AlGaAs/GaAs/AlGaAs DHBT's for high-temperature stable circuits

High-temperature devices are required for a large number of industrial applications. In order to demonstrate the feasibility of a high temperature operating circuit on GaAs an operational amplifier was designed and fabricated. A corresponding technology for transistors and circuits for operation up to 300°C with AlGaAs/GaAs/AlGaAs DHBT's is presented. For the amplifier circuit an open loop gain of 49.5 dB at room temperature and 35.8 dB at 200°C was measured, which is in good agreement with the circuit simulation. High temperature stability has been proven by a storage test at 400°C over 1000 h for the ohmic contact metallization and 200 h for the transistors     

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。     

基于GaAs/AlGaAs光波导扫描技术的研究

分析了光学相控阵的工作原理,提出了可编程的馈电方案,给出了10层P-I-N型GaAs／AlGaAs相控阵列的实验结果,通过实验证实光学相控阵是一种新颖的、高分辨率的、快速宽角度的扫描技术。     

卫星用AlGaAs／GaAs太阳能电池

介绍了ＧａＡｓ太阳能电池的基本原理，结构设计和制作工艺。用水平液相外延一室分离多片旬延石墨舟研制了ｐ－ＡｌｘＧａ１－ｘＡｓ／ｐ－ｎ－ＧａＡｓ结构的太阳能电池。在ＡＭＯ，１００ｍＷ／ｃｍ＾２２５℃的测试条件下，开路电压（Ｖｏｃ）为９９４ｍＶ，短路电流密度为２３．２ｍｃｍ＾２，填充因子（ＦＦ）为０．７９４，光电转换这１８．２5.     

AlGaAs/GaAs HBT for high-temperature applications

A high-temperature N-p-n AlGaAs/GaAs HBT with a wide-bandgap emitter which can be operated up to a ambient temperature of 350°C is presented. It is demonstrated that a high Al mole fraction of 0.45 in the emitter in combination with a GaAs base layer yields excellent temperature stability. A useful common-emitter small-signal current gain h_FE higher than 35 was measured in the range between room temperature and 350°C     

单量子阱GaAs/AlGaAs半导体激光器

本文介绍了用分子束外延法制作的梯度折射率分别限制式单量子阱GaAs/AlGaAs半导体激光器。该器件具有较低的阈值电流密度和单模运转特性,连续输出功率可达55mw。     

Electron mobility in a AlGaAs/GaAs/AlGaAs quantum well

An oscillatory dependence of the electron mobility on the quantum well (QW) thickness in a AlGaAs/GaAs/AlGaAs heterostructure with double-sided modulation doping has been observed experimentally. A steep decrease in mobility with increasing electron concentration in the QW is established. The conditions for an increase in mobility on introducing a thin barrier into the QW are determined. The first experimental observation of an increase in mobility by a factor of 1.3 in a QW of thickness L=26 nm upon introducing a thin (1–1.5 nm) AlAs barrier is reported.     

超亚微米栅AlGaAs/GaAs HEMT

在分子束外延生长的外延晶片上,用电子束刻蚀技术制作了超亚微米栅AlGaAs/GaAs高电子迁移率晶体管(HEMT),其栅长分布为25～85nm。该器件表明,速度过冲和短栅几何效应对栅长小于100nm的器件起着重要的作用。栅长为30nm的HEMT的最大本征跨导为215mS/mm,有效饱和电子速度可达3×10~7cm/s。     

GaAs/AlGaAs and InGaAs/AlGaAs MODFET inverter simulations

Although MODFET's have exhibited the fastest switching speed for any digital circuit technology, there is as yet no clear consensus on optimal inverter design rules. We therefore have developed a comprehensive MODFET device model that accurately accounts for such high gate bias effects as transconductance degradation and increased gate capacitance. The device model, which agrees with experimental devices fabricated in this laboratory, is used in the simulation of direct-coupled FET logic (DCFL) inverters with saturated resistor loads. Based on simulation results, the importance of large driver threshold voltage not only for small propagation delay times but for wide logic swings and noise margins is demonstrated. Furthermore, minimum delay times are found to occur at small supply voltages as seen experimentally. Both of these results are attributed to the reduction of detrimental high gate bias effects. The major effect of reducing the gate length on delay time is to decrease the load capacitance of the gate. Using 0.25-µm gates, delay times of 5 and 3.6 ps at 300 and 77 K, respectively, are predicted. Finally, the recently introduced In-GaAs/AlGaAs MODFET's are shown to have switching speeds superior to those of conventional GaAs/AlGaAs MODFET's.     

