基于MEMS热电堆传感器的高温测量技术

为了拓宽MEMS热电堆传感器的温度测量范围,实现高温测量,根据MEMS热电堆传感器的原理,设计完成了A2TPMB34型MEMS热电堆传感器静态与动态标定装置,通过试验得到标定结果;同时,提供了基于MEMS热电堆传感器实现瞬态高温测试的技术方案和实现手段,并对其关键部分一红外衰减片性能进行了分析和讨论。     

Dual thermopile integrated microfluidic calorimeter for biochemical thermodynamics

This article presents a new design of a silicon-based microcalorimeter made with dual thermopiles and a microchannel. The dual thermopile was fabricated with chromium and copper using a microelectromechanical system (MEMS) technique, and the microchannel was made of PDMS using soft-lithography. Each thermopile consists of 26 thermocouple pairs and 50 μm wide electrodes. The total sensitivity of thermopile is 428 μV/K. The dual thermopile system enables the microcalorimeter to acquire reliable data in a rapid and convenient manner because it detects the reaction and reference temperatures simultaneously. This self-compensation allows our device to analyze a few microliters of sample solution without the need for a surrounding adiabatic vacuum.     

Monolithically Fabricated Microgripper With Integrated Force Sensor for Manipulating Microobjects and Biological Cells Aligned in an Ultrasonic Field

This paper reports an electrostatic microelectromechanical systems (MEMS) gripper with an integrated capacitive force sensor. The sensitivity is more than three orders of magnitude higher than other monolithically fabricated MEMS grippers with force feedback. This force sensing resolution provides feedback in the range of the forces that dominate the micromanipulation process. A MEMS ultrasonic device is described for aligning microobjects suspended in water using ultrasonic fields. The alignment of the particles is of a sufficient accuracy that the microgripper must only return to a fixed position in order to pick up particles less than 100 mum in diameter. The concept is also demonstrated with HeLa cells, thus providing a useful tool in biological research and cell assays     

Performance of integrated optical microcavities for refractive index and fluorescence sensing

The performance of a novel sensor based on an integrated optical (IO) disk microcavity (MC) is theoretically studied. The MC is a resonant waveguide structure in which multiple interference of a guided mode occurs. At resonance, the MC is extremely sensitive to refractive index changes and it sustains locally enhanced optical field. Therefore, the MC is naturally suitable as an extremely responsive sensor for measuring minute changes in refractive index and/or fluorescence of an analyte. Combination of multiple interference and extremely small sampling volume (few femtoliters) provides unique sensitivity of the MC device. A factor of 9 increase in fluorescence sensitivity versus waveguide sensor is anticipated. Provided shot-noise limited detection, the refractive index resolution down to 10⁻⁹ is feasible with the MC sensor, which exceeds that of the straight waveguide interferometer by the order of magnitude. MC-sensors can be combined into arrays providing high throughput detection of both labeled and non-fluorescent biological species.     

基于永磁薄膜的MEMS磁传感器设计与制作

提出了一种基于永磁薄膜的新型MEMS磁传感器,磁传感器由MEMS扭摆、CoNiMnP永磁薄膜和差分检测电容等部分组成。分析了磁传感器的磁敏感原理和电容检测原理,提出了器件的结构参数并对器件进行了模态仿真。利用MEMS加工技术成功制作了MEMS磁传感器样品,并进行了测试。测试结果表明:得到的MEMS磁传感器的电容灵敏度可达到27.7 fF/mT,且具有良好的线性度。根据现有的微小电容检测技术,传感器的磁场分辨率可达到36 nT。     

A novel out-of-plane MEMS tunneling accelerometer

A novel out-of-plane MEMS tunneling accelerometer is designed, fabricated and characterized. ICP process, which can generate large proof mass, is used for the first time to fabricate an out-of-plane tunneling accelerometer. To reduce the high Hooke's constant in out-of-plane direction of the ICP etching structure, the beams and the proof mass are dry-etched by double mask ICP process, which reduce the Hooke's constant, thereby enhance the sensitivity of the device. The tunneling current of open loop is tested in the air by HP4145B semiconductor analyzer, which verifies the presence of tunneling current and shows the needed driving voltage. The close-loop test shows sensitivity of 811 mV/g for feedback voltage (the sensitivity of actuate voltage is about 200 mV/g) and nonlinearity of 1% in the measurement range of 0 to +1 g. The spectrum measurement is performed in general environment and the resolution of the device is 0.5 mg/rtHz (1.25–100 Hz), which shows better low frequency property.     

