Spitting is caused by hot spots. I would recommend a lower deposition
rate or a much slower ramp-up process.

Dan

-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org] On Behalf Of Daniel Fine
Sent: Monday, March 31, 2008 8:08 AM
To: mems-talk@memsnet.org
Subject: [mems-talk] Pyrex ebeam evaporation

Hello,

  My name is Daniel Fine and I am a post doc at the University of Texas
at Austin.  I am trying to ebeam evaporate Pyrex (7740) and am running
into a problem where I am finding it hard to prevent bubbling and thus
spitting of the material when I try to achieve deposition rates of 5
Angstrom per second or higher.  The films are therefore covered with
non-uniform streaks of Pyrex.  I am using a CHA evaporator.  I have
tried a steady beam spot in one place and an oscillating beam spot as
well but get the same problem of large bubble formation.  I would
greatly appreciate any input concerning how I might over come this
problem.

Thanks,
  Daniel Fine