We use argon as a sputtering background gas and 'ignite' it with a combination of RF, a filament glowing like an incadescent light bulb but with about 400 volts of bias applied to the filament. Between the three, we get 'ignition'. In the presence of just RF, there is an alternate method: in the first method, the gas pressure has to be around 4 millitorr minimum, we use between 5 and 10 millitorr usually. But another sputtering tool uses the alternate method, that is it boosts the argon pressure up to about 20 millitorr for a brief period in the presence of an RF field, that gets it going also.
Argon is like a molectular bead blaster (sand blaster) and the RF is applied to the 'target' which is the stuff we want to sputter and coat onto a substrate. In our case, aluminum, silicon dioxide (glass), silicon Carbide, and silicon chrome, all for different effects, some for power conducting lines, others for resistive values, others for insulation or a hard coating for wear resistance. But all get their little molecules or atoms knocked off the target by the combined effect of the plasma of Argon which makes a cloud of the target stuff which coats a substrate passing in front in a back and forth sweeping action. We apply coatings from 300 Angstroms thick to 20,000 Angstroms (2 microns). You are doing it with just ultra high voltage. You will find you can do it with a lot less voltage than that from a Tesla coil. Like I said, our bias is only a few hundred volts. Remember the old Neon lights? The tiny bulb ones fire at around 100 volts or less.