Theoretical and experimental studies on the parylene diaphragms for microdevices

In this paper, parylene diaphragms with planar and corrugated shapes are fabricated and tested. Although, recently in MEMS, parylene has been used for a diaphragm material due to its excellent property, no theoretical and analytical studies of the parylene diaphragm have been performed. Therefore, the characterization of the parylene diaphragms is studied through both experiments and simulations. Thermal and load-deflection analyses for diaphragms are carried out to find the effect of residual stress on the behavoir of the diaphragm. The measured deflections are compared with both analytical calculations and FEM simulations that considers the influence of the thermal stress. Those results show excellent agreement. In order to find an optimum shape of the corrugated diaphragm, the influence of the corrugation number and the corrugation depth on the mechanical sensitivity of the corrugated diaphragm is studied parametrically.The authors would like to thanks to Dr. Sang Sik Yang and coworkers in the Microsystems Lab., School of Electronics Engineering, Ajou University for the help with device processing. This research was sponsored by Institute for Applied Science and Technology of Sogang University.     

Fabrication and Characterization of a Wafer-Level MEMS Vacuum Package With Vertical Feedthroughs

This paper reports a MEMS vacuum package with vertical feedthroughs formed in a glass substrate all at the wafer level. This approach satisfies requirements for MEMS vacuum packages, including small size, vacuum/hermetic capability, sealed and low parasitic feedthroughs, wafer-level processing, compatibility with most MEMS processes, and low cost. It also enables flip-chip solder attachment to a PC board. The package has an integrated micro-Pirani gauge on a glass substrate for in situ monitoring, a silicon cap, and vertical feedthroughs through the glass. The integrated Pirani gauge has 0.6 milli-torr resolution at 0.1 torr and 0.2 torr resolution at 100 torr. Using the Pirani gauge, the fabricated vacuum package is characterized. The package has maintained ~33 torr base pressure with plusmn1.5 torr uncertainty for more than four months without a getter. The long-term measured pressure uncertainty is from the measurement setup and environment, and can be improved using a getter inside the package. [2007-0160]     

一种新型MEMS微波功率传感器的理论模型与优化设计

提出了一种新型的MEMS微波功率传感器.与传统的结构相比,新结构具有测量误差小、设计简单、使用方便等显著优点.然后在全面考虑了热传导、热对流、热辐射三种传热机制的基础上,对传感器的主要部分即热电堆建立了热模型,进而导出了灵敏度、时间常数、噪声的理论解析式.最后根据拉格朗日乘数法原理,以给定的时间常数和噪声大小为约束条件,求得灵敏度达最大时热偶长度和串联数目的最佳值.     

Structure design and test of MEMS thermocouple infrared detector

Microsystem Technologies - Aiming at the problems of large volume and low yield of MEMS thermal reactor infrared detector at present, this paper designs a MEMS thermopile infrared detector based on...     

Schottky Barrier Contact-Based RF MEMS Switch

This paper presents the design, fabrication, and measurement results for a novel Schottky barrier contact-based radio frequency (RF) microelectromechanical systems (MEMS) switch. This Schottky barrier contact allows one not only to operate the RF MEMS switch in a traditional capacitive mode when it is reverse biased but also conduct current in a forward biased state. Forward biasing the switch recombines trapped charges, thus extending the lifetime of the switch. This paper intimately combines MEMS processing with solid-state electronics to produce a truly unique RF device.$hfill$[2008-0097]      

Silicon cantilevers with piezo-resistive measuring bridge for tactile line measurement

