BY:

HEMANTH THOTA

3RD BTECH-ECE

LBR COLLEGE OF ENGINEERING

MYLAVARAM,VIJAYAWADA

Micro-Electro-Mechanical Systems It is the integration of elements, sensors, actuators, and electronics

on a common silicon substrate through micro-fabrication technology, a manufacturing technology for making microscopic devices.

Silicon is the material used to create most integrated circuits used in consumer electronics in the modern industry. The economies of scale, ready availability of cheap high-quality materials and ability to incorporate electronic functionality make silicon attractive for a wide variety of MEMS applications.

Other Materials used in MEMS Gallium Arsenide

Titanium Nickel

Piezoelectric Materials

Deposition (Material addition)spin coating, evaporation, electroplating, reactive growth, CVD, sputtering

Lithographyvarious wavelengths, mask making, alignment, exposure

Etching (Material removal)wet chemical etching, dry plasma etching, gas phase etching,

Wafer bondingSilicon on insulator wafers (SOI)

Packagingadhesion, wire bonding

There are mainly two fabrication technologies for mems:

The first established process is silicon bulk micromachining using alkaline solutions, which have a much smaller etch rate of the crystallographic plane in Si compared with other planes.

Poly silicon surface micromachining exploits differences between deposited poly silicon and silica layers to form three-dimensional features

Silicon is the most abundantelectropositive element inThe Earth’s crust. So it ischeap for fabrication process.

it has high melting point at 1410°c.

It has high boiling point at 3265°c.

:

Micro-Opto-Electro-MechanicalSystems (MOEMS) is not a special class ofMicro-Electro-Mechanical Systems(MEMS) but in fact it is MEMS mergedwith Micro-optics which involves sensingor manipulating optical signals on a verysmall size scale using integratedmechanical, optical, and electrical systems.MOEMS includes a wide variety of devicesincluding Optical switch optical cross-connect,tunable VCSEL, microbolometers amongstothers. These devices are usuallyfabricated using micro-optics and standardmicromachining technologies usingmaterials like silicon, silicon dioxide,silicon nitride and gallium arsenide.

The MEMS devices are: Switches Micro mirrors Tunable devices (delay, dispersion, wavelength, bandwidth, dynamic

gain equalization, etc)

Optical MEMS offers: Low optical insertion loss Low crosstalk Transparency (wavelength, polarization, bit rate, data format) Low power consumption

The effect of moving optical elements is stronger than electro optic,thermal-optic effects.Very efficient beam steering devices.

Silicon on insulator (SOI) technology refers to the use of a

layered silicon-insulator-silicon substrate in place of

conventional silicon substrates in semiconductor

manufacturing, especially microelectronics, to

reduce parasitic device capacitance, thereby improving

performance.REASONS FOR SOI:

•Replacement for SOS

•Need to extend Moore’s

Law

•Commercial Availability of

SOI wafers

High bit rate

transmission must be

matched by switching

capacity

Optical or Photonic

switching can provide

such capacity

Switching is the process by

which the destination of a

individual optical information

signal is controlled

The present technology for silicon-based MOEMS and some future telecommunications applications.

The key to new developments in optical MEMS is to successfully apply the underlying physics and develop cost-effective processing to make high- precision components.

SOI technology, whereby low stress mirrors and other MEMS components are made with reproducible mechanical properties and excellent control of planarity.

Low stress Si3N4 which has a high Young's modulus and has promising applications in packaging .

the necessary precision for optical MEMS can be obtained in a manufacturable way.

The combination of Porous Si and MOEMS opens the door for a new generation of silicon compatible optical interconnects.

The VLSI technology and micro electro mechanical devices will have a profound impact on society as a whole.

The need of the time is that government organization must come forward to interact various micro devices that are being developed.