Mechanical Vibrations of Thermally Actuated Silicon Membranes

Puchades, Ivan; Koz, Mustafa; Fuller, Lynn

doi:10.3390/mi3020255

Cited by 6 publications

(2 citation statements)

References 16 publications

(26 reference statements)

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“…The movement of the membrane is measured through a Wheatstone bridge of boron-implanted p+ silicon piezoresistors. During normal operating conditions, the center of the membrane has been shown to be displaced by ~120 nm when an instant power of 4 Watts is applied [29,30]. The driving and amplification circuitry are described in detail in [29].…”

Section: Resultsmentioning

confidence: 99%

“…These include the CVD-based Parylene-C [20][21][22][23][24][25], silicone-based coating, and other polymers [26][27][28]. Even though these have been proven effective at protecting packaged electronics and components placed on a PCB [28][29][30][31], few studies have shown their effectiveness when protecting actuators embedded in the sensing environment [25].…”

Section: Introductionmentioning

confidence: 99%

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Waterproofing a Thermally Actuated Vibrational MEMS Viscosity Sensor

Gan,

Choudhary,

Reddy

et al. 2024

Actuators

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An efficient and inexpensive post-process method to waterproof an electrically actuated microtransducer has been studied. The electrical signals of microtransducers operating in electrically conductive fluids must be effectively isolated from the surrounding environment while remaining in contact for sensing purposes. A thermally actuated MEMS viscosity sensor uses electrical signals for both actuation and sensing. Three post-processing materials, (1) Parylene-C, (2) flouroacrylate-based polymer, and (3) nitrocellulose-based polymer, were coated as thin layers of waterproofing materials on different sensors. All three coating materials provided adequate protection when tested under normal operating conditions. Although the vibration response of the sensors was slightly modified, it did not affect their functionality in a significant way when measuring conductive fluids based on glycerol–water mixtures. All the treated sensors lasted over 1.2 million actuations without any decay in performance or failures. When the test bias conditions were increased by 5x to accelerate failures, the flouroacrylate-based polymer samples lasted 2x longer than the others. Visual analysis of the failures indicates that the edge of the diaphragm, which undergoes the most significant stress and strain values during actuation, was the location of the mechanical failure. This work guides post-processed waterproofing coatings for microscale actuators operating in harsh and damaging environments.

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Section: Resultsmentioning

confidence: 99%