GaAs单片微波集成电路的制作工艺

GaAs单片微波集成电路工艺属于分立GaAs MESFET工艺的进一步发展。描述了GaAs制作工艺,它为微波电路设计师提供了制作所有元件的能力,其中包括MESFET、电阻、电容、电感和完整的背面接地连接。以2～12GHz单片放大器为例说明了这些元件的集成。     

Si衬底上MBE GaAs MESFET与IC制备

叙述在MBE(分子束外延)GaAs/Si材料上制作GaAs MESFET与Ic的研究。考虑到GaAsIC与Si IC单片集成的需要,采用了Ti/TiW/Au肖特基金属化和Ni/AuGe/Ni/Au欧姆接触金属化,层间介质采用等离子增强淀积氮化硅和聚酰亚胺复合材料。在该工艺基础上,制备了性能良好的GaAs/Si MESFET与IC。     

不同工艺制备的GaAs MESFET阈值电压均匀性研究

分别采用离子注入隔离凹栅工艺、自隔离平面工艺、离子注入隔离平面工艺在非掺杂半绝缘GaAs衬底上制备MESFET,对三种工艺制备的MESFET的阈值电压均匀性进行了研究。结果表明,器件工艺对MESFET阈值电压有一定的影响,开展GaAs MESFET阈值电压均匀性研究应采用适宜的工艺,以尽可能减少工艺引起的偏差。     

下期目录预告

<正> 1.4～8 GHz GaAs FET 宽带放大器的新进展2.难熔的 WN 栅自对准 GaAs MESFET 工艺及其在门阵列集成电路中的应用3.应用于雷达和通讯中的 GaAs 低噪声单片微波集成放大器4.低暗电流 InGaAs PIN 光电二极管     

四位GaAs超高速D/A转换电路的研究

本文简要介绍了目前国际上GaAs超高速D/A转换器的研制情况。在详细分析了几种常用类型D/A转换电路工作原理的基础上,结合现有GaAs VHSIC的制作工艺条件,设计并制作了一种4位单片集成GaAs MESFET D/A转换电路。测试结果表明,该电路分辨率为4位,转换速率办1Gs/s,建立时间小于1.0ns,微分线性误差小于±1/2LSB,功耗约为20mW。     

MOCVD生长GaAs/Si材料及其在MESFET中的应用

本文研究了MOCVD生长GaAs/Si复合材料的生长工艺及材料特性,并生长出用于MESFET的多层结构材料。讨论了影响外延层电阻率的因素,并给出了GaAs/Si材料在MESFET中的应用结果。     

功率GaAs MESFET微波特性的分析

本文介绍了功率砷化镓肖特基势垒栅场效应管(GaAs MESFET)微波性能的理论分析方法,叙述了对器件进行计算与实验测量的结果,讨论了典型的实验现象,证明了本文的分析对功率GaAs MESFET是适用的。     

X波段单片集成空气桥源MESFET放大器

<正> 1983年日本的H.Itoh等首先将空气桥源MESFET应用于12GHz单片集成低噪声放大器,实现器件的单边接地。但是,由于器件采用叉指结构,无法采用斜蒸发工艺缩短栅长。1986年,南京电子器件研究所也研制成空气桥源MESFET。这种器件结构适合目前广泛采用的凹槽斜蒸栅工艺,有利于亚微米栅的制备,并已将该器件应用于X波段GaAs单片集成放大器电路。其测量性能见表Ⅰ。     

太赫兹探测用GaAs MESFET Ⅰ-Ⅴ特性模拟计算

Ⅲ-Ⅴ族化合物半导体材料GaAs,由于其本征载流子浓度比Si约低104,电子迁移率约是Si的5倍,电阻率高达108 Ωcm,有利于降低寄生电容,减少漏电流;另外,GaAs材料便于加工,可方便地实现大规模集成,适用于制作MESFET器件.目前用于太赫兹探测的GaAs MESFET在国际上有了较大的发展,为了进一步研究ME...     

GaAs MESFET高速集成逻辑

本文对GaAs金属-半导体场效应晶体管(GaAs MESFET’S)在高速开关及高速数字集成电路方面的应用的可能性进行了论证。栅长为1微米的GaAs MESFET的电流增益带宽乘积f_T等于15千兆赫。在大信号开关测试中,这种器件显示出15微微秒的内部时延。在半绝缘的GaAs衬底上单片集成由MESFET和肖特基二极管组成的简单逻辑电路。无负载时,这种逻辑电路的传播时延为60微微秒,而当其输出是3个逻辑门时,其传播时延则为105微微秒。测得有效带宽约为3千兆赫。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.