The use of a liner not in contact with the hearth worries me. The idea is to have the Au hot and the liner much cooler to prevent the Au from wetting to the liner. I use a liner (graphite or tungstun) with a Temescal VES 2550 e-gun and with a long (2.5 min.), ramp, soak (2 min (below melting point)), and a slow ramp hotter pre-dep (just a little above melting), can deposite Au at 25A/sec with no spitting. I'm not sure why some of you are having so many issues with Au evaperation. Please tell me if you still have spitting issues. Brent Original Message: ----------------- From: Buncick, Milan (Contractor-AEgis TG) milan.buncick@us.army.mil Date: Fri, 26 Mar 2004 13:50:52 -0600 To: mems-talk@memsnet.org Subject: RE: [mems-talk] Metal Spitting We are using a tungsten liner and have reduced spitting by about 95%. We also elevate the liner by putting a couple of small pieces of tungsten boat material in the bottom of the crucible under the liner. By heating the liner and the gold the whole gold charge melts and eliminates the spitting. The spitting occurs at the edge of the melted charge if all the gold doesn't melt. Heat slowly and spread the e beam as suggested below and you get great films. Milan -----Original Message----- From: Jeff Simkins [simkinjr] [mailto:simkinjr@email.uc.edu] Sent: Friday, March 26, 2004 11:28 AM To: 'General MEMS discussion' Subject: RE: [mems-talk] Metal Spitting I would like to learn more about this, because gold likes to spit more than any other metal that I have evaporated. At least you are programming your soak power and deposition power. I still set up those manually, changing power depending on what is new in the pocket. Looking directly at the source (gold melt) through a filtered viewport, I cannot see spitting of the metal. It is only after I drop my view to see only above the source, that I can see little fire balls of molten gold launching from the source. I drop the power until I no longer see this effect. Deposition rate is somewhere between 2 to 5A/s. If you have pole extensions on your gun, try spreading your beam density. A high density beam (small spot) has always been trouble for me. I don't use sweep for gold. Throw distance: Are your substrates far enough away from the source that the spit does not reach your substrates? Good luck! Jeff _______________________________________________ MEMS-talk@memsnet.org mailing list: to unsubscribe or change your list options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk Hosted by the MEMS Exchange, providers of MEMS processing services. Visit us at http://www.memsnet.org/ -------------------------------------------------------------------- mail2web - Check your email from the web at http://mail2web.com/ .