Microelectromechanical systems | Wikipedia audio article
Micro. Electromechanical, systems. MEMS. Also, written as micro, electromechanical. Micro. Electromechanical, or. Micro, electronic. And micro, electromechanical. Systems. And the related micro, mechatronics. Is the technology, of microscopic. Devices. Particularly, those, with moving, parts it. Merges, at the nano scale into. Nano electromechanical. Systems. An EMS, and nano technology. MEMS. Are also referred, to as micro, machines, in Japan or. Microsystems. Technology. MST. In Europe. MEMS. Are made up of components between, 1, and 100, micrometers. In size ie. 0.001. To, 0.1. Millimeters. And MEMS, devices. Generally. Range in size from 20. Micrometers, to, a millimetre ie. 0.02. To, 1.0. Millimeters, although, components. Arranged, in arrays eg, digital. Micromirror. Devices. Can be more than 1,000, square millimeters. They. Usually consist, of, a central unit that, processes. Data the, microprocessor, and, several, components. That interact, with the surroundings. Such as micro, sensors. Because. Of the large surface area to, volume ratio of. MEMS. Forces. Produced, by ambient. Electromagnetism. Eg. Electrostatic. Charges, and magnetic, moments, and fluid, dynamics eg, surface. Tension, and viscosity are. More important, design, considerations. Than with larger, scale mechanical. Devices. MEMS. Technology is. Distinguished. From molecular. Nanotechnology or. Molecular. Electronics. And that the latter must also consider, surface. Chemistry. The. Potential. Of very small machines, was appreciated. Before the technology, existed. That could make them see for example Richard. Feynman's, famous. 1959. Lectured, there's, room, at the bottom. MEMS. Became, practical. Once they could be fabricated. Using modified. Semiconductor. Device fabrication. Technologies. Normally. Used to make electronics. These. Include, molding, and plating, wet etching Co, T, mah. And dry etching RIE and dry electro. Discharge machining, EDM. And. Other technologies. Capable. Of manufacturing. Small devices, an, early. Example of, the MEMS, device. As the resin astir an electromechanical. Monolithic. Resonator, patented. By Raymond, J Wolfinger. And the resonant, gate transistor. Developed, by Harvey, C Nathanson's. Topic. Materials. For, MEMS. Manufacturing. The, fabrication. Of MEMS, evolved. From the processed technology. In semiconductor. Device fabrication ie. The, basic, techniques, are deposition. Of material layers. Patterning. By photolithography. And, etching to produce the required shapes. Topic. Silicon. You. Silicon, as the material, used to create most integrated, circuits, used in consumer, electronics in. The modern industry. The. Economies. Of scale, ready, availability. Of inexpensive high. Quality, materials. And ability. To incorporate electronic. Functionality. Make silicon, attractive. For a wide variety, of MEMS, applications. Silicon. Also has significant. Advantages, engendered. Through its material. Properties. In single. Crystal form, silicon. Is an almost perfect Hokkien. Material, meaning that when it is flexed, there is virtually, no, hysteresis, and, hence almost, no energy dissipation. As, well. As making for highly repeatable, motion, this also makes silicon. Very reliable. As it suffers, very little fatigue, and can have service, lifetimes, in the range of billions, to trillions of. Cycles, without breaking. Topic. Polymers. Even. Though the electronics. Industry provides. An economy, of scale for the silicon, industry, crystalline. Silicon, is still a complex, and relatively, expensive, material. To produce. Polymers. On the other hand, can be produced, in huge volumes, with a great variety of, material.
