50A/s is very high. Try to lower the current to keep a rate of 2-5A/s. 1600A
is not thick, why did you use so high rate? Sputtering is another option to
have a good metal surface quality.

Good luck,

------------------------------------
Hongjun Zeng, PhD
MEMS/Nano Scientist
Nanotechnology Core Facility
(NCF formerly MAL)
University of Illinois at Chicago
3064 ERF Building
842 W. Taylor St., Chicago, IL 60607
Tel. 312-355-1259, Fax: 312-413-0447
------------------------------------


-----Original Message-----
From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org]
On Behalf Of Andrew Xiang
Sent: Monday, November 06, 2006 9:46 AM
To: General MEMS discussion
Subject: [mems-talk] grainy aluminum film

We looked at our aluminum under SEM and notice the surface is very grainy
under 40,000X. Don't know if it is normal. The Al is evaporated at 1E-6 torr
at 50A/s. Thickness about 1600A. Are there ways to reduce the grain
structure and make it more smooth?