基于MEMS技术的微电容式加速度传感器的设计

给出了一种基于MEMS技术制作的微电容式加速度传感器的结构及工艺。为了准确地把握这种微电容式加速度传感器的力学和电学特性,仔细地建立了它的力学模型。在此基础上,详细分析了它的动态特性———模态。并用有限元的方法分析和计算了微电容式加速度传感器的加速度与电容信号的非线性输入输出关系,并结合实测参数验证了模型的有效性。最后提出了一种详细的有效的基于MEMS技术的微电容式加速度传感器的结构以及加工工艺流程。基于MEMS技术制作的微电容式加速度传感器具有结构简单、工作可靠和工作范围大的特点。根据这套方法,可以比较方便地设计并加工不同测量要求的加速度计。     

基于MEMS技术的SU-8仿昆虫微扑翼飞行器设计及制作

为研制一种轻质仿昆虫微扑翼飞行器,提出了采用微机电系统(MEMS)领域的SU-8光刻胶作为结构材料的制作方案.基于仿生学原理和微机电系统加工技术,设计微扑翼飞行器结构及MEMS 工艺方法.研究结果表明,该种结构设计及制作方案满足设计要求,为仿昆虫微扑翼飞行器的研制提供了一种很好的途径.     

微陀螺仪敏感芯片的选择性电铸技术研究

介绍了一种新的MEMS器件敏感芯片的制备技术———选择性电铸技术。以金为检测电极、铜为牺牲层、正胶作为电铸胎膜,在牺牲层上经过数次电铸形成MEMS器件敏感芯片的各组成部分,腐蚀掉牺牲层后便得到了所需的敏感芯片。以微机械陀螺仪敏感芯片的制备为例,介绍了选择性电铸技术的工艺流程,进行了工艺流片,所制备的微机械陀螺仪敏感芯片结构完整、侧壁陡直、表面平整。该技术在电容式微加速度计及微机械陀螺仪等多种MEMS器件敏感芯片的制作中有广泛的应用前景。     

基于MEMS的生物微传感技术

微电子机械系统(MEMS)技术为生物微传感器和生物芯片的研制以及实现小型化、便携式、低成本,高灵敏度的生化片上系统提供了有力的技术支持。综述了基于MEMS的生物微传感技术,介绍了生物微传感器和生物芯片的原理、结构、分类及应用,并探讨了其发展和应用前景。     

一种基于感声波纹结构的光学式声传感器

设计了一种基于硅MEMS敏感结构的光学式声传感器,其光学调制原理采用强度调制型,微敏感结构采用具有低应力波纹结构的感声薄膜芯片。对光纤与微敏感结构耦合技术进行实验研究,优化光学参数,并制作传感器样品。经实验测试,灵敏度达80mV/Pa。     

I~2形原子力显微镜探针设计优化

针对基于微机电系统(MEMS)技术的I~2形原子力显微镜(AFM)探针与传统悬臂式探针相比,虽然有很多优点,但由于I~2形探针的压阻检测设计未考虑结构应变分布,导致检测灵敏度较悬臂式探针相比尚有一定差距的问题,通过对I~2形探针应变分布的考察,实现了探针结构优化设计。实验结果表明:在相同结构,相同输入前提下,改进后探针的力灵敏度达到28. 9p N/Hz~(1/2),较原有基础上提高10倍。通过进一步对检测电路的优化,力灵敏度有望满足商用需求(小于10p N/Hz~(1/2))。     

适用于RF MEMS能量耦合传输的高Q值电感

利用MEMS微电镀工艺技术制作了一种新型的适用于RF MEMS能量耦合传输的高Q值电感,采用ANSOFT公司的HFSS优化平面螺旋电感的结构。在具有高电阻率的玻璃衬底上溅射0.5μm的铜层作为下电极;PECVD淀积厚度为1μmSiO2作为中间介质层;在介质层上结合厚胶光刻技术电镀厚为22μm的铜作为电感线圈。这套电感制作工艺流程简单、易于与IC制备工艺集成。本文制备的微机械电感在微型植入系统中具有广阔的应用前景。测量结果表明:当工作频率在1GHz左右时,微电感的电感值达到55nH,Q值最大可达到25。     

用于神经电信号记录的多通道微探针

:以体硅为衬底,采用微机械加工技术(MEMS)制作了七通道的可植入到脑皮层的微探针,用于记录神经电信号.从生物相容性、减小植入损伤、工艺制作难度等方面考虑,制作了以二氧化硅/硅(SiO2/Si)为主体的微探针,并详述了其具体制作工艺流程.扫描电镜(SEM)照片显示微探针针长3 mm、针宽100 μm、针厚约为20 μm,各个记录点直径10 μm、间距120μm,实现了各通道之间良好的信号隔离.微探针距离针尖1 mm范围内的针宽以一定弧度由100 μm逐渐变窄,同时针尖锥角为6°,此种结构有利于减小植入时对脑组织的损伤.通过体外测试得到,当频率由10 kHz增加到10 MHz时,微电极各个通道阻抗由150.5 kΩ降低到6.0 kΩ.     

