Papers by Keyword: Micro-Electromechanical System (MEMS)

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Authors: Christopher Locke, G. Kravchenko, P. Waters, J. D. Reddy, K. Du, A.A. Volinsky, Christopher L. Frewin, Stephen E. Saddow
Abstract: Single crystal 3C-SiC films were grown on (100) and (111) Si substrate orientations in order to study the resulting mechanical properties of this material. In addition, poly-crystalline 3C-SiC was also grown on (100)Si so that a comparison with monocrystaline 3C-SiC, also grown on (100)Si, could be made. The mechanical properties of single crystal and polycrystalline 3C-SiC films grown on Si substrates were measured by means of nanoindentation using a Berkovich diamond tip. These results indicate that polycrystalline SiC thin films are attractive for MEMS applications when compared with the single crystal 3C-SiC, which is promising since growing single crystal 3C-SiC films is more challenging. MEMS cantilevers and membranes fabricated from a 2 µm thick single crystal 3C-SiC grown on (100)Si under similar conditions resulted in a small degree of bow with only 9 µm of deflection for a cantilever of 700 µm length with an estimated tensile film stress of 300 MPa. Single crystal 3C-SiC films on (111)Si substrates have the highest elastic and plastic properties, although due to high residual stress they tend to crack and delaminate.
Authors: M. Rizwan Malik, Tie Lin Shi, Zi Rong Tang, M. Haseeb
Abstract: Much of the recent ongoing advanced research into the quest for improved etching techniques has brought forth a broad concept for the fabrication of micro/nano-electromechanical systems (MEMS/NEMS) having high accuracy, precision, efficiency, compatibility and through-put of metallic- as well as carbon-composition structural phases. This in turn leads towards a thorough understanding of the sensing, trapping, separating, controlling, positioning, directing, concentrating and manipulating of micro-nano-sized particles - predominantly biological particles - in the emerging MEMS/NEMS technological field. This paper focuses its attention on the easiest means of wet-etching {100}-type silicon wafer surfaces by guiding the choice of [<100> or <010>] orientation (at 45° to the normal orientation). This anisotropic etching is performed in KOH solution. Here, consideration is not concerned to a large extent with process parameters as in anodic oxidation, an intensely doped boron etching stops and silicon wafer surface back-etching. The main concern of the present practical application route involves a passivating material (silicon dioxide, SiO2) and two masking stages (for a two-step etching process). As a example of this method, silicon cantilever beams having vertical edges are produced. It is concluded that the method presented will be helpful in the comprehensive study of resonators, pressure/temperature sensors, three-dimensional carbon micro-electrodes, actuators and accelerometers for bioparticle applications.
Authors: Xue Hua Tang, Zheng You, Yong Jun Yang, Hong Tao He
Abstract: In this paper, a comb-driving tunneling magnetometer based on the tunneling effect is introduced. The designation, manufacture and tests of this magnetometer are discussed, including its structure, FEA analysis, machining processes and test results. The test results indicate that the chip is coincidental with the tunneling effect and the chip is capable of sensing the magnetic signal.
Authors: Chong Du Cho, Heung Shik Lee, Chang Boo Kim, Hyeon Gyu Beom
Abstract: In this paper, a finite element code especially for micro-magnetostrictive actuators was developed. Two significant characteristics of the presented finite element code are: (1) the magnetostrictive hysteresis phenomenon is effectively taken into account; (2) intrinsic geometric feature of typical thin film structures of large length to thickness ratio, which makes it very difficult to construct finite element mesh in the region of the thin film, is considered reasonably in modeling micro-magneostrictive actuators. For verification purpose, magnetostrictive thin films were fabricated and tested in the form of a cantilevered actuator. The Tb-Fe film and Sm-Fe film are sputtered on the Si and Polyimide substrates individually. The magnetic and magnetostrictive properties of the sputtered magnetostrictive films are measured. The measured magnetostrictive coefficients are compared with the numerically calculated ones.
