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Microelectromechanical systems (MEMS) - Coggle Diagram
Microelectromechanical systems (MEMS)
Types
Capacitive
A capacitive MEMS switch is developed using a moving plate or sensing element, which changes the capacitance
Ohmic
Ohmic switches are controlled by electrostatically controlled cantilevers.Ohmic MEMS switches can fail from metal fatigue of the MEMS actuator (cantilever) and contact wear since cantilevers can deform over time
Materials for manufacturing
Polymers
Polymers on the other hand can be produced in huge volumes, with a great variety of material characteristics.
Metals
While metals do not have some of the advantages displayed by silicon in terms of mechanical properties, when used within their limitations, metals can exhibit very high degrees of reliability.
Silicon
Silicon is the material used to create most integrated circuits used in consumer electronics in the modern industry.
Ceramics
The nitrides of silicon, aluminium and titanium as well as silicon carbide and other ceramics are increasingly applied in MEMS fabrication due to advantageous combinations of material properties.
MEMS basic processes
Deposition processes
Physical deposition
Physical vapor deposition ("PVD") consists of a process in which a material is removed from a target, and deposited on a surface.
Chemical deposition
Chemical deposition techniques include chemical vapor deposition (CVD), in which a stream of source gas reacts on the substrate to grow the material desired.
MEMS manufacturing technologies
Surface micromachining
Surface micromachining uses layers deposited on the surface of a substrate as the structural materials, rather than using the substrate itself.
Thermal oxidation
This approach to MEMS fabrication relies mostly on the oxidation of silicon, as described by the Deal-Grove model. Thermal oxidation processes are used to produced diverse silicon structures with highly precise dimensional control.
Bulk micromachining
Bulk micromachining is the oldest paradigm of silicon-based MEMS. The whole thickness of a silicon wafer is used for building the micro-mechanical structures
High aspect ratio (HAR) silicon micromachining
A new etching technology, deep reactive-ion etching, has made it possible to combine good performance typical of bulk micromachining with comb structures and in-plane operation typical of surface micromachining.