[labnetwork] Striking plasma on WO3 in Lesker PVD 75 issue

[Richelson, Tucson]

Hello,

I have a Lesker PVD 75. It was working fine last week with a TiO2 target. This week I swapped out the target for WO3 and suddenly the plasma won't strike.

Normal Operating Conditions:
Turbo                    30% speed
Pressure               50mTorr of Argon
Power                   50 W

I tried putting the TiO2 target back and it wouldn't strike either.
Usually I cut a circle of copper fabric and place it between the target and the sputter gun. That has worked for the past year. Usually when the plasma won't strike, I need to replace the copper fabric. I tried that and it didn't work.
Then I put some silver paste on the target and used the copper fabric and it worked! TiO2 had plasma strike.
I switched back to WO3, and used silver paste and copper fabric, but it won't strike.

Here's what I've tried:
Turbo                    20, 30%
Pressure               15, 50, 60, 70, 95mTorr of Argon
Power                   50, 60, 70 W

Any suggestions? What do you normally put between the target and the sputter gun?



Best,
Tucson Richelson
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