Microelectromechanical systems in, short MEMS is the art of handling tiny mechanical devices which are empowered by electricity.as the name specifies it combines nano scale,nanotechnology and NEMS(NanoElectromechanical systems).These are also some times called as micro machines.MEMS were first practically used when it was fabricated using semi conduction propertied and advanced electronics. The most famous MEMS system is monolithic resonator.
How MEMS works
MEMS works by using the series of processes at different levels. Its basic processes include.
One of the fundamental is deposition building blocks in MEMS processing.it is the capability to deposit thin films of element or material with a thick No specific locations is pointed for depositing film,they could be deposit any where between 1 to 100 nm.There are two main types of deposition.
- Physical deposition
- Chemical deposition
This type of deposition refers to deposition which belongs to the existing structure of material.There are three sub types of deposition process
- Physical vapor deposition (PVD)
Chemical deposition deal with the chemical properties and bonding of the concerned material.There are two further types of chemical deposition.
- Chemical vapor deposition(CVD)
- Thermal oxidation
Patterning is a process in which transfer of specific pattern into a material takes place .It involves different kind of processes .
Lithography when considered in MEMS is the typical transfer of a pattern into a photosensitive material by huge radiation source selective exposures such as exposure to light. A photosensitive material is that which experiences a huge change in its physical characteristics when exposed to the radiations. Besides lithography many other process are used for patterning such as Photolithography, Electron beam lithography, Ion beam lithography, X-ray lithography.
There are two main categories of etching processes.
- wet etching
- dry etching
In the wet etching the material is dissolved in the chemical .This process is also known as chemical etching. Concentrated solution of chemical is required for the proper removal of material by dipping. Chemical nature of wet etching helps in obtaining a good selectivity,which means the material sensitivity and etching rate is high.Many kinds of sub etching techniques are present such as.
- Isotropic etching
- Anisotropic etching
- Hydrofluric Acid HF etching
- Electrochemical etching
In dry etching process un-wet solutions such as silicon nitride is used for dissolving the material.This kind of etching is isotropic etching which uses silicon as a key solvent.Many types of dry etching are present which includes.
Xenon difluoride etching
[Reactive ion etching (RIE)
MEMS Manufacturing Materials
Different types of manufacturing materials are used to develop the MEMS according to the required use.These materials include.
Silicon is used for developing integrated circuits which are famous in consumer electronics in the present world.Silicon also has important advantages because of its material characteristics.Any required shape can be easily obtained by the silicon
Another useful material used for manufacturing MEMS is polymers which involve wide range of its sub materials. Polymers can be produced in big volumes, with variant material properties.MEMS machines developed using polymers by processes such as injection molding, embossing or stereo lithography.
Different kind of metals are also used to create MEMS sub components.Mechanical characteristics of metals are better than silicon. The widely used metals in the creation of MEMS are gold, copper, titanium, silver, aluminum and nickel. These metals can be deposited by the processes like electroplating and sputtering.
MEMS are one of the technologies that are greatly in use and development these days. In the future, it is a possibility that consumer sector would be using more advanced form of MEMS.