AlGaAs/GaAs HBT的低频噪声

测试了AlGaAs／GaAsHBT的低频噪声，并将测试结果分解为1／f噪声、G－R噪声和白噪声，阐述了它们的产生机理，在此基础上建立了AlGaAs／GaAsHBT输入噪声电压的等效电路模型，该模型有助于AlGaAs／GaAsHBT电路的CAD。     

Low 1/f noise characteristics of AlGaAs/GaAs heterojunction bipolartransistor with electrically abrupt emitter-base junction

It is shown that the use of an electrically abrupt emitter-base junction considerably reduces the 1/f noise of self-aligned AlGaAs/GaAs heterojunction bipolar transistor (HBT). Although this device does not have depleted AlGaAs ledge passivation layer, the low-frequency noise spectra show a very low 1/f noise corner frequency of less than 10 kHz, which is much lower than previously reported value of about 100 kHz from conventional passivated or unpassivated AlGaAs/GaAs HBT's. Except for a residual generation-recombination (g-r) noise component, the noise power is comparable to that of Si BJT. It is also found that the low-frequency noise power of the AlGaAs/GaAs HBT is proportional to the extrinsic GaAs base surface recombination current square. Unlike the other HBT's reported, the noise sources associated with interface state and emitter-base (E-B) space charge region recombination are not significant for our device     

A low-noise K-Ka band oscillator AlGaAs/GaAsheterojunction bipolar transistors

The design considerations, fabrication process, and performance of the first K-Ka-band oscillator implemented using a self-aligned AlGaAs/GaAs heterojunction bipolar transistor (HBT) are described. A large-signal time-domain-based design approach has been used which applies a SPICE-F simulator for optimization of the oscillator circuit parameters for maximum output power. The oscillator employs a 2×10-μm² emitter AlGaAs/GaAs HBT that was fabricated using a pattern inversion technology. The HBT has a base current 1/f noise power density lower than 1×10^-20 A²/Hz at 1 kHz and lower than 1×10^-22 A/²/Hz at 100 kHz for a collector current of 1 mA. The oscillator, which is composed of only low-Q microstrip transmission lines, has a phase noise of -80 dBc/Hz at 100 kHz off carrier when operated at 26.6 GHz. These results indicate the applicability of the HBTs to low-phase-noise monolithic oscillators at microwave and millimeter-wave frequencies, where both Si bipolar transistors and GaAs FETs are absent     

AlGaAs/GaAs heterojunction bipolar transistors for power applications: issues of thermal effect and reliability

AlGaAs/GaAs heterojunction bipolar transistor (HBT) has the advantages of superior switching speed, wide linearity, and high current handling capability. As a result, the device has gained popularity in designing power amplifiers for RF and microwave applications. However, the high power in the HBT, together with the poor thermal conductivity of GaAs, gives rise to significant thermal effect and reduced reliability in such a device. This paper presents an overview on the simulation, modeling, and reliability of AlGaAs/GaAs HBTs. Emphasis will be placed on the effects of thermal–electrical interacting behavior on the dc and ac performance of the HBT. The thermal-induced degradation process in the HBT will also be addressed and analyzed.     

A 10 Gb/s ATM data synchronizer

Asynchronous transfer mode (ATM) data comes from different sources, and it is by nature bursty, hence causing the incoming phase and exact bit rate to vary from burst to burst. In order to retime the bursty data, a conventional yet low-Q clock recovery scheme could be used, but the downstream system components would have to cope with the consequent clock interruptions and variations in phase and frequency. This work presents a phase agile data synchronizer integrated circuit that retimes bursty ATM cells at 10 Gb/s to an external 10 GHz clock. The integrated circuit comprises an analog variable data delay, a phase detector, an edge detector, a loop filter, and a data retime. It has a total delay range of 200 pS. The integrated circuit has been fabricated in both AlGaAs/GaAs and InGaP/GaAs HBT technology     

A 3.2-V operation single-chip dual-band AlGaAs/GaAs HBT MMIC poweramplifier with active feedback circuit technique

This paper describes the design and experimental results for a 3.2-V operation single-chip AlGaAs/GaAs heterojunction bipolar transistor (HBT) monolithic microwave integrated circuit (IMMIC) power amplifier for GSM900 and DCS1800 dual-band applications. The following two new circuit techniques are proposed for implementing the power amplifier. One is an on-chip HBT bias switch which in turn switches the amplifier between 900 and 1800 MHz. The proposed switch configuration allows the switch using a high turn-on voltage of 1.3 V of AlGaAs/GaAs HBT's to operate with a 3-V low supply voltage, because the switch circuitry needs no stacked configuration. The other is an active feedback circuit (AFB) to prevent permanent failure of HBT's in the output power stage even under severe conditions of oversupply voltage and strongly mismatching load. Experimental results revealed that the proposed feedback circuit, which works as a voltage limiter, can protect the output stage HBT's from an excessive collector voltage swing even when the amplifier is operated under a condition of a 5-V oversupply voltage and a 10:1 voltage standing-wave ratio (VSWR) mismatching load. Under a normal condition of 3.2 V and a 50-Ω matching load, the IC is capable of delivering an output power of 34.5 dBm and a power-added efficiency (PaE) of 52% in a GSM900 mode, and a 32-dBm output power and a 32% PAE in a DCS1800 mode     

