• 제목/요약/키워드: Al-emitter

검색결과 84건 처리시간 0.022초

AlGaAs/GaAs HBTs의 에미터 크기에 따른 전류 이득 변화에 관한 연구 (A Study on the Current Gain Variation with the Emitter Size in AlGaAs/GaAs HBTs)

  • 정준오;이헌용;이태우;김일호;박문평;박성호;편광의
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1996년도 추계학술대회 논문집
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    • pp.10-12
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    • 1996
  • AlGaAs/GaAs Heterojunotion Bipolar Transistors (HBTs) with various emitter areas were fabricated and the device size dependence on the current gain was examined. With the different emitter areas, the passivated devices having the same peripheral length were fabricated and measured. The measured base current density in the Gummel plots shows an ideality factor of nearly 2. It is found that as the emitter area becomes small, the base current density with the ideality factor of 2 increases linearly, and as the emitter perimeter/area ratio becomes large, the surface recombination current density component increases. The current gain performance in AlGaAs/GaAs HBTs is mainly determined by either the larger emitter area or the smaller ratio of the emitter perimeter to the emitter area. These results will be compared with experimental works for GaInP/GaAs HBTs

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$ALU^+$를 이용한 결정질 태양전지 후면 전극 Screen Printing 횟수에 따른 특성 (A study on the $ALU^+$ crystalline solar cell characteristics affected by counts of rear side screen printings)

  • 최재우;김현엽;이준신
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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    • pp.123.1-123.1
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    • 2011
  • 기존의 p-type 태양전지 공정과 유사한 공정으로 제작되는 n-type $ALU^+$태양전지는 후면에 Al을 screen printing하여 emitter층을 형성한 구조이다. screen printing은 공정의 단순화와 제조 단가의 저비용으로 인해, metalization 공정에서 많이 쓰이고 있다. 본 연구에서는 양산 가능한 n-type $ALU^+$태양전지 제작을 위해, 후면 Al emitter 층을 single, dobule, triple로 변경하며 Al의 양을 가변하였고, 그에 따른 특성의 변화를 연구하였다. screen printing 횟수가 변경된 후면 Al emitter 층의 특성은 DIV와 LIV 측정을 통해 분석하였다. 실험 결과 Al을 single printing 하였을 때보다, double, triple printing을 통하여 Al의 양을 증가하였을 때, DIV 데이터에서 직렬저항(Rs)가 $24.44{\Omega}/cm^2$에서 $0.31{\Omega}/cm^2$으로 감소하였고, 단락전류(Jsc)는 1.26mA/$cm^2$에서 37.7mA/$cm^2$으로 약 300% 증가한 것을 확인할 수 있었다. 프린팅 횟수에 따른 LIV 데이터의 Fill Factor를 분석하게 되면, double printing이 64.35%로 54.75%의 triple printing보다 약 1.17배 더 향상된 것으로 확인하였다. 이러한 결과를 바탕으로 후면 Al emitter 형성시에 Al의 양이 적절하지 못한 이유로, Al emitter가 제대로 형성되지 못하거나 과하게 형성되면, 태양전지 내부에 누설 저항의 변화와 누설 전류의 증가로 인해, 단락전류(Jsc)와 Fill Factor 감소의 주요 원인이 된다는 것을 확인할 수 있었다.

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n형 규소 태양전지 emitter형성에 미치는 열처리 변수의 영향 (The effect of heat treatment parameters on the emitter formation of the n-type silicon solar cell)

  • 심지명;김영관
    • 한국결정성장학회지
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    • 제18권5호
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    • pp.179-183
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    • 2008
  • n형 실리콘를 이용히여 후면에 Al-emitter형성에 관해 �x처리조건이 Voc에 어떤 영향을 미치는지 알아보기 위하여 screen printing 방법으로 n-type Si 기판에 Al을 도포하였다. 열처기는 straight profile에서 50 inch/min의 belt speed로 $850^{\circ}C$의 peak temperature로 수행한 경우 가장 높은 Voc(585 mV)값을 보였고, 이 온도보다 낮은 경우에 불 균일한 Al-Si alloy 층이 형성되고, 이 온도보다 높은 경우에 Al층으로 Si 원자의 이동이 극심하게 발생되어 Al-Si alloy층이 파괴되는 현상으로 인하여 Voc가 감소함을 보았다.

