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