Hello
I am encountering Fe and other stainless steel (SS) element contamination in my LiCoO2 RF sputtering depositions. I suspect the source is the "etching" of the magnetron stainless steel frame during the process.
Experimental Details:
- Target: LiCoO2 (200 mm x 100 mm)
- Backing: Copper
- Power: 200 W
- Sputtering system: RF magnetron in Ar and O2 atmosphere
Observations:
- I have observed etching of the metallic SS frame that secures the target.
- I detected ferromagnetic scobs, in the target surface outside of racetrack.
- The deposited films (and the scobs) contain Fe and other SS elements, confirmed through EDS analysis.
- Presence of Ti in the scobs and deposition suggests contamination from previous depositions as well.
I am seeking advice on how to minimize Fe and other SS element contamination in my depositions.
Thanks in advance
Firstly you should avoid any SS ring attached to your target.
I really don't why some systems have this. especially vertically mount systems, and in some cases I have seen even the horizontal target mount systems also have a ring.
If you rf diode sputtering you have a problem.
But if you have a magnetron sputtering the magnets, the outer magnet ring
can be arranged in such a way, so that is away from the inner diameter of the SS frame ring used to mount the target.
1) In case your target is mounted vertically, (sideways sputtering arrangement, then you cannot avoid a SS frame.
2) Try to sputter at low powers., sorry it may not solve
3) Try to figure out a way how to mount your target without any SS ring and its screws. So that fully face of your target is facing the plasma without any ring.
2) If your target mount is horizontal, then normally you have a guard ring around the target electrode, and SS ring rests on it, and it is fully grounded.
The SS ring, and the guard ring (aluminum) should have a minimum gap of 2 to 3mm to prevent breakdown. In this design only the central target mount gets the rf power and sputters out.
K. Sreenivas thanks for you help.
It is in fact a vertical system. This effect only appear now that we use an older magnetron with new magnets, the previous one didn't show any problems like this, despite being a very similar one. This time I notice a pattern on the frame it was etched in a cyclic manner. I need to dive deeper in this. Thank for your help
I think there is easy way to avoid, if the target mounting ring is the cause . Lengthen the gun shield into target center than mounting ring edge