X波段PHEMT功率单片放大器

报道了X波段8W AlGaAs/InGaAs/GaAs PHEMT MMIC功率单片放大器的设计和研制.放大器采用两级拓扑结构,输入输出为50Ω阻抗匹配,芯片面积为4.5mm×3mm.测试结果显示,在7.5V和1.5A的DC偏置下,输出功率在8W以上,功率附加效率为30%,功率增益为15dB.     

高增益K波段MMIC低噪声放大器

基于0.25μm PHEMT工艺,给出了两个高增益K波段低噪声放大器.放大器设计中采用了三级级联增加栅宽的电路结构,通过前级源极反馈电感的恰当选取获得较高的增益和较低的噪声;采用直流偏置上加阻容网络,用来消除低频增益和振荡;三级电路通过电阻共用一组正负电源,使用方便,且电路性能较好,输入输出驻波比小于2.0;功率增益达24dB;噪声系数小于3.5dB.两个放大器都有较高的动态范围和较小的面积,放大器1dB压缩点输出功率大于15dBm;芯片尺寸为1mm×2mm×0.1mm.该放大器可以应用在24GHz汽车雷达前端和26.5GHz本地多点通信系统中.     

高增益K波段MMIC低噪声放大器

基于0.25μm PHEMT工艺,给出了两个高增益K波段低噪声放大器.放大器设计中采用了三级级联增加栅宽的电路结构,通过前级源极反馈电感的恰当选取获得较高的增益和较低的噪声;采用直流偏置上加阻容网络,用来消除低频增益和振荡;三级电路通过电阻共用一组正负电源,使用方便,且电路性能较好,输入输出驻波比小于2.0;功率增益达24dB;噪声系数小于3.5dB.两个放大器都有较高的动态范围和较小的面积,放大器1dB压缩点输出功率大于15dBm;芯片尺寸为1mm×2mm×0.1mm.该放大器可以应用在24GHz汽车雷达前端和26.5GHz本地多点通信系统中.     

14W X波段AlGaN/GaN HEMT功率MMIC

报道了研制的SiC衬底AIGaN/GaN HEMT微带结构微波功率MMIC,芯片工艺采用凹槽栅场板结构提高AlGaN/GaNHEMTs的微波功率特性.S参数测试结果表明AlGaN/GaN HEMTs的频率特性随器件的工作电压变化显著.研制的该2级功率MMIC在9～11GHz带内30V工作,输出功率大于10W,功率增益大于12dB,带内峰值输出功率达到14.7W,功率增益为13.7dB,功率附加效率为23%,该芯片尺寸仅为2.0mm×1.1mm.与已发表的X波段AlGaN/GaN HEMT功率MMIC研制结果相比,本项工作在单位毫米栅宽输出功率和芯片单位面积输出功率方面具有优势.     

14W X波段AlGaN/GaN HEMT功率MMIC

报道了研制的SiC衬底AIGaN/GaN HEMT微带结构微波功率MMIC,芯片工艺采用凹槽栅场板结构提高AlGaN/GaNHEMTs的微波功率特性.S参数测试结果表明AlGaN/GaN HEMTs的频率特性随器件的工作电压变化显著.研制的该2级功率MMIC在9～11GHz带内30V工作,输出功率大于10W,功率增益大于12dB,带内峰值输出功率达到14.7W,功率增益为13.7dB,功率附加效率为23%,该芯片尺寸仅为2.0mm×1.1mm.与已发表的X波段AlGaN/GaN HEMT功率MMIC研制结果相比,本项工作在单位毫米栅宽输出功率和芯片单位面积输出功率方面具有优势.     

Ka波段22dBm氮化镓单片集成放大器

设计了CPW式Ka波段氮化镓单片集成放大器,并基于国内的GaN外延片和工艺完成了芯片的制备。据我们所知,这是国内首次报道的Ka波段氮化镓单片集成放大器。该单级集成放大器使用了一个栅长0.25μm,栅宽275μm的AlGaN/GaN HEMT。在Vds=10V连续波测试条件下,放大器的工作带宽为1.5GHz。其中在26.5GHz的线性增益为6.3dB,最大输出功率22dBm,最大附加效率9.5%。该MMIC所使用的AlGaN/GaN HEMT在Ka波段、Vds=10V条件下的输出功率密度达到1W/mm。     

紧凑型K波段单级反馈式MMIC中功率放大器

给出了一种基于功率PHEMT工艺技术设计加工完成的紧凑型K波段单级反馈式MMIC宽带功率放大器.在21～28GHz的工作频段内,当漏极电压为6V,栅电压为-0.25V,电流为82mA时,1dB压缩点输出功率大于21dBm,小信号增益为7dB左右,输入驻波比小于3,输出驻波比均小于2.芯片尺寸为1mm×1.2mm×0.1mm.同时,给出了一种芯片级电磁场仿真验证方法,用该方法仿真的结果和测试结果非常一致,保证了电路设计的准确性.     

基于InP HBT工艺的高功率高谐波抑制W波段宽带八倍频器MMIC

基于0.7μm InP HBT工艺,设计实现了一种高功率高谐波抑制比的W波段倍频器MMIC。电路二倍频单元采用有源推推结构,通过3个二倍频器单元级联形成八倍频链,并在链路的输出端加入输出缓冲放大器,进一步提高倍频输出功率。常温25℃状态下,当输入信号功率为0 dBm时,倍频器MMIC在78.4~96.0 GHz输出频率范围内,输出功率大于10 dBm,谐波抑制度大于50 dBc。芯片面积仅为2.22 mm²,采用单电源+5 V供电。     

5W ISM波段InGaP/GaAs HBT功率放大器MMIC

通过分析InGaP/GsAsHBT器件的热学和电学特点,结合HBT大功率放大器芯片在技术性能、稳定性、可靠性及尺寸等方面的要求,通过优化设计HBT功率器件单元和匹配电路,开发了一个大功率、高效率、小尺寸的ISM波段功率放大器单片集成电路。该三级放大器的各级器件单元的发射极面积分别为320μm2,1280μm2,5760μm2,芯片内部包括了输入、输出50Ω匹配电路,面积仅为1.9mm×2.1mm。放大器采用5V单电源供电,在2.4～2.5GHz频率范围内线性增益为27dB,2dB增益压缩点输出饱和功率达到37dBm,功率附加效率为46%。     

X波段10W功率合成放大器的设计与实现

单个功放芯片输出功率的能力非常有限,通过研究平面功率合成网络的基本原理和设计方法,提出了一种基于平面功率合成技术的4路功率合成网络。测试结果表明,输出端口幅度一致性较好,输出端口的相位差小于4°,驻波小于1.5,两端口隔离度大于15 d B。设计并实现了工作在X波段、输出功率为10 W的功率合成放大器,并通过实际测试得到放大器的输出功率大于10 W,合成效率大于82%,与设计预期相符。     

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.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

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.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

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.     

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.     

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.