• 한국전자파학회논문지
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• 제30권4호
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• pp.282-285
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• 2019

본 연구에서는 2단계 게이트 리세스 방법을 사용하여 T-형 게이트 길이가 100 nm인 mHEMT 소자를 제작하였다. 제작한 소자는 65 mA의 드레인전류($I_{dss}$), 1090 mS/mm의 트랜스콘덕턴스($g_m$), -0.65 V의 문턱전압 ($V_{th}$) 등의 DC 특성을 보였다. 또한 차단주파수($f_T$) 190 GHz와 최대 공진주파수($f_{MAX}$) 260 GHz인 우수한 고주파 특성을 나타내었다. 제작한 mHEMT 소자는 향후에 W-대역의 MMIC 개발에 활용될 수 있을 것으로 기대된다.

• ETRI Journal
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• 제33권6호
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• pp.969-972
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• 2011

This letter presents a CMOS RF front-end operating in a subthreshold region for low-power Band-III mobile TV applications. The performance and feasibility of the RF front-end are verified by integrating with a low-IF RF tuner fabricated in a 0.13-${\mu}m$ CMOS technology. The RF front-end achieves the measured noise figure of 4.4 dB and a wide gain control range of 68.7 dB with a maximum gain of 54.7 dB. The power consumption of the RF front-end is 13.8 mW from a 1.2 V supply.

• 한국전자파학회논문지
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• 제28권1호
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• pp.1-9
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• 2017

본 논문에서는 한국전자통신연구원(ETRI)에서 구축한 $0.25{\mu}m$ GaN MMIC 공정 및 소자특성을 소개하고, 이를 이용한 X-대역 3 W GaN 전력증폭기 MMIC 설계 제작 결과를 논의한다. X-대역 동작에 적합한 GaN HEMT 소자를 선정하여 GaN 전력증폭기 MMIC를 1단으로 설계하고 제작하였으며, 이를 통하여 ETRI $0.25{\mu}m$ GaN MMIC 공정 및 특성을 평가하고 분석하였다. X-대역 GaN 전력증폭기 MMIC 제작 결과, 출력전력 3.5 W, 이득 10 dB 및 전력부가효율 35 % 특성을 얻었다.

• 한국전자파학회논문지
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• 제27권1호
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• pp.76-79
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• 2016

본 논문에서는 ETRI에서 개발된 50 W GaN-on-SiC HEMT 소자를 이용하여 X-band에서 동작하는 50 W 펄스 전력증폭기의 개발 결과를 정리하였다. 제작된 50 W GaN HEMT 소자는 $0.25{\mu}m$의 게이트 길이를 갖고, 총 게이트 폭은 12 mm인 소자이다. 펄스 전력증폭기는 9.2~9.5 GHz 주파수 대역에서 50 W의 출력전력과 6 dB의 전력이득 특성을 나타내었다. 전력소자의 전력밀도는 4.16 W/mm이다. 제작된 GaN-on-SiC HEMT 소자와 전력증폭기는 X-대역 레이더 시스템 등 다양한 응용분야에 적용이 가능할 것으로 판단된다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제1권1호
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• pp.70-83
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• 2001

In this paper, the recent progress of RF MEMS research for wireless/mobile communications is reviewed. The RF MEMS components reviewed in this paper include RF MEMS switches, tunable capacitors, high Q inductors, and thin film bulk acoustic resonators (TFBARs) to become core components for constructing miniaturized on chip RF transceiver with multi-band and multi-mode operation. Specific applications are also discussed for each of these components with emphasis on for miniaturization, integration, and performance enhancement of existing and future wireless transceiver developments.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.199-202
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• 1999

In this paper, a possibility of building various types of RF passive components using the silicon micromachining technique has been examined with special emphasis on the wireless and mobile communication applications. Silicon micromachining technique is compatible with conventional silicon IC process and could provide a possibility of integrating base-band signal processing units and RF passive and active circuit components all in one silicon wafer rendering implementation of system-on-chip paradigm for future mobile and wireless communication systems.

