Hello,
I have used Al target to deposited AlN with Ar & N2. However, it seems the target is failed to produce plasma. I don't have any power and it happened suddenly. There is no forward power neither voltage.
I checked the connection between anode-cathode and it looks insulator, target is not poisoned (it has high current).
However, I don't know what are the possible options to damage magnets/ or target failure to sustain plasma power.
I had high forward voltage about 240V-290 V and sometimes there was some drops in voltage to 13.