[labnetwork] Chamber pressure during reactive e-beam evaporation

[Paolini, Steven]

Aamer,
  The way I understand your question is that you don't want to run at higher chamber pressures than the increased oxygen flow will produce right? If so, you need to install a larger pump or increase conductance if possible. Since you are running without a throttle valve, the chamber and pump are essentially acting in a manner as if the throttle valve were wide open. In this scenario, a throttle valve would only be useful to increase the chamber pressure.

Steve Paolini
Principal Equipment Engineer
Harvard University Center for Nanoscale Systems
11 Oxford St.
Cambridge, MA 02138
617- 496- 9816
spaolini at cns.fas.harvard.edu
www.cns.fas.harvard.edu

From: labnetwork-bounces at mtl.mit.edu <labnetwork-bounces at mtl.mit.edu> On Behalf Of Dr. Aamer Mahmood
Sent: Thursday, February 07, 2019 3:10 PM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] Chamber pressure during reactive e-beam evaporation

Hello all,
We have been doing reactive oxide depositions with e-beam evaporation of metals and a few sccm oxygen flowing through our system. We do not have a variable position gate valve and can only control the oxygen MFC settings. The corresponding chamber pressure has been less than 2e-4 Torr.
I have recently received a request to deposit reactive metal oxide films at higher oxygen flow rates that'll correspond to higher chamber pressure during deposition.
I am hesitant to increase the deposition chamber pressure due to the increased flow rate because the manufacturer mentioned the aforementioned chamber pressure as an acceptable upper limit for the e-gun.
I'd appreciate any insights/experiences on this matter particularly 1) how does increased oxygen pressure in the chamber affect the system hardware, 2) any safety concerns etc.
Thanks in advance.

-Aamer Mahmood
Qatar Environment and Energy Research Institute
Doha, Qatar

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