高Tc超导红外探测器与焦平面列阵(II)

尽管有多种高Tc超导材料问世,但目前主要是用YBCO等Cu盐超导材料试制热敏型或光子型的红外探测器,多是用超导膜进行光刻成敏感元.它有曲折线型、微桥和天线     

基于间断性腐蚀法的铂热敏传感器的研制

针对铂湿法刻蚀工艺,提出了间断性腐蚀法,并与边腐蚀边搅拌法和静止法进行了对比,结果显示该方法腐蚀铂曲线光滑、效果好。之后,以普通硅片作为衬底材料,二氧化硅作为隔热层,采用上述微机电(MEMS)工艺加工制作了铂热敏传感器。经热敏性能测试,其电阻温度系数在20℃～80℃时为1571.2×10-6/℃;同一批次电阻阻值均匀性为0.35%;非线性度为0.57%;热时间常数为1.1μs;在0.5 h的稳定性测试中其变化幅值为0.005Ω,即精度为0.01%。该热敏传感器制作工艺简单,性能优异,可用于温度敏感、气体传感等热敏传感。     

非晶硅微测辐射热计热学和力学仿真研究

通过理论计算及有限元方法仿真研究微测辐射热计的热学和力学性能,得出了微桥桥腿尺寸与微桥的热导、热时间常数、桥面温升以及由微桥自身重力引起的位移形变的关系;提出了为了兼顾较好的热学和力学性能,需要选取合适的微桥桥腿尺寸的观点.以像元尺寸50μm×50μm的微桥结构为例,选取了非晶硅微测辐射热计理论上的最佳桥腿尺寸,得到桥腿的热导值5.05×10-7W/K,热时间常数1.18ms,桥面温升34.71mK,最大位移形变量.62×10-4μm.     

微测辐射热计微桥结构性能分析

微测辐射热计的设计难点是起支撑作用的微桥结构的设计.重点研究了现在流行的几种微桥结构,对其性能参数进行分析比较,提出了多层结构的优点.并使用有限元分析软件对不同微桥进行结构分析,以比较其稳固性.     

基于GPIB对热敏记录仪的控制及数据传输

在导弹热电池测试系统中,利用VC编写动态链接库函数,通过GPIB接口实现了计算机对WR1000热敏阵列记录仪的控制.介绍了WR1000热敏阵列记录仪常见命令的使用和内存数据输出格式,并具体说明了计算机如何获取采样数据的实现方法,该方法实用性强,对自动测控系统设计人员具有借鉴作用.     

一种新型硅基厚膜压力/温度传感器的设计和制作

设计并制作了一种新型传感器,它包含压阻式压敏元件和热敏元件两部分.其中压敏元件采用比常规更厚的50μm硅杯薄膜(500μm× 500 μm),增大了体硅上高应力区的面积,在降低工艺要求的同时提高了线性测量范围和过载压力.压敏电阻设计为折线结构,采用优化的几何尺寸,并将其部分制作在高应力体硅上以获得更高灵敏度.体硅上的温敏电阻随压敏电阻利用同步注入工艺制作,减小了工艺复杂度.该器件工艺简单,成品率高,与标准IC工艺兼容.初步的测试结果表明器件具有良好的性能.     

ANSYS在热释电薄膜红外探测器二维热分析中的应用

根据热释电薄膜红外探测器的结构和实际的测试条件,利用有限元软件ANSYS建立了不同结构组成的热释电薄膜红外探测器的二维模型,并对其进行了热分析,得到了探测器内的温度场分布.分析了复合热释电薄膜红外探测器的绝热层对温度场的影响,并将复合热释电薄膜红外探测器与微桥结构探测器的性能进行了比较.     

复合薄膜热导率测试系统研究

针对薄膜热物性测量还没有成熟的测试系统,设计了一种基于微桥静态测量法的复合薄膜热导率测试系统.该系统由PC机、仪器控制与数据采集模块、可控温真空系统构成.软件编程在LabVIEW平台上实现.利用该系统测量了由SiO2薄膜和多晶硅薄膜组成的悬臂梁结构的复合薄膜热导率.在10-4Pa真空中,测得悬臂梁平均温度320～400K范围内的等效热导率在9～12w/(m·K),其热导率随着温度升高而增大,测试结果和理论值一致.实验表明:系统测试效率高、通用性好,且易于扩展.     

