Part I: Background and Fundamentals Introduction, Mohamed Gad-el-Hak, University of Notre Dame Scaling of Micromechanical Devices, William Trimmer, Standard MEMS, Inc., and Robert H. Stroud, Aerospace Corporation Mechanical Properties of MEMS Materials, William N. Sharpe, Jr., Johns Hopkins University Flow Physics, Mohamed Gad-el-Hak, University of Notre Dame Integrated Simulation for MEMS: Coupling Flow-Structure-Thermal-Electrical Domains, Robert M. Kirby and George Em Karniadakis, Brown University, and Oleg Mikulchenko and Kartikeya Mayaram, Oregon State University Liquid Flows in Microchannels, Kendra V. Sharp and Ronald J. Adrian, University of Illinois at Urbana-Champaign, Juan G. Santiago and Joshua I. Molho, Stanford University Burnett Simulations of Flows in Microdevices, Ramesh K. Agarwal and Keon-Young Yun, Wichita State University Molecular-Based Microfluidic Simulation Models, Ali Beskok, Texas A&M University Lubrication in MEMS, Kenneth S. Breuer, Brown University Physics of Thin Liquid Films, Alexander Oron, Technion, Israel Bubble/Drop Transport in Microchannels, Hsueh-Chia Chang, University of Notre Dame Fundamentals of Control Theory, Bill Goodwine, University of Notre Dame Model-Based Flow Control for Distributed Architectures, Thomas R. Bewley, University of California, San Diego Soft Computing in Control, Mihir Sen and Bill Goodwine, University of Notre Dame Part II: Design and Fabrication Materials for Microelectromechanical Systems Christian A. Zorman and Mehran Mehregany, Case Western Reserve University MEMS Fabrication, Marc J. Madou, Nanogen, Inc. LIGA and Other Replication Techniques, Marc J. Madou, Nanogen, Inc. X-Ray-Based Fabrication, Todd Christenson, Sandia National Laboratories Electrochemical Fabrication (EFAB), Adam L. Cohen, MEMGen Corporation Fabrication and Characterization of Single-Crystal Silicon Carbide MEMS, Robert S. Okojie, NASA Glenn Research Center Deep Reactive Ion Etching for Bulk Micromachining of Silicon Carbide, Glenn M. Beheim, NASA Glenn Research Center Microfabricated Chemical Sensors for Aerospace Applications, Gary W. Hunter, NASA Glenn Research Center, Chung-Chiun Liu, Case Western Reserve University, and Darby B. Makel, Makel Engineering, Inc. Packaging of Harsh-Environment MEMS Devices, Liang-Yu Chen and Jih-Fen Lei, NASA Glenn Research Center Part III: Applications of MEMS Inertial Sensors, Paul L. Bergstrom, Michigan Technological University, and Gary G. Li, OMM, Inc. Micromachined Pressure Sensors, Jae-Sung Park, Chester Wilson, and Yogesh B. Gianchandani, University of Wisconsin-Madison Sensors and Actuators for Turbulent Flows. Lennart Loefdahl, Chalmers University of Technology, and Mohamed Gad-el-Hak, University of Notre Dame Surface-Micromachined Mechanisms, Andrew D. Oliver and David W. Plummer, Sandia National Laboratories Microrobotics Thorbjoern Ebefors and Goeran Stemme, Royal Institute of Technology, Sweden Microscale Vacuum Pumps, E. Phillip Muntz, University of Southern California, and Stephen E. Vargo, SiWave, Inc. Microdroplet Generators. Fan-Gang Tseng, National Tsing Hua University, Taiwan Micro Heat Pipes and Micro Heat Spreaders, G. P. "Bud" Peterson, Rensselaer Polytechnic Institute Microchannel Heat Sinks, Yitshak Zohar, Hong Kong University of Science and Technology Flow Control, Mohamed Gad-el-Hak, University of Notre Dame) Part IV: The Future Reactive Control for Skin-Friction Reduction, Haecheon Choi, Seoul National University Towards MEMS Autonomous Control of Free-Shear Flows, Ahmed Naguib, Michigan State University Fabrication Technologies for Nanoelectromechanical Systems, Gary H. Bernstein, Holly V. Goodson, and Gregory L. Snider, University of Notre Dame Index

The MEMS Handbook

This review gives a brief overview of microvalves, and focuses on the actuation mechanisms and their applications. One of the stumbling blocks for successful miniaturization and commercialization of fully integrated microfluidic systems was the development of reliable microvalves. Applications of the microvalves include flow regulation, on/off switching and sealing of liquids, gases or vacuums. Microvalves have been developed in the form of active or passive microvalves employing mechanical, non-mechanical and external systems. Even though great progress has been made during the last 20 years, there is plenty of room for further improving the performance of existing microvalves.

http://iopscience.iop.org/article/10.1088/0960-1317/16/5/R01/pdf

A review of microvalves

Piezoresistive sensors are among the earliest micromachined silicon devices. The need for smaller, less expensive, higher performance sensors helped drive early micromachining technology, a precursor to microsystems or microelectromechanical systems (MEMS). The effect of stress on doped silicon and germanium has been known since the work of Smith at Bell Laboratories in 1954. Since then, researchers have extensively reported on microscale, piezoresistive strain gauges, pressure sensors, accelerometers, and cantilever force/displacement sensors, including many commercially successful devices. In this paper, we review the history of piezoresistance, its physics and related fabrication techniques. We also discuss electrical noise in piezoresistors, device examples and design considerations, and alternative materials. This paper provides a comprehensive overview of integrated piezoresistor technology with an introduction to the physics of piezoresistivity, process and material selection and design guidance useful to researchers and device engineers.