Characteristics. MEMS. Devices, can, be made from polymers, by processes. Such as injection, molding, embossing. Or stereo, lithography and. Are especially, well suited to, microfluidic. Applications. Such as disposable. Blood-testing. Cartridges. Topic. Metals. Metals. Can also be used to create MEMS. Elements. While. Metals, do not have some of the advantages. Displayed, by silicon, in terms of mechanical, properties when, used within their limitations. Metals, can exhibit, very high degrees. Of reliability. Metals. Can be deposited by, electroplating. Evaporation. And sputtering. Processes. Commonly. Used metals, include, gold nickel. Aluminium. Copper, chromium. Titanium, tungsten. Platinum. And silver. Topic. Ceramics. The, nitrides, of silicon, aluminium and. Titanium as. Well as silicon, carbide. And other ceramics. Are increasingly. Applied, in MEMS, fabrication due. To advantageous. Combinations. Of material. Properties. Aln. Crystallizes. In the word site structure, and thus shows, pyroelectric. And piezoelectric. Properties. Enabling, sensors, for instance, with sensitivity. To normal, and shear forces. Tin. On the other hand, exhibits. A high electrical. Conductivity and, large elastic. Modulus, making, it possible, to implement. Electrostatic. MEMS. Actuation. Schemes, with ultra thin membranes. Moreover. The, high resistance. Of 10 against, bio corrosion. Qualifies. The material, for applications. In biogenic. Environments. And in biosensors. Topic. MEMS. Basic. Processes. Topic. Deposition. Processes. One, of the basic building blocks, in MEMS. Processing. Is the ability to deposit, thin, films, of material. With a thickness anywhere, between one, micrometer, to about 100. Micrometers. The. Nem, s process. Is the same although, the measurement, of film deposition, ranges. From a few nanometers to, one micrometer. There. Are two types of deposition. Processes, as follows. Topic. Physical. Deposition. Physical. Vapor deposition. PVD. Consists. Of a process, in which a material, is removed from a target, and deposited. On a surface. Techniques. To do this include, the process, of sputtering, in which an ion beam liberates, atoms, from a target, allowing them to move through the intervening, space, and deposit. On the desired, substrate. And evaporation. In which a material, is evaporated. From a target, using, either heat thermal, evaporation or. An electron, beam EB move apparation. In a vacuum system. Topic. Chemical. Deposition. Chemical. Deposition techniques. Include, chemical, vapor deposition. CVD. In. Which, a stream of source gas reacts. On the substrate, to grow the material. Desired. This. Can be further divided. Into categories. Depending on the details of the technique, for example, lpcvd. Low. Pressure chemical, vapor deposition and. Pecvd. Plasma. Enhanced chemical, vapour, deposition. Oxide. Films, can also be grown by the technique, of thermal, oxidation, in which the typically, silicon. Wafer, is exposed, to oxygen and/or steam to grow a thin surface layer of silicon. Dioxide. Topic. Patterning. Patterning. In MEMS as. The transfer, of a pattern, into a material. Topic. Lithography. You. Lithography. And MEMS, context. As typically, the transfer, of a pattern, into a photosensitive. Material by. Selective, exposure to, a radiation. Source such as light a. Photosensitive. Material as. A material. That experiences. A change in, its physical properties when, exposed, to a radiation. Source if a. Photosensitive. Material is. Selectively, exposed, to radiation eg. By masking, some of the radiation the pattern of the radiation, on the material, is transferred. To the material, exposed, as the properties, of the exposed, and unexposed regions. Differs. This. Exposed, region, can then be removed or, treated providing, a mask for the underlying, substrate. Photolithography. Is, typically, used with metal or other thin, film deposition wet. And dry etching.
Sometimes. Photolithography. Is, used to create structure. Without any kind of post itching. One. Example, as su-8, based lens where su-8, based square, blocks are generated. Then. The photoresist. Has melted, to form a semi, spear, which acts as a lens. Topic. Electron, beam lithography, electron. Beam lithography, often. Abbreviated, as a beam lithography is. The practice, of scanning a beam of electrons in. A patterned, fashion, across a surface, covered, with a film called the resist, exposing. The resist, and of selectively, removing, either exposed. Or non exposed, regions, of the resist, developing. The. Purpose, as with, photo lithography is. To create very small structures. In the resist, that can subsequently, be transferred. To the substrate, material often. By etching, it. Was developed, for manufacturing. Integrated. Circuits, and is also used for, creating. Nanotechnology. Architectures. The, primary. Advantage, of electron, beam lithography is. That it is one of the ways to beat the diffraction, limit of, and make features, in the nanometer, range, this. Form, of maskless, lithography has. Found wide usage in photo mask making, used, in photo lithography low, volume production of semiconductor. Components and, research, and development, the. Key limitation. Of electron, beam lithography as. Throughput ie the, very long time it takes to expose, an entire, silicon. Wafer, or glass substrate. A