MIM capacitor fabrication and assessment for GaAs MMICs

Metal-insulator-metal, MIM, capacitors have been fabricated using plasma deposited silicon nitride, SiN_x, films deposited under varying deposition conditions. The electrical properties of the MIM capacitors and the corresponding physical properties of the SiN_x films have been determined. The breakdown field strength of the films, which varied between 0.4–3.0 MVcm⁻¹, has been related to the amount of hydrogen incorporated in the SiN_x layers during deposition. Frenkel-Poole conduction through the silicon nitride has been observed at room temperature and this conduction mechanism is shown to be predominant and independent of the breakdown field strength, for the films investigated.     

Process and terminations variations aware stability criteria for microwave amplifiers

Two novel process variations aware, necessary and sufficient conditions suitable for implementation in CAD optimizers are proposed to check amplifiers stability. Case studies are presented, showing that the new criteria allow robust amplifier design, under variation of active device immittance parameters in pre‐specified rectangular regions, due to manufacturing tolerances. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE 23: 619–626, 2013.     

An improved analytical model of 4H-SiC MESFET incorporating bulk and interface trapping effects

An improved analytical model for the current-voltage (I-V) characteristics of the 4H-SiC metal semiconductor field effect transistor (MESFET) on a high purity semi-insulating (HPSI) substrate with trapping and thermal effects is presented. The 4H-SiC MESFET structure includes a stack of HPSI substrates and a uniformly doped channel layer. The trapping effects include both the effect of multiple deep-level traps in the substrate and surface traps between the gate to source/drain. The self-heating effects are also incorporated to obtain the accurate and realistic nature of the analytical model. The importance of the proposed model is emphasised through the inclusion of the recent and exact nature of the traps in the 4H-SiC HPSI substrate responsible for substrate compensation. The analytical model is used to exhibit DC I-V characteristics of the device with and without trapping and thermal effects. From the results, the current degradation is observed due to the surface and substrate trapping effects and the negative conductance introduced by the self-heating effect at a high drain voltage. The calculated results are compared with reported experimental and two-dimensional simulations (Silvaco^®-TCAD). The proposed model also illustrates the effectiveness of the gate-source distance scaling effect compared to the gate-drain scaling effect in optimizing 4H-SiC MESFET performance. Results demonstrate that the proposed I-V model of 4H-SiC MESFET is suitable for realizing SiC based monolithic circuits (MMICs) on HPSI substrates.     

应用于MICs／MMICs中高次模式提取的混合FDTD-SVD方法综述

针对微波集成电路／单片微波集成电路中不连续性的导波结构,系统地综述了一种提取高次模的方法。该方法基于时域有限差分（FDTD）法的麦克斯韦方程求解技术,结合频域奇异值分解分析方法而实现。对基于系统的传输模态分析,该方法用于研究微波集成电路／单片微波集成电路中的不连续性,可确定系统的模式散射参数（S-参数）。文中所有结构宽波段的分析结果表明,这种方法计算准确、高效。     

K Band SiGe HBT single ended active inductors

The study of monolithic integration of active inductors (AI) on a 0.25 μm SiGe BiCMOS technology with 4 metal layers and HBTs with f_T=120 GHz is presented. Two topologies are presented and their performance discussed. Q values higher than 30 were obtained on a 3.4 GHz bandwidth at 28 GHz and maximum values as high as 100. Active inductors can be biased with low power, such as 2 V with a nominal DC current of 0.6 mA. The inductance value is controlled by external bias voltages and adjustments up to 40% were measured. Simple gyrators topologies with only 2 transistors are used for low power consumption and good performance at K Band is proved. The internal parameters of small signal model of HBT were studied and the crucial parameter to enhance the negative resistance and so the Q of the AI was identified.     

砷化镓衬底上螺旋电感的建模和分析

针对砷化镓(GaAs)衬底上螺旋电感提出了一种改进形式的集总参数等效电路模型,该等效电路模型能很好地表征螺旋电感的高频效应.同时,应用电磁场全波分析方法对螺旋电感进行仿真,并分析各参数对电感性能的影响.从得到的散射参数中提取出有效电感、Q值和自谐振频率.基于参数优化方法提取等效电路模型中各元件值,并利用曲线拟合技术给出其相应的闭合表达式.这些表达式可用于射频和微波集成电路的设计,从而提高电路设计的性能和效率.     

Nonlinear circuit stability under large‐signal pumping: Three‐port μ stability factor versus conversion matrix system identification—application to a millimeter‐wave band MMIC up‐converter

This article presents and discusses a method to determine stability in nonlinear three‐port circuits based on a generalized three‐port μ stability factor applied to linearized S parameters under large‐signal pumping. A comparison with an extension of the conversion matrix–based, system pole–zero identification used to analyze circuit stability is also presented. The relationship between the two techniques has been verified by means of an ideal two‐port nonlinear circuit, and then, it has been applied in the design of a three‐port millimeter‐wave Monolithic Microwave Integrated Circuit (MMIC) up‐converter. The circuit has been fabricated in a commercial GaAs process. On‐wafer measurements showed an average conversion loss about 3.5 dB in a RF bandwidth between 40.4 and 41.5 GHz with local oscillator (LO) frequency fixed at 42.5 GHz. A RF/LO isolation better than 25 dB was measured in the whole band, also showing outstanding intermodulation performance. With the proposed approach, the appearance of spurious oscillations was prevented. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

InAlAs/InGaAs PHEMTs的设计及其110GHz全频段小信号建模

90-nm T-shaped gate InP-based In_0.52Al_0.48As/In_0.6Ga_0.4As pseudomorphic high electron mobility transistors were designed and fabricated with a gate-width of 2×30 μm,a source-drain space of 2.5 μm,and a source-gate space of 0.75 μm.DC,RF and small-signal model characterizations were demonstrated.The maximum saturation current density was measured to be 755 mA/mm biased at V_gs=0.6 V and V_ds=1.5 V.The maximum extrinsic transconductance was measured to be 1006 mS/mm biased at V_ds=—0.1V and V_ds=1.5 V.The extrapolated current gain cutoff frequency and maximum oscillation frequency based on S-parameters measured from 0.5 to 110 GHz were 180 and 264 GHz,respectively.The inflection point（the stability factor k=1）where the slope from-10 dB/decade（MSG） to-20 dB/decade（MAG） was measured to be 83 GHz.The smallsignal model of this device was also established,and the S-parameters of the model are consistent with those measured from 0.5-110 GHz.     

一种实用的磷化铟MMIC背面工艺技术

采用湿法技术发展了磷化铟 MMIC的背面通孔刻蚀工艺 ,PMMA用作粘片剂 ,In P衬底粘附于玻璃版上 ,溅射钽膜用作湿法刻蚀掩膜 ,HCl+H3PO4 腐蚀液实现 10 0 μm的通孔腐蚀 .已证实这种湿法通孔工艺宽容度大 ,精确可控