convergence engineering
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• 제10권2호
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• pp.200-204
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• 2012

This study has presented the analysis of breakdown voltage for a double-gate metal-oxide semiconductor field-effect transistor (MOSFET) based on the doping distribution of the Gaussian function. The double-gate MOSFET is a next generation transistor that shrinks the short channel effects of the nano-scaled CMOSFET. The degradation of breakdown voltage is a highly important short channel effect with threshold voltage roll-off and an increase in subthreshold swings. The analytical potential distribution derived from Poisson's equation and the Fulop's avalanche breakdown condition have been used to calculate the breakdown voltage of a double-gate MOSFET for the shape of the Gaussian doping distribution. This analytical potential model is in good agreement with the numerical model. Using this model, the breakdown voltage has been analyzed for channel length and doping concentration with parameters such as projected range and standard projected deviation of Gaussian function. As a result, since the breakdown voltage is greatly changed for the shape of the Gaussian function, the channel doping distribution of a double-gate MOSFET has to be carefully designed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.202-209
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• 2000

This paper introduces the main function and protection method of IGBT gate driver that designed by KOROS. Recently, the applications of insulated gate bipolar transistors(IGBTs) have expanded widely, particularly in the area of railway converters. This driver is suitable for railway traction applications, so they are designed for circumstance of railway vehicle such as vibration. The input control power for this driver is supplied from battery charger of railway. it is no necessary an isolated power supply board or auxiliary power supply, with substantial savings in cost and space in railway applications. This gate driver can be used wide range of input voltage. So, performance of the driver has no relation with the battery voltage(70V∼110V). The protection methods of IGBT gate driver have many kind of ways, but this gate driver it designed to apply to converter for railway system, so this gate driver includes protection for arm short current and low control power voltage, etc. And the process of protection method and protection reference value are optimized by means of sufficient test with our own facilities.

• Journal of information and communication convergence engineering
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• 제5권1호
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• pp.45-49
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• 2007

The analytical transport model in subthreshold regime for double gate MOSFET has been presented to analyze the short channel effects such as subthreshold swing, threshold voltage roll-off and drain induced barrier lowering. The present approach includes the quantum tunneling of carriers through the source-drain barrier. Poisson equation is used for modeling thermionic emission current, and Wentzel-Kramers-Brillouin approximations are applied for modeling quantum tunneling current. This model has been used to investigate the subthreshold operations of double gate MOSFET having the gate length of the nanometer range with ultra thin gate oxide and channel thickness under sub-20nm. Compared with results of two dimensional numerical simulations, the results in this study show good agreements with those for subthreshold swing and threshold voltage roll-off. Note the short channel effects degrade due to quantum tunneling, especially in the gate length of below 10nm, and DGMOSFETs have to be very strictly designed in the regime of below 10nm gate length since quantum tunneling becomes the main transport mechanism in the subthreshold region.

• Journal of Electrical Engineering and Technology
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• 제9권6호
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• pp.2079-2088
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• 2014

In this paper, we propose new physically based threshold voltage models for short channel Surrounding Gate Silicon Nanowire Transistor with two different geometries. The model explores the impact of various device parameters like silicon film thickness, film height, film width, gate oxide thickness, and drain bias on the threshold voltage behavior of a cylindrical surrounding gate and rectangular surrounding gate nanowire MOSFET. Threshold voltage roll-off and DIBL characteristics of these devices are also studied. Proposed models are clearly validated by comparing the simulations with the TCAD simulation for a wide range of device geometries.

• 전자공학회논문지D
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• 제35D권7호
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• pp.79-87
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• 1998

Nitrided oxides which have been investigated as alternative gate oxide for metal-oxide-semiconductor field effect devices were grown by two-step process using N$_{2}$O gas, and were chaacterized via a fowler-nordheim tunneling(FNT) electron injection technique. Electrical characteristics of nitrided gate oxides were superior to that of control oxides.Further, the FNT electron injection into the nitrided gate oxides reveals that gate oxides degrade more both if electrons were foreced to inject from the gate metal and if thicker nitrided gate oxides were used in the thickness range of 90~130.angs.. Models are suggested to explain these phenomena.

• 한국수자원학회논문집
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• 제37권8호
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• pp.675-685
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• 2004

본 연구에서는 FLOW-3D를 이용하여, 테인터수문이 설치된 표준 월류형 여수로에서 수문을 부분 개방했을 경우에 대한 월류흐름 거동을 해석하였다. 모의결과, 유량계수는 약 0.685에서 0.723의 범위를 가지는 것으로 분석되었다. 수문을 완전 개방한 경우의 월류유량을 이용하여 수문을 부분 개방한 경우의 월류유량을 효과적으로 산정 할 수 있는 방법을 제시하였다. 수문의 개방고와 개방도에 따라 여수로면과 수문에 작용하는 압력분포의 특성을 분석하였다. 일정한 수문 개방고에 대해 수문의 개방도가 감소할수록 그리고 일정한 개방도에 대해 수문의 개방고가 높을수록, 여수로면에서 부압은 크게 발생하며 수문에 작용하는 무차원 최대압력은 증가하는 것으로 분석되었다.

• 한국유체기계학회 논문집
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• 제14권5호
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• pp.39-47
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• 2011

Flow control range of valve, which is installed on pipeline, varies according to valve type, pipe diameter, pipe length, roughness, and elevation difference of both ends of pipeline. A lot of computation efforts and knowledge are needed to estimate flow control range of valve, considering above many parameters. The table of flow control range of each valve type is presented for convenience of pipeline design engineers who must make decision of valve size and type in this study. Also the reason that butterfly valve is recommended for flow control, and gate valve is forbidden is presented via quantification and figures in this study.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2783-2785
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• 1999

A fast switching gate driver suitable for high performance self resonant electronic ballasts is presented. The proposed gate driver has negligible switching loss and driving loss owing to pnpn structure and zero voltage switching( ZVS ); moreover, the gate driver has frequency control capability. Therefore, a self resonant inverter using proposed gate driver can operate as external exciting resonant inverters. The experiments confirm that the proposed gate driver perform the desired operations over full power control range for 40W fluorescent lamp electronic ballast.