long. Exposure, time, leaves, the user vulnerable. To beam drift, or instability. Which may occur during the exposure. Also. The turnaround, time for reworking or, redesign. As lengthened. Unnecessarily. If the pattern, is not being, changed the second, time. Topic. Ion. Beam lithography. It is known that focused. Ion beam, lithography has, the capability. Of writing, extremely. Fine lines less, than 50, nanometers line. And space has been achieved, without proximity. Effect. However. Because, the writing field, in ion beam lithography is. Quite small large, area, patterns, must, be created, by stitching together the small fields. Topic. I on, track, technology. I. On. Track technology. As a deep cutting tool with a resolution, limit, around 8 nanometers, applicable. To radiation, resistant, minerals, glasses. And polymers. It. Is capable of generating holes. In thin films, without any development. Process. Structural. Depth can be defined, either by ion range or by material. Thickness. Aspect. Ratios, up to several, 104. Can be reached the. Technique, can shape and texture materials. At a defined, inclination, angle. Random. Pattern, single. Ion tracks structures, and aimed pattern, consisting. Of individual. Single tracks, can be generated. Topic. X-ray. Lithography. X-ray. Lithography as. A process. Used in electronic. Industry to, selectively, remove, parts, of a thin film it. Uses. X-rays, to transfer, a geometric. Pattern from a mask to a light-sensitive, chemical. Photoresist. Or simply. Resist. On the, substrate. A series. Of chemical treatments. Then engraves, the produced, pattern, into the material, underneath, the photoresist. Topic. Diamond. Patterning. A simple. Way to carve, or create patterns, on the surface of nanodiamonds. Without damaging. Them could lead to a new photonic. Devices diamond. Patterning, as a method, of forming diamond MEMS. It. Is achieved, by the lithographic. Application. Of diamond films, to a substrate, such as silicon. The. Patterns, can be formed, by selectively, deposition. Through a silicon, dioxide mask. Or by deposition, followed. By micromachining. Or focused, ion beam, milling. Topic. Itching. Processes. There, are two basic, categories of, itching processes.
Wet Etching and dry etching in, the. Former, the material. As dissolved, when immersed in a chemical, solution in. The. Latter the material. Is sputtered, or dissolved, using, reactive, ions, or a vapor phase etchant. Topic. Wet, @ chain. Wet, chemical etching, consists. In selective, removal of material by, dipping a substrate, into a solution, that dissolves, it the. Chemical, nature of this etching process. Provides, a good selectivity, which, means the etching, rate of the target, material is, considerably. Higher than the mask material if, selected carefully. Topic. Isotropic. Etching. Edging. Progresses. At the same speed, in all directions. Long. And narrow holes, in a mask will produce v-shaped. Grooves, in the silicon. The. Surface, of these grooves, can, be atomically, smooth, if the etch is carried, out correctly, with dimensions. And angles, being extremely, accurate. Topic. Anisotropic. Etching, some single, crystal, materials, such, as silicon. Will have different edging, rates depending. On the crystallographic. Orientation. Of the substrate. This. Is known as anisotropic. Etching, and one of the most common, examples as, the etching, of silicon, in Koh potassium. Hydroxide, where. Seaplanes etch, approximately. 100, times slower, than other planes. Crystallographic. Orientations. Therefore. Edging, a rectangular hole. In a 100. C wafer, results, in a pyramid-shaped edge pit with 54, point seven, degrees walls. Instead. Of a hole with curved sidewalls, as with isotropic, etching. Topic. Hf--. Chain. Hydrofluoric. Acid as, commonly, used as an aqueous acient, for silicon, dioxide. Silicon. Oxide, also known as box, for SOI, usually. In, 49%, concentrated. Form 5 to 1 10, to 1 or 20 to 1 bill buffered, oxide etching, or bhf, buffered, HF, they. Were first, used in medieval times for. Glass etching, it, was used in IC, fabrication for. Patterning, the gate oxide until. The process step was replaced, by RIE. Hydrofluoric. Acid as considered, one of the more dangerous acids. In the cleanroom, it. Penetrates. The skin upon, contact, and it diffuses, straight to the bone. Therefore. The damage, has not felt until, it is too late. Topic. Electrochemical. Etching. Electrochemical. Etching easiiy. For, dopant selective, removal of, silicon, as a common, method to automate, and to selectively, control, a chain an, active. PN, diode, Junction, as required, and either type of dopant, can be the etch resistant. Edge stop. Material. Boron. As the most common, edge stop dopant, in, combination. With wet anisotropic. Etching, as described, above ECE. Has, been used successfully for. Controlling, silicon. Diaphragm thickness. In commercial, piece or resistive, silicon, pressure sensors. Selectively. Doped, regions, can be created. Either by implantation. Diffusion. Or epitaxial. Deposition. Of silicon. Topic. Dry, at chain. Topic. Vapour itching. Topic. Xenon. Difluoride. Xenon. Difluoride, xenon. Difluoride is. A dry vapor phase, isotropic. Etch for silicon, originally. Applied for MEMS in. 1995. At university. Of california, los angeles. Primarily. Used for releasing, metal, and dielectric, structures. By undercutting, silicon. Xenon. Difluoride has. The advantage, of a stiction free, release, unlike, wet etchants, it's. Etched selectivity. To silicon, is very high, allowing. It to work with photoresist. Silicon. Oxide, silicon. Nitride, and various. Metals, for masking. Its. Reaction. To silicon, as plasma. Less is, purely. Chemical and, spontaneous. And is often operated. In pulsed, mode. Models. Of the etching action. Are available. In university. Laboratories. And various, commercial, tools offer solutions, using, this approach. Topic. Plasma. At chain. Modern. VLSI. Processes. Avoid wet etching and use plasma, etching instead. Plasma. Etch is can operate, in several modes by adjusting, the parameters of the plasma. Ordinary. Plasma. Etching operates. Between. 