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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Hi Nava,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>I completely agree with Bob’s comments. We do the same at UCSB. We have a negative pressure regulator and are still capable of supplying the low sccm requirements of multiple systems. Cylinder temp will make a difference as our gas rooms are not conditioned, but we are in CA so it is not drastic climate change. If your cabinet is located behind the tool you should have no problem with this technique. I would have a quality two stage reg, set it as low a pressure (+10-20%) as possible to meet your tool requirements and make sure no one readjusts after that. It will be much simpler and we have not had an issue since this was implemented in more than 10 years.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Thanks, Tom</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Calibri",sans-serif'>--------------------------------------------------------------<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Calibri",sans-serif'>Tom Reynolds, Lab Manager<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Calibri",sans-serif'>UCSB Nanofabrication Facility<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Calibri",sans-serif'>Electrical and Computer Engineering Dept.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Calibri",sans-serif'>Engineering Science Bldg #225, Room 1109E<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Calibri",sans-serif'>Santa Barbara, CA 93106<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Calibri",sans-serif'>805-893-3918 x215 office<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Calibri",sans-serif'>805-451-3979 cell<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Calibri",sans-serif'>805-893-3918 fax<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Calibri",sans-serif'>reynolds@ece.ucsb.edu<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>From:</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> labnetwork-bounces@mtl.mit.edu [mailto:labnetwork-bounces@mtl.mit.edu] <b>On Behalf Of </b>Robert M. HAMILTON<br><b>Sent:</b> Tuesday, August 23, 2016 10:13 AM<br><b>To:</b> Nava Ariel Sternberg <na2661@columbia.edu><br><b>Cc:</b> Labnetwork <labnetwork@mtl.mit.edu><br><b>Subject:</b> Re: [labnetwork] Heating of BCl3 lines<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>Nava Ariel,<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>I recommend you do not heat (heat-trace) a BCl3 delivery line. Liquid BCL3 will then condense at any location along that line that is cooled and will pool as a liquid. I say this with decades of experience delivering BCl3 as an etch gas and as a dopant. There are several simple ways to deliver BCl3; the easiest being a low pressure or sub atmospheric pressure regulator. <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>The vapor pressure of BCl3 at room temp is ~ 19.4 psia or about 4.7 psi gauge. Use a regulator to reduce this pressure by ~ 50% of cylinder pressure, for the delivery you are assured BCl3 will remain a gas everwhere along the delivery line and within the tool. This pressure is also low enough to preclude adiabetic expansion with an associated phase change across the orifice of a gas flow controller or mass flow controller. We have been able to deliver several hundred sccm's, to multiple etchers using this delivery scheme. Note, our typical BCL3 cylinder is a 15 lb supply kept in a ventilated gas cabinet. Air movement in the cabinet adds enough heat to keep the cylinder temperature relatively constant given our delivery rates (we the same scheme for SiCl4). <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>The only cylinder gas issues I've seen in a research lab delivering a gas where the addition of heat was considered was at high NH3 flow rates. The cylinder temperature dramatically dropped at high flows thus reducing the available pressure and starving the line. Nitrous oxide is touted to have similar issues; however, our use rates are too small to be an issue.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>There's a caveat, however. We do not use outdoor storage our online cylinders and we live along a coast with moderated temperatures. A cold winter day might obviate the above approach. <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Regards,<o:p></o:p></p></div><div><p class=MsoNormal>Bob Hamilton<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div></div><div><p class=MsoNormal><br clear=all><o:p></o:p></p><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><p class=MsoNormal><br>Robert Hamilton<o:p></o:p></p></div><p class=MsoNormal>University of CA, Berkeley<br>Marvell NanoLab Equipment Manager<o:p></o:p></p></div><p class=MsoNormal>Rm 520 Sutardja Dai Hall, MC 1754<o:p></o:p></p></div><p class=MsoNormal>Berkeley, CA 94720<o:p></o:p></p></div><p class=MsoNormal>Phone 510-809-8618 (desk - preferred)<o:p></o:p></p></div><p class=MsoNormal>Mobile 510-325-7557 (my personal mobile)<o:p></o:p></p></div><p class=MsoNormal>E-mail preferred: <a href="mailto:bob@eecs.berkeley.edu" target="_blank">bob@eecs.berkeley.edu</a><br><a href="http://nanolab.berkeley.edu/" target="_blank">http://nanolab.berkeley.edu/</a><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div></div></div></div></div></div></div></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>On Tue, Aug 23, 2016 at 5:51 AM, Nava Ariel Sternberg <<a href="mailto:na2661@columbia.edu" target="_blank">na2661@columbia.edu</a>> wrote:<o:p></o:p></p><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in'><div><div><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-family:"Tahoma",sans-serif'>Dear all, <o:p></o:p></span></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-family:"Tahoma",sans-serif'>We have recently purchased a new Oxford Plasma Pro System100 Cobra RIE that we intend to use with Cl chemistry (III-V etc.). Oxford recommended heating the gas lines of BCl3. Does anyone have experience with it? We are low on $$$ right now. How necessary that is? What is the best way to do this? <o:p></o:p></span></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-family:"Tahoma",sans-serif'>Any thought would be appreciated. <o:p></o:p></span></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-family:"Tahoma",sans-serif'>Thanks!<o:p></o:p></span></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-family:"Tahoma",sans-serif'>Nava<o:p></o:p></span></p></div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><p class=MsoNormal><span style='font-family:"Tahoma",sans-serif'>Nava Ariel-Sternberg, Ph.D.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Tahoma",sans-serif'>Director of CNI Facilities</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Tahoma",sans-serif'>Columbia University</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Tahoma",sans-serif'>530 W120th Street, NY 10027<br>Room 1015/MC 8903<br>Office: <a href="tel:212-854-9927" target="_blank">212-854-9927</a></span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Tahoma",sans-serif'>Cell: <a href="tel:201-562-7600" target="_blank">201-562-7600</a></span><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div><p class=MsoNormal style='margin-bottom:12.0pt'><br>_______________________________________________<br>labnetwork mailing list<br><a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a><br><a href="https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork" target="_blank">https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork</a><o:p></o:p></p></blockquote></div><p class=MsoNormal><o:p> </o:p></p></div></div></body></html>