Amigo Rafael,

I would invest in a decent Quartz crystal thickness monitor. When properly
calibrated, it could take most of the uncertainties away.

Also, make sure the vacuum stays high (<10-6 Torr) during the deposition, as
Aluminum oxidizes quite readily.

Good luck,

Pedro Barrios

-----Original Message-----
From: mems-talk-bounces+pedro.barrios=nrc-cnrc.gc.ca@memsnet.org [mailto:mems-
talk-bounces+pedro.barrios=nrc-cnrc.gc.ca@memsnet.org] On Behalf Of Rafael
García Valverde
Sent: March 22, 2011 4:07 AM
To: General MEMS discussion
Subject: [mems-talk] Problems with Al evaporation

Hi everybody,

We need some advice, critics or suggestion.

We are trying to thermally evaporate Al layers on glass substrates. We are
using Tungsten filaments in spring form and holding the Al filaments inside
the Tungsten spring. Our vacuum arrives to 10^(-6) mbar and the DC current
is gradually raise to 18-20A (the tungsten filament becomes incandescent),
we keep the DC current until we don't see any Al inside the tungsten spring..
Apperently everything is right and the first days we achieved some
acceptable layers, but after a few days the Al layers are extremelly thin
(almost invisible).

Maybe the chamber is dirty? Any possible treatment for cleaning it?

Thanks in advance.

Regards

Rafael García Valverde, PhD