• Nuclear Engineering and Technology
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• 제55권11호
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• pp.4238-4245
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• 2023

In order to predict the lifetime of InP Heterojunction Bipolar Transistor (HBT) devices and related circuits in the space radiation environment, a novel model including gamma radiation effects is proposed in this paper. Based on the analysis of radiation-induced device degradation effects including both DC and AC characteristics, a set of empirical expressions describing the device degradation trend are presented and incorporated into the Keysight model. To validate the effective of the proposed model, a series of radiation experiments are performed. The correctness of the novel model is validated by comparing experimental and simulated results before and after radiation.

• 한국진공학회지
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• 제10권2호
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• pp.219-224
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• 2001

N형 InGaAs에 대한 Pd/Ge/Ti/Pt 오믹 접촉 특성을 조사하였다. $450^{\circ}C$까지의 급속 열처리에 의해 우수한 오믹 특성을 나타내어 $400^{\circ}C$, 10초의 급속 열처리 조건에서 최저 $3.7\times10^{-6}\; \Omega\textrm{cm}^2$ 의 접촉 비저항을 나타내었다. 이는 열처리에 의해 생성된 Pd-Ge계 화합물의 형성 및 Ge의 InGaAs 표면으로의 확산과 관련이 있었다. 그러나 열처리 시간을 연장할 경우 접촉 비저항이 $low-10^5\; \Omega\textrm{cm}^2$로 약간 증가하였다. 고온 열처리 후에도 오믹 재료와 InGaAs의 평활한 계면을 유지하면서 우수한 오믹 특성을 나타내어, 화합물 반도체 소자의 오믹 접촉으로 충분히 응용 가능하다고 판단된다.

• E2M - 전기 전자와 첨단 소재
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• 제9권6호
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• pp.564-571
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• 1996

We calculated the drift-velocities of electrons and holes of I $n_{0.53}$(A $l_{x}$G $a_{1-x}$ )$_{0.47}$As, which is used for semiconductor materials of high performance HBTs, along with the various doping concentrations and Al mole fractions as well as the electric fields by Monte Carlo experiment. Especially, for the valence bands the accuracy of hole-drift-velocity was improved in the consideration of intervalley scattering due to the inelastic scattering of acoustic phonon. From the results the empirical formulas of the low- and high field mobility of electrons and holes were extracted by using nonlinear least square fitting method. The accuracy of the formulas was proved by comparing the formula of low-field electron mobility as well as drift-velocity of I $n_{0.53}$ G $a_{0.47}$As and of low-field hole mobility of GaAs with the measured values, where the error was below 10%. For the high-field mobilities of electron and hole the results calculated by the formulas were very well matched with the MC experimental results except at the narrow field range where the electrons produced the velocity overshoot and the corresponding error was about 30%.0%. 30%.0%.

• 전자공학회논문지A
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• 제31A권9호
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• pp.104-113
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• 1994

We have fabricated n-p-n HBTs using 3-inchAlgaAs/GaAs hetero structure epi-wafers grown by MBE. DC and AC characteristics of HBT devices were measured and analyzed. For HBT epi-structure, Al composition of emitter was graded in the region between emitter cap and emitter. And base layer was designed with concentration of 1${\times}10^{19}/cm^{3}$ and thickness of 50nm, and Be was used as the p-type dopant. Principal processes for device fabrication consist of photolithography using i-line stepper, wet mesa etching, and lift-off of each ohmic metal. The PECVD SiN film was used as the inslator for the metal interconnection. HBT device with emitter size of 3${\times}10{\mu}m^{2}$ resulted in cut-off frequency of 35GHz, maximum oscillation frequency of 21GHz, and current gain of 60. The distribution of the ideality factor of collector and base current was very uniform, and the average values of off-set voltage and current was very uniform, and the average values of off-set voltage and current gain were 0.32V and 32 within a 3-inch wafer.

• 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.

• ETRI Journal
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• 제31권6호
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• pp.749-754
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• 2009

The design and performance of an InGaAs/InP transimpedance amplifier and post amplifier for 40 Gb/s receiver applications are presented. We fabricated the 40 Gb/s transimpedance amplifier and post amplifier using InGaAs/InP heterojunction bipolar transistor (HBT) technology. The developed InGaAs/InP HBTs show a cut-off frequency ($f_T$) of 129 GHz and a maximum oscillation frequency ($f_{max}$) of 175 GHz. The developed transimpedance amplifier provides a bandwidth of 33.5 GHz and a gain of 40.1 $dB{\Omega}$. A 40 Gb/s data clean eye with 146 mV amplitude of the transimpedance amplifier module is achieved. The fabricated post amplifier demonstrates a very wide bandwidth of 36 GHz and a gain of 20.2 dB. The post-amplifier module was fabricated using a Teflon PCB substrate and shows a good eye opening and an output voltage swing above 520 mV.

