硅基HgCdTe面阵焦平面器件结构热应力分析

红外焦平面器件是一个多层结构,包含外延衬底、HgCdTe芯片、Si读出电路、互连In柱、粘结胶以及引线基板等,由于各层材料之间的热膨胀系数不同导致焦平面器件在工作中承受很大的热应力,热应力是导致红外焦平面器件失效的重要因素之一。本文运用一维模型以及有限元分析方法对硅基HgCdTe320×240焦平面器件结构进行热应力分析,结果表明,改变Si衬底厚度、粘结胶的杨氏模量以及基板的热膨胀系数,都会不同程度地影响HgCdTe薄膜上的受力,其中基板的热膨胀系数对HgCdTe薄膜所受的应力影响最大。通过选用合适的基板可以有效降低HgCdTe薄膜所受的应力,从而降低器件失效率。     

2048×2048 HgCdTe红外焦平面杜瓦冷头热应力有限元分析

利用有限元方法对2048×2048(15 μm)红外焦平面杜瓦冷头的原始结构以及加入的平衡层结构进行了分析.在陶瓷基板下方增加膨胀系数较小的平衡层,对探测器芯片变形及热应力有一定的缓解作用.通过增大AlN平衡层上表面的直径,减小了芯片中心以外的翘曲范围,缓解了应力过于集中的问题.当直径超过芯片对角长度时,最大热应力骤减,最终趋于稳定;芯片变形量随之迅速减小.在直径为36 mm时,达到最小值(6.86 μm);随后缓慢增加并趋于稳定.当AlN平衡层的直径超过芯片对角长度后,AlN平衡层的厚度对芯片变形的影响开始减小.通过加入AlN平衡层能够有效改善大面阵焦平面探测器芯片的变形及热应力,同时通过调节AlN平衡层的结构,可进一步优化探测器杜瓦组件的可靠性.     

红外探测器组件引线熔断分析

二代红外焦平面探测器组件微型杜瓦中的金属引线是跨接在探测器芯片以及陶瓷引线环之间,其作用是作为介质为探测器芯片提供数字以及模拟信号,并将探测器组件的输出信号导出。本文介绍了二代焦平面探测器组件的杜瓦结构,并对金属引线在低温77K时的物理特性进行了分析,从理论上对金属引线可流过的最大电流进行计算,并通过试验进行验证。     

红外焦平面探测器热应力的有限元仿真方法分析

以64×64红外焦平面探测器为例,构建了包含探测器芯片、铟柱、填充胶和读出电路的全尺寸有限元仿真模型,与探测器芯片、填充层和读出电路的简化模型进行对比。研究表明,两种模型在芯片热应力的变化趋势上保持一致。由于铟材料与碲镉汞材料之间的热膨胀系数相差较大,随着芯片尺寸的增大,铟柱的影响逐渐增加,填充层简化模型计算得到的芯片热应力与全尺寸模型的热应力的差距会越来越大。     

碲镉汞红外焦平面器件热失配应力研究

采用有限元分析方法研究了碲镉汞红外焦平面器件在低温下由于不同热膨胀系数引起的热失配应力,提出了两种焦平面器件结构,可以有效地降低热应力,并应用于实际器件的制备,明显提高了碲镉汞焦平面器件的可靠性.     

碲镉汞线列红外探测器模块温度循环的可靠性

针对直接倒焊(Ⅰ型)、间接倒焊(Ⅱ型)两种红外探测器模块,两者中的探测器芯片、硅读出电路和引线基板的尺寸完全相同,只在倒焊封装结构上有所差异,用有限元方法分析比较了这两种封装形式的基本模块于液氮温度时的热应力和形变大小情况,分析结果与实验现象符合较好,模块低温形变值的测量验证了有限元分析结果的合理性.     

红外焦平面低温形变测试方法及其误差分析

在研制制冷型红外探测器组件的过程中,降低功能模块的热应力是设计及制造的核心目标之一,这要求首先能够对焦平面模块的热应力进行测量表征,工程上一般通过形变等间接量来表征碲镉汞的热应力。基于此研究了激光干涉法测量制冷型红外焦平面探测器的表面形变并对其误差进行了分析,该方法克服了常规的台阶仪测量方法所固有的温度控制不够理想、测试过程中样品表面有结霜等困难,它利用相干光在标准镜上干涉形成的干涉图样来反映样品表面的形变。试验表明:该方法可以进行实时变温的表面形变测量,为制冷型红外焦平面组件的封装设计提供可靠的形变测试数据,实现了焦平面模块在封装杜瓦内的表面形变的低温在线测量。     

CO2激光对HgCdTe焦平面器件热力作用的理论分析

利用有限元分析方法,对CO2连续激光辐照HgCdTe红外焦平面器件的温升效应和热应力效应进行模拟计算,模型的建立加入了In柱对实验的影响.对温度及热应力分布进行分析,结果表明,探测器的温度分布随着激光辐照时间的增加而出现明显的变化.在感光层与In柱阵列的交界面上所产生的热应力对HgCdTe红外焦平面器件造成的损伤有可能先于温升损伤而发生.     

硅基非致冷混合式焦平面探测器阵列研究

本文报道一种32×48元高灵敏非致冷混合式焦平面探测器厚膜阵列.提出了一种采用掺杂钛酸锶钡厚膜作为敏感材料的硅基微机械加工电容式红外探测器像元结构,对其工作原理、器件性能优化设计与制作工艺流程进行了分析,得出了优化的结构参数.分析了影响器件性能的关键因素,给出了器件所用铁电材料的基本物理和电学特性参数以及器件的热隔离技术和相应参数.本结构的像元电容值增量接近相同敏感面的体材料红外探测器,减小了像元与衬底电极引线的寄生电容.采用这种结构的红外探测器阵列对电路的精度要求低,便于研制集成电路.该红外探测器阵列结构的设计思路,符合大阵列红外焦平面像元结构设计的发展趋势,为开展非致冷红外焦平面阵列探测器研究奠定了基础.     

10.6 μm激光对HgCdTe焦平面器件热应力的分析

建立了HgCdTe红外焦平面器件的多膜层理论模型,利用有限元分析的方法,对10.6μm激光辐照下HgCdTe红外焦平面器件的升温情况与热应力分布情况进行模拟,并通过参考已有文献的实验结果,验证了理论模型的合理性。理论分析结果表明:激光作用时探测器的温度场变化剧烈,200 W/cm2连续激光作用1 s后,HgCdTe感光层所受热应力为-986 MPa;脉宽100 ns,功率密度15 MW/cm2脉冲激光作用后,HgCdTe感光层所受热应力为-1300 MPa,都比器件制造过程中由于热失配而产生的热应力大;应力损伤发生的概率增大,可能比热损伤先发生,是HgCdTe红外焦平面器件激光损伤中的重要原因。     

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.