• 한국전기전자재료학회논문지
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• 제32권3호
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• pp.201-206
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• 2019

This report constitutes the first demonstration in Korea of single-crystal lateral gallium oxide ($Ga_2O_3$) as a metal-oxide-semiconductor field-effect-transistor (MOSFET), with a breakdown voltage in excess of 480 V. A Si-doped channel layer was grown on a Fe-doped semi-insulating ${\beta}-Ga_2O_3$ (010) substrate by molecular beam epitaxy. The single-crystal substrate was grown by the edge-defined film-fed growth method and wafered to a size of $10{\times}15mm^2$. Although we fabricated several types of power devices using the same process, we only report the characterization of a finger-type MOSFET with a gate length ($L_g$) of $2{\mu}m$ and a gate-drain spacing ($L_{gd}$) of $5{\mu}m$. The MOSFET showed a favorable drain current modulation according to the gate voltage swing. A complete drain current pinch-off feature was also obtained for $V_{gs}<-6V$, and the three-terminal off-state breakdown voltage was over 482 V in a $L_{gd}=5{\mu}m$ device measured in Fluorinert ambient at $V_{gs}=-10V$. A low drain leakage current of 4.7 nA at the off-state led to a high on/off drain current ratio of approximately $5.3{\times}10^5$. These device characteristics indicate the promising potential of $Ga_2O_3$-based electrical devices for next-generation high-power device applications, such as electrical autonomous vehicles, railroads, photovoltaics, renewable energy, and industry.

• 한국전기전자재료학회논문지
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• 제33권2호
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• pp.99-104
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• 2020

In this study, we fabricated a metamorphic high-electron-mobility transistor (mHEMT) device with a T-type gate structure for the implementation of W-band monolithic microwave integrated circuits (MMICs) and investigated its characteristics. To fabricate the mHEMT device, a recess process for etching of its Schottky layer was applied before gate metal deposition, and an e-beam lithography using a triple photoresist film for the T-gate structure was employed. We measured DC and RF characteristics of the fabricated device to verify the characteristics that can be used in W-band MMIC design. The mHEMT device exhibited DC characteristics such as a drain current density of 747 mA/mm, maximum transconductance of 1.354 S/mm, and pinch-off voltage of -0.42 V. Concerning the frequency characteristics, the device showed a cutoff frequency of 215 GHz and maximum oscillation frequency of 260 GHz, which provide sufficient performance for W-band MMIC design and fabrication. In addition, active and passive modeling was performed and its accuracy was evaluated by comparing the measured results. The developed mHEMT and device models could be used for the fabrication of W-band MMICs.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 1999년도 1st Korea-Japan Advanced Semiconductor Packaging Technology Seminar
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• pp.127-154
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• 1999

Interconnect - Wire bonding-> Flip chip interconnect ; At research step, Au stud bump bonding seems to be more proper .Package -Plastic package-> $Z_{0}$ controlled land grid package -Flip Chip will be used for RF ICs and CSP for digital ICs -RF MCM comprised of bare active devices and integrated passive components -Electrical design skills are much more required in RF packaging .Passive Component -discrete-> integrated -Both of size and numbers of passive components must be reduced

• Applied Biological Chemistry
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• 제2권
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• pp.36-39
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• 1961

It has been ascertained that S-(1, 2-dichlorovinyl) L-cysteine (DCVC) is probably the toxic component in the trichloro-ethylene extracted soybean oil meal on the bovine. For the study of the metabolites of DCVC, the components with radioactive $S^{35}$-in the urine of the calf, to which $S^{35}$-DCVC was administrated, were separated using of cellulose powder with propanol-water (70:30 V/V) which is easily removable by evaporation. As the results followings were obtained: Peak 1, which shows fractions containing single $S^{35}$-radioactive components, whose Rf is 0.815 Peak 2, which shows fractions containing jingle $S^{35}$-radioactive component, whose Rf is 0.447 Peak 3, which shows fractions containing both $S^{35}$-radioactive components whose Rfs are 0.090 and 0.171 Peak 4, which shows fractions containing single $S^{35}$-radioactive component, whose Rf is 0.142. Peak 5, which shows fractions containing single $S^{35}$-radioactive component, whose Rf is 0.084. Besides these, two of small peak were obtained. Although, the resolving power of the cellulose powder column is not sufficient, it is applicable for the study of the components of metabolytes of DCVC conveniently with the rest of removable solvent easily. Also the components with radioactive $S^{35}$ in the feces of the calf were separated using citrate buffer gradient system of Moore and stein. As the results; three $S^{35}$-radioactive components were separated.