In RF sputtering system, there is control panel in build with the system, which is used to control and adjust the cathode power, here my question is that what is Reverse Power (RP)...? while we are applying the power (for example 100 watts) means, reverse power is showed that 20 watts. I thought that the target power of 100 watts should not be there in the cathode,
Kindly give your valuable ideas and suggestions for this above-mentioned questions, which may be useful for me.
It should be reflected power, not reverse power,
RF powder is coupled to the target capacitively. If there is an impedance mismatch, then the power applied (say 100 watts) will not be fully coupled with the target, and there will be reflected power which you see as 20 watts in your case.
In other words this is known as max power transfer theorem, which is taught in electronics.
For a good coupling of power to the target the reflected power should be zero watts. Sometime in some systems, due to some mismatch there is some problem or the other, and you see some reflected power.
Be careful if you see a much larger value for the reflected power (say > 25 watts, or it keeps on increasing), for an applied forward power of 100 watts, it is not good for the system (power generator) to see a large value of reflected power.
In you rf system if your have the tuning and coupling knobs, then you should properly adjust them for achieving good impedance matching, so that you see a minimum of reflected power (say zero watts). Which means all the forward power of 100 watts which you have applied is efficiently transferred to the target.
K. Sreenivas
Dear Professor,
Thank you for your valuable and reasonable answer.
Thanks and Regards
G.Durai.
maybe i can help you but need more explanation what you want exactly!
Dear Fatemeh Jafari,
I am working with sputtering instrument to deposit thin films for my research work, so in that case, while I am applying the RF power (for example 100 watts) means, reverse power is showed that 20 watts I don't know why ? For this question, I would like to know the answer.
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