Single-crystal silicon is being increasingly employed in a variety of new commercial products not because of its well-established electronic properties, but rather because of its excellent mechanical properties. In addition, recent trends in the engineering literature indicate a growing interest in the use of silicon as a mechanical material with the ultimate goal of developing a broad range of inexpensive, batch-fabricated, high-performance sensors and transducers which are easily interfaced with the rapidly proliferating microprocessor. This review describes the advantages of employing silicon as a mechanical material, the relevant mechanical characteristics of silicon, and the processing techniques which are specific to micromechanical structures. Finally, the potentials of this new technology are illustrated by numerous detailed examples from the literature. It is clear that silicon will continue to be aggressively exploited in a wide variety of mechanical applications complementary to its traditional role as an electronic material. Furthermore, these multidisciplinary uses of silicon will significantly alter the way we think about all types of miniature mechanical devices and components.

Silicon as a mechanical material

We survey progress over the past 25 years in the development of microscale devices for pumping fluids. We attempt to provide both a reference for micropump researchers and a resource for those outside the field who wish to identify the best micropump for a particular application. Reciprocating displacement micropumps have been the subject of extensive research in both academia and the private sector and have been produced with a wide range of actuators, valve configurations and materials. Aperiodic displacement micropumps based on mechanisms such as localized phase change have been shown to be suitable for specialized applications. Electroosmotic micropumps exhibit favorable scaling and are promising for a variety of applications requiring high flow rates and pressures. Dynamic micropumps based on electrohydrodynamic and magnetohydrodynamic effects have also been developed. Much progress has been made, but with micropumps suitable for important applications still not available, this remains a fertile area for future research.

https://microfluidics.stanford.edu/Publications/Micropumps_Cooling/Laser%20Review%20of%20Micropumps%20in%20JMM.pdf

A review of micropumps

An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.

Semiconductor device, and manufacturing method thereof

http://nathan.instras.com/documentDB/paper-69.pdf

Porous silicon: a quantum sponge structure for silicon based optoelectronics

An electrostatically deflectable beam spatial light modulator with the beams (30), address electrodes (42, 46), and landing electrodes (40, 41) to provide soft-landing of the beams on the landing electrodes (40, 41) which gives uniform large-angle deflection plus high reliability.

Spatial light modulator and method

In an ink jet printing system, a single nozzle or an array of nozzles are etched in a semiconductor material such as silicon. Each nozzle has polygonal or N-sided entrance and exit apertures of different cross-sectional area. Preferably, the nozzle is in the shape of a truncated pyramid with the entrance and exit apertures being substantially square in cross-section. The corners of the apertures and wall interfaces may be rounded to reduce stress concentrations.

Ink jet nozzle

The practice of this disclosure obtains a monolithic structure useful for electrohydrodynamically synchronizing the formation of droplets in a jet stream exiting from a jet nozzle. The monolithic structure is primarily adaptable for ink jet printing. The jet nozzle structure provided by the practice of this disclosure includes a jet nozzle design in a crystalline semiconductor block, e.g., of silicon (Si), germanium (Ge) or gallium arsenide (GaAs), with an electrode structure which is integrally incorporated therewith whereby a variable electric field is established proximate to the orifice of the jet nozzle structure. The electric field electrohydrodynamically perturbs the jet stream emitting from the jet nozzle structure so that formation of drops in the jet stream is controllably achieved, e.g., synchronously when the variable electric field is oscillating with a given periodicity.

Jet nozzle structure for electrohydrodynamic droplet formation and ink jet printing system therewith

A mirror array light valve is described comprising a transparent substrate, a plurality of post members arranged in a regular array on said substrate, and a plurality of deflectable square, rectangular, hexagonal or the like light-reflecting elements arranged in a regular array on said post members such that a post member is positioned under a corresponding corner of each element; methods for making the mirror array light valve are also described.

Mirror array light valve

Silicon-VLSI-compatible photodetectors, in the form of a metal-semiconductor-metal photodetector (MSM-PD) or a lateral p-i-n photodetector (LPIN-PD), are disclosed embodying interdigitated metallic electrodes on a silicon surface. The electrodes of the MSM-PD have a moderate to high electron and hole barrier height to silicon, for forming the Schottky barriers, and are fabricated so as to be recessed in the surface semiconducting layer of silicon through the use of self-aligned metallization either by selective deposition or by selective reaction and etching, in a manner similar to the SALICIDE concept. Fabrication is begun by coating the exposed Si surface of a substrate with a transparent oxide film, such that the Si/oxide interface exhibits low surface recombination velocity. The interdigitated pattern is then etched through the oxide film by lithography to expose the Si surface and metallic electrode members are formed selectively in the exposed Si surface, using self-aligned metallization to produce thin interdigitated electrodes recessed below the silicon surface, which itself may be on a comparatively thin Si layer. The electrodes may be spaced to minimize the interdigital carrier transit time and maximize the sensitivity and the entire process and structure are compatible with conventional silicon integrated circuit (IC) technology. A further feature involves isolating the semiconductor surface layer from the substrate by a layer that may be either 1) transparent and insulating, 2) optically absorbing, or 3) optically reflecting, so that the photocarriers recombine before they can be collected by the field. In the latter case, the photodetector acts as a resonant cavity, resulting in an increase in the number of carriers that are generated, and hence a more sensitive device.

High speed silicon-based lateral junction photodetectors having recessed electrodes and thick oxide to reduce fringing fields

Disclosed is a sculpted probe pad and a gray scale etching process for making arrays of such probe pads on a thin flexible interposer for testing the electrical integrity of microelectronic devices at terminal metallurgy. Also used in the etching process is a novel fixture for holding the substrate and a novel mask for 1-step photolithographic exposure. The result of the invention is an array of test probes of preselected uniform topography, which make ohmic contact at all points to be tested simultaneously and nondestructively.

Ernest Bassous

Papers

Ink jet nozzle

Jet nozzle structure for electrohydrodynamic droplet formation and ink jet printing system therewith

Mirror array light valve

High speed silicon-based lateral junction photodetectors having recessed electrodes and thick oxide to reduce fringing fields

Gray scale etching for thin flexible interposer