PCB制作中成像和电路制作的方式

对多个图像进行转移是PCB制作中图像成像的重最工作,也是PCB制作的重要内容。一般的,在进行图形转移制作中使用CAD技术,或者使用钻通孔,钻微孔图像,或者通过构建内层电路图像和外层电路图像,或者构建抗蚀层等步骤来完成。PCB电路的制作也是PCB制作中的重点内容,电路一般通过光刻或者是通过丝网印刷,为了做好电路的制程,要对材料进行不同程度的蚀刻,电镀和抗蚀层剥离等操作。本文对半加成工艺和加成工艺,激光成像的选择,喷墨,投影进行分析探究,这对完善PCB制作具有积极的作用。     

基于Windows CE的物流车载终端设计

提出一种基于Windows CE嵌入式操作系统的物流车载终端设计方案.在此方案中集成了电子地图、GPS定位、GPRS无线通信、热敏打印机、电子秤等功能.文中给出了相应的实现及测试结果.     

Performance of GaAs microbridge thermocouple infrared detectors

GaAs microbridge thermocouples with lengths ranging from 40 to 650 μm and operating at room temperature have been fabricated for the detection of infrared radiation. A CO₂ laser of a 10.6 μm wavelength was used to characterize the performance of the detectors in air and in vacuum. A responsivity of 4.2 V/W with a corresponding detectivity D*=8×10⁶ cm Hz^1/2/W and a time constant of 2.2 ms have been measured in vacuum for 650-μm-long bridges, and a shorter time constant of 50 μs was obtained for 40-μm-long bridges. An analytic thermal transport model has been used to simulate the operation of the sensors. The heat-transfer coefficient has been evaluated by comparing the data from air and vacuum measurements. The spectral response and the absorbance of the microbridge have also been presented     

Creep behavior of undoped and La–Nb codoped PZT based micro-piezoactuators for micro-optical modulator applications

Time-dependent deformation (creep) behaviors of piezoelectric microactuators have been investigated. Position (or gap height) drift of microbridged actuator beam and its displacement amplitude change with time could be attributed to the anelastic behavior of the driving unit itself based on lead zirconate titanate (PZT) in the actuator, and as well as to the mechanical stress states established in the microactuator beam after the surface release of the micromachined actuator structure. From creep analyses of a simple microcantilever and microbridge beam structures, it was turned out that the overall creep behavior in microbridged piezoactuator structure was mainly dependent on the actuator beam initial deflection configuration governed both by residual stress of the actuating part Pt/PZT/Pt stack and the stress gradient through the silicon nitride (SiNx) microbridge beam.     

基于悬浮吸收层的热电堆红外探测器结构设计

在这项工作中,设计一种新颖的热电堆红外探测器结构。该检测器利用悬浮吸收层-热电堆双层结构来实现高性能,同时具有相对小的尺寸。该双层结构的实现是通过引入两个分离的牺牲层,分别包括热电堆下方的多晶硅膜和其上方的聚酰亚胺沉积实现。尺寸优化后的仿真结果表明,该红外探测器的探测率、响应率和响应时间分别可以达到2.85e8 cmHz （ 1/2） / W, 1800 V / W和6毫秒。此外,本文提出热电堆红外探测器的制造方法是高度兼容于标准的CMOS工艺,这就使其高产量和低成本的生产成为可能。     

Magnetic and mechanical properties of micromachined strontiumferrite/polyimide composites

In this work, strontium ferrite/polyimide composite thin films are fabricated and characterized for micromachining applications. The application of these materials in microelectronics and micromachining dictates the use of different polymers than those previously used for conventional plastic magnets due to fabrication compatibility constraints. The material investigated here consists of magnetically anisotropic strontium ferrite particles suspended in a benzophenone tetracarboxylic dianhydride-oxydianiline/metaphenylene diamine polyimide matrix. Magnetic mechanical, and processability properties of these composites are investigated for a strontium ferrite loading range of 55%-80% by volume. Intrinsic coercivity H_ci residual magnetic flux density B_r and maximum energy product (BH)_max have been determined. For an 80% by-volume concentration loading of ferrite, H_ci of 318 kA/m B_r, approaching 0.3 T, and (BH)_max of 11900 T·A/m have been achieved. Biaxial Young's modulus and residual stress are determined using a slightly modified in situ load/deflection technique. The biaxial Young's modulus increases with increasing the magnetic powder loading. The materials have been deposited and patterned using two techniques: (1) screen-printing and (2) spin-casting, followed by photolithography. Finally, a simple magnetic microactuator made with those materials has been fabricated and tested, which demonstrates the usefulness of those materials to micromachining     

微型风速风向传感器研制

阐述了微型风速风向传感器的工作原理,结构设计及工艺研究,该传感器采用硅微机械加工技术制成微悬桥结构,将加热电阻器与感温电阻器排布在悬桥上,降低了功耗,提高了传感器灵敏度,实现低风速风场测量。     

