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Thanks everyone for your comments/suggestions last week. In case you're interested,
<a href="https://chanl.unc.edu/wp-content/uploads/sites/18385/2024/05/BowTie_EBL1.jpg" id="LPlnk" title="https://chanl.unc.edu/wp-content/uploads/sites/18385/2024/05/BowTie_EBL1.jpg">
here</a> are some optical images of the structure provided by the user. Additional details about the fabrication are included. The user is pretty convinced that the issue is not with the EBL process (beam blanking, charging, incomplete development, etc).
We're considering electron deflection magnets, which apparently are offered by the vendor (KJLC). </div>
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Best,</div>
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Bob</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Youry Borisenkov <yb2471@columbia.edu><br>
<b>Sent:</b> Wednesday, May 22, 2024 10:31 AM<br>
<b>To:</b> Geil, Bob <bob.geil@unc.edu><br>
<b>Cc:</b> labnetwork@mtl.mit.edu <labnetwork@mtl.mit.edu><br>
<b>Subject:</b> Re: [labnetwork] Ebeam evaporation - arcing between features</font>
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<div dir="ltr">Hi,
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<div>What materials is the user trying to deposit?<br>
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<div>There is definitely charging happening during ebeam evaporation (my symptoms were bubbles in PMMA resist). <br>
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<div>I would recommend switching to thermal evaporation if possible, or lowering the power/rate during the deposition. It could also be caused by contamination in the crucible. </div>
<div>Using magnets around the substrate to deflect electrons from reaching the substrate also showed good results on a small area samples.</div>
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<div>Thank you,</div>
<div>Youry</div>
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<div dir="ltr" class="x_gmail_attr">On Tue, May 21, 2024 at 6:44 PM Geil, Bob <<a href="mailto:bob.geil@unc.edu">bob.geil@unc.edu</a>> wrote:<br>
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Hello labnetwork,</div>
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I have a user that is fabricating some electrodes and has observed what appears to be arcing between the sharp points of the electrodes. Imagine features like this: > < where the distance between them is 2um - 8um. The substrate is quartz. Fabrication approach
is 1) ebeam lithography 2) ebeam evaporation and 3) lift-off.</div>
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After EBL development, the electrode circuit is open, as intended</div>
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After evaporation +lift-off, there is a line about few 100nms wide that is shorting the electrodes: >-<</div>
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There is not a short between the electrodes with the 8um gap, however, there are some metal lines extending from the two sides: >- -<</div>
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All of this suggests that arcing is occurring. Has anyone observed this before and can you suggest ways to get around it?</div>
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Thanks,</div>
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Bob</div>
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Bob Geil, PhD </div>
<div style="margin:0px; font-family:Arial,sans-serif; color:rgb(0,0,0)"><span style="font-size:10pt">Technical Director
</span><span style="font-size:13px">•</span><span style="font-size:10pt"> CHANL</span></div>
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Dept. of Chemistry • UNC-CH</div>
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Chapel Hill, NC </div>
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