热处理时间对氧化钒薄膜相变性能的影响

采用直流磁控溅射的方法在普通玻璃上制备了低价的氧化钒薄膜,在氧气和氩气混合气氛中,对所制备的薄膜进行不同时间的热处理,得到具有相变特性的VO2薄膜。分别利用X射线衍射(XRD)和场发射扫描电镜(SEM)分析了薄膜的组分、结晶结构和表面形貌,利用四探针法测试了薄膜的电阻。结果表明:热处理前的氧化钒薄膜主要成分为V2O3,经过热氧化处理后,低价的氧化钒被氧化,薄膜中VO2含量增加,薄膜发生金属-半导体相变,其中450℃、2h为最佳处理参数,其电阻相变幅度超过2个数量级,薄膜的相变温度仅为30℃。     

磁控溅射结合快速热处理制备相变氧化钒薄膜

采用直流对靶磁控溅射结合快速热处理工艺制备了具有金属-半导体相变特性的氧化钒(VOx)薄膜。利用XRD,XPS和SEM对薄膜结晶结构、薄膜中V的价态与组分及表面微观形貌进行分析,利用四探针测试法及太赫兹时域频谱系统对薄膜的电学和光学特性进行测量。结果表明:新制备VOx薄膜以非晶态V2O5为主;350℃,30 s快速热处理后,薄膜中V的整体价态降低,表面颗粒分布更加致密;500℃,30 s快速热处理后,薄膜中VO2(002)向单斜结构的VO2(011)转变,VO2(011)占主要成分,薄膜显示出明显的金属-半导体相变特性,方块电阻下降达到3个数量级,太赫兹透过率下降接近70%,热致相变性能良好。     

快速热处理对磁控溅射VO2薄膜光电特性的影响

采用反应磁控溅射法制备二氧化钒(VO2)薄膜,并对其进行快速热处理(RTP)。主要研究500℃快速热处理10、15、20s工艺条件下VO2薄膜结晶状况和光电性能的变化。在20℃～80℃温区内,应用四探针薄膜电阻测试方法和太赫兹时域频谱技术(THz-TDS)测量了各样品的电学相变特性和光学相变特性。结果表明,经过快速热处理的样品电学相变幅度均达到了2个数量级以上;THz波的透射率在半导体-金属相变前后的最大变化达到了57.9%。同时发现,热处理500℃,10s时VO2的电学和光学相变幅度相对要大,当热处理时间达到15s左右时薄膜的相变幅度变化不再明显。快速热处理时间的长短对热致相变温度点的影响较小,但热致电学相变和光学相变的相变温度点不同:光学相变的温度为60℃左右,电学相变温度则在56℃附近。     

氧化热处理对VO2薄膜红外光学相变特性的影响

采用直流磁控溅射法在硅基底上制备VO2薄膜,并对薄膜氧化热处理。分别对热处理前后薄膜进行X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)透射率测试,分析了热处理对VO2薄膜晶相成分与红外透射率相变特性的影响。实验分析表明,经热处理的VO2发生非晶态向晶态转变,单斜金红石结构VO2(011)晶体具有明显择优取向,晶粒尺寸均匀度提高,且薄膜的红外透射率具有明显相变特性,相变温度为60.5℃,3~5μm、8~12μm波段的红外透射率对比值达到99%,适合应用于红外探测器的激光防护研究。     

氧化热处理对VO2薄膜特性的影响研究

采用直流磁控溅射法,结合氧化法热处理在硅基底上制备VO2薄膜,通过SEM、XRD、XPS、FTIR红外透射率等测试,从多角度分析了氧化热处理对VO2薄膜截面结构、晶相成分、成分价态、红外透射率相变特性的影响。实验分析表明,采用直流磁控溅射与氧化热处理相结合的方法,可获得主要成分为具有明显择优取向单斜金红石结构VO2(011)晶体的氧化钒薄膜,氧化热处理有利于VO2晶粒生长并增加薄膜致密性,同时其红外透射率具有明显相变特性,相变温度为60.5 ℃,3~5 m、8~12 m波段的红外透射率对比值达到99.5%,实现了对红外波段辐射的开关功能,适合应用于红外探测器的激光防护研究,同时可为深入研究对薄膜的氧化热处理提供参考依据。     