一种新型MEMS双稳态微电磁驱动器的研究

介绍了一种新型MEMS双稳态微电磁驱动器,通过理论分析和有限元分析工具Ansys对器件的结构参数进行了优化设计,并证明了设计的可行性。利用金属基表面微加工技术与体硅微加工技术成功制作出这种驱动器,并对其弹性平台的弹性系数进行了标定,对驱动器的双稳态进行了调试。结果表明：此驱动器具有良好的双稳特性,响应时间短（约10ms）的特点。     

一种用于微喷的感应加热器设计与仿真

提出了一种用于热微喷头的感应加热器新结构。进行了相关的结构和工艺设计,在MEMS工艺环境下制作出了可以非接触加热,工艺结构简单,使用寿命长的微感应加热器。使用ANSYS对微感应加热器进行了建模和仿真分析,结果显示:感应加热器的最大加热功率可达到5 mW以上,满足设计要求,同时得到了感应加热器的功率影响因素。     

Equivalent area nonlinear static and dynamic analysis of electrostatically actuated microstructures

Nonlinear dynamic investigation of electrostatically actuated micro-electro-mechanical-system (MEMS) microcantilever structures is presented. The nonlinear analysis aims to better quantify, than the linear model, the instability threshold associated with electrostatically actuated MEMS structures, where the pull-in voltage of the microcantilever is determined using a phase portrait analysis of the microsystem. The microcantilever is modeled as a lumped mass-spring system. The nonlinear electrostatic force is incorporated into the lumped microsystem through an equivalent area of the microcantilever for a given electrostatic potential. Electro-mechanical force balance plots are obtained for various electrostatic potentials from which the static equilibrium positions of the microcantilever are obtained and the respective conservative energy values are determined. Subsequently, phase portrait plots are obtained for the corresponding energy values from which the pull-in voltage is estimated for the microsystem. This pull-in voltage value is in good agreement with the previously published results for the same geometric and material parameters. The results obtained for linear electrostatic models are also presented for comparison.     

Influence of bending-extension coupling on the modal frequencies of nonsymmetrically laminated MEMS microcantilevers

Many microelectromechanical systems (MEMS) devices are based on some aspect of the modal vibration response of microcantilever beams, and these microcantilevers often have nonsymmetrically laminated construction. Such construction can lead to complex mechanical coupling effects which are not included in elementary beam theory, yet this theory is often used to estimate the modal frequencies of microcantilevers. In this paper, the bending-extension coupling effects on the modal frequencies of a typical two-layer microcantilever beam element in a MEMS chemical sensor are analyzed. Classical Lamination Theory is combined with a Rayleigh-Ritz analysis to develop a model for the modal frequencies of this microcantilever. Results are compared with those from the elementary beam theory and a finite element model. Bending-extension coupling effects are found to depend on the beam length-to-thickness ratio, on the coating thickness-to-beam thickness ratio, and on the mode number. [1369].     

Micron-scale polymer-metal cantilever actuators fabricated by focused ion beam

Polymer-metal microcantilever actuators have been fabricated using an innovative approach based on focused ion beam micromachining technology. The fabrication involves depositing a thin metal film onto the surface of the polymer and machining using the ion beam. The microcantilever created is then extracted and transferred to a desirable support using a micromanipulator. This approach demonstrates the potential for maskless and resistless prototyping of cantilevers that can be evaluated for use as MEMS/NEMS actuators. Nanometer-scale displacement of the resulting polystyrene-platinum bimorph microactuator with respect to temperature change is demonstrated via visual monitoring in a scanning electron microscope with a heating stage. The performance of the bimorph cantilever microactuators is verified using both analytical and finite element modeling.     

Simple fabrication of an uncooled Al/SiO2 microcantilever IR detector based on bulk micromachining

A simple microfabrication process to make an uncooled aluminum/silicon dioxide bi-material microcantilever infrared (IR) detector using silicon bulk micromachining technology is presented in this work. This detector is based on high banding of the microcantilever due to the large dissimilar in thermal expansion coefficients between the two materials. It consists of a 1 μm SiO₂ layer deposited by 200 nm thin Al layer. Since no sacrificial layer is used in this process, complexity related to releasing sacrificial layer is avoided. Moreover Al is protected in Si etchant using dual-doped tetramethyl ammonium hydroxide. The other advantage of this process is that only three masks are used with four photolithography process. Thermal and thermal mechanical behaviors of this structure are obtained using finite element analysis, and the maximum temperature and displacement at the end of cantilever at 100 pW/μm² absorbed IR power density on top surface are 7.82°K and 1.924 μm, respectively.     

