微波双栅GaAs MESFET

按照一种新的双栅器件设计理论,采用阶梯栅和两栅间嵌入虚接地点的结构,使GaAs双栅FET获得了优良的噪声和增益性能。二栅在管壳内通过电容射频接地,有助于稳定性的改善。器件最好水平为f_0:12GHz,N_F:2.42dB,G_(?):13.89dB。该器件设计合理,工艺经过优化,使器件具有较高的成品率及优品率。     

12GHz波段GaAs双栅MESFET单片混频器

研制了用于直播卫星接收机的12GHz波段GaAs双栅MESFET单片混频器。为了缩小芯片面积,把一个缓冲放大器直接与混频器的中频端口连接,而不采用中频匹配电路。混频器和缓冲放大器分开制造在两个芯片上,以便单独测量。混频器芯片尺寸为0.96×1.26mm~2,缓冲放大器芯片尺寸为0.96×0.60mm~2。混频器的双栅FET,以及缓冲放大器的单栅FET的电极间距很小。栅长和栅宽各1μm和320μm。在11.7～12.2GHz,带有缓冲放大器的混频器提供转换增益为2.9±0.4dB,单边带噪声系数12.3±0.3dB。本振(LO)频率为10.8GHz。低噪声变频器由单片前置放大器、镜象抑制滤波器,以及单片中频放大器与混频器连接构成。在同一频段,变频器提供转换增益为46.8±1.5dB,单边带噪声系数为2.8±0.2dB。     

GaAs微波双栅功率MESFET

本文报导了C和X波段GaAs微波双栅功率MESFET的研制情况和器件设计的主要原则、制作技术、器件性能以及使用情况。CX651型较好器件,f_0=12GHz,P_0=195mW,G_p=13.7dB,第二栅可控增益△G_P=34.4dB;DX591型较好器件,f_0=6GHz,P_0=310nN,G_P=7.1dB,第二栅可控增益△G_P=33dB。代表了目前我国双栅功率器件的最高水平。     

X波段功率GaAs双栅MESFET的设计与制造

本文叙述微波功率双栅MES FET的设计与制造。介绍了实验结果。器件微波性能已达到10GHz下输出功率188mW,相应增益达9.7dB。用已定型的器件产品组成单级可变增益放大器,在9.952GHz下,输出功率大于100mW,相应增益达8dB,增益控制范围达30dB以上。     

C波段大栅宽GaAs MESFET的研制

采用高质量的ＭＢＥ材料,成功地制作了单胞栅宽２０ｍｍ的芯片。用栅与ｎ＾＋凹槽自对准和辅助侧墙工艺制作了栅长０．４５μｍ的ＴｉＰｔＡｕ栅,欧姆接触采用ＡｕＧｅＮｉ合金工艺,采用ＰＥＣＶＤ ＳｉＮ钝化,空气桥结构及芯片减薄Ｖｉａ－Ｈｏｌｅ工艺。经内匹配得到了单胞芯片３．７￣４．２ＧＨｚ下Ｐ。≥７．３Ｗ,Ｇｐ≥８ｄＢ,ηａｄｄ〉２５％;４胞合成器件Ｐ。≥２５Ｗ,Ｇｐ〉７ｄＢ,ηａｄｄ〉２５％的良好结果。     

C波段大栅宽GaAs MESFET的研制

采用高质量的 MBE材料 ,成功地制作了单胞栅宽 2 0 mm的芯片。用栅与 n+凹槽自对准和辅助侧墙工艺制作了栅长 0 .45 μm的 Ti Pt Au栅 ,欧姆接触采用 Au Ge Ni合金工艺 ,采用 PECVD Si N钝化 ,空气桥结构及芯片减薄 Via-Hole工艺。经内匹配得到了单胞芯片 3.7～ 4.2 GHz下 Po≥ 7.3W,Gp≥ 8d B,ηadd>2 5 % ;4胞合成器件 Po≥ 2 5 W,Gp>7d B,ηadd>2 5 %的良好结果。     

GaAs双栅MESFET单片行波混频器

本文根据GaAs MESFET单片行波放大器的原理,研制了一种新型宽带单片混频器.混频电路制在厚为0.1mm,面积为2.7×1.8mm的GaAs基片上,RF和LO分别通过等效特性阻抗为50Ω的G_1线和G_2线进入混频电路,且这两个频率在4个GaAs双栅MESFET(DGFET)中混频.这种MMIC混频器在中频频率为1.0GHz.射频频率在2～12GHz范围内得到约为8.5dB的变频损耗(无中频匹配电路),其平坦度约为±0.6dB.这一结果有助于进一步研究与实现单片宽带微波接收机.     

微波宽带双栅GaAs MESFET的模型

本文介绍GaAs MESFET(砷化镓金属半导体场效应晶体管)的一种多倍频程模型。它包括28个频率独立元件,可在2到11千兆赫之间有效工作。该模型考虑了栅间有无欧姆接触两种情况。模型是在实际偏压条件下分别利用有源器件的直流和高频特性以及等效电路的测定而得到的,因此,可达到两个目的:1)总模型的拓朴学特性可根据熟知的比较简单的部分模型导出;2)最优化的初始值足以精确地提供可靠的物理解。     

高低沟道结构的GaAs双栅MESFET

<正>1971年Turner等人提出了在源漏之间设立两个独立的肖特基势垒栅,这种双栅GaAsMESFET由于它具有增益高、稳定性好、信号调制能力强等优点,因此,近来发展较快,在一些领域获得广泛的应用.     

