Abstract
This report demonstrates the tuning the quality factor of a micromachined structure using the air damping of a small squeezed-film area (300 μm 2 to 800 μm 2 ). Two micromachining processes have successfully been established to fabricate novel stationary structures using thin films and bulk silicon, in which the stationary structure and a vibrating micromachined cantilever form a squeezed-film region. Measurements showed that, under the assistant of bulk silicon stationary structure, the quality factor of the vibrating beam decreased by 48% when the squeezed-film area was increased from 300 μm 2 to 800 μm 2 under a 760-torr ambient pressure. Moreover, even when the ambient pressure was only 20 mtorr, the quality factor of the beam still decreased by 20% for the same increase in area. Under the assistant of thin film stationary structure, the quality factor of the vibrating beam decreased by 35% when the squeezed-film area was increased from 300 μm 2 to 500 μm 2 under a 760-torr ambient pressure. Consequently, the proposed two stationary structures can be exploited to significantly alter the quality factor of dynamic systems. © Springer-Verlag 2005.