In this article a variety of applications of a microelectromechanical system (MEMS) including a cantilever with an integrated piezo-resistive bridge is described. With the low-noise integrated piezo-resistive bridge a resolution in the nanometer range is possible. This sensor obtains a typical resolution in the vertical displacement of 2 nm (due to noise floor Δf = 1.6 kHz). Due to the low spring constant of D = 1 to 10 N/m, measurements with contact forces of <100 μN can be realized. This allows a non-destructive examination of polymer structures. Furthermore, the sensor is characterized by a high eigenfrequency (>2.7 kHz), a slight mass (≈0.1 mg) and a measuring velocity of up to 10 mm/s. The important applications of the MEMS cantilever are fast inline control of building panels, measurement of optical structures, inside measurement of fuel injection nozzle micro holes. Furthermore, it is possible to provide different tip geometries (e.g. cone or ball) at the end of the cantilever for an ideal surface measurement.     

Isothermal titration calorimetry in a polymeric microdevice

Microelectromechanical systems (MEMS) technology can enable the integration of isothermal titration calorimetry (ITC) on a single chip for direct thermodynamic characterization. However, existing ITC microdevices either do not yet allow proper control of reaction conditions for thermodynamic characterization of biomolecular reaction systems or do not yet suitable for practical applications because of a lack of reliability, high costs, and other issues. This paper aims to address these limitations with polymeric MEMS-based quantitative ITC measurements. The polymer-based ITC device design eliminates the use of silicon and exploits the low thermal conductivity of the polymer substrate to achieve thermal isolation of reaction samples in the absence of any complex or fragile freestanding structures. The low-cost availability of polymers and the elimination of the freestanding structures simplify the fabrication process, increase the fabrication yield, reduce the device cost, and improve the device reliability. During the ITC device operation, reactants and reference solutions are introduced to their respective measurement chambers, and the reaction-induced differential thermal power is measured and used to compute the thermodynamic binding parameters associated with the reaction. The potential utility of the device has been demonstrated with quantitative ITC measurements of a model reaction system in which the ligand BaCl₂ is titrated into the receptor 18-C-6 at a concentration of 2 mM.     

Piezoresistive Feedback Control of a MEMS Thermal Actuator

Feedback control of microelectromechanical systems (MEMS) devices has the potential to significantly improve device performance and reliability. One of the main obstacles to its broader use is the small number of on-chip sensing options that are available to MEMS designers. A method of using integrated piezoresistive sensing is proposed and demonstrated as another option. Integrated piezoresistive sensing utilizes the inherent piezoresistive property of polycrystalline silicon from which many MEMS devices are fabricated. As compliant MEMS structures flex to perform their functions, their resistance changes. That resistance change can be used to transduce the structures' deflection into an electrical signal. The piezoresistive microdisplacement transducer (PMT) is a demonstration structure that uses integrated piezoresistive sensing to monitor the output displacement of a thermomechanical inplane microactuator (TIM). Using the PMT as a feedback sensor for closed-loop control of the TIM provided excellent tracking with no evident steady-state error, maintained the positioning resolution to $pm$29 nm or less, and increased the robustness of the system such that it was insensitive to significant damage.$hfill$ [2007-0136]      

微机械热电堆红外探测器的设计

阐述了微机械热电堆的设计原理、所用材料及主要结构,并研究了3×3阵列的微机械制造工艺,该热电堆结构支撑结构为氮化硅—氧化硅—氮化硅的复合介质膜。热电偶材料采用多晶硅和铝,热电偶采用并列排布的结构,对冷端覆盖了绝热层,用以提高热电堆的探测率。由于该制作工艺与标准IC工艺兼容,使得硅基热电堆红外探测器得到了越来越广泛的应用。     

硅一金属温差电堆结构及性质研究

本文研究的温差电堆的单元对为多晶硅-金属(Au或Al)结构,其中多晶硅经连续波A_r~+激光再结晶处理后,电阻值降低,温差电堆器件的塞贝克系数和响应率得到提高.所制温差电堆最大集成达76对.     