0.1. And five Torr, this unit, of pressure commonly. Used in vacuum engineering. Equals, approximately. 133. Point 3 Pascal's, the plasma, produces, energetic. Free radicals, neutrally. Charged, that react, at the surface, of the wafer. Since. Neutral, particles, attack, the wafer, from all angles this process, is isotropic. Plasma. Etching can, be isotropic, ie. Exhibiting. A lateral, undercut, rate on a patterned, surface, approximately. The same as its downward edge rate or can be anisotropic.
Ie, Exhibiting. A smaller lateral, undercut, rate than its downward edge rate. Such. An isotropy, has maximized. In deep reactive ion etching, the. Use of the term and I sought repiy for plasma etching should, not be conflated. With the use of the same term when. Referring to orientation. Dependent. Etching. The. Source gas for the plasma usually. Contains, small, molecules. Rich, in chlorine or fluorine. For. Instance, carbon, tetrachloride, carbon. Tetrachloride, h's. Silicon, and aluminium and, tri fluoro methane, h's silicon, dioxide and, silicon. Nitride, a, plasma. Containing, oxygen is, used to oxidize ash. Photoresist. And facilitate. Its removal. Ion, milling or sputter, etching, uses, lower pressures, often, as low as 10 -4, tor 10 Mille Pascal's. It. Bombards the, wafer, with energetic, ions, of noble, gases often. Our Plus which, knock atoms, from the substrate, by transferring, momentum. Because. The etching, is performed. By ions, which approach, the wafer, approximately. From one direction this, process, is highly anisotropic, on. The. Other hand, it tends, to display, poor selectivity. Reactive. Ion etching RIE, operates. Under conditions. Intermediate. Between sputter. And plasma, etching between. 10 to 3, and 10 - 1 Torr. Deep. Reactive ion etching, dry. Modifies. The right technique, to produce deep, narrow features. Topic. Sputtering. Topic. Reactive. Ion etching Rai. In reactive. Ion etching RIE, the substrate, is placed inside, a reactor, and several, gases are introduced, a. Plasma. Is struck in the gas mixture using. An RF, power source, which breaks the gas molecules. Into, ions, the. Ions, accelerate. Towards, and react, with the surface of the material, being etched forming, another gaseous. Material, this. Is known as the, chemical, part of reactive, ion etching, there. Is also a physical, part which is similar, to the sputtering, deposition. Process, if the. Ions, have high enough energy, they can knock atoms, out of the material, to be etched without, a chemical, reaction it, is. A very complex, task to, develop dry, etch processes. That balance, chemical, and physical etching, since, there are many parameters to, adjust. By. Changing, the balance it is possible, to influence, the anisotropy. Of the etching since, the chemical part is isotropic, and, the physical, part highly, anisotropic the. Combination. Can form side walls that have shapes from rounded, to vertical. Deep. Rai dry, is a special. Subclass, of RIE that is growing in popularity in. This. Process, each depths. Of hundreds, of micrometers, are, achieved, with almost vertical, sidewalls. The. Primary, technology. Is based on the so called Bosch. Process. Named. After the German, company Robert. Bosch which, filed the original patent, where two different, gas compositions. Alternate, in the reactor. Currently. There are two variations, of, the DRI the. First variation. Consists. Of three distinct, steps the original, Bosch process, while the second, variation only, consists, of two steps in. The. First variation, the, etch cycle, as as follows, I. Sf6. Isotropic. Etch. Ec4. F/8, passivation. Ii. Sf6. Anisotropic. Etch, for floor cleaning in. The. Second, variation steps. I and II are combined. Both. Variations, operate. Similarly, the, c4, f8, creates, a polymer, on the surface, of the substrate, and the second, gas composition. Sf6. And Oh two H's. The substrate. The. Polymer, has immediately, sputtered, away by the physical, part of the etching but, only on the horizontal. Surfaces. And not the sidewalls. Since. The polymer, only dissolves, very slowly. In the chemical, part of the etching it builds, up on the sidewalls, and protects, them from etching, as a. Result, edging, aspect, ratios, of 50, to 1 can be achieved, the. Process, can easily, be used to etch completely. Through a silicon, substrate and, etch rates are three to six times higher, than wet etching. Topic. Thy, preparation. After. Preparing, a large number of MEMS. Devices, on, a silicon. Wafer, individual. Dyes have, to be separated, which is called dye preparation.
