Extending on Shay and Al's observations, let me add that reducing the surface-
to-volume ratio through design could be beneficial, i.e. taller vs. planar
structures.  But defects as they manifest on the top and bottom surfaces
(handling concerns) will be very different from those that appear along etched
sidewalls.

Raj

--
Raj Gupta
Volant Technologies
http://terahz.org




________________________________
From: Shay Kaplan 
To: General MEMS discussion 
Sent: Wed, November 11, 2009 11:20:09 PM
Subject: Re: [mems-talk] Si stress-strain relationship and allowable stress

The main cause for fracture in single crystal devices is stress
concentration - this may be design related but also, scratches, defects
surface pinhole etc are reducing the actual fracture strength of the
crystal.

Actually, the smaller the device area, the higher if fracture strength since
statistically it will have less defects.

Shay