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Byoung-Gue MIN,Chul-Won JU,Jong-Min LEE,Kyung-Ho LEE,Seong-Il KIM 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.3
A significant degradation of current gain of InP/InGaAs/InP double heterojunction bipolar transistors was observed after passivation. The amount of degradation depended on the degree of surface exposure of the p-type InGaAs base layer according to the epi-structure and device structure. The deposition conditions such as deposition temperature, kinds of materials (silicon oxide, silicon nitride and aluminum oxide) and lm thickness were not major variables to aect the device performance. The gain reduction was prevented by the BOE treatment before the passivation. A possible explanation of this behavior is that unstable non-stoichiometric surface states produced by excess In, Ga, or As after mesa etching are eliminated by BOE treatment and reduce the surface recombination sites.
Analysis of issues in gate recess etching in the InAlAs/InGaAs HEMT manufacturing process
Byoung-Gue Min,Jong-Min Lee,Hyung Sup Yoon,Woo-Jin Chang,Jong-Yul Park,Dong Min Kang,Sung-Jae Chang,Hyun-Wook Jung Electronics and Telecommunications Research Instit 2023 ETRI Journal Vol.45 No.1
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.
Min Byoung-Gue,Chang Sung-Jae,Jung Hyun-Wook,Yoon Hyung Sup,Lee Jong-Min,Jang Woo-Jin,Kang Dong-Min 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.77 No.2
In the fabrication of InAlAs/InGaAs metamorphic high-electron-mobility transistor (mHEMT), the determination of whether etching has been completed to the desired gate recess depth is made by measuring whether the drain current through the channel layer has reached the target current. Non-uniformity of the etching rate occurs during wet etching with citric acid. In this study, the cause of that non-uniformity was investigated. We confirmed that an electrochemical potential caused by the electrolyte of the etching solution was induced between the ohmic electrode and the epitaxial layer of the recess region, resulting in a non-uniform etching rate. In particular, the case where the Au of an ohmic electrode is exposed by the monitor window for the measuring channel current was considered. The gate recess etch rate was changed by the presence, location and size of the photoresist openings on the ohmic electrodes.
AlGaN/GaN HEMT 소자 제작에서 게이트 리세스 공정 개선에 의한 소자 DC 특성의 변화
민병규(Byoung-Gue Min),윤형섭(Hyung Sup Yoon),안호균(Ho-Kyun Ahn),김해천(Haecheon Kim),조규준(Kyu-Jun Cho),이종민(Jong-Min Lee),김성일(Seong-Il Kim),강동민(Dong-Min Kang),이상흥(Sang-Heung Lee),주철원(Chul-Won Ju),김동영(Dong-Young K 대한전자공학회 2015 대한전자공학회 학술대회 Vol.2015 No.6
In the fabrication of AlGaN/GaN HEMT on SiC, it is critical to establish a stable process condition of a gate recess. In this study, we etched the AlGaN layer by a low-energy ICP with variations of etch times. In addition, HC1 treatment followed the etch step. The 2-times process of SiN deposition and etch was tried to reduce the gate length by mis-aligned lithography. A proportional relationship between Vth(or Gm) and recess etch depth was identified. There also was a surface-improving effect to reduce the leakage current by HC1 treatment.
W-Band MMIC chipset in 0.1-㎛ mHEMT technology
Lee, Jong-Min,Chang, Woo-Jin,Kang, Dong Min,Min, Byoung-Gue,Yoon, Hyung Sup,Chang, Sung-Jae,Jung, Hyun-Wook,Kim, Wansik,Jung, Jooyong,Kim, Jongpil,Seo, Mihui,Kim, Sosu Electronics and Telecommunications Research Instit 2020 ETRI Journal Vol.42 No.4
We developed a 0.1-㎛ metamorphic high electron mobility transistor and fabricated a W-band monolithic microwave integrated circuit chipset with our in-house technology to verify the performance and usability of the developed technology. The DC characteristics were a drain current density of 747 mA/mm and a maximum transconductance of 1.354 S/mm; the RF characteristics were a cutoff frequency of 210 GHz and a maximum oscillation frequency of 252 GHz. A frequency multiplier was developed to increase the frequency of the input signal. The fabricated multiplier showed high output values (more than 0 dBm) in the 94 GHz-108 GHz band and achieved excellent spurious suppression. A low-noise amplifier (LNA) with a four-stage single-ended architecture using a common-source stage was also developed. This LNA achieved a gain of 20 dB in a band between 83 GHz and 110 GHz and a noise figure lower than 3.8 dB with a frequency of 94 GHz. A W-band image-rejection mixer (IRM) with an external off-chip coupler was also designed. The IRM provided a conversion gain of 13 dB-17 dB for RF frequencies of 80 GHz-110 GHz and image-rejection ratios of 17 dB-19 dB for RF frequencies of 93 GHz-100 GHz.
