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<p class="MsoNormal">Aamer,<o:p></o:p></p>
<p class="MsoNormal"> The way I understand your question is that you don’t want to run at higher chamber pressures than the increased oxygen flow will produce right? If so, you need to install a larger pump or increase conductance if possible. Since you are
running without a throttle valve, the chamber and pump are essentially acting in a manner as if the throttle valve were wide open. In this scenario, a throttle valve would only be useful to increase the chamber pressure.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-size:14.0pt">Steve Paolini<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">Principal Equipment Engineer<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">Harvard University Center for Nanoscale Systems<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">11 Oxford St.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">Cambridge, MA 02138<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">617- 496- 9816<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">spaolini@cns.fas.harvard.edu<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">www.cns.fas.harvard.edu</span><span style="font-size:14.0pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>From:</b> labnetwork-bounces@mtl.mit.edu <labnetwork-bounces@mtl.mit.edu>
<b>On Behalf Of </b>Dr. Aamer Mahmood<br>
<b>Sent:</b> Thursday, February 07, 2019 3:10 PM<br>
<b>To:</b> labnetwork@mtl.mit.edu<br>
<b>Subject:</b> [labnetwork] Chamber pressure during reactive e-beam evaporation<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">Hello all,
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">We have been doing reactive oxide depositions with e-beam evaporation of metals and a few sccm oxygen flowing through our system. We do not have a variable position
gate valve and can only control the oxygen MFC settings. The corresponding chamber pressure has been less than 2e-4 Torr. <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">I have recently received a request to deposit reactive metal oxide films at higher oxygen flow rates that'll correspond to higher chamber pressure during deposition.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">I am hesitant to increase the deposition chamber pressure due to the increased flow rate because the manufacturer mentioned the aforementioned chamber pressure as
an acceptable upper limit for the e-gun. <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">I'd appreciate any insights/experiences on this matter particularly 1) how does increased oxygen pressure in the chamber affect the system hardware, 2) any safety
concerns etc.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">Thanks in advance.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">-Aamer Mahmood<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">Qatar Environment and Energy Research Institute<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">Doha, Qatar<o:p></o:p></span></p>
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