Vapor Phase Lubrication of MicroElectro Mechanical Systems (MEMS): An atomistic approach to solve friction and stiction in MEMS

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dc.contributor.advisor Jacqueline Krim, Committee Chair en_US Varma, Manju R en_US 2010-04-02T18:15:12Z 2010-04-02T18:15:12Z 2003-09-05 en_US
dc.identifier.other etd-09022003-143319 en_US
dc.description.abstract The motivation for this thesis is the desire to overcome the problem associated with reliability and yield of these staggeringly small devices called MicroElectro Mechanical Systems (MEMS). The field of microelctromechanical systems involves the interaction of the physical environment with electrical signals through the use of microbatch-fabricated devices. MEMS is an emerging technology which finds applications in diverse fields such as automotive, medicine, aeronautics, communication and defense. The device dimensions range well into the micrometer regime and are soon approaching the length scales studied by nanotribologists Though the MEMS technology has made a substantial impact over the past decade at the device or component level, it has yet to realize a wide range commercial success. Stiction, adhesion, friction and wear seem to be the main deterrents to their lifetime, and hence full commercialization of these devices. These problems can be attributed to the high surface-to-volume ratio, substantial solid surface nanocontacts, close proximity of microstructures and a myriad other device complications. Several researchers have come up with solutions to avoid release-related stiction, but in-use stiction and friction still persist, proving detrimental to the life span of these microstructures. Though a variety of engineering solutions have been employed to solve them, lubrication of these microelectromechanical systems still remains to be a difficult issue because, the semiconductor like fabrication and small size makes lubrication a challenge in crevices and surfaces beyond the line of sight. In this study, an attempt is made to investigate the in-use stiction and frictional effects by screening vapor phase lubricants on materials of relevance to MEMS using modern nanotribological techniques. The surface effects of silicon after screening vapor phase lubricants are studied using Quartz Crystal Microbalance (QCM) technique in ultra high vacuum. The most promising candidates are then screened on specially designed microstructures called Sidewall tribometers or Friction testers, to study the frictional and wear characteristics. The primary advantage of thermally activated vapor phase lubrication approach is conformality and in-situ replenishment of the lubricant as the lubricating film is worn away. We have studied the adsorption of the vapor phase lubricant t-butyl phenyl phosphate (TBPP) on Si and Si-OTS (octadecyltrichlorosilane) surfaces. Results show that this particular vapor phase lubricant and the SAM coating of OTS show a synergistic relationship. TBPP not only lubricates OTS but acts as a protective coat at high temperatures. We have managed to build a system for the uptake of vapor phase lubricants on the MEMS friction testers under vacuum conditions. This new and improved friction test setup will help in understanding the frictional characteristics of these microstructures, and possibly aid in developing a reliable solution to overcome the myriad problems associated with friction and stiction of MicroElectro Mechanical Systems. The following thesis report describes the status of the project and a summary of results. en_US
dc.rights I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. en_US
dc.subject MEMS en_US
dc.subject Vapor en_US
dc.subject Lubrication en_US
dc.subject Stiction en_US
dc.subject Friction en_US
dc.title Vapor Phase Lubrication of MicroElectro Mechanical Systems (MEMS): An atomistic approach to solve friction and stiction in MEMS en_US MS en_US thesis en_US Electrical Engineering en_US

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