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- 2018
- Multi-input and multi-output
- half adder
- DEMUX
- electrostatic and electrothermal actuation
- MEMS resonators
- Optoelectronic Information Science and Engineering
- King Abdullah University of Science and Technology
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[IEEE 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Xiamen, China (2019.12.17-2019.12.20)] 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Detection of Weak Strain and Vibration Signal at Multipoints of a Bridge with Optical Fiber Bragg Gratings
摘要： In this paper, we present a new method for detecting in-plane displacements in microelectromechanical systems (MEMS) with an unprecedented sub-?ngstr?m accuracy. We use a curve-fitting method that is commonly employed in spectroscopy to find peak positions in a spectrum. We fit a function to the intensity profile of the image of a silicon beam that was captured with a CCD camera on an optical microscope. The position resolution depends on the amount of pixel noise and on how the moving feature is spread across the detector pixels. The resolution is usually limited by photon shot noise, which can be controlled and lowered in several ways. To demonstrate the technique we measure the adhesion snap-off of two silicon surfaces. We assess the accuracy of the technique using two different silicon MEMS devices and an experimental ultrananocrystalline diamond device. The lowest position noise that we report is obtained by summing 1 577 image lines and is as low as 60 pm [2014-0040] root mean square.
关键词： Displacement measurement,optical noise,MEMS,optical image processing,subpixel resolution,optical position measurement
更新于2025-09-23 15:19:57
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[IEEE 2018 IEEE 13th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS) - Singapore, Singapore (2018.4.22-2018.4.26)] 2018 IEEE 13th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS) - Optical Coupling of 3D Silicon Micromirrors
摘要： Free space optical coupling is considered the important feature which affects on the performance of the optical systems. Where coupling elements such as lenses and mirrors are aided in overcome the divergence of the Gaussian beams and to achieve phase matching. Here we concentrate on the studying of the free space coupling of 3D (spherical) mirror based on the propagation of a Gaussian beam. The design and fabrication of 3D mirror in the Optical microelectromechanical systems (MEMS) are studied. The coupling efficiency is a very important factor in the design of any MEMS circuit. High coupling efficiency is obtained by assembling optical parts which increase the integration effort. In this work, we report a high coupling efficiency, monolithically integrated 3D silicon micromirror that is capable of influencing on the Gaussian beams which propagate in the plane of the silicon substrate. A micromachining method is presented for fabricating the 3D micromirror.
关键词： micromachining,3D silicon micromirrors,optical coupling,MEMS,Gaussian beams
更新于2025-09-23 15:19:57
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Adhesion Behavior between Multilayer Graphene and Semiconductor Substrates
摘要： A high bonding strength between graphene and a semiconductor surface is significant to the performance of graphene-based Micro-Electro Mechanical Systems/Nano-Electro Mechanical Systems (MEMS/NEMS) devices. In this paper, by applying a series of constant vertical upward velocities (Vup) to the topmost layer of graphene, the exfoliation processes of multilayer graphene (one to ten layers) from an Si semiconductor substrate were simulated using the molecular dynamics method, and the bonding strength was calculated. The critical exfoliation velocities, adhesion forces, and adhesion energies to exfoliate graphene were obtained. In a system where the number of graphene layers is two or three, there are two critical exfoliation velocities. Graphene cannot be exfoliated when the Vup is lower than the first critical velocity, although the total number of graphene layers can be exfoliated when the Vup is in the range between the first critical velocity and second critical velocity. Only the topmost layer can be exfoliated to be free from the Si surface if the applied Vup is greater than the second critical velocity. In systems where the number of graphene layers is four to ten, only the topmost layer can be free and exfoliated if the exfoliation velocity is greater than the critical velocity. It was found that a relatively low applied Vup resulted in entire graphene layers peeling off from the substrate. The adhesion forces of one-layer to ten-layer graphene systems were in the range of 25.04 nN–74.75 nN, and the adhesion energy levels were in the range of 73.5 mJ/m2–188.45 mJ/m2. These values are consistent with previous experimental results, indicating a reliable bond strength between graphene and Si semiconductor surfaces.
