Wear Life Test and Mechanisms of Silicon MEMS Devices under Different Gas Environments
Microelectromechanical systems (MEMS) are usually fragile to wear problems. In this research, a bulk-fabricated side-wall Si-MEMS tribotester with the feature of on-chip buckle loading mechanism was designed and used to study the wear life and the mechanisms of early stage wear of resonant MEMS devices in different gas environments. Two distinguishable wear mechanisms are recognized: (1) in dry N2 or O2/N2 mixture environments, wear exhibited an adhesive feature that the instantaneous wear rate is inversely proportional to the wear depth; (2) if corrosive vapors, such as fatty alcohols, are introduced into the environment, chemical reaction can limit the wear rate as a constant. In more complex situation, such as trifluoroethanol vapor, the rubbing process shows a transition from a short adhesive wear phase to a corrosive wear process. The thermal- and tribo-solvolysis could not give a full explanation of the life-time tests for the tested fatty alcohols. Therefore, there must be derivative reactions of grafting groups at silicon surfaces, which cause the instability of such groups. A mechanochemical mechanism is established to understand the stability of grafting groups in friction situation. Compared with fatty alcohols, fluoroalcohol is much more stable and can be used as vapor lubricant for Si-MEMS devices.
MEMS wear solvolysis mechanochemistry
Sihan Shen Yonggang Meng
State Key Laboratory of Tribology,Tsinghua University,Beijing 100084,China
国际会议
北京
英文
1-10
2013-06-16（万方平台首次上网日期，不代表论文的发表时间）