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Mems technology ppt

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Mems technology ppt

  2. 2. CONTENTS 1.Introduction 2.Differences between IC and MEMS 3.Basic elements of MEMS 4.Manufacturing process of MEMS technology 5.RF MEMS 6.RF MEMS switches 7.Fabrication 8.Comparision of MEMS Switches with solid state switches 9.Advantages and Disadvantages 10.Applications 11.Conclusion 12.Reference DEPT OF E&C 2
  3. 3. Introduction • Micro-Electro-Mechanical Systems • Miniaturized mechanical and electro mechanical elements using micro fabrication. • Most promising Technology of 21st century. DEPT OF E&C 3
  4. 4. Block diagram of IC+MEMS fabrication DEPT OF E&C 4
  5. 5. DIFFERENCES: ICs Vs MEMS MEMS • 3D complex structures • Doesn’t have any basic building block • May have moving parts • May have interface with external media • Functions include Biological,Chemical,Optical • Packaging is very complex ICs • 2D structures • Transistor is basic building block • No moving parts • Totally isolated with media • Only Electrical • Packaging Techniques are well developedDEPT OF E&C 5
  6. 6. Basic Functional Elements of MEMS DEPT OF E&C 6
  7. 7. Manufacturing process of MEMS Technology 1.Photolithography 2.Silicon Micromachining a)Bulk Micromachining b)Surface Micromachining 3.Excimer Laser Micromachining DEPT OF E&C 7
  9. 9. Surface Micromachining DEPT OF E&C 9
  10. 10. Basic techniques of Silicon micromachining •Deposition of thin films •Wet Chemical Etching •Dry Chemical Etching DEPT OF E&C 10
  11. 11. Wet Chemical Etching DEPT OF E&C 11
  12. 12. Lift off DEPT OF E&C 12
  13. 13. Excimer Laser Micromachining DEPT OF E&C 13
  14. 14. RF MEMS •MEMS those with RF range are RE MEMS •Compound solid state switches have larger insertion loss(on state) and poor electrical isolation (off state) •RF MEMS Switches provides lower insertion loss, higher isolation, zero static power consumption DEPT OF E&C 14
  15. 15. RF MEMS Switches 1.RF series contact switch 2.RF shunt capacitive switch DEPT OF E&C 15
  16. 16. RF series contact Switch DEPT OF E&C 16
  17. 17. RF shunt capacitive Switch DEPT OF E&C 17
  18. 18. Limitations •Series contact switches tend to fail in the open circuit. •Even though the bridge is collapsing and making the contact with transmission line, conductivity of contact metallization area decreases until unacceptable levels of power losses are achieved •Shunt capacitive switches often fail due to charge tapering, both at the surface and bulk states of the dielectric. DEPT OF E&C 18
  19. 19. Fabrication Process flow (a) Seed layer deposition (b)Dielectric layer deposition and patterning (c) Spacer coater and patterning (d)Transmission line electroplating (e)Membrane deposition and patterning (f)membrane releasing DEPT OF E&C 19
  20. 20. Comparision of MEMS switches with Solid State switches DEPT OF E&C ;PPParameter RFRF MEMS MEMS PPIN DIODE FFEFET Voltage(mA) 20-80 3-5 3-5 Current(mA) 0 0-20 0 Power consumption (mW) 0.5-1 5-100 -0.5-0.1 switching 1-300uS 1-100ns 1-100ns Power handling(W) <1 <10 <10 20
  21. 21. ADVATAGES OF MEMS •Can reduce the weight,size,power consumption and component counts. •Promise superior performance •Can be built with high producibility •New functionality DEPT OF E&C 21
  22. 22. DISADVANTAGES OF MEMS:- •Due to their size, significant power transfer is impossible •Due to its base material cannot be loaded with large load •Design standards are not well developed •And some Reliability issues.. DEPT OF E&C 22
  23. 23. Applications •In Navigation field •Pressure sensors •Medical field •High frequency circuits •Security field DEPT OF E&C 23
  24. 24. Conclusion •Low power consumption, high isolation and ability to integrate with other elements make MEMS switches an alternative to solid state switches. •MEMS is one of the promising technology •Proper design standards have to be build. •High performance RF MEMS switches, high voltage MOSFET and CMOS devices can be integrated on the same chip. DEPT OF E&C 24
  25. 25. References [1] Sazzadur Choudhury, M. Ahmadi, and W.C. Miller, “Micromechanical system for System-on-Chip Connectivity”, IEEE Circuits and Systems, Page(s) 112-132 September 2002 [2] J. B. Muldavin, G. M. Rebeiz, "High Isolation RF MEMS Shunt Switches-Part 2: Design", IEEE Tran. On Microwave Theory and Techniques, Vol.6, Page(s): 253-276. June 2000, [3] P. Osterberg, H. Yie, X. Cai, J. White, and S. Senturia, “Self-consistent simulation and modeling of RF MEMS,“ in Proc. IEEE MEMS Conf. January 1994, Page (s)28-32. [4] Gopinath. A and Ranklin.JB, IEEE Electronic development,” GaAs FET RF switches “, vol. 12, Page(s) 18-37, August 2003 DEPT OF E&C 25
  26. 26. THANK YOU DEPT OF E&C 26