太赫兹器件用新型复合多层金刚石材料的研究

微波器件频率进入太赫兹,输能窗的厚度减小至一百甚至几十微米。常规的介质材料,或者多晶金刚石材料已经难以满足强度和真空密封性能的要求。为此设计并研制出一种新型微/超纳米复合多层金刚石膜。该膜采用微波等离子体化学气相沉积法(MPCVD),通过反应气源和沉积参数的改变,实现在硅衬底上依次原位生长微米尺度和超纳米尺度的金刚石膜。研制的复合多层金刚石膜表面粗糙度Ra<0.5μm,生长面的断裂强度高达1550MPa,是普通多晶金刚石膜的三倍。用该膜封接的输能窗目前已经通过真空密封性测试,将首次应用于太赫兹真空器件。     

太赫兹行波管输能窗用复合金刚石膜的设计

为解决现有多晶金刚石用于太赫兹(THz)真空电子器件输能窗存在慢性漏气风险的技术难题,介绍了一种高断裂强度、良好真空密封性能、低微波损耗的新型超薄复合多层金刚石膜的研制方法。该复合超薄金刚石膜采用微波等离子体化学气相沉积(MPCVD)技术,通过合理的结构设计和优化工艺,实现微米晶金刚石(MCD)和超纳米晶金刚石(UNCD)交替沉积的三明治结构。测量100 μm厚不同结构的复合膜断裂强度,是同样厚度的MCD的2~3倍。将研制的复合多层金刚石膜用于180 GHz和220 GHz 太赫兹行波管输能窗,通过气密性检测,漏率≤1×10-10 Pa?m3/s。窗的冷测结果显示,180 GHz窗的S11≤-15 dB(10 GHz带宽),220 GHz窗的S11≤-10 dB(20 GHz带宽),均具有良好的射频(RF)性能,满足使用要求。为太赫兹行波管输能窗的研制提供了一种成本低、可靠性高的超薄金刚石膜的技术途径。     

微波等离子体化学气相沉积超纳米晶金刚石膜研究

超纳米晶金刚石(UNCD)在短毫米波特别是太赫兹真空器件输能窗中具有潜在的应用价值。本文介绍了UNCD膜的制备工艺和性能表征。利用微波等离子体化学气相沉积法在一种贫氢、富氩的反应气体中合成UNCD膜。扫描电子显微镜分析表明,合成的UNCD膜表面光滑平整,晶粒为纳米尺度,断面结构致密。X射线衍射分析显示,超纳米晶金刚石薄膜主要是以(220)取向为主的多晶体结构,计算得到的平均晶粒尺寸为10nm。拉曼光谱分析呈现出典型的超纳米晶金刚石特性,膜中存在一定的sp2相。UNCD的光学透过率测试显示:在波长≥4μm范围内,光学透过率≥60%。     

金刚石在太赫兹电真空器件中的应用

金刚石材料具有低的介电常数、小的微波损耗、良好的导热性能,成为太赫兹电真空器件发展过程中非常有研究价值和应用价值的材料。它可以作为输能窗的介质窗片和高频结构的介质支撑材料。本文介绍了微波等离子体化学气相沉积(MPCVD)金刚石材料在太赫兹电真空器件中的具体应用实例,以及在W波段行波管中的实际应用情况,包括MPCVD金刚石的制备过程,及其与金属材料的封接工艺。研制出的W波段金刚石窗冷测结果显示其在75 GHz-110 GHz频段内性能良好:驻波系数(VSWR)≤1.5,传输损耗≤0.5 dB。这种窗已经成功用于W波段折叠波导连续波与脉冲行波管中。     

CVD金刚石在电真空器件中的应用

介绍了化学气相沉积（CVD）金刚石膜应用于电真空器件夹持杆及输能窗方面的研究进展,和国外对CVD金刚石封接的几种技术解决方案以及国内CVD金刚石膜金属化及封接方面的研究情况。     

