[labnetwork] DEZ compatibility

[Hathaway, Malcolm]

Hi Yasmin,

ALD systems generally have stainless steel plumbing from the reactor back to the precursor cylinders.  On all the systems I’ve seen (including CVD and various plasma systems), VCR fittings are standard, with (on ALD systems) SS gaskets.  This is both for purity and chemical compatibility.  The precursor cylinders can be either SS or pyrex-like glass.  After the reactor, SS is still used for the plumbing, but viton orings and Quik-flange fittings are sufficient down to the pump.

In our system, the chamber is SS, but the lid is aluminum.  This can be an issue over time, as the chamber oring (often Kalrez but sometimes viton) can outgas fluorine, which changes to HF, which attacks the lid near the oring, causing pitting.  Not the end of the world (and curiously doesn’t seem to cause leaking, as the oring itself appears to protect the actual sealing surface), but it does lead to a bit more maintenance, (sanding or machining the general oring area to remove the pitting).

As for compatibility in the valve, below is a link to the Swagelok collection of ALD valves.  I’m not sure what the valve seating material is, but I’ve never heard of any compatibility issue with any ALD precursor with this line of valve. 

http://www.swagelok.com/search/find_products_home.aspx?SEARCH=/search/Atomic+Layer+Deposition+Valves/id-10002261/type-1&item=2aaa50c9-2b77-44aa-a4f9-63650971d876

Hope this helps!

Mac Hathaway
Harvard CNS

________________________________________
From: labnetwork-bounces at mtl.mit.edu [labnetwork-bounces at mtl.mit.edu] On Behalf Of Yasmin Afsar [yafsar at princeton.edu]
Sent: Thursday, October 04, 2012 12:20 PM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork]  DEZ compatibility

Dear colleagues,

I am a graduate student at Princeton currently working on a new system
for plasma-enhanced atomic layer deposition (PEALD) of ZnO and Al2O3.
We are outsourcing the production of the gas manifold, and we need to
supply this company with information about compatibility of our
metal-organic precursors with various components in the manifold.

Does anyone know the valve seat material compatibility for DEZ
(diethyl zinc) vapor, or what type of seat material is typically used
with DEZ? Since our group is new to ALD and to these materials, we
really do not know.

Any advice would be much appreciated!

Thank you,
Yasmin


Yasmin Afsar
Graduate Student
Electrical Engineering
Princeton University
yafsar at princeton.edu

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