Dear Debashish,

when you vary the power or pressure in the system , then the number of
charge particles/ or excited particles and their energy level varies. shift
in color is due to change in available energy levels.

what sort of plasma system do you have? RF CCP?

 thanks

On Tue, Sep 7, 2010 at 5:59 PM, DEBASHIS MAJI wrote:

> Dear All,
>
> I would like to ask why does the color of the argon plasma during
> sputtering
> changes form light purple to bright blue as the deposition power is
> increased or the working pressure is increased to about 0.1 m bar? Is the
> shift in color towards deep blue, due to formation of increased number of
> energy states...? if so  how is it happening with increased power and/or
> with increased working pressure..?
>
> Thanks in advance....
>
> Debashis Maji,

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