• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.292-295
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• 2004

The SIT was introduced by Nishizawa. in 1972. When compared with high-voltage, power bipolar junction transistors, SITs have several advantages as power switching devices. They have a higher input impedance than do bipolar transistors and a negative temperature coefficient for the drain current that prevents thermal runaway, thus allowing the coupling of many devices in parallel to increase the current handling capability. Furthermore, the SIT is majority carrier device with a higher inherent switching speed because of the absence of minority carrier recombination, which limits the speed of bipolar transistors. This also eliminates the stringent lifetime control requirements that are essential during the fabrication of high-speed bipolar transistors. This results in a much larger safe operating area(SOA) in comparison to bipolar transistors. In this paper, vertical SIT structures are proposed to improve their electrical characteristics including the blocking voltage. Besides, the two dimensional numerical simulations were carried out using ISE-TCAD to verify the validity of the device and examine the electrical characteristics. A trench gate region oxide power SIT device is proposed to improve forward blocking characteristics. The proposed devices have superior electrical characteristics when compared to conventional device. Consequently, the fabrication of trench oxide power SIT with superior stability and electrical characteristics is simplified.

• 대한전자공학회논문지
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• 제27권1호
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• pp.51-58
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• 1990

NPN Si bipolar transistors with two different emitter widths are designed and fabricated. The effects of the emitter width on the small signal parameters of BJTs are measured and discussed. A new ac method for determining the current gain, the cut off frequency and the internal capacitances from the input impedance circle characteristics as a function of the varied external series resistances is presented. This method allows an accurate characterization of bipolar transistors with high current gain. The variation of the I-V curves of the emitter junction with the reverse collector junction voltages is discussed from the changes in the intsrinsic base resistances.

• 전자공학회논문지A
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• 제31A권8호
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• pp.46-52
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• 1994

DC and AC current crowding effects for microwave and high speed bipolar transistors are investigated in detail using a new and accurate measurement technique based on Z-parameter equationa. Using the new measurement technique dc and ac current crowding effects have been explained clearly in bipolar junction transistors. To model ac crowding effects a capacitive element defined as base capacitance (C$_b$), called ac crowding capacitance is added to base resistance in parallel thereby treating the base resistance(R$_b$) as base impedance Z$_b$. It is shown that base resistance decreases with increasing collector current due to dc current crowding and approaches to a certain limited value at high collector current due to current crowding and approaches to a certain limited value at high collector currents regardless of the emitter size. It is also observed that due to ac current crowding base capacitance increases with increasing collector current. To quantigy the ac crowding effects for SPICE circuit simulation the base capacitance(C$_b$) including the base depletion and diffusion components has been modeled with an analytical expression form.

• 전자공학회논문지A
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• 제30A권10호
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• pp.20-26
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• 1993

The base-collector capacitance of an npn bipolar transistor in bipolar or BiCMOS technology has significant influence on the switching performances, and comprises pnjunction component and MOS component. Both components have complicated dependences on the isolation oxide structure, epitaxial doping density, and bias voltage. Analytical/empirical formulas for both components are derived in this paper for a generic isolation structure as a function of epitaxial doping density and bias voltage based on some theoretical understanding and two-dimensional device simulations. These formulas are useful in estimating the effect of device isoation schemes on the switching speed of bipolar transistors.

• 전자공학회지
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• 제33권5호
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• pp.91-104
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• 2006

• 전기의세계
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• 제59권2호
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• pp.29-32
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• 2010

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.462-465
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• 1991

In this paper, a newly developed uninterruptible power supply adopted insulated gate bipolar transistors (IGBT'S) is introduced. The focus is on harmonic reduction, high efficiency and so on. The overview, hardware and software of the newly developed ups system are also discussed. Finally, the merit of the newly developed ups compared with conventional ups is described.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 추계학술대회 논문집
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• pp.353-356
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• 1996

Ultra-high-speed analog and digital ICs (integrated circuits) fur 10Gbit/sec optical communication systems have been designed, fabricated and analyzed in this research. These circuits, which are laser diode (LD) driver, pre-amplifier, automatic gain controlled (AGC) amplifier, limiting amplifier and decision circuit, have been implemented with AIGaAs/GaAs heterojunction bipolar transistors (HBTs). The optimized AIGaAs/GaAs HBTs for the 10Gbps circuits in this work showed the cutoff and maximum oscillation frequencies of 65㎓ and 53㎓, respectively. It is demonstrated in this paper that the 10Gbps optical communication system can be realized with the ICs designed and fabricated using AlGaAs/GaAs HBTs.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 추계학술대회 논문집
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• pp.349-352
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• 1996

When the ideality factor of collector current of AIGaAs/GaAs Heterojunction Bipolar Transistors (HBTs) is larger than unity, conventional $I_{CO}$ / $T^2$ versus 1000/T plot used in the determination of the barrier height of base-emitter junction of HBT was deviated from the straight line. We introduced the effective temperature $T_{eff}$ as nT in the Thermionic-emission equation. The modified $I_{CO}$ /TB versus 1000/ $T_{eff}$ plot was on the straight line in the temperature range considered. The activation energy obtained from the modified plot is 1.61 eV. The conduction band discontinuity calculated using this value was 0.305 eV and this value is coincident with the generally accepted value of 0.3 eV. eV.

• 대한전자공학회논문지SD
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• 제41권7호
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• pp.7-12
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• 2004

본 논문에서는 교류전류 집중현상이 고려된 바이폴라 등가모델에서 내부 베이스-컬렉터 캐패시턴스(C/sub μ/)와 외부 베이스-컬렉터 캐패시턴스(C/sub μx/)를 분리해서 추출하는 개선된 방법을 연구하였다. 먼저, 기존 추출방법들의 문제점들을 파악하고, 교류전류 집중 캐패시턴스가 포함된 차단모드 등가회로로부터 개선된 추출방정식들을 유도하였다. 이렇게 추출된 C/sub μx/와 C/sub μx/를 사용하여 모델 된 전류 및 전력이득 주파수 응답곡선들은 기존 추출방법으로 얻어진 곡선보다 측정 데이터와 훨씬 잘 일치되었으며, 이는 개선된 추출방법의 정확도를 증명한다.