In Reply to: Re: need help with ignition and stability of plasma (Perkin-Elmer 2400) posted by Pat McMahon on 07/10/02 at 10:05 PM:
Thank you very much for your advice.
The problem with ignition happens with all targets, so contamination of bell-jar is very probable. I rather thought that after arcing of Si-target some parts are contaminated with silicon.
So maybe I should clean the dark shields.
Oxygen can be present in the system, because I use also SiO2 target.
I will check also water-vacuum sealing.
The system is pumped with turbo and rotary pumps, so I thought it is not necessary to use nitrogen trap, but it seems I'm wrong.
I was also suspicious about electric circuit.
Do you think that arcing target can damage tuning circuit or ignitor?
Also the target may be damaged itself - I mean, if the surface become porous Si, maybe I won't be able to grow high-quality films anymore (because of Si-lumps)?
First, I will check water-vacuum sealing, as you advice.
(I also checked partial-pressure meter, and it shows, that among the contaminants H2O is number one...)