Microsensor substrate

Figure 16. (a) SEM of gas microsensor substrate prepared by localized porous-type anodization of Al. (b, c) Optical images of gas microsensor substrate without and with electrodes, (d) Packaged humidity sensor with microheater. Images reproduced from Ref. 7 with permission from ECS - The Electrochemical Society and from Ref. 69 with permission from ASME. 

Device Fabrication. A four-mask process was used for the fabrication of tin oxide microsensors on silicon substrates. The major processing steps are shown in Figure 1 ... 

Formation of platinum fractal-like structures is possible by PA-CVD (19% Ar, 80% O2, 1% SnMe4) on tin oxide thin films using Pt(acac)2 as starting material . The platinum aggregates show a dendritic structure of fractional dimension D ca 1.1-1.6 (Figure 10). The occurrence of such aggregates has been correlated to the concentration of the platinum precursor and to the radio-frequency power applied to the substrate electrode. Fabrication of microsensors integrated on silicon wafers with the help of photoresistors is possible . 

The continuous operation of noncontinuous substrates, e.g., contact lenses, video disks, microsensors, etc., is performed by placing a certain number of substrate in an evacuation/transfer chamber, in which the evacuation is carried out and samples are transferred to the adjacent sample holding chamber in vacuum. The evacuated sample holders are placed on a conveyer one by one and pass through glow discharge zones. The coated substrates follow the reverse process at the downstream end of a reactor to be taken out in the ambient environment. Thus, the substrate charge is done in butch mode, but the LCVD process is done continuously. 

Catalyst-assisted CVD processes can also be used to fabricate delicate microcomponents. Coiled fibres of carbon and refractory carbides are examples of such components which may be used in functional applications such as microsprings, microsensors and fillers of electromagnetic shielding materials. The microstructure of some coiled fibres is shown in Figure 3.39a. The device for the production of coiled fibre fabrication is shown in Figure 3.39b. A graphite plate substrate is placed at the central part of a horizontal CVD reaction chamber, and a metal... 

Biosensors based on the heat produced by enzyme/substrate reactions have traditionally used microcalorimeters (1), thermistors (2), and Peltier or other macro devices <3,A) The area has been reviewed by Guilbault (5). The size, response time, and thermal mass of these detectors suggests that thermally responsive microsensors need to be explored. The ideal sensor would be inexpensive, and require simple, low cost support electronics. A fiber optic based sensor (Part A), and a pyroelectric polymer film based sensor (Part B) are described below. 

Roussel P, Lysenko V, Remaki B, Delhomme G, Dittmar A, Barbier D (1999) Thick oxidised porous silicon layers for the design of a biomedical thermal conductivity microsensor. Sens Actuators A 74 100-103 Sakly H, MUka R, Chaabane H, Beji L, Ben OH (2006) Anodically oxidized porous silicon as a substrate for EIS sensors. Mater Sci Eng C 26 232-235... 

In addition to forming continuous organometallic multilayer thin films, we explored the LbL deposition of polyferrocenylsilane polyions onto, for instance, hydrophilically/hydrophobically modified substrates with the aim of building two-dimensionally patterned organometallic multilayers. In general, surfaces modified with microscopically patterned conducting, luminescent, or redox-active polymer films have potential use in microelectronic and optoelectronic devices and microsensor arrays. Area-selective deposition of polyferrocenylsilane polyions can be an attractive method to obtain two-dimensionally patterned redox active films, which may be used as electrochemically modulated diffraction gratings. ... 

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