In Semiconductor. Technology. For. Some applications. The separation. Is preceded, by wafer. Back grinding, in order to reduce the wafer, thickness. Wafer. Dicing may, then be performed either, by sawing, using, a cooling, liquid or a dry laser process. Called stealth, dicing. Topic. MEMS. Manufacturing. Technologies. Topic. Bulk, micromachining. Bulk. Micromachining, is. The oldest, paradigm, of silicon based MEMS. The. Whole thickness of a silicon, wafer is, used for building the micro mechanical. Structures. Silicon. Is machined, using various, edging, processes. Anodic. Bonding of, glass plates, or additional, silicon, wafers, is used for adding features in the third dimension and, for hermetic, encapsulation. Bulk. Micromachining, has. Been essential, in enabling, high performance. Pressure sensors. And accelerometers that. Changed, the sensor, industry, in the 1980s, and, 90s. Topic. Surface. Micromachining. Surface. Micromachining. Uses, layers deposited. On the surface of a substrate, as the structural, materials. Rather, than using the substrate. Itself. Surface. Micromachining. Was created, in the late 1980s. To render micromachining. Of silicon, more compatible, with planar, integrated. Circuit, technology with. The goal of combining. MEMS. And integrated. Circuits, on the same silicon, wafer. The. Original, surface, micromachining. Concept. Was based on thin, polycrystalline. Silicon, layers patterned. As movable mechanical. Structures, and released by sacrificial. Edging of the underlying, oxide, layer. Interdigital. Comb electrodes. Were used to produce in-plane. Forces. And to detect in plane movement capacitively. This. MEMS. Paradigm. Has enabled the manufacturing. Of low-cost. Accelerometers. For eg, automotive. Airbag systems. And other applications. Where low performance. And/or high G ranges, are sufficient. Analog. Devices, has, pioneered, the, industrialization. Of surface, micromachining. And has realized, the cointegration, of. MEMS, and, integrated. Circuits. Topic. High, aspect. Ratio par. Silicon. Micromachining. Bulk and surface silicon. Micromachining, are. Used in the industrial, production of, sensors, inkjet. Nozzles, and other devices. But. In many cases the, distinction, between these, two has diminished, a new. Etching, technology. Deep reactive ion, etching, has, made it possible to combine good, performance. Typical, of bulk micromachining, with. Comb structures. And in-plane operation. Typical, of surface, micromachining. While. It is common in surface, micromachining. To have structural, layer thickness, in the range of 2 micrometers, in harsh, silicon, micromachining, the. Thickness, can be from 10 to 100 micrometers. The. Materials. Commonly, used, in harsh silicon, micromachining, are, thick polycrystalline. Silicon, known, as epi poly, and bonded, silicon, on insulator SOI. Wafers. Although, processes. For bulk silicon, wafer, also, have been created, scream. Bonding. A second, wafer, by glass frit bonding, anodic. Bonding or. Alloy, bonding, is used to protect the MEMS, structures. Integrated. Circuits, are typically, not combined, with har silicon, micromachining. Topic. Applications. Some. Common, commercial, applications. Of MEMS, include. Inkjet. Printers, which use, piezoelectrics. Or thermal, bubble ejection, to deposit ink, on paper. Accelerometers. In modern, cars for, a large number of purposes including. Airbag, deployment, and, electronic. Stability control. Inertial. Measurement, units, Imus, MEMS. Accelerometers. And MEMS. Gyroscopes. In remote controlled, or autonomous. Helicopters. Planes, and multirotors. Also, known as drones used, for automatically. Sensing, and balancing, flying characteristics. Of, roll pitch, and yaw. MEMS. Magnetic. Field sensor. Magnetometer. May also be incorporated, in such devices, to provide directional. Heading.
