[labnetwork] Heating of BCl3 lines

[Vito Logiudice]

Hi Nava,

I would definitely heat trace a BCl3 line as I would be concerned about the risk of condensation at any cold spots along the distribution network. I believe the initial cost of the heat trace & insulation would be cheap compared to the possible damage caused by condensing BCl3 inside the lines. I’m sure other, much more qualified people will be able to offer relevant insights on this particular point (perhaps our friends at Critical Systems – Tom?).

If it can help, I’ve attached a screenshot of the installation instructions that came with the heat trace we used for our dichlorosilane lines. If you do decide to go that route, I recommend the heat trace be kept in intimate contact with the gas line via the use of aluminum tape all along the line. One of our heat traces ended up failing because of gaps between the trace and the tubing. I think I learned of this possibility via the lab network where someone had used aluminum tape to minimize the risk of these gaps in their installation (I think it was John Shott from Stanford). If you search past posts you might come across my original posting and the related suggestions; it may have been back in early 2015 if memory serves correctly. We ended up using aluminum tape rated for 350F and subsequently insulated the entire heat traced line from gas cabinet to point of use. We’ve had no issues since then (thanks, John!).

The second attachment is a photo of the insulated line when it first failed. The IR thermometer shows one of the locations (elbow) where the heat trace had failed since it had not been originally installed in intimate contact with the SS tubing at the elbow. Temperatures along the line were typically hovering at 20C but it was measured to be 31C at this particular elbow. The final attachment is a snapshot of the failed heat trace at this particular spot.

Hope this helps.

Best,
Vito
--
Vito Logiudice  P.Eng.
Director of Operations, Quantum NanoFab
University of Waterloo
Lazaridis QNC 1207
200 University Avenue West
Waterloo, ON           Canada N2L 3G1
Tel.: (519) 888-4567  ext. 38703
Email: vito.logiudice at uwaterloo.ca<mailto:vito.logiudice at uwaterloo.ca>
Website: https://fab.qnc.uwaterloo.ca


From: <labnetwork-bounces at mtl.mit.edu<mailto:labnetwork-bounces at mtl.mit.edu>> on behalf of Nava Ariel Sternberg <na2661 at columbia.edu<mailto:na2661 at columbia.edu>>
Date: Tuesday, August 23, 2016 at 8:51 AM
To: "labnetwork at mtl.mit.edu<mailto:labnetwork at mtl.mit.edu>" <labnetwork at mtl.mit.edu<mailto:labnetwork at mtl.mit.edu>>
Subject: [labnetwork] Heating of BCl3 lines

Dear all,

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?

Any thought would be appreciated.

Thanks!

Nava

Nava Ariel-Sternberg, Ph.D.
Director of CNI Facilities
Columbia University
530 W120th Street, NY 10027
Room 1015/MC 8903
Office: 212-854-9927
Cell: 201-562-7600

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