Dear Debashish,

At higher energy Ar Plasma color goes to purple to blue: (email me directly
at main@nanomaster.com) to see two pictures on
the bottom of the WG where one plate is in Ar plasma the second one is in
the same plasma with -1000V bias.

On the other hand, in sputtering, plasma in front of the magnetron changes
color with the material being sputtered as well; for example Cu would make
the plasma color Green.

Power and pressure relates to brightness of the color (plasma density) but
if you further increase or lower the pressure you would lose the plasma
altogether.

Regards,

Birol Kuyel, Ph.D.
Nano-Master Inc.

-----Original Message-----
From: mems-talk-bounces+main=nanomaster.com@memsnet.org
[mailto:mems-talk-bounces+main=nanomaster.com@memsnet.org] On Behalf Of
DEBASHIS MAJI
Sent: Wednesday, September 08, 2010 9:57 AM
To: General MEMS discussion
Subject: Re: [mems-talk] Argon plasma color

Dear Ranjini,

Thanks for your help. The sputtering system that we are using here is a DC
sputtering unit. I shall be highly obliged if you can kindly elaborate me on
the topic and/ or provide me with any relevant books or paper describing
this observation.

Also does the shift towards blue indicate that transitions are shifting from
higher energy levels (purple color) to lower energy levels (blue color)...
if so why is it happening at high voltages and/or high pressure..? Plz
correct me if I am wrong...

I shall be highly obliged if you can kindly provide me some insight to the
matter.

Thanking you,
Debashis
PhD scholar, IIT Kharagpur, India - 721302