MPCVD金刚石膜沉积技术及金刚石膜材料在微波电真空器件中的应用

金刚石膜是一种集众多优异性能于一身的新材料,尤其是其热导率高、绝缘性能好以及微波介电损耗低等特点,使金刚石膜在微波电真空器件领域有着重要的应用前景。目前,以微波等离子体化学气相沉积（MPCVD）方法制备高品质金刚石膜的技术已趋向成熟。本文将针对微波电真空器件这一应用背景,简要介绍国内外高品质金刚石膜MPCVD沉积技术的发展现状,进而对金刚石膜材料应用于微波电真空器件领域的一些典型实例进行简单的介绍。     

太赫兹行波管倍频器用金刚石输能窗研究

本文主要研究一种太赫兹行波管倍频器的输能系统,采用双频分路输能窗方案,分别对W波段基波和太赫兹谐波盒型窗进行了设计.利用MPCVD设备研制了RF级金刚石窗片材料,并对窗片的制备、金属化及窗的封接工艺进行了研究.研制出了基波系统金刚石窗,测试结果显示,在28 GHz频带内电压驻波比小于1.3,传输损耗小于0.5dB,已在W波段行波管中得到了实际应用;谐波输能窗已完成了设计.     

固态微波毫米波、太赫兹器件与电路的新进展

固态微波毫米波、太赫兹器件与电路是微电子、纳电子领域的战略制高点之一,SiCMOS技术进入纳米加工时代,GaAs,InP材料的"能带工程"(超晶格、异质结),GaN材料的宽禁带和界面特性以及石墨烯纳米级新材料的创新发展都深刻影响着固态微波毫米波、太赫兹器件与电路的进展。描述了固态微波、毫米波和太赫兹器件与电路当前发展的新亮点,包括纳米加工技术、石墨烯新材料、GaN MMIC功率合成突破3 mm频段百瓦级、三端器件进入太赫兹和两端器件倍频链突破2.7 THz微瓦功率。并重点就当前发展的RF CMOS,SiGe HBT,LDMOS,GaAsPHEMT,GaAs MHEMT,InP HEMT,InP HBT,GaN HEMT,GFET和THz倍频链等10个领域的发展特点、2011年最新发展以及未来发展趋势进行介绍。     

近太赫兹频段线性注真空器件的研究

介绍了太赫兹频段真空电子器件的研究和开发进展,包括慢波结构理论、设计、模拟及优化,微加工和微组装技术,整管技术等。这些器件包括行波管、返波管、斜注管、止带振荡器及行波管谐波放大器等,高频结构以折叠波导慢波结构为主,在太赫兹返波管中则利用叶片加载波导慢波结构。器件技术包括微机电系统(MEMS)技术,微波等离子体化学气相沉积(MPCVD)金刚石生长、金属化和封接技术等。最后给出W波段、G波段以及340 GHz部件和器件所达到的性能。     

SiC基GaN上多晶金刚石散热膜生长及其影响

通过微波等离子体化学气相沉积(MPCVD)法,在SiC基GaN高电子迁移率晶体管(HEMT)异质结构材料上生长多晶金刚石散热膜,采用光学显微镜(OM)、拉曼光谱、非接触霍尔测试系统、X射线衍射(XRD)和扫描电子显微镜(SEM)对生长样品进行表征,研究了生长温度、多晶金刚石散热膜厚度对GaN HEMT异质结构材料性能的影响。测试结果表明,当多晶金刚石生长温度为625℃,散热膜厚度为20μm时,GaN材料载流子迁移率降低9.8%,载流子浓度上升5.3%,(002)衍射峰半高宽增加40%。生长温度越高,金刚石散热膜的生长速率越快。当金刚石散热膜厚度相差不大时,生长温度越高,GaN所受拉应力越大,材料电特性衰退越明显。多晶金刚石高温生长过程中,金刚石引入的应力未对GaN结构产生破坏作用,GaN材料中没有出现孔洞等缺陷。     

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.     

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.     

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.     

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.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

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.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks