[labnetwork] Sputter problem

[Gupta, Su]

Hi Keith:

Can you give me some more details about your sputter system and the processs? For instance, are you sputtering reactively from a Ti target or is it TiO2? If you are doing DC reactive sputtering from an elemental target, then the target voltage is the best indicator of what is going on with the process. For instance, the target may be oxidizing further with each run (even with the preclean) and you may be dropping down the slope of the hysteresis loop from the 'metallic' rate to the "oxidized" rate, which would be accurately reflected in a drop in the target voltage. A small leak or outgassing could also cause this type of problem, but it probably would not be as regular and systematic as what you are observing.

Regards,
Su Gupta
Assoc. Prof, MTE
Faculty Director, uamcro
Univ. of Alabama
________________________________
From: labnetwork-bounces at mtl.mit.edu [labnetwork-bounces at mtl.mit.edu] On Behalf Of Keith Bradshaw [bradshaw1234 at gmail.com]
Sent: Thursday, June 23, 2011 5:09 PM
To: labnetwork at mtl.mit.edu; Steven Foland
Subject: [labnetwork] Sputter problem

We are sputtering TiO2 .

We begin the day with a 250 angstrom rate....each subsequent run is reduced by 10-15% in rate until we are at a 125 angstrom rate.  We are not changing anything.

Next day we begin again at 250.

Tried argon clean between runs, tried 3 hour wait between runs, we are using a load lock and vacuum looks stable , still rate drops on each run.

Any ideas?

cordially,

Keith Bradshaw
Dallas