Very thin SiC membranes for micromachined vacuum sensors

Pham, H.T.M.; Fan, Chuanhong; Pandraud, G.; Creemer, Fredrik; Sarro, P.M.; Pers, N. M. van der; Visser, Peter; Kwakernaak, Kees

doi:10.1109/icsens.2008.4716643

Cited by 3 publications

(2 citation statements)

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“…This deposition is performed using a LPCVD furnace employing diclorosilane (SiH 2 Cl 2 ) and acetylene (C 2 H 2 ) as precursor gasses. In order to obtain a polycrystalline layer the deposition temperature is set to 860°C [42], [43]. The pressure is set to 60 Pa and gas flows of SiH 2 Cl 2 and C 2 H 2 are set to 400 and 100 sccm, respectively.…”

Section: Fabricationmentioning

confidence: 99%

Stiction-Induced Sealing of Surface Micromachined Channels

Morana

Poelma

Fiorentino

et al. 2014

J. Microelectromech. Syst.

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We established a technique to achieve low temperature hermetic sealing of surface micromachined channels by exploiting stiction. Using a wing-shaped structural layer, microchannels automatically seal during the drying step that follows the sacrificial etch. This avoids the need of plugging layers to close the apertures of the sacrificial etch. To demonstrate the technique, we designed a surface micromachined channel with a structural layer made of polycrystalline silicon carbide (poly-SiC). This layer integrates an array of anchored pillars to achieve long and wide microchannels (5.4 mm × 0.43 mm × 0.001 mm). To dimension the sealing-wing, we estimate the minimum adhesion energy between the poly-SiC and silicon. This is done by analytical modeling and experimental characterization of test structures in the shape of centrally-supported circular plates. The bending and adhesion of the sealing-wing is followed in situ by optical microscopy. The closed microchannels are annealed at 100°C. Some structures are exposed to thermal stress at 760°C. The results are inspected by white light interferometry, scanning electron microscopy, and helium leak testing. Microchannels result hermetically sealed showing leak rates below the detection limit (4 × 10 −9 Pa · m 3 /s). The seal is effective to at least 600 kPa.[2013-0122]

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Section: Fabricationmentioning

confidence: 99%