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<span style="color:rgb(0,0,0); font-size:13pt; font-family:Calibri,Helvetica,sans-serif">Hi,</span></div>
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<span style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif; font-size: 13pt;">We use a Leybold univex 400 with EV M-8 ferrotec e-gun assembly for out metal coatings. We have been using an optimized recipe for Al deposition in Cu crucibles
for long. </span><br>
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<pre><span style="color:rgb(0,0,0); font-size:13pt; font-family:Calibri,Helvetica,sans-serif">Power % : Raise 1: 10% (V= 10 KV and I ~ 110 mA), 5 mins, hold 2 mins
Raise 2: 22% (V= 10 KV and I ~ 220 mA), 5 mins, hold 2 mins
During the deposition Power % goes up to 24% and the current
goes up to 240 mA ( V = 10 KV constant)</span></pre>
</span><span style="font-family:Calibri,Helvetica,sans-serif; background-color:rgb(255,255,255); color:rgb(0,0,0); font-size:13pt; display:inline!important">Some spit is seen during raise 2.</span></div>
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<span style="font-family:Calibri,Helvetica,sans-serif; color:rgb(0,0,0); font-size:13pt">But recently we got serious concern of Cu crucible melting, mostly towards the gun side. We set the beam as spot pattern (for Ti, beam profile is infinity pattern), but
it looks elongated. Beam is centred well. We set the deposition rate to 0.3 nm/sec. Hearth cooling is done at 20 deg C, with water flow rate at 6 litre per minute. Al source fill in crucible is around 70-80%. Beam ramp down is 5 minutes. Chamber venting is
set after 25 minutes.</span><br>
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<span style="color:rgb(0,0,0); font-size:13pt; font-family:Calibri,Helvetica,sans-serif">We used an infinity beam pattern to deposit a thick Al metal coating sometime back. We changed all our settings back to spot pattern again. This issue started after that.
Seems, somehow the beam did not come back to previous focus.</span></div>
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<span style="color:rgb(0,0,0); font-size:13pt; font-family:Calibri,Helvetica,sans-serif">We need to know, has anyone came across something like this, and how to overcome this. Any information would be helpful.</span></div>
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Thanks.</div>
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Savitha</div>
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<div>Dr. Savitha P<br>
Chief Operating Officer</div>
<div>National Nanofabrication Centre<br>
Centre for Nanoscience and Engineering<br>
Indian Institute of Science<br>
Bangalore - 560012<br>
India.<br>
Ph. +91 80 2293 3319<br>
www.cense.iisc.ac.in</div>
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