We have a Diborane-Nitrogen system, and would like to use duplex panels w/ two stage regulators. Can we use this type of a panel set up instead of cabinets on a Diborane-Nitrogen system?

For systems involving diborane, we would recommend fully automated gas cabinets instead of manual gas panels for the following reasons.

  1. According to the UFC, gases such as diborane must be housed in an exhausted enclosure. Having them in a gas bunker, but open to the room doesn’t protect the operator should an accidental discharge occur while a technician is in the room.
  2. Known issues with Diborane systems. We have other customers who are running diborane systems on manual panels, and they have experienced a number of failures. One of the key reasons that gases like these are controlled by automated systems is that an automated cylinder reduces the mistakes caused by human error that happen with manual cylinder changes. A cycle purge needs to be performed a certain way each time to be effective, and this must happen before the empty cylinder is changed, and again after the new cylinder is brought online. People can get busy or lose track of the number of cycles, or it can happen where a smaller number than anticipated of cycle purges occurs, gas is introduced and you get a contaminated gas panel, potentially sending contaminated gas down the delivery line to the process tool. With the automated system, the number of cycle purges are entered into the system, and the system walks the operator through the cycle purge sequence assuring that each purge sequence is done properly. Diborane is a particularly problematic gas. When it is combined with nitrogen and subject to pressure drops, the Joule-Thomson effect across orifices causes the diborane to break down forming decaborane (B10H6) which prevents the seats from completely closing and you get across the seat leaks in the regulators. If you introduce moisture from ambient air into the equation, which can be caused by insufficient or incorrect bottle change procedures, then you can get a gummy, sticky boric acid residue that often contaminates the whole gas line. We have seen other users with diborane issues set their cycle purges often over 100 pre and post purges to avoid the problem.
  3. Critical Systems reputation. We have provided hundreds of gas delivery systems over the 12 years we have been in business, and we have an excellent track record of safety, long product life and superior product knowledge. If we would recommend manual systems, and they don’t last, our reputation with the becomes tarnished. We would rather “no quote” the manual system and lose the order rather than providing something we’re pretty sure won’t work, and seeing an unsatisfied customer down the road.

Click here for some quick tips for handling diborane gas systems.

Click here for a writeup on Diborane composition.

 

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