0.25 μm AlGaN/GaN HEMT 소자 및 9 GHz 대역 전력증폭기
강동민(Dong-Min Kang),민병규(Byoung-Gue Min),이종민(Jong-Min Lee),윤형섭(Hyung-Sup Yoon),김성일(Sung-Il Kim),안호균(Ho-Kyun Ahn),김동영(Dong-Young Kim),김해천(Hae-Cheon Kim),임종원(Jong-Won Lim),남은수(Eun-Soo Nam) 한국전자파학회 2016 한국전자파학회논문지 Vol.27 No.1
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 μm의 게이트 길이를 갖고, 총 게이트 폭은 12mm인 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 시스템등 다양한 응용분야에 적용이 가능할 것으로 판단된다. This paper describes the successful development and the performance of X-band 50 W pulsed power amplifier using a 50 W GaN-on-SiC high electron mobility transistor. The GaN HEMT with a gate length of 0.25 μm and a total gate width of 12 mm were fabricated. The X-band pulsed power amplifier exhibited an output power of 50 W with a power gain of 6 dB in a frequency range of 9.2~9.5 GHz. It also shows a maximum output power density of 4.16 W/mm. This 50 W GaN HEMT and X-band 50 W pulsed power amplifier are suitable for the radar systems and related applications in X-band.
김성일(Seong-Il Kim),안호균(Ho-Kyun Ahn),이상흥(Sang-Heung Lee),강동민(Dong-Min Kang),이종민(Jong-Min Lee),민병규(Byoung-Gue Min),김해천(Haecheon Kim),윤형섭(Hyung Sup Yoon),장유진(Yoo Jin Jang),신민정(Min Jeong Shin),임종원(Jong-Won 대한전자공학회 2016 대한전자공학회 학술대회 Vol.2016 No.6
This paper describes modeling of AlGaN/GaN High Electron Mobility Transistors(HEMTs) for X-band applications. The AlGaN/GaN HEMTs with a gate length of 0.25 ㎛ and a total gate width of 800 um were fabricated by ETRI. The model of GaN HEMT devices is Angelov-GaN model for high power applications. Procedure of modeling is as follows. 1. DC measurements, 2. NWA(Network Analyzer) calibration, 3. NWA De-embedding, 4. S-parameter measurement, 5. DC extraction, 6. S-parameter extraction, 7 Global optimization, 8. HB simulation to verify Spectrum. Comparing with model simulation and measurement data, the model parameters were obtained. We will design X-band PA MMIC using Angelov-GaN model.
Jong-Min Lee,Byoung-Gue Min,주철원,Kyung-Ho Lee,김성일 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.III
Disclosed is a simple and reliable method for providing close spacing between the emitter mesa and the base ohmic metal of an InP-based heterojunction bipolar transistor. The sides in [011] crystallographic direction on the emitter electrode periphery were eliminated because the mesa planes of these sides revealed positive slope by wet etching. Thus, the emitter electrode was designed with a long hexagonal shape, whose major sides had a negatively inclined mesa plane. The selfaligned device fabricated by using these crystallographic characteristics of etching profile exhibited excellent high-frequency performance with fT of 168 GHz and fmax of 268 GHz, respectively, superior to a non-self-aligned one on the same epitaxy wafer.