纳米VO2薄膜相变特性的红外透射表征研究

采用双离子束溅射VOx薄膜附加热处理的方式制备纳米VO2薄膜,利用X射线衍射仪和扫描电子显微镜分别对其结晶结构和表面形貌进行了测试,利用傅立叶变换红外光谱仪(FTIR)对热驱动下纳米VO2薄膜相变过程中的光学性能进行测试与分析。实验结果表明,经400℃N2热处理后,获得了由纳米颗粒组成的VO2薄膜;在所测试的红外波段,纳米VO2薄膜内颗粒发生相变的初始温度随波长的增加而升高,薄膜的相变温度点随波长增加也逐渐升高。     

调整VO2薄膜相变特性和TCR的制备及辐照方法

采用不同的真空还原时间、真空退火温度和衬底制备出了VO2薄膜,并对制备出的薄膜进行电子辐照.通过测试辐照前后的VO2薄膜相变电学性能及低温半导体相电阻温度系数(TCR),表明不同的制备工艺和不同注量的电子辐照可明显改变VO2薄膜相变过程中电学性能,提高薄膜的电阻温度系数.对影响VO2热致相变薄膜电学性能及电阻温度系数的因素进行了讨论.     

云母表面不同厚度VO2薄膜的红外光学特性

以天然白云母的解理面为基底,采用无机溶胶-凝胶法在其表面制备不同厚度的VO2薄膜,并研究了厚度对VO2薄膜的微观结构和红外光学特性的影响.利用SEM、XRD等手段分析了薄膜的表面形貌和晶体结构,利用原位FTlR分析了VO2薄膜半导体-金属相变特性.结果表明,云母表面VO2薄膜室温下具有(011)择优生长取向,随着厚度增...     

VO2/Al2O3复合膜系制备及其相变特性

钒的氧化物具有对温度敏感的半导体-金属可逆相变特性.在多种钒氧化合物中,VO2的相变温度点约为68℃,适用于很多应用领域.VO2长期暴露在空气中时,会被氧化.研究了通过制备VO2/Al2O3复合膜系来保持氧化钒薄膜的稳定性的方法.采用TFCalc薄膜设计软件,设计了VO2/Al2O3复合膜系.依据材料的折射率和消光系数,优化了膜系各膜层的厚度,分析了复合膜系的相变特性.采用磁控溅射方式制备了氧化钒薄膜,再通过氧氩混合气氛热处理得到VO2占主要成分的氧化钒薄膜.在氧化钒薄膜上采用射频磁控溅射方法封装了120 nm厚的Al2O3膜.利用分光光度计测量分析了膜系的相变特性,Al2O3膜对VO2膜的相变性能影响很小.Al2O3膜适于VO2薄膜的封装.     

VO2/TiO2复合薄膜的结构和红外光学性质研究

采用溶胶凝胶法在白云母沿（001）方向的解理表面制备VO2/TiO2热致相变复合薄膜。利用X射线衍射仪（XRD）,X射线光电子能谱仪（XPS）,原子力显微镜（AFM）等手段分析了薄膜的微观结构和表面形貌,通过原位傅里叶变换红外光谱（in-situ FTIR）分析复合薄膜在不同温度下的红外透过率,研究其热致相变特性。结果表明,复合薄膜在云母解理面表面呈VO2（011）/TiO2（101）取向生长,表面致密平整。复合薄膜在金属-半导体相变前后表现出优异的光学开关效应,相变过程中的红外光（波长为4 m）透过率变化（Tr）为75.5%;相变过程陡然,透过率变化率（-dTr/dT）达15.7%/℃,滞回温宽减小到8 ℃。     

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.     

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.     

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.     

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