Self-aligned AlGaAs/GaAs HBT with InGaAs emitter cap layer

A new self-aligned AlGaAs/GaAs HBT with an InGaAs emitter cap layer is presented. This HBT has nonalloyed ohmic contacts to the emitter and base that are formed simultaneously and in a self-aligned manner. The low emitter contact resistance of 1.4×10-7 ?cm2 and the high transconductance per unit area of 3.3 mS/?m2 demonstrate the effectiveness of this structure.     

Self-aligned AlGaAs/GaAs HBT with low emitter resistance utilizingInGaAs cap layer

A self-aligned AlGaAs/GaAs heterojunction bipolar transistor (HBT) with an InGaAs emitter cap layer that has very low emitter resistance is described. In this structure, a nonalloyed emitter contact allows the emitter and base electrodes to be formed simultaneously and in a self-aligned manner. The reduction of emitter resistance greatly improves the HBT's transconductance and cutoff frequency. In fabricated devices with emitter dimensions of 2 μm×5 μm, a transconductance-per-unit-area of 16 mS/μm² and a cutoff frequency of 80 GHz were achieved. To investigate high-speed performance, a 21-stage ECL ring oscillator was fabricated using these devices. Propagation delay times as low as 5.5 ps/gate were obtained, demonstrating the effectiveness of this structure     

Improved AlGaAs/GaAs HBT performance by InGaAs emitter cap layer

The effects of the emitter resistance reduction on the DC and high-frequency characteristics in an AIGaAs/GaAs HBT with an InGaAs emitter cap layer are investigated. In fabricated devices, a transconductance per unit area of 16mS/?m2 and a cutoff frequency of 80 GHz have been achieved.     

微空气桥隔离的自对准AlGaAs/GaAs异质结双极晶体管

利用微空气桥隔离和自对准技术成功地研制出了自对准结构的AlGaAs/GaAs异质结双极晶体管.器件展现出良好的直流和高频特性.对于发射极面积为2μm×15μm的器件,直流电流增益大于10,失调电压(Offsetvoltage)200mV;电流增益截止频率f_T大于30GHz,最高振荡频率f_max约为50GHz.     

Isolated emitter AlGaAs/GaAs HBT integrated with emitter-down HI2L technology

A process that integrates isolated-emitter heterojunction bipolar transistors (HBTs) with common-emitter HBTs in the emitter-down epi structure on n⁺ substrates is discussed. Overgrowth of the epi onto a p^- implanted region results in back-to-back diodes for ~12-V vertical isolation. Isolated transistors are used in emitter-follower output buffers for heterojunction injection logic (HI ²L) ring oscillators, demonstrating the integration of the two transistor types     

自对准AlGaAs/GaAs微波异质结双极晶体管(HBT)

本文提出了一种制作HBT采用的垂直台面结构自对准工艺.利用该工艺及对A1GaAs/GaAs具有高选择比的化学湿法腐蚀剂,已研制成微波HBT.发射区台面与基极电极间隙为0.1μm,最大直流电流增益为40,截止频率f_T为10GHz.     

A new self-aligned AlGaAs/GaAs HBT based on refractory emitter andbase electrodes

A self-alignment technique for AlGaAs/GaAs heterojunction bipolar transistors (HBTs) using refractory metal film, W, as the emitter and base electrodes is presented. A nonalloyed contact formation combined with selective reactive ion etching of W or WSi_x against GaAs and SiO₂ produces a self-aligned structure. An emitter contact that is thermally stable is obtained by using a Zn diffusion process to make the extrinsic base contact layer. An f_T value as high as 82 GHz was obtained. The self-alignment technique combined with the Zn diffusion process will achieve a much higher f_T if a thinner base HBT structure is used     

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     

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     

Submicron-square emitter AlGaAs/GaAs HBTs with AlGaAshetero-guardring

Successful operation of submicron-square emitter AlGaAs/GaAs HBTs is demonstrated for the first time by using a fully mesa-structure-type emitter-base junction-area definition method with an AlGaAs hetero-guardring. The hetero-guardring reduces surface recombination current at the emitter-mesa edge to 1.4 μA/μm. This is 1/10 of that for devices without the guardring. Here, dc gains of 20, 26, and 40 are achieved for 0.5 μm×0.5 μm, 0.7 μm×0.7 μm, and 0.9 μm×0.9 μm emitter HBTs, respectively. An f_T of 40 GHz, and an f_max of 30 GHz are obtained for 0.9 μm×0.9 μm at a J_C of 1.0×10⁵ A/cm²     

