[labnetwork] Bubble defects in Ebeam evaporated gold

[Matt Moneck]

Hi Sunanda,

We had similar issues in the past with a Fabmate (i.e. graphite) crucible.
We had the same gold nodules on the side of the crucible and we had similar
"bubbles" in some of our films.  We also saw carbon residue on the Au
charge.  After discussing with some companies, our Process Engineer prompted
the switch to a tungsten crucible and it solved all of our problems.  The
bubbles and nodules went away, and the the sheet resistance of our films
improved.  Tungsten is more expensive, but it is worth it in my opinion.

Best Regards,

Matt

-- 
Matthew T. Moneck, Ph.D.
Executive Manager, Carnegie Mellon Nanofabrication Facility
Electrical and Computer Engineering | Carnegie Mellon University
5000 Forbes Ave., Pittsburgh, PA 15213-3890
T: 412.268.5430
F: 412.268.3497
www.ece.cmu.edu
nanofab.ece.cmu.edu

-----Original Message-----
From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu]
On Behalf Of sunanda.babu at cense.iisc.ernet.in
Sent: Saturday, July 23, 2016 8:31 AM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] Bubble defects in Ebeam evaporated gold

Hi all,

We see bubble like defects in e-beam evaporated gold. One of the suspect is
the graphite crucible that we are currently using.

We see small gold nodules sticking to the walls of the graphite crucible.
These crucibles were procured from Testbourne(Glossy coated Graphite
crucible). The one we are using currently for gold evaporation is almost 2
years old. I was wondering whether there is a lifetime for these
crucibles.Do we use these crucibles until they crack? Does the glossy
coating degrade with time? Does the C start to contaminate the gold? I plan
to do an EDX analysis on this gold.

Has someone on Labnetwork faced a similar issue? Can you please advise?

thanks and best regards,
Sunanda Babu
Technology Manager(Thin Films and Dry Etch), National Nanofabrication
Centre, Centre for Nanoscience and Engineering, Indian Institute of Science,
Bangalore, India



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