Neisseria Meningitidis Detection Based on a Microcalorimetric Biosensor With a Split-Flow Microchannel

This paper proposes and demonstrates a novel microcalorimetric sensor for detecting Neisseria meningitidis. To eliminate additional heating structures and calibration steps, a split-flow microchannel is integrated into the microcalorimeter. The split-flow microchannel constantly maintains the output of the microcalorimeter near a zero level without the use of any heating elements when there is no biochemical reaction. With the use of the split-flow microchannel, an active heating element such as a heater is no longer required. In addition, to improve the sensitivity of the microcalorimeter, a thermal sensing component, which is a thermopile in this case, has been fabricated on a high thermal resistivity layer, which reduces the parasitic heat transfer to the silicon substrate and concentrates the released thermal energy to the thermopile. The characteristics of the proposed microcalorimeter were investigated by measuring the reaction heat of the biotin-streptavidin pairs. The sensitivity of the microcalorimeter was measured to be 0.21 V/cal. Then, a biological reaction between Neisseria meningitidis group B (NMGB) and its antibody was detected by using the proposed microcalorimeter. In order to verify the reliability of the measurement, exactly the same number of NMGB was reacted with its antibody and an optical density was measured by an enzyme-linked immunosorbent assay as a known reference.     

A novel parametric-effect MEMS amplifier

This paper presents the theory and measurements of a mechanical parametric-effect amplifier with a 200-kHz input signal and a 1.84-MHz output signal. The device used is a MEMS time-varying capacitor which is composed of an array of low-stress metallized silicon-nitride diaphragms, and is pumped by a large-signal voltage at 1.64 MHz. This induces a large change in the capacitance, and results in parametric amplification of an input signal at 200 kHz. The parametric amplifier capacitance is 500 pF, resulting in an output impedance of 140 Ω. A higher impedance can also be achieved with a lower capacitance. To our knowledge, this device is the first-ever MEMS mechanical up-converter parametric-effect amplifier developed with an up-conversion ratio of 9:1. The measurements agree very well with theory, including the effect the series resistance and the and of the MEMS time-varying capacitor. The application areas are in amplifiers which operate at very high temperatures (200°C-600°C), under high particle bombardment (nuclear applications), in non-semiconductor-based amplification, and in low-noise systems, since parametric amplifiers do not suffer from thermal, shot, or 1/f noise problems     

Raman spectroscopy characterization of a thermal bimorph actuator used in a bio-MEMS device

Devising a MEMS (Micro Electro Mechanical System) sensor is a very challenging task. When movement is required, a transducer has to be integrated, capable to convert electrical into mechanical energy. Different types of actuators can be selected, using electrostatic forces, magnetic fields or thermal expansion, and reliability of actuators has proven to be a critical element in MEMS devices. In this paper we have demonstrated that the Raman spectroscopy technique (using the Raman peaks shift) is a suitable tool to assess the temperature of a thermal actuator in a MEMS device. The technique used is a spectrometric characterization, benefitting from the Raman peaks shift caused by an increase in temperature. This method shows that it is possible to map areas with a resolution of a few microns and a temperature accuracy of around 0.01 %/full scale. This technique provides good resolution and accuracy and allows several analyses: from simple thermal mapping to determination of the system’s thermal physical parameters and constant thermal resistance variation at a micrometric scale.     

基于切割成型的侧壁表面压阻制作及其参数优化

为了提高MEMS执行器件对面内运动位移（或力学信号）检测的灵敏度并改善侧壁检测电阻制作工艺与其他工艺及其不同器件结构之间的兼容性问题,提出一种基于离子注入工艺和深度反应离子刻蚀（DRIE）工艺相结合制作检测梁侧壁压阻的方法。在此基础上,详细分析了影响位移检测灵敏度和分辨率的各种因素,并对侧壁压阻的结构尺寸及其工艺参数进行优化。最后,给出了侧壁表面压阻在几种不同类型典型MEMS执行器件中的应用,取得了很好的应用效果。