Microelectromechanical structures

Shaw KA, Zhang ZL, MacDonald NC (1994) SCREAM 1 a single mask, single-crystal sihcon, reactive ion etching process for microelectromechanical structures. Sens Actuators 40 63-70... 

Williams P, Papadakis S, Falvo M, Patel A, Sinclair M, Seeger A, Helser A, Taylor R, Washburn S, Superfine R (2002) Controlled placement of an individual carbon nanotube onto a microelectromechanical structure. AppI Phys Lett 80(14) 2574-2576... 

CVD is used to produce microelectromechanical structures (MEMS), very small devices. MEMS technology allows both electrrMiic circuits and mechanical devices to be manufactured on a silicon chip. MEMS structures can be made from silicon wafers with CVD deposits of polycrystalline sUicOTi (polysDicon) films and sacrificial silicon dioxide layers that are later removed by chemical etching [14]. 

As physical structures used in technological applications have been reduced in size, there has been an increasing need to understand the limiting processes of adhesion and to try to minimize them. For example, adhesion due to humidity is known to have a major effect on the durabihty and friction forces experienced at the recording head/disk interface. Microelectromechanical systems (MEMS) are also detrimentally affected by nanoscale adhesion, with their motion being perturbed or prevented. 

Despite the fact that dry etching techniques have improved dramatically in recent decades, the manufacture of microelectromechanical systems (MEMS) is still a domain of wet etching and silicon electrochemistry. The multiplicity of structures that can be achieved with silicon, together with its excellent mechanical properties [Pe6], have led to an immense variety of micromechanical applications. 

MEMS (microelectromechanical systems) are systems with small device sizes of 1-100 pm. They are typically driven by electrical signals. To fabricate such systems materials like semiconductors, metals, and polymers are commonly used. MEMS technology fabrication is very cost-efficient. The structures are transferred by processes, which are applied to many systems on one substrate or even many of them simultaneously. The most important fabrication processes are physical vapor deposition (PVD), chemical vapor deposition (CVD), lithography, wet chemical etching, and dry etching. Typical examples for MEMS are pressure, acceleration, and gyro sensors [28,29], DLPs [30], ink jets [31], compasses [32], and also (bio)medical devices. 

Tang BD, Xie X, Boning DS. Damascene chemical-mechanical polishing characterization and modeling for polysilicon microelectromechanical system structures. J Electrochem Soc 2005 152(7)G582-G587. 

Jiang, L., Anderson, S., Thong, E. Fabrication of Hall device structures in 3C-SiC using microelectromechanical processing technology, Microelectron. Eng., 83(4-9), 1396-1399 (2006). 

Three-dimensional machining (or 3D photopolymerization or stereolithography) gives the possibility to make objects, even with complex forms, for prototyping applications. A laser beam is used for the excitation. Creating 3D microscale structures for microelectromechanical, microoptics and microfluidic applications requires to use high peak power laser pulses allowing a multiphoton (typically two photon) of the photoinitiator at the focal point. 

BeUoy, E., Pawlowski, A. G, Sayah, A., and Gijs, M. A. M., Microfabrication of high-aspect ratio and complex monohthic structures in glass. Journal of Microelectromechanical Systems 11, 521-527, 2002. 

J. Judy, Microelectromechanical systems (MEMS) Fabrication, design and applications. Smart Materials and Structures, 10(6), 1115-1134, 2001. 

C. D. Meinhart and H. Zhang The flow structure inside a microfabricated inkjet printhead. Journal Microelectromechanical Systems, 9(1), 67-75 (2000). 

Microneedles are a type of micromachined structure that promotes the transport of substance through an interface or media, via enhanced permeability or microchannels. In most cases, microneedles are similar in shape to hypodermic needle but are much smaller in size, enabling localized and painless delivery of drugs into cells or tissues. Microneedles, which can be either singular or grouped in arrays, are prepared using microelectromechanical systems (MEMS)... 

Microelectromechanical systems (MEMS) technology has opened up many new opportunities for optics. For the first time, reliable microactuators and three-dimensional optomechanical structures can be monolithically integrated with micro-optical elements. This new technology will impact many applications including display, scanning, and telecommunications. In this paper, we will discuss two MEMS applications optical systems on a chip and monolithic integration of a large array of optomechanical devices. 

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