一种新型三轴电容式加速度计的设计分析

设计了一种新型结构的体硅工艺梳齿电容式加速度计,该设计采用2个检测质量块,分别检测水平方向和垂直方向的加速度。x,y水平方向不对称梳齿的设计,消除了z轴对水平轴向加速度的干扰,同时z轴支撑梁的设计,解决了水平轴向对z轴的干扰。电容的差分结构有利于提高加速度计的检测性能。用Ansys仿真软件对敏感结构进行静态和模态分析,理论上验证了所提出的三轴电容式加速度计整体结构的可行性。     

二维电容式硅微加速度传感器的刚度求解

硅微电容式加速度传感器具有灵敏度高、噪音低、漂移小、功耗低、结构简单等优点 ,在军民两用市场中有着广泛的应用前景。本文针对自主开发设计的一种带折叠梁的二维叉指电容式硅微加速度传感器 ,采用力法求解了其主轴刚度 ,为进一步研究该二维微加速度传感器的动态响应特性提供了理论依据     

二维电容式硅微加速度传感器的刚度求解

硅微电容式加速度传感器具有灵敏度高、噪音低、漂移小、功耗低、结构简单等优点,在军民两用市场中有着广泛的应用前景.本文针对自主开发设计的一种带折叠梁的二维叉指电容式硅微加速度传感器,采用力法求解了其主轴刚度,为进一步研究该二维微加速度传感器的动态响应特性提供了理论依据.     

二维电容式硅微加速度传感器的刚度求解

硅微电容式加速度传感器具有灵敏度高、噪音低、漂移小、功耗低、结构简单等优点，在军民两用市场中有着广泛的应用前景。本文针对自主开发设计的一种带折叠梁的二维叉指电容式硅微加速度传感器，采用力法求解了其主轴刚度，为进一步研究该二维微加速度传感器的动态响应特性提供了理论依据。     

微硅加速度传感器的发展

本文介绍了微硅加速度传感器自六、七十代发展至今,其代表产品的特点,对微硅加速度计三种典型代表形式进行了分析、指出其优缺点,并对目前微硅加速度计的发展趋势－检测空间加速度的三维加速度计进行了重点讨论。     

电容式加速度传感器设计及工艺加工北大核心

针对精确制导的应用需求,设计了一种量程为100g"三明治"电容式加速度传感器,通过ANSYS仿真软件在100g及10 000g高过载条件下进行应力分析和模态分析,并通过Matlab分析、优化结构参数从而确定传感器敏感结构的具体尺寸。利用阻抗分析仪分析得到了传感器的静态电容为14.09 pF,结构输出灵敏度为0.281 8 pF/g,传感器的输出灵敏度为13.5μV/g。根据结构特性设计工艺流程并进行关键工艺加工:硅基质量块双面湿法腐蚀、ICP干法刻蚀及玻璃通孔电镀工艺。最终,通过实验验证电容式加速度传感器设计的可行性。     

新型声表面波三轴加速度传感器的设计仿真

该文提出一种新型声表面波三轴加速度传感器,并对传感器进行了建模和有限元仿真分析,获得了不同加速度载荷下传感器结构的位移和应变分布。该传感器采用四端五梁结构,通过谐振器位置和算法的设计消除了温度漂移对x、y轴向加速度响应的影响,并实现了各轴向加速度的解耦。从理论和仿真上验证了所提出的三轴加速度传感器整体设计的可行性。结果表明,对传感器结构的模态分析为避免实际应用中对传感器的破坏提供了一定的依据。对所设计传感器进行模态分析,求得传感器的固有频率,以规避传感器的共振损伤。     

PVDF压电传感器在实验模态分析中的应用

提出通过聚偏氟乙烯(PVDF)压电传感器替代加速度计对振动结构进行实验模态分析。在固支梁表面分别布置矩形PVDF压电传感器和加速度计,测量外界激励与振动结构响应之间的频率响应函数,通过模态软件对数据进行分析,得到模态参数并将结果进行对比。实验结果表明,利用PVDF压电传感器对振动结构进行实验模态分析效果良好,且具有附加质量小,频响宽,操作简便等特点,与加速度计相比,具有明显的优越性。     