1.5-W CW S-band GaInP/GaAs/GaInP double heterojunction bipolartransistor

We report the first large-signal power result from a double heterojunction bipolar transistor (DHBT) based on the GaInP/GaAs/GaInP material system. A CW output power of 1.51 W and a power added efficiency of 52% were achieved at 3 GHz. Because the GaInP collector has a relatively high bandgap of 1.89 eV, high DC bias voltage operation with collector bias extending to 20 V (for a 40-V swing) is possible in this GaInP/GaAs/GaInP DHBT. This high DC bias voltage operation represents a unique advantage over the more conventional AlGaAs/GaAs HBT     

应用Volterra级数分析AlGaAs/GaAsHBT的三阶互调失真

分析了AlGaAs／GaAsHBT的非线性失真产生的机理,应用Volterra级数理论计算了AlGaAs／GaAsHBT的三阶互调失真,理论值与实测值吻合较好,获得了AlGaAs／GaAsHBT的非线性失真量比较弱的结果,其值并不像人们认为的那样强,并解释了HBT高线性度的原因,这证明了AlGaAs／GaAsHBT在抗干扰方面的潜在能力。     

AlGaAs／GaAs HBT集成电路的CAD

介绍了一套用于ＡｌＧａＡｓ／ＧａＡｓＨＢＴ集成电路的ＣＡＤ软件，它可完成ＨＢＴ的器件模拟、模型参数提取及电路模拟。应用该软件对ＨＢＴ运算放大器进行了模拟，为电路的研制提供了依据。     

Failure mechanism and SPICE modeling of AlGaAs/GaAs HBT long-term current instability

The long-term current instability of AlGaAs/GaAs heterojunction bipolar transistor (HBT) is studied, and the physical mechanism contributing to such a behavior is investigated. Based on this, a model capable of predicting the HBT long-term current drift and mean time to failure (MTTF) is developed. In addition, such a model is implemented into SPICE circuit simulator, thus allowing the simulation of HBT circuits subjected to an electrical and thermal stress condition.     

10 GB/s bit-synchronizer circuit with automatic timing alignment byclock phase shifting using quantum-well AlGaAs/GaAs/AlGaAs

A bit-synchronizer circuit is presented which operated up to a bit rate of Gb/s. The circuit comprises two master-slave flip -flops for data sampling, two EXCLUSIVE-OR gates for clock phase adjustment, an active signal splitter, and an EXCLUSIVE-OR gate for data transition detection. The gain of the EXCLUSIVE-OR phase comparator circuit is measured to be 302 mV/rad for a 1010-bit sequence. The margins for monotonous phase comparison are ±54° relative to the `in bit cell center' position of the sampling clock edge. The circuit is fabricated by using an enhancement/depletion 0.3 μm recessed-gate AlGaAs/GaAs/AlGaAs quantum-well FET process. The chip has a power dissipation of 230 mW at a supply voltage of 1.90 V     

Performance comparison of state-of-the-art heterojunction bipolar devices (HBT) based on AlGaAs/GaAs, Si/SiGe and InGaAs/InP

This paper presents a comprehensive comparison of three state-of-the-art heterojunction bipolar transistors (HBTs); the AlGaAs/GaAs HBT, the Si/SiGe HBT and the InGaAs/InP HBT. Our aim in this paper is to find the potentials and limitations of these devices and analyze them under common Figure of Merit (FOM) definitions as well as to make a meaningful comparison which is necessary for a technology choice especially in RF-circuit and system level applications such as power amplifier, low noise amplifier circuits and transceiver/receiver systems. Simulation of an HBT device with an HBT model instead of traditional BJT models is also presented for the AlGaAs/GaAs HBT. To the best of our knowledge, this work covers the most extensive FOM analysis for these devices such as I-V behavior, stability, power gain analysis, characteristic frequencies and minimum noise figure. DC and bias point simulations of the devices are performed using Agilent's ADS design tool and a comparison is given for a wide range of FOM specifications. Based on our literature survey and simulation results, we have concluded that GaAs based HBTs are suitable for high-power applications due to their high-breakdown voltages, SiGe based HBTs are promising for low noise applications due to their low noise figures and InP will be the choice if very high-data rates is of primary importance since InP based HBT transistors have superior material properties leading to Terahertz frequency operation.     