关键词： adhesion force,bonding mechanism,adhesion energy,exfoliation behavior,MEMS/NEMS,molecular dynamics,graphene
更新于2025-09-23 15:19:57
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Research on Wafer-Level MEMS Packaging with Through-Glass Vias
摘要： A MEMS fabrication process with through-glass vias (TGVs) by laser drilling was presented, and reliability concerns about MEMS packaging with TGV, likes debris and via metallization, were overcome. The via drilling process on Pyrex 7740 glasses was studied using a picosecond laser with a wavelength of 532 nm. TGVs were tapered, the minimum inlet diameter of via holes on 300 μm glasses was 90 μm, and the relative outlet diameter is 48 μm. It took about 9 h and 58 min for drilling 4874 via holes on a four-inch wafer. Debris in ablation was collected only on the laser inlet side, and the outlet side was clean enough for bonding. The glass with TGVs was anodically bonded to silicon structures of MEMS sensors for packaging, electron beam evaporated metal was used to cover the bottom, the side, and the surface of via holes for vertical electrical interconnections. The metal was directly contacted to silicon with low contact resistance. A MEMS gyroscope was made in this way, and the getter was used for vacuum maintenance. The vacuum degree maintained under 1 Pa for more than two years. The proposed MEMS fabrication ?ow with a simple process and low cost is very suitable for mass production in industry.
关键词： through glass via (TGV),laser drilling,MEMS devices,wafer level packaging
更新于2025-09-19 17:15:36
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[IEEE 2018 IEEE SENSORS - New Delhi, India (2018.10.28-2018.10.31)] 2018 IEEE SENSORS - C-MEMS Derived Glassy Carbon Electrodes as Sensitive Electrochemical Biosensors
摘要： Electrochemical biosensors have high potential for application in point of care setting, as they involve simpler measurements compared to optical counterparts and can operate in complex analyte. In this context, carbon electrodes have been widely explored since it is more stable than other metals. Pyrolyzed carbon electrodes have been deployed for protein sensing but the detection limit achieved is not satisfactory, probably due to the selection of the carbon precursor. In this paper, we have prepared glassy carbon electrodes using conventional carbon-microelectromechanical systems (C-MEMS) process. SU-8 photoresist has been used as the carbon precursor. The carbon thin film electrodes have then been tested by cyclic voltammetry measurements in the potential range of -800 mV to 800 mV in presence of 10 mM potassium ferricyanide solution. The samples have been immobilized with anti-Hep-B monoclonal antibody. The presence of antibodies has been further confirmed by UV-VIS spectrophotometry. It has been observed that the current peak reduces distinctly and the fractional change in current magnitude is around 30% and 83% at the potential of 175 mV for 1 fM and 1 pM concentrations respectively. Hence, the presented study is the proof-of concept of sensitive electrochemical detection of Hep-B using functionalized glassy carbon electrodes which when integrated with a low cost microfluidic platform can become suitable for point-of-care diagnostics.
关键词： biosensor,cyclic voltammetry,glassy carbon,C-MEMS,electrochemical sensing,Hep-B
更新于2025-09-19 17:15:36
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[IEEE 2018 IEEE International Ultrasonics Symposium (IUS) - Kobe, Japan (2018.10.22-2018.10.25)] 2018 IEEE International Ultrasonics Symposium (IUS) - High-Volume Production and Non-Destructive Piezo-Property Mapping of 33% SC Doped Aluminium Nitride Thin Films
摘要： Scandium-doped aluminum nitride (ScAlN) thin films with 22% scandium content (Sc0.22Al0.78N) were deposited on a 100-mm sapphire substrate using a sputtering tool. The films exhibit enhanced piezoelectric properties compared to pure AlN, making them promising for microelectromechanical systems (MEMS) applications. The dielectric constant and loss tangent were measured at 100-mm and 20-mm wavelengths, showing values of εr ≈ 11.7 ± 0.2 and tanδ ≈ 0.002 ± 0.001, respectively. These results indicate high potential for voltage manufacturing and sensing devices.
关键词： dielectric properties,piezoelectric,sputtering,ScAlN,thin films,MEMS
更新于2025-09-19 17:15:36
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Qualitative Identification of the Static Pull-In and Fundamental Frequency of One-Electrode MEMS Resonators
摘要： This paper attempts to qualitatively identify the static pull-in position, pull-in voltage, and fundamental frequency of one-electrode microresonators from a physical perspective. During theoretical derivation, a generalized one-degree-of-freedom (1-DOF) model in nondimensional form derived using the differential quadrature method (DQM) is first introduced and then transformed for frequency normalization. Based on the deduced formulas, the upper and lower bounds of the static pull-in position and pull-in voltage are both deduced through mathematical proof. To distinguish the monotonic and nonmonotonic behavior of the fundamental frequency versus direct current (DC) voltage, a critical condition decided only by cubic stiffness is then determined. For the first time, two extreme static positions, as well as the corresponding fundamental frequencies and DC voltages to identify different frequency behaviors are derived, and their variations versus cubic stiffness are then discussed and verified. During the simulation process, a high-order DQM and COMSOL 2D model are both applied for numerical analyses. Guided by nondimensional results, typical behaviors with specific physical parameters are examined in detail. Results demonstrate that the curve tendencies between all the qualitative results and quantitative numerical simulations in dimensional form agree well with each other, implying the possibility of using 1-DOF model to qualitatively discuss physical parameters effects on the system statics and dynamics.