• 한국산학기술학회논문지
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• 제5권4호
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• pp.367-370
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• 2004

초고속 RF IC의 핵심소자인 SiGe 에피텍시층을 가진 이종양극트란지스터(hetero junction bipolar transistor: HBT)를 0.35㎛급 Si-Ge BiCMOS공정으로 제작하였다. 낮은 VBE영역에서의 current gain의 선형성을 향상시키기 위하여 SiGe에피텍시층의 결함밀도를 감소시킬 수 있는 캐핑실리콘의 두께와 EDR온도의 최적화 공정조건을 알아보았다. 캐핑 실리콘의 두께를 200Å과 300Å으로 나누고 초고속 무선통신에서 요구되는 낮은 노이즈를 위한 EDR(Emitter Drive-in RTA)의 온도와 시간을 900-1000℃, 0-30 sec로 각각 변화시키면서 최적조건을 확인하였다. 실험범위 내에서의 최적공정조건은 300Å의 capping 실리콘과 975℃-30sec의 EDR 조건을 확인하였다.

• 한국전기전자재료학회논문지
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• 제15권5호
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• pp.449-454
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• 2002

The use of a thin film of indium between the ITO and the $n^+-lnP$ contact layers for InP/InGaAs HPTs was studied without degrading its excellent optical transmittance properties. $ITO/n^+-lnP$ ohmic contact was successfully achieved by the deposition of indium and annealing. The specific contact resistance of about $6.6{\times}10^{-4}\Omega\textrm{cm}^2$ was measured by use of the transmission line method (TLM). However, as the thermal annealing was just performed to $ITO/n^+-lnP$ contact without the deposition of indium between ITO and $n^+-lnP$, it exhibited Schottky characteristics. In the applications, the DC characteristics of InP/InGaAs HPTs with ITO emitter contacts was compared with those of InP/InGaAs HBTs with the opaque emitter contacts.

• JSTS:Journal of Semiconductor Technology and Science
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• 제4권3호
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• pp.189-195
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• 2004

A 10 Gb/s limiting amplifier IC with the emitter area of $1.5{\times}10{\mu}m^2$ for optical transmission system was designed and fabricated with a AIGaAs/GaAs HBTs technology. In this stud)', we evaluated fine pitch bump using WL-CSP (Wafer Level-Chip Scale Packaging) instead of conventional wire bonding for interconnection. For this we developed WL-CSP process and formed fine pitch solder bump with the $40{\mu}m$ diameter and $100{\mu}m$ pitch on bonding pad. To study the effect of WL-CSP, electrical performance was measured and analyzed in wafer and package module using WL-CSP. In a package module, clear and wide eye diagram openings were observed and the riselfall times were about 100ps, and the output" oltage swing was limited to $600mV_{p-p}$ with input voltage ranging from 50 to 500m V. The Small signal gains in wafer and package module were 15.56dB and 14.99dB respectively. It was found that the difference of small signal gain in wafer and package module was less then 0.57dB up to 10GHz and the characteristics of return loss was improved by 5dB in package module. This is due to the short interconnection length by WL-CSP. So, WL-CSP process can be used for millimeter wave GaAs MMIC with the fine pitch pad.

• 전자공학회논문지D
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• 제36D권3호
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• pp.66-74
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• 1999

HMC(Hybrid Monte Carlo)시뮬레이션을 이용하여 InAlGaAs/InGaAs HBT의 비평형 고속전송을 해석하였고, 전송시간 및 차단주파수를 향상시키기 위하여 에미터-베이터 이종접합과 콜렉터 구조를 최적 설계 하였다. 시뮬레이션 결과, 에미터 조성경사영역에서 Al 몰비를 xf=1.0에서 xf=0.5로 변화시킬 경우 베이스 전송시간이τb=0.21ps로 가장 짧았다. 콜렉터 전송시간을 단축시킬 목적으로 콜렉터와 베이스 사이에 n\sup +\형 (콜렉터-Ⅰ), I형(콜렉터-Ⅱ), p형(콜렉터-Ⅲ), 콜렉터를 삽입하여 베이스-콜렉터 공간전하영역의 전계분포를 전자의 비평형고속전송을 유지하도록 설계하였다. 콜렉터-Ⅲ 구조에서는 전자의 음이온화된 억셉터가 콜렉터의 전계를 감소시킴으로써 전자가 Γ 밸리에서 먼 거리까지 전송을 가능하게 하여 가장 짧은 콜렉터 전송시간을 나타내었다. 결론적으로 가장 짧은 전송시간 τec는 Al 몰비가 xf=0.5인 에미터 구조와 콜렉터-Ⅲ에서 0.87psec이었고, 차단주파수 ft=183GHz를 나타내었다.