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     

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。     

Novel doubly self-aligned AlGaAs/GaAs HBT

A novel, doubly self-aligned process technology for AlGaAs/GaAs heterojunction bipolar transistors (HBT) has been developed. This doubly self-aligned process enables self-alignment for all emitter, base, and collector contacts and the fabricated device occupies an area approaching the intrinsic device area. The resulting base-collector capacitance of a fabricated device is reduced below half of the base-collector capacitance of conventional devices. The reductions in the capacitance are reflected in the superior cutoff frequency and maximum oscillation frequency of the doubly self-aligned devices as compared with conventional devices.<>     

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。     

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。     

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。     

高功率密度自对准结构AlGaAs/GaAs 异质结双极晶体管

利用各向异性的湿法刻蚀和侧墙隔离技术实现了发射极金属和基极金属的自对准,采用该自对准技术成功地研制出了自对准结构的AlGaAs/GaAs异质结双极晶体管,器件直流电流增益大于20,电流增益截止频率fT大于30GHz,最高振荡频率fmax大于50GHz,连续波功率测量表明：在1dB增益压缩时,单指HBT可以提供100mW输出功率,对应的功率密度为6.67W/mm,功率饱和时最大输出功率112mW,对应功率密度为7.48W/mm,功率附加效率为67%．     

Selfaligned AlGaAs/GaAs HBT grown by MOMBE

The very low parasitic resistance n-p-n GaAs/AlGaAs heterojunction bipolar transistors (HBT) grown by metal organic molecular beam epitaxy (MOMBE) using all gaseous source dopants are reported. The carbon and tin dopants were introduced through the uses of trimethygallium (TMGa) and tetraethyltin (TESn). To achieve the low parasitics, the graded InGaAs emitter cap layer was doped with tin to 5*10/sup 19/ cm/sup -3/ and the doping level in the subcollector was 3*10/sup 18/ cm/sup -3/. The emitter and collector sheet resistances were 25 Omega / Square Operator and 10 Omega / Square Operator , respectively. The 800 AA thick base layer was carbon doped to a level of 7*10/sup 19/ cm/sup -3/. The base contact resistance and sheet resistance were 0.1 Omega mm and 180 Omega / Square Operator , respectively. With a thin AlGaAs surface passivation layer for the emitter-base junction, the common emitter DC current gain was maintained up to 25, even for 2*5 mu m/sup 2/ emitter size devices. The unity short circuit current gain cutoff frequency f/sub T/, and maximum oscillation frequency f/sub max/, were 48 and 63 GHz, respectively.<>     

高功率密度自对准结构AlGaAs/GaAs异质结双极晶体管

利用各向异性的湿法刻蚀和侧墙隔离技术实现了发射极金属和基极金属的自对准 ,采用该自对准技术成功地研制出了自对准结构的 Al Ga As/ Ga As异质结双极晶体管 ,器件直流电流增益大于 2 0 ,电流增益截止频率 f T 大于30 GHz,最高振荡频率 fmax大于 5 0 GHz,连续波功率测量表明 :在 1d B增益压缩时 ,单指 HBT可以提供 10 0 m W输出功率 ,对应的功率密度为 6 .6 7W/ m m,功率饱和时最大输出功率 112 m W,对应功率密度为 7.48W/ m m,功率附加效率为 6 7%     

AlGaAs/GaAs bipolar transistors with a modulation-doped superlattice emitter

A new emitter-base concept for heterojunction bipolar transistors is proposed and demonstrated. The abrupt or graded emitter-base heterojunction drawbacks are circumvented by means of a modulation-doped stack of ternary compound alternating with binary compound layers. This stack provides efficient barriers to the hole current while preserving good diode characteristics. These concepts are demonstrated by experimental results on small-area devices with a common-emitter gain of ~40 and a collector-emitter voltage offset of ~80mV.