减小交叉耦合的三维微加速度计的设计

介绍了一种减小交叉耦合的三维微加速度计的设计,该设计采用全差分电容式结构,X轴和Y轴采用梳齿电容式加速度计,Z轴采用扭摆电容式加速度计,三个轴向各自具有不同的敏感质量块,能够有效减小交叉耦合度。通过公式计算得到三个轴向的机械噪声,X轴为-60μg/Hz,Y轴为-66μg/Hz,Z轴为-53μg/Hz。从计算结果来看,三个维度的噪声系数较低,在电路噪声保证足够小的情况下,该三维微加速度计能够达到较高的精度。最后,采用COMSOL MULTIPHYSICS软件对该结构三个维度进行了模态仿真,仿真结果表明该设计能够有效减小三个维度的交叉耦合度。     

微加速度计在冲击环境下的力学分析与仿真

微加速度计用于测量载体的加速度,并提供相关的速度和位移信息。该文主要对一种硅基压阻式高加速度g(g=9.8m/s2)值微加速度计在冲击加速度环境下进行有限元仿真分析。分析结果表明,所设计的压阻式高g值微加速度传感器在15×104 g量程内可正常并有效工作,且可承受40×104 g高速冲击,当加速度超过40.8×104 g时,加速度计发生失效变形。分析了加速度计在冲击环境下的主要失效模式及失效机理,得出了压阻式加速度计在冲击环境下的失效主要从梁与边框和质量块连接处开始,随着冲击时间(即冲击强度)的增加,结构应力逐渐达到屈服极限,材料发生屈服效应,然后发生断裂。     

Optimization of Microlenses for InSb Infrared Focal-Plane Arrays

In this work, three designs of spherical refractive microlenses have been investigated. The simulation results show that the response and crosstalk of photodetectors with silicon microlenses are one order of magnitude better than for photodetectors with InSb microlenses or silicon thin-film microlenses. Additionally, we determined the optimum position for the focused beam as a function of the radius of curvature of the microlenses. This optimum position is dependent only on the absorption characteristics of the InSb material.     

高稳定度激光稳功率仪

本文介绍了一种NLiNbO3电光晶件作调制器，高稳定性硅光电二级管作监测器并有高质量光反馈电子元件的高稳定度激光功率稳定仪。只要输出功率大于1mW、稳定度优于5％／小时，使用本稳功率性后，功率稳定度可忧于0．05％小时。激光功率稳定范围在三个量稳内可调。     

3D Free‐Form Patterning of Silicon by Ion Implantation,Silicon Deposition,and Selective Silicon Etching

A method for additive layer‐by‐layer fabrication of arbitrarily shaped 3D silicon micro‐ and nanostructures is reported. The fabrication is based on alternating steps of chemical vapor deposition of silicon and local implantation of gallium ions by focused ion beam (FIB) writing. In a final step, the defined 3D structures are formed by etching the silicon in potassium hydroxide (KOH), in which the local ion implantation provides the etching selectivity. The method is demonstrated by fabricating 3D structures made of two and three silicon layers, including suspended beams that are 40 nm thick, 500 nm wide, and 4 μm long, and patterned lines that are 33 nm wide.     

MOEMS光开关静电驱动的优化设计

给出基于硅的微机械光开关的设计分析。优化设计了光开关结构，提出了一种降低扭臂式结构光开关驱动电压的方法。并根据不同结构，给出了静电驱动等方面的分析结果。     

Grain boundary segregation in multicrystalline silicon: correlative characterization by EBSD,EBIC, and atom probe tomography

