Hi,
  Electrical breakdown in general is governed by the Paschen curve.
This is usually written as a graph of breakdown voltage vs. the product
of pressure and gap size. One finds a minimum in the curve (for planar
electrodes) around 1-10 torr-cm in air. In your case you are on the left
side of the Paschen minimum. Of course any sharp geometrical features
will reduce the breakdown voltage but another effect to be aware of is
production of "beta" electrons. These are produced from your electrode
surface by colision of primary electrons, ions, or energetic neutrals.
So have a look at the work function of your "electrode" material. It
might be advisable to coat your device with a low workfunction material
such as silicon dioxide.

A couple of refs:
  Physics of Ionized Gases, B.M. Smirnoz, Wiley and Sons, Inc.

  Electrical Breakdown in Gases, Edited by J.A. Rees, Halsted Pres.

Feel free to contact me off line..

-Mike Martin, U. of Louisville

>>> thodge@capellaphotonics.com 03/14/03 10:50AM >>>
Hi All,
Does anyone have experience with electrical breakdown of narrow air
gaps
(several microns) between silicon electrodes ? My experience is that
the
breakdown voltage strongly depends on contamination of these narrow
trenches
and would like to find out more information.

Regards,
Tom H. Hodge
Capella Photonics Inc.
19 Great Oaks Blvd Suite 20
San Jose, Ca. 95119
Ph 408-360-4257
Fax 408-225-6248
email thodge@capellaphotonics.com
www.capellaphotonics.com


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