Aluminum is highly stressed and easily attacked.  Either alter the
deposition method/rate/etc. to reduce stress or switch materials.  We make
nickel structures with much success.

--Jason Tauscher
        Silicon Designs, Inc.
        www.silicondesigns.com

-----Original Message-----
From: Robert Dean [mailto:rdean@memsoptical.com]
Sent: Saturday, June 13, 1998 2:32 PM
To: MEMS@ISI.EDU
Subject: aluminum bowing


Hello,

I am trying to fabricate a suspended aluminum (99% Al, 0.5% Si, 0.5% Cu)
structure, 1.15um thick on a silicon wafer.  The suspended length is
approximately 130um.  After the structure is released etched from the
silicon using XeF2, the aluminum bridge bows and twists due to stresses.
What causes this and how can I prevent it?  Thank you.

Sincerely,

Robert Dean
RF CMOS Designer
MEMS Optical
205 Import Circle
Suite 2
Huntsville, AL 35806
Tel. 256-859-1886
FAX 256-859-5890
email rdean@memsoptical.com