Bending Fatigue Life of Polycrystalline Silicon Microcantilever Beam
| Autor: | Hung, Jeng-Nan, 洪政男 |
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| Rok vydání: | 2012 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 100 In light of the rapid advancement in IC/MEMS/NEMS technology, the reliability is an essential factor for a successful microdevice product. However, the reliable application of these devices often depends on the fatigue of their microstructure. Microcantilever beam and polycrystalline silicon (polysilicon) are the most often used structure and material in microdevices, respectively. Therefore, their mechanical fatigue properties need to be characterized to predict the lifetime of the microdevices. This study presents the fatigue life of polysilicon microcantilever beam in bending by various testing methods, including microactuator, MTS Tytron250 microforce testing system and piezoelectric actuator. During microactuator testing, the fatigue life persists up to millions of cycles without failure, because the amplitude of displacement is small. Based on the results of the MTS Tytron250 microforce testing system and the piezoelectric actuator, it can be concluded that large stress reduces the number of cycles, namely the fatigue life is inversely proportional to the stress. In this study, an empirical correlation is established for predicting bending fatigue of polysilicon microcantilever beam. This correlation demonstrated the influence of applied frequency on fatigue life. The high stress reduced the fatigue life, and low frequencies enhanced this effect. Moreover, the collective plot of polysilicon by various testing mechanisms, such as tension, bending and torsion, will provide the microdevice designer and researcher with a good reference for various applications. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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