等效模型分析微机械薄膜谐振器的力学特性

通过引入折合的概念,将多层微机械谐振悬臂梁等效为单层结构,建立了多层微悬臂梁的弯曲振动方程,结合边界条件求出了微悬臂梁的固有频率。等效概念的引入大大简化了多层微机械谐振器件振动特性的理论分析过程,与传统只考虑绝对占优层的方法相比,等效模型不仅更加精确,而且突出了多层微机械谐振梁中的主要矛盾,为多层微机械谐振式器件的结构优化设计奠定了基础。     

A novel, electrically protein-manipulated microcantilever biosensor for enhancement of capture antibody immobilization

This study demonstrated a microcantilever biosensor for enhancement of capture antibody immobilization. The electrically protein-manipulated, microcantilever biosensor is featured with enhanced capture antibody immobilization, miniaturization, and high sensitivity. Thanks to the electric property of biological substances in a real environment, given charged proteins can be manipulated with attraction in solution under an electric field. It is evident that higher amount of capture antibody molecules immobilized onto sensing surfaces captures or detects specific molecules, indicating greater deflection and stresses as well. This however leads to significant cost in biosensors. With the merit of MEMS technique that allows highly fabrication-compatible integration into microcantilever biosensors, sparsely distributed antibody molecules in solution are attracted in focus onto a sensing solid surface under electric fields. As the sensing element of the gold-coated, V-shaped silicon nitride microcantilever also serves as an electrode, the electric fields are applied in a channel of flowing microfluidics by locally in-plane electrodes or by a top electrode arranged for three-dimensional fields. As expected, most charged proteins distributed in solution are effectively attracted onto the sensing area within the electric fields. This improves the efficiency of capture antibody immobilization and achieves an eight-fold reduction over the necessary amount of capture antibodies without applying electric fields. With such a successful manipulation of charged proteins, the novel microcantilever biosensor exhibits efficient use of capture antibodies in solution.     

Piezo-resistive method for tuberculosis detection using microcantilever biosensor

Microcantilever device is utilized in several biosensors for detection of bio-molecule of interest. Biosensors task is to identify presence of targeted molecule and supply result into a measurable signal. Comparing with conventional biological equipments, micro scale biosensors are very fast, reliable and price effective. Microelectromechanical systems (MEMS)/nanoelectromechanical systems are used for designing of such biosensors, which might be utilized in several biological applications. Sensing mechanism of biosensor is varied with the application. This paper is focused on detection of bio-molecule using microcantilever beam. Biosensor has shown here uses piezo-resistive method for detection of targeted bio-molecule. This Bio-MEMS device is designed and simulated using coventorware software. This biosensor wants to identify a presence of T.B. in a very suspected patient. For detection of primary stage of tuberculosis (ESAT-6), specific antibodies need to immobilize on top of microcantilever. Once patient sample (consist of ESAT-6) is placed on functionalized cantilever surface, biochemical reaction happen between tuberculosis antigens ESAT-6 and antibodies. Adsorption of antigens will increase mass working on cantilever and results in bending of microcantilever. This deflection shows the presence of tuberculosis within the patient sample.     

MEMS技术在变压器故障监测中应用研究

分析了变压器在线检测过程,重点分析了热导池检测器检测原理,并针对传统的热导池检测器的不足,设计了一种基于MEMS技术的热导池检测器并应用于变压器在线监测系统。测试结果证明：该装置能够满足对变压器油中微量故障特征气体的精确分析。     

Reduction of Sheet Resistance and Low-Thermal-Budget Relaxation of Stress Gradients in Polysilicon Microcantilever Beams Using Nickel-Silicides

Nickel-silicide (Ni_xSiy) is formed by the reaction of nickel and silicon at the temperature of couple of hundred degrees Celsius. Nickel-silicide technology is employed for the purpose of application in polysilicon-based microelectromechanical systems (MEMS) devices to reduce sheet resistance as well as to control residual stress gradients of the structures. To improve the compatibility of nickel-silicide with MEMS micromachining, anticorrosion release method is developed using cathodic protection. In situ study of stress evolutions during the reaction of a nickel film with polysilicon is quantitatively investigated using wafer curvature measurements. The phase of nickel-silicide is validated by using X-ray diffraction. The stress developed during the silicidation is utilized to control the stress gradient in polysilicon microcantilever beams. The experimental results show that the sheet resistance changes from over 20 000 Omega/sq. (insulating material) to less than 10 Omega/sq. The stress gradient is relaxed by counterbalancing the tensile residual stress at the upper part of a cantilever with a built-up compressive stress when the annealing temperature is 290 degC     

微悬臂梁传感器在环境检测中的应用

微悬臂梁传感器以其实时、高灵敏度、非标记等优点,成为一种新型环境检测手段。介绍了微悬臂梁传感器的工作原理,包括其工作模式、读出技术,总结了其在环境检测等方面的研究动态,并对其在环境检测领域的发展进行了展望。