This study aims to better understand the influence of crystallographic structure and impurity decoration on the recombination activity at grain boundaries in multicrystalline silicon. A sample of the upper part of a multicrystalline silicon ingot with intentional addition of iron and copper has been investigated. Correlative electron‐beam‐induced current, electron backscatter diffraction, and atom probe tomography data for different types of grain boundaries are presented. For a symmetric coherent Σ3 twin boundary, with very low recombination activity, no impurities are detected. In case of a non‐coherent (random) high‐angle grain boundary and higher order twins with pronounced recombination activity, carbon and oxygen impurities are observed to decorate the interface. Copper contamination is detected for the boundary with the highest recombination activity in this study, a random high‐angle grain boundary located in the vicinity of a triple junction. The 3D atom probe tomography study presented here is the first direct atomic scale identification and quantification of impurities decorating grain boundaries in multicrystalline silicon. The observed deviations in chemical decoration and induced current could be directly linked with different crystallographic structures of silicon grain boundaries. Hence, the current work establishes a direct correlation between grain boundary structure, atomic scale segregation information, and electrical activity. It can help to identify interface–property relationships for silicon interfaces that enable grain boundary engineering in multicrystalline silicon. Copyright © 2015 John Wiley & Sons, Ltd.     

Focused ion beam fabrication of curved structures using the concept of beam shaping and variable dwell time

This paper introduces a technique for the direct fabrication of curved structures using focused ion beams called beam shaping method (BSM). It is based on the concept of variable dwell time and simulations of sputtering and redeposition to shape overall ion dose profile which is composed of individual focused single pixel beam profile. The pixel dwell times are kept small enough to avoid sputtering yield enhancement due to a locally inclined surface. This provides better control over the fabrication process and allows the combination of the individual overlapped beams (separated by the pixel spacing) into a dose profile for use in the simulation. Varying the dwell time at each pixel we optimize the dose profile for the fabrication of the desired structure using repeated simulation. We demonstrate this technique on a silicon substrate by realizing fundamental structures such as circular and triangular optical gratings. The resultant fabricated structures agree well with the desired geometry within tolerance. Detailed explanation of the technique with experimental verifications is given, and the optimized ion dose profiles are discussed.     

碘过饱和KOH溶液对硅(110)晶面腐蚀的改善

将非金属元素碘作为硅的KOH腐蚀液的添加物,在对(100)和(110)单晶硅片的各向异性腐蚀中,获得了更为丰富的异向腐蚀特性和更为光滑的腐蚀表面。当温度在95℃,KOH腐蚀液中碘的摩尔比为0.5时,得到了粗糙度均小于10nm的Si-(100)和(110)光洁表面,两晶面的腐蚀速率均为1.4μm/min。这两晶面在相同的条件下同时达到最佳光洁度,说明腐蚀速率是获得高光洁度表面的关键。实验还证明碘在热碱溶液中的稳定性和持久性要高于现在已被大量研究的双氧水和过硫等,尤其是对硅(110)表面光洁度的改善具有积极的促进作用。     

用激光束成像法测量双E型硅弹性膜应变

报道了用激光束成像法对双E型传感器的硅弹性膜在不同压力情况下的应变进行的研究,并测出该弹性膜的应变情况。此方法对其他形式的敏感芯片应变的研究具有一定的参考价值。     

悬梁式陶瓷微热板的设计及热性能研究

结合传统陶瓷厚膜气体传感器和硅微加工气体传感器的特点,设计了基于陶瓷基底的悬梁式微热板结构,并提出一种无内引线的封装方式。对微热板的传热过程进行分析,并通过有限元工具对具有不同结构参数器件的热特性进行模拟,得到结构参数与器件热特性间的关系。通过控制工艺参数,在Al2O3陶瓷基底上制作出性能良好的Pt加热电阻及电极,并采用激光微加工技术实际制作了梁宽为0.2 mm和0.4 mm的两种结构器件。对器件的加热功率-温度关系进行测试,0.2 mm梁结构器件在400 mW加热功率下板上平均温度约为250℃,同模拟结果一致。     

A novel biosensor with enhanced sensitivity based on grating coupled double-layered porous silicon waveguide

The enhanced sensitivity of a guided mode biosensor is analyzed by employing double-layered porous silicon grating structures. The grating-coupled waveguide structure consists of two porous silicon grating layers with different refractive indices. simulations are carried out by changing the refractive index, which is due to the binding of biological molecules on the porous silicon pore can increase the refractive index of porous silicon. The numerical results show that this novel guided mode biosensor with a double-layered grating can provide not only a very high sensitivity but also a better reflectivity characteristic.