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OVERVIEW
INTRODUCTION TO MEMS
MEMS RESONATORS
ARCHITECTURE
ADVANTAGES AND DISADVANTAGES
FABRICATION
FUTURE SCOPE AND CONCLUSIONS
REFERENCES

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1) INTRODUCTION TO MEMS
The technology of very small mechanical devices driven by electricity.
1 to 100 micrometers in size.
Large surface area to volume ratio of MEMS, surface effects dominate volume effects
MEMS could be fabricated using modified semiconductor device fabrication technologies

2) MEMS RESONATOR
Resonators with Q's over 10,000 at GHz frequencies .
Excellent thermal and aging stability
Excited using a combination of AC and DC voltages
Maximum output is obtained at resonance.
Hence used as a filter.

Disk resonator
Bank of resonators
3) ARCHITECTURE A. Replacement of off-chip components
B.An RF channel select architecture
 C.An all-mems RF front end architecture

4) ADVANTAGES AND DISADVANTAGES
Inherent voltage controlled tunability.
Power savings.
Flexibility in choice of materials.
High Q of order of 10k @ 3 GHz.
More components can be fabricated on to silicon.
Impedance flexibility.
They are very difficult to fix.
A micro machine fabrication facility is very costly to set up.

5) FABRICATION
Two methods depending on thickness
Surface micromachining.
Bulk micromachining.

Method depend on thickness
If t>10µm bulk micromachining.
If t<10µm surface micromachining.


a) Surface micromachining
a) Surface micromachining
LPCVD of a thin silicon nitride layer .
LPCVD phosphosilicate glass is patterned.
LPCVD of polysilicon.
The polysilicon is dry etched.
HF etch removes the spacer layer.

6) FUTURE SCOPE AND CONCLUSIONS
Ceiling temperature to be around 300°C
MEMS-CMOS integration.
Sufficient linearity and power handling capability;


7) REFERENCES
[1] C. T.-C. Nguyen, “Integrated Radio Front Ends…. “ International Symposium on VLSI Technology, Systems and Applications, 2009.
[2] C. T.-C. Nguyen, "MEMS technology for ...,"IEEE Trans. Ultrason. Ferroelect., Freq. Contr., vol. 54, no. 2, pp. 251-270, Feb. 2007.
[3] M. Dillinger, et al., Software Defined Radio. Architectures, Systems, and Functions. New York, NY: Wiley, 2003.
[4] http://en.wikipediawiki/
Microelectromechanicalsystems. Date 31/7/2010..