Specialized Susceptors for SSI RTP in URnano
A new user in URnano has used the “old” susceptor for a ~270 C (I might have the exact number wrong, but it is relatively low temp) to heat In on GaAs. I don’t think there was ever a good reason for using the RTP for this process, but what is done is done. I found a new susceptor in SiMPore’s storage bin and placed it on the bottom shelf of the RTP table and labeled is “Si, SiO2, and SiN only”.
Chris- I hope this is okay. The susceptor hasn’t been used yet, so if you foresee any problems I can hide it and we can order another one etc…
Be careful! There is also a susceptor similarly kept but for “Carbonization” only.
Hopefully utilizing the 3 separate susceptors will be sufficient to avoid contamination between users/processes.
I think this one process at this low temperature is probably OK. Hopefully the Indium simply melted on the sample and did not touch the susceptor. The fact that a susceptor was used instead of a cheap Si wafer shows that an inexperienced or potentially untrained person was involved.
Are the susceptors in some sort of protective box? My concern is that they cost $3000 each, so should be treated with care, as they cannot be repaired once damaged. I also worry that if all 3 susceptors are out, we have no backup. We were using that older susceptor and holding the new one as a backup. If we start using the new one, another should really be purchased.
We have got to get this tool labeled as a “CLEAN” tool. It is insane that this is the only high-temp capability in the URNano, but that’s the world in which we live. If we don’t put some restrictions on it, people will start using it to make pancakes and waffles, so how do we start this process. Can we change the password today or will that tick too many people off? Have you mentioned anything to Alex?
Thanks!
I brought this up with Alex and Brian yesterday. We had a relatively long discussion where I clearly “asked” them to make rules to reduce risk of contamination, since we aren’t allowed to make rules and there are currently none in place. Using the different susceptors was my suggestion. The susceptor used for In/GaAs is currently residing on top of the RTP, as it always has been in the past. The newer, “clean”, suscpetor is on the shelf below.
I realized midway through our conversation yesterday that Brian did not know that the process had already taken place. I don’t believe he would have okayed it without at least a heads up to us. He also argued that the user should have used a different tool, if possible.
Alex got the info from the susceptor labels, hopefully so that he could check prices. I’m shocked by the $3000 price tag. I’m sure they will be as well.
All that said, I believe changing the password would really make them angry. Brian pointed out that he pays to fix it, and he needs to get other users in URnano. I would suggest that we instead propose some sort of a review process for new users using “our” tools, such as the AJA, SSI RTP, and YES system. But for all I know, that already exists.
I’m curious how much he actually “pays” for this tool. There was a very major repair involving the fluid flow in the chamber that SiMPore handled entirely, and he certainly did not pay for the current quartz chamber or any of the susceptors. I think he just paid for a repair of the tray and a couple of the TCs. It really costs him very little.
These susceptors are machined from a pure graphite substrate and coated with over 100um of SiC. These materials are specifically designed to handle the rigors of the rapid thermal environment. Unfortunately your average machine shop cannot make these things….