用于HBT的AlGaAs/GaAs MOVPE材料

通过LP-MOVPE研制了实用化的AlGaAs/GaAsHBT材料。采用CCl4作为P型掺杂剂进行基区重掺杂。所作HBT增益为20～35,截止频率fT>50GHz,最大振荡频率fmax>60GHz,X波段功率HBT输出功率大于5W。     

10 Gbit/s low-power bit synchroniser with automatic retiming phase alignment

A 10 Gbit/s bit-synchroniser circuit has been fabricated using an enhancement/depletion 0.3 mu m recessed-gate AlGaAs/GaAs/AlGaAs quantum well FET process. The differential gain of the exclusive-or phase comparator circuit is measured to be 371 mV/rad. The phase margins for monotonous phase comparison are -54/+21 degrees relative to the 'in bit cell centre' position of the negative going clock edge. The chip has a power dissipation of 160 mW when using a supply voltage of 1.90 V.<>     

Large-signal microwave characterization of AlGaAs/GaAs HBT's basedon a physics-based electrothermal model

A physics-based multicell electrothermal equivalent circuit model is described that is applied to the large-signal microwave characterization of AlGaAs/GaAs HBT's. This highly efficient model, which incorporates a new multifinger electrothermal model, has been used to perform dc, small-signal and load-pull characterization, and investigate parameter-spreads due to fabrication process variations. An enhanced Newton algorithm is presented for solving the nonlinear system of equations for the model and associated circuit simulator, which allows a faster and more robust solution than contemporary quasi-Newton nonlinear schemes. The model has been applied to the characterization of heterojunction bipolar transistor (HBT) microwave power amplifiers     

AlGaAs/GaAs HBT电压比较器

本文对异质结双极晶体管(HBT)电压比较器进行了理论分析,设计并制作了国内第一个AlGaAs/GaAs HBT电压比较器电路。首先,分析了HBT的基本工作原理;然后比较详细地分析了ECL电压比较器的工作原理并进行了设计。随后介绍了HBT的E-M模型,提取了模型参数,并对电路进行了模拟;最后全面介绍了AlGaAs/GaAs HBT电压比较器的制作过程。测试结果表明,HBT器件直流电流增益大于100,f_T为15.2GHz,f_(max)为14.8GHz;电路具有取样和锁存能力,并具有电压比较器的初步功能。     

AlGaAs/GaAs heterojunction bipolar transistor decision circuit

An AlGaAs/GaAs heterojunction bipolar transistor (HBT) decision circuit has been designed and characterised for optical communications, using 3.5 mu m emitter width transistors with cutoff frequency of 27 GHz. The maximum bitrate for a BER of 10/sup -9/ was 4.2 Gbit/s. At 2.0 Gbit/s, the clock phase margin was 240 degrees .<>     

A unified model for single/multifinger HBTs including self-heatingeffects

This paper presents a unified analytical large-signal model that includes self-heating effects. The model is applied to a single-finger AlGaAs/GaAs heterojunction bipolar transistor (HBT) and a multifinger InGaAs/GaAs HBT. The self-heating effect in the HBT is simulated as a feedback from the collector current to the base-emitter voltage. The main advantage of the circuit presented here is that additional analysis of coupling between electrical and thermal circuits is not required, as is the case with the existing models. The small-signal HBT model is implemented based on the S-parameters at multiple frequencies measured at multiple bias points. This model is verified by comparing the measured and simulated S-parameters. The large-signal model is based on the forward Gummel plot and is built over the small-signal model. This model is verified by comparing the simulated and measured dc I-V characteristics     

High-efficiency Ku-band HBT MMIC power amplifier

A Ku-band monolithic HBT power amplifier was developed using a metal-organic chemical vapor deposition (MOCVD)-grown AlGaAs/GaAs heterojunction bipolar transistor (HBT) operating in common-emitter mode. At a 7.5 V collector bias, the amplifier produced 0.5 W CW output power with 5.0 dB gain and 42% power-added efficiency in the 15-16 GHz band. When operated at a single frequency (15 GHz), 0.66 W CW output power and 5.2 dB of gain were achieved with 43% PAE     

Long-term base current instability in AlGaAs/GaAs HBTs: physical mechanisms, modeling, and SPICE simulation

This paper provides an overview of the long-term base current instability in the AlGaAs/GaAs heterojunction bipolar transistor (HBT), which is a main mechanism governing the HBT long-term current gain drift and thus a major concern for the HBT reliability. Topics covered include: (1) types of base current instability and their underlying physical mechanisms; (2) leakage currents in the HBT and their relevance to the reliability; (3) electrothermal interaction and their impact on the HBT reliability; (4) analytic model for predicting the HBTs mean time to failure (MTTF); and (5) SPICE implementation and simulation of HBT circuit reliability. Measurements and device simulation results are also included in support of the modeling and analysis.