에미터 구조변화에 따른 AlGaAs/GaAs HBT의 고주파 특성 (Emitter structure dependence of the high frequency performance of AlGaAs/GaAs HBTs)

    • 한국진공학회지
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    • 제9권2호
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    • pp.167-171
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    • 2000
  • AlGaAs/GaAs HBT의 동작특성에 미치는 에미터 구조의 영향을 조사하였다. 에미터의 크기 변화에 의해 차단주파수와 최대공진주파수가 변화하였으며, 이는 에미터 구조에 따라 저항과 접합용량이 변하기 때문이다. 또한 에미터의 주변길이와 접합면적도 HBT의 고주파 특성에 영향을 미치는 것을 알 수 있다.

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$WN_{x}$ 에미터 전극을 갖는 자기정렬 AlGaAs/GaAs HBT의 제작과 특성 (Fabrication and Character istics of self-aligned AlGaAs/GaAs HBT using $WN_{x}$ as emitter metal)

  • 이종민;이태우;박문평;최인훈;박성호;박철순
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 1998년도 하계종합학술대회논문집
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    • pp.461-464
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    • 1998
  • Self-aligned AlGaAs/GaAs HBTs with the emitter area of 1.5*10.mu.$m^{2}$ were fabricated usng $WN_{x}$ as emitter metal. Their DC and RF characteristics were investigated. The common emitter current gain was 45 at $J_{c}$ = 6*$10^{4}$A/$cm^{2}$. From the Gummel plot, the ideality factors of $I_{c}$ and $I_{B}$ were 1.18 and 1.70, respectively. Emitter and base resistance were extracted from voltage drop region in gummel plot, and their values were 5.3.ohm. and 38.2.ohm.. The extrapolated $f_{T}$ = 72GHz and $f_{max}$ = 81GHz were obtained at $V_{CE}$ = 2V.

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Influence of Emitter Width on the Performance of 975-nm (In,Ga)(As,P)/(Al,Ga)As High-power Laser Diodes

  • Yang, Jung-Tack;Kim, Younghyun;Pournoury, Marzieh;Lee, Jae-Bong;Bang, Dong-Soo;Kim, Tae-Kyung;Choi, Woo-Young
    • Current Optics and Photonics
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    • 제3권5호
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    • pp.445-450
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    • 2019
  • The influence of high-power laser diode (HPLD) emitter width on the device performance is investigated for 975-nm (In,Ga)(As,P)/(Al,Ga)As broad-area HPLDs, using self-consistent electro-thermal-optical simulation. To guarantee the simulation's accuracy, simulated results are matched with the measured results for a sample HPLD with fitting parameters. The influences of HPLD emitter width on temperature distribution, output power, and the beam product parameter (BPP) are analyzed for three different emitter widths of 50, 70, and $90{\mu}m$. It is found that a device with smaller emitter width exhibits both thermal rollover and thermal blooming at lower output power, but smaller BPP.

High operating temperature stable OLEDs with reduced reflectivity cathodes

  • Popovic, Zoran D.;Aziz, Hany;Vamvounis, George;Hu, Nan-Xing;Paine, Tony
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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    • pp.21-24
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    • 2003
  • The understanding of the mechanism of device degradation has been accomplished recently, for devices using $AlQ_3$ electron transport and emitter molecule. In this presentation the experimental evidence for the degradation mechanism of $AlQ_3$ based devices will be reviewed, showing that the hypothesis of an unstable $AlQ_3^+$ cation explains a large amount of experimental data. This hypothesis, however, explains not only the room temperature device degradation in time but also sheds light on temperature stability of OLEDs. Dependence of half-life of a series of devices with an emitter layer composed of a mixture of $AlQ_3$ and different hole transport molecules (mixed emitter layer) will be discussed when they are operated at elevated temperatures. These results can also be explained in the framework of an unstable $AlQ_3^+$ species. An OLED structure containing a doped mixed emitter layer will be described, which shows extraordinary stability, half-life of 1200 hours at operating temperature of 70 C and initial luminance of 1650 $cd/m^2$. We will also discuss a novel Black $Cathode^{TM}$ OLED with reduced optical reflectivity, which is also stable at elevated temperatures. The new cathode utilizes a conductive light-absorbing layer made of a mixture of metals and organic materials.

