GaN基蓝光激光器光场特性模拟

采用有限差分法对GaN基多量子阱(MQWs)脊形激光器进行二维光场模拟.InGaN和AlGaN材料的折射率分别由修正的Brunner以及Bergmann方法得到.分析了激光器单模特性和远场发散角同器件的脊形刻蚀深度和脊形条宽的关系.研究了在脊形上用Si/SiO2膜取代传统SiO2介质膜这种新的脊形设计对激光器结构参数的影响.模拟结果发现,脊形条宽越窄,脊形刻蚀深度越深,平行结平面方向的发散角越大,但由此会引起单模特性不稳定,两者之间有一个折衷值.通过引入新的脊形设计,可以降低对器件刻蚀深度精度的要求,同时有很好的单模稳定性.     

表面高阶曲线光栅半导体激光器横模特性分析

半导体激光器在光通信、生物医疗、激光雷达等领域中得到广泛应用,其单模稳定输出特性一直是国内外的研究热点。制备了一种基于表面高阶曲线光栅的宽脊波导半导体激光器,刻蚀曲线型高阶光栅后高阶横模损耗远大于基横模损耗,同时设置宽脊电流限制注入结构,使得高阶横模激射阈值高于基横模阈值,从而改善器件的横模特性并压窄光谱线宽。利用温控模块将器件的工作温度控制为18℃,对腔长为2 mm、条宽为500μm的器件进行测试,在0.5 A电流下测得慢轴发散角为5.3°,快轴发散角为29.2°,在1 A驱动电流下测得3 dB光谱线宽为0.173 nm,边模抑制比为22.6 dB。实验结果表明,表面高阶曲线光栅对宽脊波导半导体激光器中的高阶横模起到了抑制作用且能够压窄光谱线宽,有助于实现半导体激光器的单模稳定输出,同时器件采用紫外光刻工艺,大幅降低了器件的制备难度。     

InP/InGaAsP脊波导的单模特性与偏振特性研究

以InP/InGaAsP脊形波导结构为研究对象,采用有限元算法(FEM),系统地仿真分析了在固定芯层厚度的情况下,不同脊高和脊宽条件下脊形波导的单模特性和偏振特性.在芯层厚度一定的情况下,脊宽越窄,刻蚀深度越浅,波导的传输模式越接近单模.在深刻蚀情况下,脊波导模双折射系数受到脊宽的影响较大,波导的偏振不敏感性较差;在浅刻蚀情况下,模双折射系数(△n=nTE-nTM)受到脊宽和脊高的影响较为微弱,稳定在1.2×10-3.相关仿真和分析为基于InP/InGaAsP脊波导的光电子器件的结构设计提供了一定的理论支持.     

沟槽肖特基器件Si深槽刻蚀工艺

深硅刻蚀工艺是制造沟槽肖特基器件的关键技术.Si深槽的深度影响肖特基反向击穿电压,深槽的垂直度影响多晶Si回填效果,侧壁平滑度及深槽底部长草现象对器件的耐压性能影响显著.采用SF6/O2常温刻蚀工艺刻蚀Si深槽.研究了工艺压力、线圈功率、SF6/O2比例以及下电极功率等参数对沟槽深度均匀性和垂直度的影响.得到了使Si深槽形貌为槽口宽度略大于槽底,侧壁光滑,且沟槽深度均匀性为2.3％左右的工艺条件.利用该刻蚀工艺可实现沟槽多晶Si无缝回填.该工艺条件成功应用于沟槽肖特基器件制作中,反向击穿电压达到58 V,反向电压通48 V,漏电流为11.2 μA,良率达到97.55％.     

国产CF4＋O2混合气体在Si3N4腐蚀中的应用

一、引言Si3N4膜的腐蚀是一个比较老的课题，早在70年代的发光二极管器件制造中就开始了等高于腐蚀Si3N4的应用。目前，在大规模集成电路制造工艺中，Si3N4膜通常作为局部氧化（LOCOS）掩模材料，因此如何刻蚀好Si3N4就显得比较重要。随着器件尺寸的不断缩小，为了消除或最大限度地抑制鸟嘴对有源区的侵入，要求Si3N4层下面的SiO2厚度越来越薄，以确保有源区面积，同时为防止刻蚀中等离子辐射对衬底Si的损伤，影响器件的电特性及成品率，要求在等离子刻蚀中Si3N4膜对SiO2有高的选择性、均匀性，以及解决颗粒沾污问题。刻蚀Si3N4的…     

9.0μm锥形量子级联激光器

本文报道了波长为9.0μm的锥形量子级联激光器。与普通的脊形量子级联激光器相比,锥形量子级联激光器的水平远场发散角更小。系统的研究了锥形角度对脊形区宽度约为11μm的锥形量子级联激光器器件性能的影响,结果表明3°的锥形角是一个优化的角度,锥形角为3°时量子级联激光器具有较高的功率和仅为7.1°的水平远场发散角。     

2µm波段低发散角瓦级GaSb基宽区量子阱激光器

通过在宽区GaSb基半导体激光器波导中引入鱼骨型微结构, 实现了瓦级激光输出并且改善了侧向发散角.本文通过分析微结构的刻蚀深度对激光功率和远场特性的影响, 研究并发现了微结构的引入可以明显的提高激光器输出功率, 同时深刻蚀的微结构对降低模式数和侧向发散角有着更明显的改善作用.相比于未引入微结构的激光器, 引入深刻蚀微结构的宽区激光器侧向95%功率定义的远场发散角降低了大约57%, 并且实现了超过1.1 W的最大连续输出功率.     

InAs/InP量子点激光器制备工艺研究

报道了通过化学湿刻蚀制备窄脊条InAs/InP量子点激光器的方法。激光器脊条主要是由半导体材料InGaAs和InP构成,通过选择合适配比的H2SO4∶H2O2∶H2O和H3PO4∶HCl腐蚀溶液和InP的腐蚀方向,在室温下选择性地腐蚀了InGaAs和InP,获得了窄脊条宽为6μm的量子点激光器。此激光器能够在室温连续波模式下工作,激射波长在光纤通信重要窗口1.55μm,单面最大输出功率超过12mW。     

2微米波段低发散角瓦级GaSb基宽区量子阱激光器（英文）

通过在宽区GaSb基半导体激光器波导中引入鱼骨型微结构,实现了瓦级激光输出并且改善了侧向发散角.本文通过分析微结构的刻蚀深度对激光功率和远场特性的影响,研究并发现了微结构的引入可以明显的提高激光器输出功率,同时深刻蚀的微结构对降低模式数和侧向发散角有着更明显的改善作用.相比于未引入微结构的激光器,引入深刻蚀微结构的宽区激光器侧向95%功率定义的远场发散角降低了大约57%,并且实现了超过1.1 W的最大连续输出功率.     

基于AlxNy绝缘介质膜的新型窗口大功率半导体激光器

提升半导体激光器的腔面抗光学灾变(COD)损伤的能力,改善半导体激光器的工作特性,一直是大功率半导体激光器器件工艺研究的难点.基于薄膜应力使基底半导体材料带隙变化的原理,采用直流磁控溅射方法在不同条件下溅射生成不同内应力的AlxNy绝缘介质膜.通过研究大功率半导体激光器腔面退化机理,借助AlxNy等应力膜设计制作了一种新型非吸收透明窗口结构的宽条形半导体激光器,使器件平均最大输出功率提高46.5%,垂直发散角达到21°,水平发散角达到6.1°,2000 h加速老化试验,其千小时退化速率小于0.091%.     

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.     

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.