蓝宝石衬底AlGaN/GaN共栅共源微波HEMTs器件

报道了蓝宝石衬底AlGaN/GaN共栅共源器件的制备与特性.该器件包括栅长为0.8μm共源器件与栅长为1μm的共栅器件.实验表明,共栅器件的第二栅压会显著影响器件饱和电流与跨导特性,从而控制功率增益.与共源器件相比,共栅共源器件表现出稍低的 f T、较低的反馈、显著增加的功率资用增益及较高的端口阻抗.     

AlGaN/GaN共栅共源HEMTs器件

研究了蓝宝石衬底AlGaN／GaN共栅共源器件的特性。该器件包括栅长0．8μm共源器件与栅长1μm的共栅器件。研究表明,共栅共源器件的第二栅压对的器件饱和电流与跨导有明显的调制作用,容易实现功率增益控制。与共源器件相比,共栅共源器件在微波特性上fT大约9GHz,比共源器件稍小,但是具有较低的反馈,显著增加的功率资用增益及较高的端口阻抗,与共源器件相比,稳定性更好,可以避免振荡的产生,结合GaN的高功率特性GaN共栅共源器件非常适合微波频段宽频大功率领域的应用。     

100GHz高增益InP基MMIC共源-共栅放大器

本文介绍了一种高增益InP MMIC共源-共栅放大器,当偏置在最大带宽时,该器件在75～100GHz下的平均增益为8.0dB;当偏置在最高增益时,80GHz下的增益高于12dB。这是目前报道的W波段(75～100GHz)增益最高的放大器。所用的有源器件是栅长为0.1μm晶格匹配的InGaAs-InAlAs高电子迁移率晶体管(HEMT)。该放大器以共面波导(CPW)作为传输线,芯片总面积为600μm×500μm。     

折叠式共源共栅运算放大器的0.6μm CMOS设计

折叠式共源共栅结构的运算放大器不仅能提高增益、增加电源电压噪声抑制能力,而且在输出端允许自补偿.基于0.6μm CMOS工艺,验证了一种折叠共源共栅的运算放大器的参数指标.理论计算和实际分析相结合,仿真结果达到设计指标要求.     

一款高性能共源共栅运算放大器设计

基于CSMC 0.5μm标准CMOS工艺,采用复用型折叠式共源共栅结构,设计一种折叠式共源共栅运算放大器。该电路在5V电源电压下驱动5pF负载电容,采用Cadence公司的模拟仿真工具Spectre对电路进行仿真。结果表明,电路开环增益达到了71.7dB,单位增益带宽为52.79MHz,开环相位裕度为60.45°。     

高性能折叠式共源共栅运算放大器的设计

折叠式共源共栅结构能够提供足够高的增益,并且能够增大带宽、提高共模抑制比和电源电压抑制比.基于Chartered 0.35 μm工艺,设计了一种折叠式共源共栅结构的差分输入运算放大器,给出了整个电路结构.Spectre仿真结果表明,该电路在3.3V电源电压下直流开环增益为121.5dB、单位增益带宽为12 MHz、相位裕度为61.4°、共模抑制比为130.1dB、电源电压抑制比为105 dB,达到了预期的设计目标.     

一种低压低功耗CMOS折叠-共源共栅运算放大器的设计

本文设计了一种低压低功耗CMOS折叠一共源共栅运算放大器.该运放的输入级采用折叠-共源共栅结构,可以优化输入共模范围,提高增益;由于采用AB类推挽输出级,实现了全摆幅输出,并且大大降低了功耗.采用TSMC 0.18μm CMOS工艺,基于BSIM3V3 Spice模型,用Hspice对整个电路进行仿真,结果表明:与传统结构相比,此结构在保证增益、带宽等放大器重要指标的基础上,功耗有了显著的降低,非常适合于低压低功耗应用.目前,该放大器已应用于14位∑-△模/数转换电路的设计中.     

GaAs功率MESFET性能与器件参数关系的实验研究

用实验的方法研究了GaAs功率MESFET性能与器件参数的关系。功率增益、输出功率随栅长的变化很灵敏,随着栅长的增加,功率增益的率是1.7dB/μm,输出功率的降低率是0.67dB/μm。栅指的宽度对微波性能的影响不明显,在8GHz下栅指宽度一直增大到200μm,其性能尚未开始变坏。对于GaAs功率MESFET微波性能与温度的关系以及热阻与器件几何参数的关系也进行了定量研究。随着器件温度的升高,功率增益的降低率是0.026dB/°C。     

双栅MOSFET高频特性的实验研究

设计制作了不同沟道长度、栅材料以及栅电极构形的各种双栅MOSFET。通过实验全面研究了设计和工艺参数对器件高频特性的影响,阐明了双栅MOSFET的高频设计思想,给出了全离子注入高频低噪声工艺。有效沟道长度为1μm的超高频双栅MOSFET在900MHz下功率增益为17dB,有效沟道长度为1.5μm的甚高频器件在200MHz下功率增益为23dB.     

高跨导AlGaN/GaN HEMT器件

报道了生长在蓝宝石衬底上的AlGaN/GaN HEMT器件的制造工艺以及在室温下器件的性能.器件的栅长为1.0μm,源漏间距为4.0μm.器件的最大电流密度达到1000mA/mm,最大跨导高达198mS/mm,转移特性曲线表现出增益带宽较宽的特点.同时由所测得的S参数推出栅长为1.0μm器件的截止频率(fT)和最高振荡频率(fmax)分别为18.7GHz和19.1GHz.     

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.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

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.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.