AlGaN/GaN MSM紫外探测器特性

在蓝宝石衬底上,用MOCVD(金属有机物气相沉积)法外延生长AlGaN/GaN异质结样品.溅射Ti/Al/Ni/Au和Ni/Au金属膜,在氮气气氛中高温快速退火,分别与样品形成欧姆接触和肖特基接触.随着退火时间的增加,MSM(金属-半导体-金属)结构的I-V特性曲线保持良好的对称性,但C-V曲线逐渐失去其对称性.MSM探测器的紫外响应曲线具有良好的对比度和选择性,出现明显的光电导增益效应.     

AlGaN/GaN MSM紫外探测器特性

在蓝宝石衬底上,用MOCVD(金属有机物气相沉积)法外延生长AlGaN/GaN异质结样品.溅射Ti/Al/Ni/Au和Ni/Au金属膜,在氮气气氛中高温快速退火,分别与样品形成欧姆接触和肖特基接触.随着退火时间的增加,MSM(金属-半导体-金属)结构的I-V特性曲线保持良好的对称性,但C-V曲线逐渐失去其对称性.MSM探测器的紫外响应曲线具有良好的对比度和选择性,出现明显的光电导增益效应.     

AlGaN/GaN MSM紫外探测器特性

在蓝宝石衬底上,用金属有机物气相沉积(MOCVD)法外延生长AlGaN/GaN异质结样品.溅射Ti/Al/Ni/Au和Ni/Au金属膜,在氮气气氛中高温快速退火,分别与样品形成欧姆接触和肖特基接触.随着退火时间的增加,金属-半导体金属(MSM)结构的I V特性曲线保持良好的对称性,但C V曲线逐渐失去其对称性.MSM探测器的紫外响应曲线具有良好的对比度和选择性,出现明显的光电导增益效应.     

A1GaN／GaN MSM紫外探测器特性

在蓝宝石衬底上,用金属有机物气相沉积(MOCVD)法外延生长AlGaN／GaN异质结样品。溅射Ti／Al／Ni／Au和Ni／Au金属膜,在氮气气氛中高温快速退火,分别与样品形成欧姆接触和肖特基接触。随着退火时间的增加,金属一半导体金属(MSM)结构的I-V特性曲线保持良好的对称性,但C-V曲线逐渐失去其对称性。MSM探测器的紫外响应曲线具有良好的对比度和选择性,出现明显的光电导增益效应。     

Ni/Au与p-GaN的比接触电阻率测量

通过采用环形传输线方法(CILM),电流-电压(I-V)曲线、表面形貌等方法,研究不同的Ni/Au厚度比和空气气氛下合金退火温度对p型氮化镓欧姆接触特性造成的影响。根据Ni/Au与p型氮化镓欧姆接触的形成机制,采用合适的Ni/Au厚度比及退火温度,得到比接触电阻率(ρc)为1.09×10-5Ω.cm2的Ni/Au-p-GaN电极,并分析了Ni在退火过程中对形成良好的欧姆接触中所起到的作用。     

Ti/Al/Ni/Au金属体系在N-polar GaN上的欧姆接触特性

利用金属有机化合物化学气相淀积(MOCVD)在SiC衬底上外延生长了N-polar GaN材料,采用传输线模型(TLM)分析了Ti/Al/Ni/Au金属体系在N-polar GaN上的欧姆接触特性.结果表明,Ti/Al/Ni/Au (20/60/10/50 nm)在N-polar GaN上可形成比接触电阻率为2.2×10-3Ω·cm2的非合金欧姆接触,当退火温度升至200℃,比接触电阻率降为1.44×10-3 Ω·cm2,随着退火温度的进一步上升,Ga原子外逸导致欧姆接触退化为肖特基接触.     

AlGaN/GaN异质结构的欧姆接触

通过改变Ti/Al的结构及退火条件,研究了AlGaN/GaN异质结构上Ti/Al/Ni/Au金属体系所形成的欧姆接触.结果表明,Ti/Al/Ni/Au金属厚度分别为20,120,55和45nm,退火条件为高纯N2气氛中850℃、30s时在AlGaN/GaN异质结构上获得了良好的欧姆接触,其比接触电阻率为3.30×10-6Ω·cm2.SEM分析表明该条件下的欧姆接触具有良好的表面形貌,可以很好地满足高性能AlGaN/GaN高电子迁移率晶体管制造的要求.     

AlGaN/GaN异质结构的欧姆接触

通过改变Ti/Al的结构及退火条件,研究了AlGaN/GaN异质结构上Ti/Al/Ni/Au金属体系所形成的欧姆接触.结果表明,Ti/Al/Ni/Au金属厚度分别为20,120,55和45nm,退火条件为高纯N2气氛中850℃、30s时在AlGaN/GaN异质结构上获得了良好的欧姆接触,其比接触电阻率为3.30×10-6Ω·cm2.SEM分析表明该条件下的欧姆接触具有良好的表面形貌,可以很好地满足高性能AlGaN/GaN高电子迁移率晶体管制造的要求.     

Ge／Pt／Au,Ge／Au／Ni／Au—n型GaAs欧姆接触的对比研究

对用快速热合金方法（RTP）形成Ge/Pt/Au,Ge/Au/Ni/Au-n型GaAs欧姆接触进行了对比研究。实验结果表明，在合金形貌和欧姆接触特性兼顾的情况下，Ge/Pt/Au和Ge/Au/Ni/Au有不同的“温度－时间”窗口的接触电阻率。合金后，Auger能谱分析表明，Ge/Au/Ni/Au金属系统扩散进GaAs体内的净施主Ge浓度较高，因而接触电阻率较低。两种欧姆接触金属系统经高温存贮一定时间后，发现其接触电阻率都有所降低。     

用于紫外探测器的AlGaN/GaN异质结构的Ti/Al/Ni/Au欧姆接触特性

采用Ti/Al/Ni/Au多层金属体系在Al0.27Ga0.73N/GaN异质结构上制备了欧姆接触.分别采用线性传输线方法(LTLM)和圆形传输线方法(CTLM)对其电阻率进行了测试.当Ti(10nm)/Al(100nm)/Ni(40nm)/Au(100nm)金属体系在650℃高纯N2气氛中退火30s时,测量得到的最小比接触电阻率为1.46×10-5Ω·cm2.并制备了Al0.27Ga0.73N/GaN光导型紫外探测器,通过测试发现探测器的暗电流.电压曲线呈线性分布.实验结果表明在Al0.27 Ga0.73N/GaN异质结构上获得了好的欧姆接触,能够满足制备高性能AlGaN/GaN紫外探测器的要求.     

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.     

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.     

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.     

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.