Microbridge testing on symmetrical trilayer films

In this paper, we extended the microbridge testing method to characterize the mechanical properties of symmetrical trilayer thin films. Theoretically, we analyzed the deformation of a trilayer microbridge sample with a deformable boundary condition and derived load-deflection formulas in closed-form. The slope of a load-deflection curve under small deformation gives the relationship between the bending stiffness and the residual force of a trilayer microbridge. Taking this relationship, we were able to assess simultaneously the Young's modulus of two kinds of materials composing the symmetrical trilayer film and the thickness-averaged residual stress of the film. Experimentally, we fabricated symmetrical trilayer microbridge samples of SiO/sub 2//Si/sub 3/N/sub 4//SiO/sub 2/ on 4-inch p-type (100) silicon wafers and conducted the microbridge tests with a load and displacement sensing nanoindenter system equipped with a microwedge indenter. The experimental results verified the proposed microbridge testing method. The thickness-averaged residual stress of the 1.1-/spl mu/m trilayer thin films was determined to be 8.8 MPa, while the Young's modulus of the 0.3-/spl mu/m silicon oxide layers and the Young's modulus of the 0.5-/spl mu/m silicon nitride layer were evaluated to be 31 GPa and 294 GPa, respectively.     

Deformation control of microbridges for flow sensors

To obtain good performance from a microbridge flow sensor, we have investigated the buckling mechanism of microbridges by fabricating various shapes of bridges. We have achieved deformation control for both the longitudinal axis and the transverse axis of Pt/SiNx double-layered microbridges by appropriate selection of the residual bridge stress of Pt/SiNx structures and of the stress gradient between the Pt film and the SiNx film. The deformation directions of the longitudinal axis of bridges for the beam bridge (Type I) are all the same as that of cantilevers and may be predicted via the stress gradient between the Pt and SiNx films of the bridges. The deflection of the transverse axis of the table bridge supported by four beams (Type II) changes linearly with the residual bridge stress of the Pt/SiNx structure and the deformation changes for the transverse axis are the same as that of completely free films, as predicted from the stress gradient between the Pt film and the SiNx film. The interesting result is that the deformation direction for the longitudinal axis of the Type II bridge is opposite to that of the Type I with the same film structure. We discuss the reason for this opposition via differences in the progress of the anisotropic etching. We consider that this result will expand the range of manufacturable shapes and film structures of microbridges.     

Surface plasmon resonance study on the optical sensing properties of nanometric polyimide films to volatile organic vapours

The optical sensing properties of nanometric polyimide films towards ethanol and methanol vapours have been investigated by surface plasmon resonance technique. To this purpose polyimide sensing layers have been deposited onto gold/glass substrates by glow-discharge-induced vapour deposition polymerization technique. The sensible layer shows reversible and stable responses to different concentrations of methanol and ethanol vapours. A linear dependence between the change in reflectivity and the vapours concentration is observed being the sensitivity to both vapours similar, however, the response is larger in presence of ethanol vapours. Numerical fitting routines on surface plasmon resonance curves indicate that optical changes are motivated by an absorption process of the analyte. This produces a detectable increase of the real refractive index and a swelling process in the polyimide layer.     

Recovery of stiction-failed MEMS structures using laser-induced stress waves

Stiction, or adhesion between suspended structures and the underlying surface, is a hurdle in batch fabricating long, freestanding MEMS structures. A novel technique is presented in this paper to release stiction. In this technique, a nanosecond rise time stress wave is launched on the backside of the Si substrate by impinging a 2.5 ns-duration Nd:YAG laser pulse onto a 3-mm-dia area. The compressive stress wave propagates through the Si substrate and arrives at the site of several stiction-failed cantilevers on the front Si surface. The compressive stress wave propagates through the cantilevered structures and is reflected into a tensile wave from their free surfaces. The returning tensile wave pries off the interface, releasing the cantilevers. The procedure is demonstrated on a MEMS chip with stiction-failed cantilevers with varying lengths from 100 /spl mu/m to 1000 /spl mu/m. The threshold laser energy to release stiction increased linearly with cantilever lengths. Beam recovery began at a laser fluence of 11 kJ/m/sup 2/ laser energy. 70% of the tested beams had been recovered after impingement with a fluence of 26 kJ/m/sup 2/. After the highest applied laser fluence of 40 kJ/m/sup 2/, 90% of the tested beams had been recovered. No damage to the structures or surrounding features was observed below 40 kJ/m/sup 2/. Because of rather low laser fluence, no thermal damage to the back surface of Si was noted. Since it literally takes few seconds to release stiction, the proposed technique can be implemented in MEMS foundry, and for repair of in-use stiction failed MEMS devices.