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에미터와 베이스의 기하구조가 AlGaAs/GaAs HBT의 전기적 특성에 미치는 영향 (Emitter-base geometry dependence of electrical performance of AlGaAs/GaAs HBT)

  • 박성호;최인훈;최성우;박문평;김영석;이재진;박철순;박형무
    • 전자공학회논문지A
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    • 제32A권2호
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    • pp.57-65
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    • 1995
  • The effects of device geometry and layout on high speed performance such as current gain outoff frequency(f$_{T}$) and maximum oscillation frequency(f$_{max}$) are of very improtant for the scaling-down of geterojunction bipolar transistors(HBT$_{s}$). In this paper AlGaAs/GaAs HBTs are fabricated by MBE epitaxial growth and conventional mesa process, and the experimental data of emitter-base geometru dependency of HBT performance are presented in order to provide the quantitative information for optimum device structure design. It is shown that f$_{T}$ and f$_{max}$ are inversely proportional to the emiter stripe width, while the low emitter perimeter/area ratio is better to f$_{T}$ and worse ot f$_{max}$. It is also demonstrated the f$_{T}$ and f$_{max}$ are highly improved by the emitter-base spacing reduction resulting in less parsitic effects. As the result f$_{T}$ of 42GHz and f$_{max}$ of 23GHz are obtained for fabricated HBT with emitter area of 3${\times}20^{\mu}m^{2}$ and E-B spacing of 0.2$\mu$m.m.m.

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산화물이 코팅된 전도성 금속 분말의 제조 및 태양전지 전면 전극으로의 응용 (Synthesis of Metal Oxide-Coated Conductive Metal Powders and Their Application to Front Electrodes for Solar Cells)

  • 박진경;이영인
    • 한국재료학회지
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    • 제24권9호
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    • pp.502-507
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    • 2014
  • Recently, improvement in the conversion efficiency of silicon-based solar cells has been achieved by decreasing emitter doping concentration, because the lightly doped emitter can effectively prevent the recombination of electrons and holes generated by solar light irradiation. This type of emitter is very thin due to the low doping concentration, thus conductive materials (i.e., silver) used for front electrodes can easily penetrate the emitter during a firing process because of their large diffusivity in silicon. This results in junction leakage currents which might reduce cell efficiencies. In this study, $Al_2O_3$-coated Ag powders were synthesized by an ultrasonic spray pyrolysis method and applied to the conductive materials of the front electrode to control the junction leakage current. The $Al_2O_3$ shell obstructs the Ag diffusion into the emitter during the firing process. The powder is spherical with a core-shell structure and the thickness of the $Al_2O_3$ shell is tens of nanometers. Solar cells were fabricated using pure Ag powders or the $Al_2O_3$-coated Ag powder as front electrode materials, and the conversion efficiency and junction leakage current were compared to investigate the role of the $Al_2O_3$ shell during the firing processes.

AlgaAs/GaAs SABM HBT의 제작 및 특성 (Fabrication and characteristics of AlGaAs/GaAs SABM HBTs)

  • 이준우;김영식;서아람;서영석;신진호;김범만
    • 전자공학회논문지A
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    • 제32A권1호
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    • pp.129-137
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    • 1995
  • AlGaAs/GaAs HBTs have been fabricated using SABM (Self-Aligned Base Metal) process technique. The mesa type HBTs were fabricated through following steps: isolation implant, wet etching, metal lift-off, and airbridge interconnection process. The fabricated HBTs with 2umx10um size emitter showed a common emitter current gain of 10 at a collector current density of Jk=100kA/cm$^{2}$, a breakdown volgate BVCEO of 8V, and the ideality factors of base and collector junctions of 1.6 and 1.1, respectively. On-wafer S-Parameter measurement at 0.5~18GHz has been made for the characterization of the common emitter HBTx with a 2umx10um size emitter. The extrapolated current gain cut-off frequency of ft=30GHz and maximum oscillation frequency of fmax=23 GHz were obtained at a collector current density of Jc=70kA/cm$^{2}$. Small signal HBT equivalent circuit was extracted from the S-Parameter data.

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