/pdf/review-semiconductor-piezoresistance-for-microsystems-2i2jehwa4g.pdf

Review: Semiconductor Piezoresistance for Microsystems

3D printing technology can produce complex objects directly from computer aided digital designs. The technology has traditionally been used by large companies to produce fit and form concept prototypes (‘rapid prototyping’) before production. In recent years however there has been a move to adopt the technology as full-scale manufacturing solution. The advent of low-cost, desktop 3D printers such as the RepRap and Fab@Home has meant a wider user base are now able to have access to desktop manufacturing platforms enabling them to produce highly customised products for personal use and sale. This uptake in usage has been coupled with a demand for printing technology and materials able to print functional elements such as electronic sensors. Here we present formulation of a simple conductive thermoplastic composite we term ‘carbomorph’ and demonstrate how it can be used in an unmodified low-cost 3D printer to print electronic sensors able to sense mechanical flexing and capacitance changes. We show how this capability can be used to produce custom sensing devices and user interface devices along with printed objects with embedded sensing capability. This advance in low-cost 3D printing with offer a new paradigm in the 3D printing field with printed sensors and electronics embedded inside 3D printed objects in a single build process without requiring complex or expensive materials incorporating additives such as carbon nanotubes.

/pdf/a-simple-low-cost-conductive-composite-material-for-3d-1ptnzs3ir8.pdf

A Simple, Low-Cost Conductive Composite Material for 3D Printing of Electronic Sensors

Microfluidics is an emerging field that has given rise to a large number of scientific and technological developments over the last few years. This review reports on the use of various materials, such as silicon, glass and polymers, and their related technologies for the manufacturing of simple microchannels and complex systems. It also presents the main application fields concerned with the different technologies and the most significant results reported by academic and industrial teams. Finally, it demonstrates the advantage of developing approaches for associating polymer technologies for manufacturing of fluidic elements with integration of active or sensitive elements, particularly silicon devices.

https://iopscience.iop.org/article/10.1088/0960-1317/17/5/R01/pdf

Lab-on-chip technologies: making a microfluidic network and coupling it into a complete microsystem : a review

Microactuators and their technologies

Polycrystalline Si (poly-Si) has found various applications in microelectronics and micromechanical devices such as pressure sensors, accelerometers and actuators. Poly-Si films deposited on an oxidized Si substrate can combine the excellent mechanical properties of Si with the efficient electrical insulation of poly-Si piezoresistors, so that improved stability and high-temperature operation can be obtained. Different poly-Si fabrication techniques are reviewed with emphasis on their applications to pressure sensors. The theoretical interpretation and models of the piezoresistivity in poly-Si and experimental results are presented. The calculation of the longitudinal and transverse gauge factors and their correlation with the crystallographic structure of the poly-Si film are discussed. The possibility of sensor performance optimization including mechanical, temperature and piezoresistive properties of a device is demonstrated. Two examples of commercially manufactured poly-Si sensors and an example of a new poly-Si technology are also presented.

Piezoresistive pressure sensors based on polycrystalline silicon

Important characteristics of boron-doped LPCVD polysilicon layers with regard to sensor applications are presented. Properties such as the resistivity, temperature coefficient of the resistance, gauge factor and long-term stability are described. A pressure sensor utilizing polysilicon piezoresistors with a measurement range of 1 bar and a sensitivity of roughly 11 mV/V FS, a laser-trimmed polysilicon temperature sensor with a sensitivity of −3.4 × 10 −3 K −1 and non-linearity of less than 0.5% and a pressure sensor with polysilicon-based on-chip calibration and temperature compensation are described.

Polysilicon as a material for microsensor applications

The measurement of wall pressure and wall pressure fluctuations in fluid mechanics is of great importance for the investigation of turbulent flow phenomena. This paper is focused on the design, fabrication and test of a micro electromechanical system (MEMS) pressure sensor array for high-resolution wall pressure measurements in turbulent flows. In contrast to pressure sensor arrays in literature this array is highly sensitive and can be flush mounted on top of a cylinder without using pin holes and flexible tubes. Employing silicon-on-insulator (SOI) technology and deep silicon etching the sensors developed achieve a pressure resolution of 0.5 Pa. Three different types of sensors, featuring a diaphragm thickness of 3 μm and diaphragm sizes of 500 μm, 700 μm, and 900 μm (square diaphragm), have been fabricated and characterized. Simulation of the dynamic behavior yields resonance frequencies of 50 kHz (900 μm-diaphragm), 82 kHz (700 μm-diaphragm), and 160 kHz (500 μm-diaphragm). Sensitivities of 12 μV/(VPa) (900 μm-sensor), 7 μV/(VPa) (700 μm-sensor), and 3 μV/(VPa) (500 μm-sensor) are obtained in measurement ranges of ±200 Pa, ±500 Pa, and ±1 kPa, respectively, featuring a non-linearity of less than 1%. The array was flush mounted on a cylinder (radius 60 mm, height 240 mm) and tested in a wind tunnel.

AeroMEMS sensor array for high-resolution wall pressure measurements

An electrothermal ink jet print head is constructed in layer structure, wherein the expansion direction of the ink vapor bubble is directed opposite to the ink-ejection direction. Each ink channel (16) of the ink jet print head is supplied with ink by flow throttles for a highest degree of effectiveness. For this purpose, a cover plate (1) is furnished with openings (2). The openings (2) join into an ink storage container. The openings (2) are connected with recess openings (25) to the ink channel (16) in the chip (11). Selectively, the recess openings (25) can be furnished in the chip (11) or in the cover plate (1). A method is provided for producing the recess openings (25).

Ernst Obermeier

Papers

Microactuators and their technologies

Piezoresistive pressure sensors based on polycrystalline silicon

Polysilicon as a material for microsensor applications

AeroMEMS sensor array for high-resolution wall pressure measurements

System for an electrothermal ink jet print head