关键词： static pull-in,one-electrode,resonator,fundamental frequency,MEMS
更新于2025-09-19 17:15:36
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Research on a 3D Encapsulation Technique for Capacitive MEMS Sensors Based on Through Silicon Via
摘要： A novel three-dimensional (3D) hermetic packaging technique suitable for capacitive microelectromechanical systems (MEMS) sensors is studied. The composite substrate with through silicon via (TSV) is used as the encapsulation cap fabricated by a glass-in-silicon (GIS) reflow process. In particular, the low-resistivity silicon pillars embedded in the glass cap are designed to serve as the electrical feedthrough and the fixed capacitance plate at the same time to simplify the fabrication process and improve the reliability. The fabrication process and the properties of the encapsulation cap were studied systematically. The resistance of the silicon vertical feedthrough was measured to be as low as 263.5 m?, indicating a good electrical interconnection property. Furthermore, the surface root-mean-square (RMS) roughnesses of glass and silicon were measured to be 1.12 nm and 0.814 nm, respectively, which were small enough for the final wafer bonding process. Anodic bonding between the encapsulation cap and the silicon wafer with sensing structures was conducted in a vacuum to complete the hermetic encapsulation. The proposed packaging scheme was successfully applied to a capacitive gyroscope. The quality factor of the packaged gyroscope achieved above 220,000, which was at least one order of magnitude larger than that of the unpackaged. The validity of the proposed packaging scheme could be verified. Furthermore, the packaging failure was less than 1%, which demonstrated the feasibility and reliability of the technique for high-performance MEMS vacuum packaging.
关键词： vertical interconnect,capacitive,glass reflow,MEMS,3D encapsulation
更新于2025-09-19 17:15:36
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Thermoresistance of <i>p</i> -Type 4H-SiC Integrated MEMS Devices for High-Temperature Sensing
摘要： There is an increasing demand for the development and integration of multifunctional sensing modules into power electronic devices that can operate in high temperature environments. Here, the authors demonstrate the tunable thermoresistance of p-type 4H–SiC for a wide temperature range from the room temperature to above 800 K with integrated flow sensing functionality into a single power electronic chip. The electrical resistance of p-type 4H–SiC is found to exponentially decrease with increasing temperature to a threshold temperature of 536 K. The temperature coefficient of resistance (TCR) shows a large and negative value from (cid:1)2100 to (cid:1)7600 ppm K corresponding to a thermal index of 625 K. From the threshold temperature of 536–846 K, the electrical resistance shows excellent linearity with a positive TCR value of 900 ppm K. The authors successfully demonstrate the integration of p–4H–SiC flow sensing functionality with a high sensitivity of 1.035 μA(m s)^(-0.5) mW^(-1). These insights in the electrical transport of p–4H–SiC aid to improve the performance of p–4H–SiC integrated temperature and flow sensing systems, as well as the design consideration and integration of thermal sensors into 4H–SiC power electronic systems operating at high temperatures of up to 846 K.
关键词： thermoresistance,MEMS sensors,silicon carbide,high temperatures
更新于2025-09-19 17:15:36
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A novel miniature planar gas ionization sensor based on selective growth of ZnO nanowires
摘要： In this study, a novel planar MEMS-based gas ionization sensor based on the field ionization of zinc oxide nanowires is reported. Selective and seedless ZnO nanowires have been grown directly on gold electrodes by low-cost and low-temperature hydrothermal method. Low operating voltage with fast response and recovery times have been achieved for detecting Argon, Helium, Air + %32 RH, Nitrogen, Dry Air, Oxygen, and Carbon dioxide at ambient temperature in atmospheric pressure. Sharp tips of ZnO nanowires reduce the gas breakdown voltage of different gases as shown for Helium and Argon to about 115 V, 85 V respectively due to their local electric field enhancement characteristic. Furthermore, an excellent semi linear response (about 80 V decrease in breakdown voltage) was observed by introducing 250 ppm of NH3 to pure N2 in 4 stages from 0 ppm to 1000 ppm as ammonia gas sensor. In addition, ZnO nanowires protect high conductive Au cathode and anode against sputtering and deformation due to their superior physical, chemical and mechanical properties.
关键词： Nanowire,Planar gas ionization sensor,ZnO,Selective growth,MEMS
更新于2025-09-19 17:15:36