STEP 10- a)Removing all of the PSG(oxide) sacrificial layer and the second sacrificial layer by etching to release the rotor, so that the rotor is rotatbly supported by the bearing. Conclusion: Surface micromachining has developed since the early1980’s from academic “proof-of-concept” demonstrations into a commercially important technology. Material properties are now understood sufficiently that polysilicon based surface-micro machined MEMS are a commercial success. MICROFABRICATION of polysilicon microstructures has made monolithic structures feasible. In these sophisticated interface and control circuits, one can fully exploit simple mechanical elements. These integrated technologies continue to evolve, with different options on how best to merge microstructure and electronic processes From the above work it is observed that the rotor is held off the base layer of polysilicon by the bearing which leads to a line contact of rotor bottom with the bearing instead of a plane contact as in the prior designs.Therefore, the bearing structure of the present work can greatly reduce the frictional torque during micro motor motion avoiding the quick wear of the bearing and the wobbling of the rotors. References: [1] Fan,L.-S.Tai,Y.-C.,&Muller,R.S.,”IC-Processes for Electrostatic Micro-motors”,IEEE International Electronics Devices Meeting, Dec1988, pp.666-669. [2] Trimmer, W.S.N., &Gabriel, K.J.,”Design considerations for Practical Electrostatic Micro motors”, Sensors&Actuators, vol-11, 1987, pp.189-206 [3] Mehragny, M.Gabriel, K.J., &Trimmer, W.S.N.,”Integrated Fabrication of Polysilicon Mechanisms”, IEEE Transactions on electronic devices,vol-ED-35, no-6,1988,pp.719-723 [4] “MEMS” Wikipedia online encyclopedia. http://www.wikipedia.org/wiki/surfacemicromachining [5] Livemore Carol,”Micro fabrication of MEMS: PART 2” http://ocw.mit.edu/ 146
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