정민규(Min Gue Jung),김동욱(Dong Wook Kim),김병곤(Byoung Gon Kim) 한국산업경제학회 2017 산업경제연구 Vol.30 No.2
본 연구에서는 한국기업을 대상으로 지배주주의 초과지배권이 기업의 레버리지 의사결정에 미치는 영향을 분석하였다. 이를 위해 첫째, 지배주주가 초과지배권을 갖고 있는 경우 레버리지를 증가시키는가? 둘째, 지배주주는 초과레버리지정책을 통해 획득한 초과자원을 터널링에 활용하는가 혹은 투자에 사용 하는가를 분석하였다. 또한 우리나라 재벌기업의 경우 초과지배권의 발생 가능성이 높고, 경영의사결정이 지배주주의 이해에 크게 영향을 받을 가능성이 있다는 점을 감안하여 전체표본을 재벌기업과 비재벌기업으로 나누어 지배주주의 초과지배권과 레버리지정책 간의 관계도 분석하였다. 본 연구에서 표본은 2004년부터 2014년까지 한국거래소 유가증권시장에 상장된 기업 중에서 지배주주가 존재하는 총 5,707개의 기업-연도 자료를 사용하였다. 분석방법은 패널자료를 이용한 2SLS 방법을 사용하였다. 분석결과를 요약하면 다음과 같다. 첫째, 전체기업을 대상으로 분석한 결과에 의하면, 초과지배권이 존재하는 기업은 초과레버리지를 발생시키고, 이렇게 발생된 초과자원은 기업내부대출 보다는 NPV가 정(+)인 투자안에 투자되는 경향이 있다는 것을 알 수 있었다. 즉 초과지배권이 존재하는 기업에서는 초과레버리지가 발생하지만 이는 자본지출과 더 연관되고, 지배주주에 의한 터널링과는 연관되지 않는 것으로 이해되었다. 둘째, 재벌기업과 비재벌기업으로 나누어 분석한 결과에서, 재벌기업과 비재벌기업 모두에서 지배주주가 초과지배권을 갖는 경우에 초과레버리지정책이 채택된다는 것을 확인하였다. 또한 이렇게 초과레버리지정책에 의해 조달된 초과자원은 지배주주에 대한 기업내부대출 보다는 자본지출에 사용되는 경향이 있다는 것을 확인하였다. 즉 초과지배권이 존재하는 재벌기업과 비재벌기업 모두에서 초과레버리지가 발생하지만 이는 자본지출과 더 연관되고, 지배주주에 의한 터널링과는 연관되지 않는 것으로 이해되었다. Most studies argue that the controlling shareholders are strongly motivated to pursue their private benefit by tunneling resources out of the listed company because they obtain all the benefits without bearing the full financial consequences. They conjecture that value-destroying financial policies such as higher leverage are usually adopted in order to expropriate the interests of minority shareholders, especially when controlling shareholders have excess control rights. This paper examines the effect of controlling shareholders’ tunneling on the leverage decision made by Korean listed firms. Using cross-sectional data on total 5,707, we estimate the relationship among excess control rights, excess leverage and inter-corporate loans to controlling shareholders for 11 years, from 2004 to 2014, with 2SLS panel data analysis. we find that we find that firms with excess control rights have more excess leverage and their controlling shareholders use the resources for investing in positive NPV projects rather than for inter-corporate loans to controlling shareholders. Also we find that Chaebol and non-Chaebol with excess control rights have same excess leverage policy, and their controlling shareholders use the excess resources for investing in projects rather than for tunneling.
0.5 W PA MMIC Module Using InGaP/GaAs HBTs for IMT-2000 Handset Operational at 3.3 V
성일 김,Byoung-Gue Min,Chang-Woo Kim,Hyun Shin,Jong-Min Lee,Kyung-Ho Lee,Kyu-Seong Chae 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.42 No.III
A 0.1 cc power amplifier(PA) multi-chip module (MCM) for an IMT-2000 handset has been developed using InGaP/GaAs heterojunction bipolar transistors (HBT). PA MMIC with maximum power and efficiency considering linearity was designed and fabricated. An active-bias circuit has been employed for temperature compensation and reduction in idling current of a PA. The fabricated PA MMIC chip size is 1.5 $\times$ 1.1 mm$^2$ and the output power results showed gain = 26.3 dB, $P_{out}$ = 27 dBm, and power added efficiency, PAE = 33 \% for load-pull measurement with output matching. An MCM package with input-output matching circuit is adopted for low-cost and very small size package. For the module, bare ICs' were wire-bonded on the package substrate and the thermal vias under the substrate for effective thermal dissipation were formed. The matching circuits could be modified by adding ``off-chip'' elements for a maximum output power. Under 3.3 V operation, the MCM achieved an output power of 27.5 dBm, a PAE of 32 \%, and a gain of 26 dB.