Authors: Li Bo Zhao, Xu Dong Fang, Yu Long Zhao, Zhuang De Jiang, Yong Li
Abstract: A pressure sensor in the range of 25 MPa with circular diaphragm is designed and fabricated, and the calibration experiments prove its excellent performance, which also reflects the correct choice of design after analyzing the effect of diaphragm dimension, location and shapes of piezoresistors. Circular diaphragms of different thickness and diameters are simulated to meet the pressure requirement of 25 MPa. It also displays the advantage of piezoresistive sensors over others and the difference characteristics between different types of piezoresistive sensors. And then the effect of piezoresistor location is analyzed and simulated to attain high accuracy and sensitivity after the circular diaphragm chip is packaged with borosilicate glass ring. The whole fabrication process of the chip is inexpensive and compatible with standard MEMS process. The experimental results show the developed high pressure sensor with the sensitivity of 2.533 mV/MPa has excellent performance, such as linearity of 0.08%FS, hysteresis of 0.03%FS, accuracy of 0.11%FS and repeatability of 0.03%FS under high temperature of 200 °C.
Authors: Yun Kui Zhang, Feng Cui, Zhen Wan, Kai Li, Wu Liu, Wei Ping Zhang
Abstract: In this paper, differential capacitors sandwiched structure of a high-G capacitive microaccelerometer with round metal proof mass supported by multi-beam and its characteristic are presented. The operation principle and built-in self-calibration and self-test functions are described. The fabrication process and the fabricated chip of the microaccelerometer based on UV-LIGA technology are reported. The detection and closed-loop control circuits of the microaccelerometer are designed and calibrated. The range of the detection channel is ±6pF, the sensitivity is 89.3mV/pF, and the linearity is 2.59%.
Authors: Li Bo Zhao, En Ze Huang, Gui Ming Zhang, Yu Long Zhao, Xiao Po Wang, Zhuang De Jiang, Zhi Gang Liu
Abstract: A kind of fluid density sensor based on MEMS (Micro-Electro-Mechanical-System) technology is introduced with trapezoidal cantilever structure. The rectangular cantilever and trapezoidal cantilever, based on the same parameters, are analyzed. The simulation results show that the sensitivity of trapezoidal cantilever is higher than that of rectangular cantilever. Four different sizes of trapezoidal cantilever are analyzed by modal and harmonic simulation with ANSYS Software, the optimum solution will be obtained from simulation results.
Authors: Wei Wang, Wei Guo Liu, Jin Long Zou, Peng Fei Huo
Abstract: In order to realize the miniaturization of fuze safety mechanism, a novel MEMS safe and arm is proposed through concept, analysis, design and initial prototyping. A microscale inertial mechanical logic for mechanical safe and arm functions in the form of sliders, springs, and locks that interact on a planar substrate in response to setback acceleration and centrifugal force to thereby arm the fuze, and the bulk fabrication process were analyzed. The safety criteria, design principles, modeling and simulation methods for arming slider, setback lock, and arming lock are introduced. Air gun testing demonstrates the feasibility of MEMS safe and arm device and the validity of the design method.
Authors: Jun Hui Ni, Bei Zhi Li, Jian Guo Yang
Abstract: This paper presents a novel low-cost poly(dimethylsiloxane) (PDMS) micropump with simple planar design featuring use of compliant in-contact check valves for reliable operation and easy system integration. The micropump mainly consists of two PDMS functional layers: one through-opening layer incorporating the planar in-contact check valves, pump chamber and flow channels, and the other thin membrane layer covering the chamber with a miniature permanent magnet on top for actuation. A special clamping molding technique was used to fabricate the through-opening functional layer, with which the flap-stopper based planar check valve was manipulated to contact each other enabling the minimized leakage flow. The micropump was then characterized by investigating the dependence of pumping flow rate on the driving frequency and backpressure. Testing results exhibit that the micropump is able to produce a flow rate at least of 3.0 μL/min, and work reliably against a backpressure of 1900 Pa, demonstrating the feasibility of this micropump for potential use in various lab-on-a-chip systems.
Authors: Shao Peng Liu, Zhao Ying Zhou, Qiong Wang, Qi Guo, Zhi Guang Ma
Abstract: One wireless attitude measurement system based on a MEMS multi-sensor has been developed. The data from 3-axis MEMS accelerators and 3-axis MEMS gyroscopes are used to determine the pitch angle and the roll angle by using an extended Kalman filter (EKF) equation deduced from the direction cosine matrix. The attitude angles can be resolved from the EKF algorithm based on Quaternion. The system can be used in dynamic as well as static environments by adjusting the measurement noise matrix of the extended Kalman filter equation. Results indicate that system is determined with standard deviations below 5º even in high dynamics and 1º in static state. The system can collect wireless data from over six nodes simultaneously with a sampling rate up to 100 Hz. The system node measuring 22x15x10mm and weighing 4.5g contains wireless communication module, 3-axis gyroscope, magnetometer and accelerometer.
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