MEMS. Are also used, in inertial, navigation systems. I and SS, of modern, cars airplanes. Submarines. And other vehicles, to detect, yaw pitch, and roll. For example, the autopilot, of an airplane. Accelerometers. In consumer. Electronics devices. Such, as game, controllers. Nintendo. Wii personal. Media players, cellphones, virtually. All smartphones, various. HTC. PDA, models. And a number of digital cameras. Various, Canon digital ixus models. Also. Used, in PCs to park the hard-disk head, when freefall, is detected, to prevent, damage, and data loss. MEMS. Microphones, in, portable, devices, eg. Mobile. Phones headsets. And laptops. The. Market, for smart microphones. Includes, smartphones, wearable. Devices smart. Home and automotive, applications. Silicon. Pressure, sensors. Eg, car, tyre pressure, sensors, and disposable. Blood, pressure sensors. Displays. Eg. The digital, micromirror. Device, DMD. Chip, in a projector, based on DLP. Technology which. Has a surface, with, several, hundred thousand. Micro, mirrors or single, micro, scanning, mirrors also called, micro, scanners. Optical. Switching, technology. Which, is used for switching, technology. And alignment, for data communications. Bio. MEMS applications. In. Medical, and health related technologies. From lab on chip to, micro total analysis, bio sensor chemo, sensor, or embedded. In medical, devices, eg, stents. Interferometric. Modulator, display, iMod. Applications. In consumer. Electronics. Primarily. Displays, for mobile devices used. To create. Interferometric. Modulation. -, reflective. Display, technology. As found in Mirasol, displays. Fluid. Acceleration. Such as for micro, cooling. Micro. Scale energy harvesting. Including. Piezoelectric. Electrostatic. And electromagnetic. Micro. Harvesters. Micromachined. Ultrasound. Transducers. Topic, industry, structure the global, market, for micro, electromechanical. Systems. Which, includes, products. Such as automobile. Airbag, systems, display, systems, and inkjet cartridges. Totaled 40 billion dollars in, 2006. According to global MEMS. Microsystems. Markets, and opportunities, a research, report from, semi, and yeol development. And is forecasted. To reach 72. Billion, dollars, by 2011, companies. With strong MEMS. Programs, come, in many sizes. Larger. Firms specialize. In manufacturing. High-volume. Inexpensive. Components, or packaged, solutions for. End markets, such as automobiles. Biomedical. And electronics. Smaller. Firms, provide, value, and innovative. Solutions and, absorb, the expense, of custom, fabrication with.
High Sales margins. Both. Large, and small companies, typically. Invest, in R&D to, explore, new MEMS. Technology. The. Market, for materials, and equipment, used to manufacture. MEMS. Devices, topped, 1 billion dollars, worldwide in. 2006. Materials. Demand, is driven by substrates. Making, up over 70%. Of the market, packaging, coatings, and increasing, use of chemical. Mechanical planarization. CMP. While. MEMS. Manufacturing. Continues to be dominated, by used, semiconductor. Equipment there, is a migration, to 200, millimetres, lines and, select new tools including. Etch and bonding, for certain, MEMS. Applications. Topic. See, also. Brain, computer, interface. Cantilever. One of the most common, forms of MEMS. Electrostatic. Motors. Used, where coils, are difficult, to fabricate. Kelvin. Probe force microscope. MEMS. Sensor, generations. MEMS. Thermal, actuator. MEMS. Actuation. Created, by thermal, expansion. Micro. Opto, electromechanical. Systems. M OEMs. MEMS. Including. Optical, elements. Merle. Dust millimeter. Sized devices. Operated. As wirelessly. Powered nerve, sensors. Photo. Electoral, wedding MEMS. Optical. Actuation. Using, photo sensitive. Wedding. Micro. Power hydrogen. Generators. Gas turbines, and electrical. Generators. Made of etched silicon. Millipede. Memory, MEMS. Technology for. Non-volatile. Data storage. Of more than a terabit, per square, inch. Nano. Electromechanical. Systems. Are similar to MEMS. But smaller. Scratch. Drive actuator. MEMS. Actuation. Using, repeatedly. Applied, voltage, differences.