12GHz 1.5dB低噪声GaAs MESFET

本文叙述了12GHz低噪声GaAs MESFET的设计和制造.用普通光刻技术制成了高性能GaAs MESFET.在12GHz下测得器件最小噪声系数为1.4dB,相关增益7.5dB.     

Submicron Single-Gate and Dual-Gate GaAs MESFET's with Improved Low Noise and High Gain Performance

Microwave performance of single-gate and dual-gate GaAs MESFET's with submicron gate structure is described. Design consideration and device technologies are also discussed. The performance of these GaAs MESFET's exceeds previous performance with regard to lower noise and higher gain up to X band: 2.9-dB noise figure (NF) and 10.0-dB associated gain at 12 GHz for a 0.5-mu m single-gate MESFET, and 3.9-dB NF and 13.2-dB associated gain at the same frequency for a dual-gate MESFET with two 1-mu m gates.     

GaAs MESFET中的背栅效应

随着集成电路集成度的提高 ,器件间距不断减小 ,在 Ga As MESFET中产生了一种被称为背栅效应的有害寄生效应。由于器件间距越来越小 ,某一个器件的电极可能就是另一个器件的背栅 ,背栅效应影响了集成电路集成度的提高 ,因此背栅效应在国内外引起了重视。本文介绍了背栅效应及其可能的起因     

Impact ionization in GaAs MESFETs

A method to measure impact ionization current in GaAs MESFETs is presented. The impact ionization current is then used to calculate the maximum electric field in the channel and the impact ionization coefficient. Data for the electron impact ionization coefficient in 〈110〉 GaAs are extended beyond previous studies by five orders of magnitude. Impact ionization is taken into account in a new gate current model     

L波段砷化镓单片低噪声放大器

设计、研制了一种工作在Ｌ波段的ＧａＡｓ单片低噪声放大器。该放大器在ＨＰ－８５１０Ｂ网络分析仪和ＨＰ－８９７０Ｂ自动噪声仪上的测试结果为：１．１～１．５ＧＨＺ频段，ＮＦ≤２．０ｄＢ，Ｇ≥１８ｄＢ，ＶＳＷＲ（ｉｎ，ｏｕｔ）≤２：１，增益起伏≤０．５ｄＢ；在１．５～２．０ＧＨＺ频段ＮＦ≤２．５ｄＢ，Ｇ≥１８ｄＢ，ＶＳＷＲ（ｉｎ，ｏｕｔ）≤２：１，增益起伏≤±０．５ｄＢ。     

器件结构和材料质量对GaAs MESFET噪声系数的影响

本文从栅源串联电阻R_s和有效栅长L_f两方面论述了深槽自对准斜蒸栅结构可明显减小R_s与缩短L_f,有利于降低器件的噪声系数。 本文还用相关栅长L_a和器件在低温下的性能说明GaAs材料的质量对器件噪声系数的影响。提高GaAs半绝缘衬底和缓冲层质量以及与有源层交界面附近的迁移率,可较明显地缩短相关栅长L_a,降低器件噪声。 采用这一器件结构,并选用质量较高的GaAs材料,制得的MESFET,在12GHz下相关增益G_a为7.5dB,噪声系数NF_(min)为1.4dB,与理论预计值相符。     

Negative differential resistance in GaAs MESFETs

The occurrence of stationary domains and negative differential resistance in GaAs MESFETs is shown to be favoured for a certain range of combinations of pinch-off voltage, gate voltage and saturation voltage. Outside this range the transistor either shows instability or normal JFET behaviour. The predictions are in good agreement with available experimental data.     

High-performance millimeter-wave ion-implanted GaAs MESFETs

GaAs MESFETs (metal-epitaxial-semiconductor-field-effect transistors) with ion-implanted active channels have been fabricated on 3-in-diameter GaAs substrates which demonstrate device performance comparable with that of AlGaAs/InGaAs pseudomorphic HEMT (high-electron-mobility transistor) devices. Implanted MESFETs with 0.5-μm gate lengths exhibit an extrinsic transconductance of 350 mS/mm. From S-parameter measurements, a current-gain cutoff frequency f₁ of 48 GHz and a maximum-available-gain cutoff frequency f_max greater than 100 GHz are achieved. These results clearly demonstrate the suitability of ion-implanted MESFET technology for millimeter-wave discrete device, high-density digital, and monolithic microwave and millimeter-wave IC applications     

Surface passivation of GaAs MESFETs

The metal semiconductor field effect transistor (MESFET) represents a more realistic test for “passivation” efficacy than conventional capacitor test structures due to its prototypical fabrication process. This paper evaluates Gallium-Arsenide (GaAs) surface passivation films utilizing the MESFET as a test vehicle. For this study, gate-to-drain leakage current, gate-to-drain breakdown voltage, complex impedance versus frequency, and low-frequency noise measurements are performed on MESFETs with various passivation films. The results indicate that a hydrogen plasma used to “pre-clean” the GaAs surface in conjunction with an in situ plasma-enhanced chemical vapor deposition (PECVD) Si₃N₄ passivation film yields the best performance. In contrast, atomic-layer-epitaxial ZnSe demonstrated inferior performance (even in comparison to PECVD Si₃N₄ passivation films that did not receive a hydrogen “pre-clean”)