<div dir="ltr"><div>I would check your beam steering. You made need to adjust where it is dropping.</div><div>Also check the wiring to beam steering magnets on the e-gun. If a wire is broken it could cause misdirection.</div><div>Next, you may need to clean or replace the hearth assembly. You may be losing conductivity under the crucible due to buildup.</div><div><br></div><div>Jim</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Dec 13, 2021 at 7:51 AM Savitha P <<a href="mailto:savithap@iisc.ac.in">savithap@iisc.ac.in</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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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
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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">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>
<a href="http://www.cense.iisc.ac.in" target="_blank">www.cense.iisc.ac.in</a></div>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><span style="font-size:12.8px"><font face="verdana, sans-serif" color="#990000"><i><b>James Mitchell</b></i></font></span><div style="font-size:12.8px"><font color="#990000"><span style="font-size:12px;background-color:rgb(248,248,248)"><i><font face="verdana, sans-serif"><b>Specialty Trades Technician</b></font></i></span></font></div><div style="font-size:12.8px"><font face="verdana, sans-serif" color="#990000"><i>Dept. of Electrical and Computer Engineering</i></font></div><div style="font-size:12.8px"><font face="verdana, sans-serif" color="#990000" style="letter-spacing:0.2px"><i>NCSU Nanofabrication Facility</i></font></div><div style="font-size:12.8px"><font face="verdana, sans-serif" color="#990000" style="letter-spacing:0.2px"><i>MRC RM243A </i></font><font color="#990000" face="verdana, sans-serif" style="letter-spacing:0.2px"><i>Box 7911</i></font><font face="verdana, sans-serif" color="#990000"><i><br></i></font></div><div style="font-size:12.8px"><font color="#990000" face="verdana, sans-serif" style="letter-spacing:0.2px"><i>2410 Campus Shore Dr., Raleigh, NC 27606</i></font></div><div style="font-size:12.8px"><a href="mailto:jtmitch5@ncsu.edu" target="_blank"><font face="verdana, sans-serif" color="#990000"><i>jtmitch5@ncsu.edu</i></font></a></div><div style="font-size:12.8px"><font face="verdana, sans-serif" color="#990000"><i>Desk: 919-515-5394</i></font></div><div style="font-size:12.8px"><font face="verdana, sans-serif" color="#990000"><i>Cell: 919-717-7325</i></font></div><div style="font-size:12.8px"><font face="verdana, sans-serif" color="#990000"><i><img src="https://docs.google.com/uc?export=download&id=1wEnuxEKmYrE8wihsULSXEFOKuDnyUWXs&revid=0B6IsvvpTMVVfNlZ5cGRoRGhzSy9TVklabnlnMFZWdzdqYm00PQ" width="200" height="112"><br></i></font></div></div></div></div></div></div></div></div></div>