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How to make a vacuum chamber in a capacitor?

Posted Sep 17, 2013, 9:18 a.m. EDT MEMS & Nanotechnology, MEMS & Piezoelectric Devices, Materials, Structural Mechanics Version 4.2, Version 4.2a, Version 4.3, Version 4.3a 3 Replies

Yu Y.Y
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Hi, I am trying to model a MEMS capacitor built on the silicon substrate. The thin top plate(membrane) of the capacitor is also made of silicon. The gap between the plates is vacuum sealed. So with zero bias voltage on the capacitor, this thin top plate (membrane) is deflected to the bottom substrate due to the surrounding air pressure. I don't konw how to make the vacuum chamber in the device to model the deflection. Emi physics is used in modeling.
Any suggestions is appreciated!
3 Replies Last Post Sep 20, 2013, 6:34 a.m. EDT
Edgar J. Kaiser Certified Consultant
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Posted: 1 decade ago Sep 19, 2013, 9:35 a.m. EDT
Hi,

it is not the vacuum deflecting the membrane, it is the atmospheric pressure. Can't you apply a pressure BC to the outside of the membrane?

Cheers
Edgar

--
Edgar J. Kaiser
emPhys Physical Technology
Hi, it is not the vacuum deflecting the membrane, it is the atmospheric pressure. Can't you apply a pressure BC to the outside of the membrane? Cheers Edgar -- Edgar J. Kaiser emPhys Physical Technology
Yu Y.Y
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Posted: 1 decade ago Sep 20, 2013, 5:33 a.m. EDT
Hi,Edgar
Thank you for your solution! It is a good way to apply the atmospheric pressure as the BC on the membrane to model the deflection. However, the membrane will vibrate by the AC voltage applied on the capacitor. What I am not certained is that the air in the gap may act as the air cushion, which damps the vibration. I want to eliminate the damping caused by the air inside the gap.
Hi,Edgar Thank you for your solution! It is a good way to apply the atmospheric pressure as the BC on the membrane to model the deflection. However, the membrane will vibrate by the AC voltage applied on the capacitor. What I am not certained is that the air in the gap may act as the air cushion, which damps the vibration. I want to eliminate the damping caused by the air inside the gap.
Edgar J. Kaiser Certified Consultant
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Posted: 1 decade ago Sep 20, 2013, 6:34 a.m. EDT
Well, I don't have the MEMS module and you were asking about deflection not about damping. Maybe one of the MEMS experts can help ...?

Cheers
Edgar

--
Edgar J. Kaiser
emPhys Physical Technology
Well, I don't have the MEMS module and you were asking about deflection not about damping. Maybe one of the MEMS experts can help ...? Cheers Edgar -- Edgar J. Kaiser emPhys Physical Technology

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