Fabrication of Sio2-based microcantilevers by anisotropic chemical etching of (100) single crystal Si (original) (raw)
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Modern lab-on-a-chip systems can benefit from integration of nanoelectromechanical system/microelectromechanical system (NEMS/MEMS) and complementary metal– oxide semiconductor technology with emphasis on low temperature processing. In the present work process, parameters for deposition of silicon oxide (SiOx ) by inductively coupled plasma chemical vapour deposition (ICPCVD) at low temperature (708C) are optimised. The sacrificial layer poly(methyl methacrylate) (PMMA) is in-house prepared and optimised. This PMMA sacrificial solution not only gives a low cost wide range of viscosity solutions, but it is also low temperature NEMS process compatible. With optimisations mentioned above, it has been possible to fabricate the whole device without exceeding the thermal budget 1008C. To the best of the authors’ knowledge, this is the first report on sub-1008C, surface micromachined SiOx cantilevers deposited by ICPCVD and using PMMA as the sacri- ficial layer for low temperature NEMS applications
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The conventional photolithography of crystalline silicon techniques is limited to two-dimensional and structure scaling. It is also requiring a lot of time and chemical involves for the whole process. These problems can be overcome by using laser micromachining, which a technique capable of producing three-dimensional (3D) structure and simultaneously avoiding the needs for photomasks. This paper reported the use of RapidX-250 excimer laser micromachine with 248 nm KrF to create in-time mask design and assisting ifabrication of piezoresistive microcantilever structures.Laser micromachining parameters is investigated in order to fabricate the microcantilever, which can be used in multiple applications including acceleration, vibration, bio/chemical detections and also in energy harvesting. Preliminary result shows that the fabricated sensor able to define the differences force and acceleration given regarding the unique electrical characteristic on fabricated piezoresistor.
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Microcantilevers are extensively used in Micro Electro Mechanical Systems for a variety of sensing applications. This study presents the modeling, design and simulation of piezoresistive microcantilevers with an embedded heater based on Multi User MEMS Process. Simulations were carried out for the heater, microcantilever and the piezoresistor using a commercially available Finite Element Solver. Electro-thermal analysis of the embedded heater showed [75% temperature uniformity on the microcantilever surface. It was observed that the deflection of the microcantilever tend to become nonlinear with load at elevated temperatures. Piezoresistive simulation showed an increase in sensitivity (DI/I), with displacement magnitude of the microcantilever. Fabricated microcantilevers showed that the piezoresistor stayed nearly at ambient temperature up to 5 V heater bias.
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We fabricate and characterize the metal-oxidesemiconductor (MOS) transistor tip integrated micro cantilever, which is proposed for a future high-density data storage system. The integrated MOS transistor tip as the sensing part has some advantages; it detects the electric signal with the fast speed compared with the previous SPM probes, and it can reduce the required equipments such as the lock-in-amplifier. The MOS transistor tip is fabricated 3-dimensionally, utilizing the lateral diffusion and the anisotropic wet etching with TMAH solution, since the etch rate of {211} plane is much higher than those of {100} or {111} planes. The gate area is formed by self-aligned technique, using crystallographic dependant wet etching. The well-known convex corner compensation pattern is used for the gate length control during the tip fabrication process. The characteristics of the fabricated device are measured and the results show the well-established detection properties.