Argon is introduced, then
ionized in the chamber which contains the substrate and the target of the film
material to be sputtered. The target is maintained at a negative potential relative to
the positively charged argon atom. The positive ion accelerates towards the
negative charge, striking the target with sufficient force to remove material. The
argon atom does not become imbedded in the target. It slams into it like a steel
ball into the wall and tears off some of the target material. Since the chamber is
maintained at a vacuum, the liberated material settles on everything in the
chamber, mainly the substrates.