<div dir="ltr">Nava Ariel,<div><br></div><div>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. </div><div><br></div><div>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). </div><div><br></div><div>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.</div><div><br></div><div>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. </div><div><br></div><div>Regards,<br></div><div>Bob Hamilton</div><div><br></div><div><br></div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div><div><div><div><div><br>Robert Hamilton<br></div>University of CA, Berkeley<br>Marvell NanoLab Equipment Manager<br></div>Rm 520 Sutardja Dai Hall, MC 1754<br></div>Berkeley, CA 94720<br></div>Phone 510-809-8618 (desk - preferred)<br></div>Mobile 510-325-7557 (my personal mobile)<br></div>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></div><div dir="ltr"><br></div><div dir="ltr"><br><div><div><div><div><div><div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>
<br><div class="gmail_quote">On Tue, Aug 23, 2016 at 5:51 AM, Nava Ariel Sternberg <span dir="ltr"><<a href="mailto:na2661@columbia.edu" target="_blank">na2661@columbia.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_default" style="font-family:tahoma,sans-serif">Dear all, <br><br></div><div class="gmail_default" 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? <br><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">Any thought would be appreciated. <br><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">Thanks!<br><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">Nava<br><br></div><div><div data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><span style="font-family:tahoma,sans-serif">Nava Ariel-Sternberg, Ph.D.</span></div><div><span style="font-family:tahoma,sans-serif">Director of CNI Facilities</span></div><div><span style="font-family:tahoma,sans-serif">Columbia University</span></div><div><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" value="+12128549927" target="_blank">212-854-9927</a><br></span></div><div><span style="font-family:tahoma,sans-serif">Cell: <a href="tel:201-562-7600" value="+12015627600" target="_blank">201-562-7600</a></span><br></div><div><br></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>
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