Sputtering
The substrate is placed in a vacuum chamber with a target of the material to be deposited. A plasma is generated in a passive source gas (ie. Argon) in the chamber, and the ion bombardment is directed towards the target, causing material to be sputtered off the target and condense on the chamber walls and the substrate. A strong magnetic field (magnetron) can be used to concentrate the plasma near the target to increase the deposition rate.