Silicon carbide MEMS for harsh environments

Mehregany, Mehran; Zorman, Christian A.; Rajan, N.; Wu, Chien-Hung

doi:10.1109/5.704265

Cited by 428 publications

(187 citation statements)

References 49 publications

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“…In addition, functionally graded multilayer systems can remain stable in the long-term and in humid environments, which certainly makes them a favorable choice for chronic neural implants. [14] If the materials cohesive energy, their binding state as well as their binding mechanism are dissimilar the chances that they return to a more favorable energetic state over the course of time are high. A system that varies with time is in general undesirable for implantable devices, as it would lack the initial bonded state of the materials and promote delamination and failure of the entire implant in the long term.…”

Section: Introductionmentioning

confidence: 99%

Incorporation of Silicon Carbide and Diamond‐Like Carbon as Adhesion Promoters Improves In Vitro and In Vivo Stability of Thin‐Film Glassy Carbon Electrocorticography Arrays

Vomero¹,

Castagnola

Ordonez³

et al. 2017

Adv. Biosys.

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Thin‐film neural devices are an appealing alternative to traditional implants, although their chronic stability remains matter of investigation. In this study, a chronically stable class of thin‐film devices for electrocorticography is manufactured incorporating silicon carbide and diamond‐like carbon as adhesion promoters between glassy carbon (GC) electrodes and polyimide and between GC and platinum traces. The devices are aged in three solutions—phosphate‐buffered saline (PBS), 30 × 10−3 and 150 × 10−3m H2O2/PBS—and stressed using cyclic voltammetry (2500 cycles) and 20 million biphasic pulses. Electrochemical impedance spectroscopy (EIS) and image analysis are performed to detect eventual changes of the electrodes morphology. Results demonstrate that the devices are able to undergo chemically induced oxidative stress and electrical stimulation without failing but actually improving their electrical performance until a steady state is reached. Additionally, cell viability tests are carried out to verify the noncytotoxicity of the materials, before chronically implanting them into rat models. The behavior of the GC electrodes in vivo is monitored through EIS and sensorimotor evoked potential recordings which confirm that, with GC being activated, impedance lowers and quality of recorded signal improves. Histological analysis of the brain tissue is performed and shows no sign of severe immune reaction to the implant.

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Section: Introductionmentioning

confidence: 99%

Incorporation of Silicon Carbide and Diamond‐Like Carbon as Adhesion Promoters Improves In Vitro and In Vivo Stability of Thin‐Film Glassy Carbon Electrocorticography Arrays

Vomero¹,

Castagnola

Ordonez³

et al. 2017

Adv. Biosys.

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“…Since silicon-based devices lack high-temperature capabilities with respect to both mechanical and electrical properties, SiC is being developed as a structural material for high-temperature microsensor and microactuator applications (Shor et al 1993;Mehregany et al 1998). SiC can also be desirable for high-frequency micromechanical resonators, in the GHz range, owing to its high modulus of elasticity to density ratio and consequently high resonance frequency.…”

Section: Tribological Studies Of Silicon and Related Materialsmentioning

confidence: 99%

Nanotribology and nanomechanics in nano/biotechnology

Bhushan

2008

Phil. Trans. R. Soc. A.

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Owing to larger surface area in micro/nanoelectromechanical systems (MEMS/NEMS), surface forces such as adhesion, friction, and meniscus and viscous drag forces become large when compared with inertial and electromagnetic forces. There is a need to develop lubricants and identify lubrication methods that are suitable for MEMS/NEMS. For BioMEMS/BioNEMS, adhesion between biological molecular layers and the substrate, and friction and wear of biological layers may be important, and methods to enhance adhesion between biomolecules and the device surface need to be developed. There is a need for development of a fundamental understanding of adhesion, friction/stiction, wear, the role of surface contamination and environment, and lubrication. MEMS/NEMS materials need to exhibit good mechanical and tribological properties on the micro/nanoscale. Most mechanical properties are known to be scale dependent. Therefore, the properties of nanoscale structures need to be measured. Componentlevel studies are required to provide a better understanding of the tribological phenomena occurring in MEMS/NEMS. The emergence of micro/nanotribology and atomic force microscopy-based techniques has provided researchers with a viable approach to address these problems. This paper presents an overview of micro/nanoscale adhesion, friction, and wear studies of materials and lubrication studies for MEMS/NEMS and BioMEMS/BioNEMS. It also presents a review of scale-dependent mechanical properties, and stress and deformation analysis of nanostructures.

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“…SiC has been identified as the most promising candidate for use as a refractory structural material due to its high stiffness, strength, and chemical stability at elevated temperatures [9], [10]. However, techniques for microfabricating single crystalline SiC to the high level of precision required for the microengine are not yet available primarily due to the lack of precise and fast SiC etching techniques.…”

Section: Si-sic Microfabrication Processmentioning

confidence: 99%

Development of Si–SiC Hybrid Structures for Elevated Temperature Micro-Turbomachinery

Moon

Choi

Spearing

2004

J. Microelectromech. Syst.

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Abstract-The design of the Massachusetts Institute of Technology (MIT) microengine is limited in part by the material capability of Si primarily due to the pronounced thermal-softening and strain-softening at temperatures higher than the brittle-to-ductile transition temperature (BDT), approximately 550 C. In order to circumvent this limitation, it has been proposed to reinforce the Si with chemical vapor deposited (CVD) SiC in strategic locations to create a Si-SiC hybrid microengine turbine spool. Detailed design of Si-SiC hybrid structures for high temperature micro-turbomachinery, however, has been hampered by the lack of understanding of the mechanical behavior of Si and SiC hybrid structures at elevated temperatures and by the unavailability of accurate material properties data for both Si and SiC at the temperatures of interest. In this work, a series of initial thermomechanical FE analyzes have been performed to assess the advantage of the hybrid structures, and to provide structural design criteria and fabrication requirements. Then, the feasibility of the Si-SiC hybrid structures concept for elevated temperature micro-turbomachinery was verified based on more rigorous mechanical testing at high temperatures. Finally, the Si-SiC hybrid spool design was critically reevaluated with regard to creep using a Si constitutive model developed as a separate effort.[0988]Index Terms-Finite element analysis, mechanical testing, Massachusetts Institute of Technology (MIT) microengine, Si-SiC hybrid structures.

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Silicon carbide MEMS for harsh environments

Cited by 428 publications

References 49 publications

Incorporation of Silicon Carbide and Diamond‐Like Carbon as Adhesion Promoters Improves In Vitro and In Vivo Stability of Thin‐Film Glassy Carbon Electrocorticography Arrays

Incorporation of Silicon Carbide and Diamond‐Like Carbon as Adhesion Promoters Improves In Vitro and In Vivo Stability of Thin‐Film Glassy Carbon Electrocorticography Arrays

Nanotribology and nanomechanics in nano/biotechnology

Development of Si–SiC Hybrid Structures for Elevated Temperature Micro-Turbomachinery

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