Ultra-submicrometer-gate AlGaAs/GaAs HEMTs

Ultra-submicrometer-gate AlGaAs/GaAs high-electron-mobility transistors (HEMTs) that have gate lengths ranging from 25 to 85 nm and were fabricated using electron-beam lithographic techniques on epitaxial wafers grown by molecular beam epitaxy are discussed. These devices show that velocity overshoot and short-gate geometry effects play an important role for the gate lengths less than 100 nm. The maximum intrinsic transconductance is 215 mS/mm, and the effective saturated electron velocity reaches 3×10⁷ cm/s for a 30-nm HEMT     

AlGaAs/GaAs/AlGaAs渐变异质结光致发光仿真研究

分析了AlGaAs/GaAs/AlGaAs渐变异质结的光致发光特性。根据理论及仿真结果,确定了GaAs发光的最优能带结构为双异质结P-AlGaAs/P-GaAs/P-AlGaAs或者N-AlGaAs/N-GaAs/ N-AlGaAs,并且异质结两边能带渐变。基于所选结构,研究了能带渐变及层宽对发光效率的影响。研究结果表明,外体区吸收层的能带渐变,且外体区激发层的能带不变,发光区域的载流子最多,发光能量值最大。激励光源的波长不同,各层有不同的最优宽度,为器件的整体优化提供了依据。AlGaAs/GaAs/AlGaAs渐变异质结的光致发光研究为高效率器件如太阳电池、发光二极管等的实用化设计、研制提供了有价值的参考。     

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。     

Analysis of a new microwave low-loss and velocity-matched III-Vtransmission line for traveling-wave electrooptic modulators

A new microwave transmission line with low loss and velocity matched to a lightwave for a III-V traveling-wave electrooptic modulator has been analyzed using the spectral domain technique. A bandwidth of >40 GHz and a half-wave voltage V_π of <6 V are predicted for the modulator     

AlGaAs/GaAs superlattice solar cells

A theoretical model is performed to study the viability of the AlGaAs/GaAs superlattice solar cell (SLSC). Using the Transfer Matrix Method, the conditions for resonant tunneling are established for a particular SL geometry with variably spaced quantum wells. The effective density of states and the absorption coefficient are calculated to determinate the J–V characteristic. Radiative, non‐radiative, and interface recombination were evaluated from a modeled SLSC, and their values were compared with a multiple quantum well solar cell of the same aluminum composition. A discussion about the conditions, where SLSC performance overcomes that of a multiple quantum well solar cell, is addressed. Copyright © 2011 John Wiley & Sons, Ltd.     

AlGaAs/GaAs HBT linearity characteristics

Communication systems require linear power amplifiers with high efficiency and very low intermodulation distortion. AlGaAs/GaAs heterojunction bipolar transistors (HBT's) were found to have very low intermodulation distortion in power operation. Two-tone tests were carried out on both common-emitter (CE) and common-base (CB) power HBT's. At 7 GHz, the CE HBT showed -20 dBc IM₃ (third-order intermodulation ratio) and 12% power added efficiency (PAE) per tone at the 1 dB gain compression point; IM₃ dropped to -30 dBc at 1.5 dB output power backoff. The CE HBT has lower intermodulation distortion than CB HBT. Load pull data were collected to aid the understanding of the intermodulation. Parameters of the Gummel-Poon model (as used in SPICE) were derived for HBT's based on dc data and small-signal S parameters at various bias points. The accuracy and validity of the model were confirmed by comparison to experimental two-tone results. SPICE predicts that the emitter and base resistances linearize the HBT and reduce the third-order intermodulation distortion. The excellent third-order intermodulation performance of the CE HBT makes it a very attractive choice for linear power amplifiers     

GaAs/AlGaAs量子级联激光器

利用分子束外延方法生长了激射波长约为9μm的GaAs/Al0.45Ga0.55As量子级联激光器.条宽35μm,腔长2mm的器件准连续激射温度最高达120K,81K下未经收集效率修正的峰值功率超过70mW.     

Millimeter-wave AlGaAs/GaAs p-n-p HBT

The total emitter-to-collector delay for a p-n-p AlGaAs/GaAs heterojunction bipolar transistor (HBT) has been reduced to 5.7 ps by extending the cutoff frequency for these devices to the millimeter-wave range. A total charging delay of 1.2 ps was obtained by a lightly doped emitter and by reducing the collector resistance. Low transit delays totaling 4.5 ps were achieved with a thin (440 Å) uniformly doped base and a thin (2800 Å) collector. The reduction in these delays permitted a non-self-aligned (1-μm emitter mesa/base contact separation) device with two emitters (2.6×10 μm² each) and a single base contact to exhibit an f_t of 28 GHz