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<p class="MsoNormal">If this was improperly shut down(not allowed to cool off and turned off) the palladium plates can crack and cause gasses to leak through the material.
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<p class="MsoNormal"><b><span style="color:#002060;text-transform:uppercase">Deon D. Collins<o:p></o:p></span></b></p>
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<i>FACILITY MANAGER</i><br>
</span><span style="color:#002060">Holonyak Lab</span><span style="color:#002060"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#002060">University of Illinois at Urbana-Champaign</span><span style="color:#1F497D"><br>
</span><span style="color:#13294B">208 N Wright St Rm. 248 | 2250</span><span style="color:#1F497D"><br>
</span><span style="color:#13294B">Urbana, IL 61801</span><span style="color:#1F497D"><br>
</span><span style="color:#13294B">217-300-7531 | </span><span style="color:#1F497D"><a href="mailto:deonc69@illinois.edu"><span style="color:#0563C1">deonc69@illinois.edu</span></a><br>
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</span><a href="http://illinois.edu/"><span style="color:#1F497D;text-decoration:none"><img border="0" width="119" height="21" style="width:1.2395in;height:.2187in" id="Picture_x0020_1" src="cid:image001.png@01D7C5A7.A4DC24A0" alt="https://webtools.illinois.edu/webservices/js/ds/signature_logo.png"></span></a><span style="color:#1F497D"><br>
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</span><i><span style="color:#666666">Under the Illinois Freedom of Information Act any written communication to or from university employees regarding university business is a public record and may be subject to public disclosure.
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<p class="MsoNormal"><b><span style="font-size:10.0pt;color:#A3238B">I’m so tired of being tired, Sure as night will follow day, Most things I worry about never happen anyway.<o:p></o:p></span></b></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;color:#A3238B"> Tom Petty<o:p></o:p></span></b></p>
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<p class="MsoNormal"><b>From:</b> labnetwork <labnetwork-bounces@mtl.mit.edu> <b>
On Behalf Of </b>Rachel Schoeppner<br>
<b>Sent:</b> Wednesday, October 20, 2021 10:51 AM<br>
<b>To:</b> labnetwork@mtl.mit.edu<br>
<b>Cc:</b> Lillian Hughes <lbhughes@ucsb.edu><br>
<b>Subject:</b> [labnetwork] Johnson Matthey H2 Purifier<o:p></o:p></p>
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<p class="MsoNormal">Good Morning, <o:p></o:p></p>
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<p class="MsoNormal">We have a Johnson Matthey HP-25 hydrogen purifier that we suspect is not functioning properly. In its idle state it is kept under low UHP N2 flow, and we think that some of this is getting through the purifier into the lines of our CVD.
At the start of deposition when we start H2 flow and ignite the initial plasma we see an unexpected peak in nitrogen (verified both in the emission spectrum of the plasma as well as nitrogen that is incorporated in the epitaxial film as measured with SIMS).
When we flow the hydrogen gas through the growth chamber for ~20 min before deposition, no nitrogen peak is observed, suggesting that it is coming in as an initial “plug” through the purifier at the very beginning that can be flushed through. There is also
a low amount of background nitrogen throughout the deposition (this could be an impurity in the methane, but I am not sure how likely that is). <o:p></o:p></p>
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<p class="MsoNormal">We have leak checked the line running from the purifier to the CVD chamber and cannot detect any leaks that might be causing the initial nitrogen spike.<o:p></o:p></p>
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<p class="MsoNormal">We are wondering if anyone has experience with these purifiers or ideas on how to diagnose their proper functionality. If it is letting unwanted species through, then what would be our options for fixing or replacing it?<o:p></o:p></p>
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<p class="MsoNormal">Thank you!<o:p></o:p></p>
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<p class="MsoNormal">Rachel<o:p></o:p></p>
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— <o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black">Rachel Schoeppner, Ph.D</span></b><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black">Nanostructure Cleanroom Facility Manager<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black">California NanoSystems Institute (CNSI)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black">University of California, Santa Barbara<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black"><a href="mailto:rlschoeppner@ucsb.edu">rlschoeppner@ucsb.edu</a><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black"><a href="mailto:rachel@cnsi.ucsb.edu">rachel@cnsi.ucsb.edu</a><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black">(805)893-2296<o:p></o:p></span></p>
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