as he ne ar kr xe although reactive gases such as o 2 n 2 co 2 f 2 ch 3 or combinations thereof can also be used when these ions are from an inert gas source the target material 2 is sputtered and then deposits as a film on the substrate 4 on substrate holder 5 when these ions are from a reactive gas source they can combine with target material 2 and the product of this chemical combination is what is sputtered and deposited as a film on the substrate 4 commonly the bombarding ions should have energies of several hundred ev u2014 a range of 200 ev to 10 kev being preferred the ion flux or current should be sufficiently high gt 10 13 ions cm 2 s to maintain practical deposition rates gt 0 1 nm min typically the process pressure is about 10 u2212 4 torr with a preferred range 10 u2212 3 10 u2212 5 torr the target material can be elemental such as si ti mo cr or it can be multi component such as moxsiy or it can be a compound such as sio 2 the substrate can be positioned at a distance and orientation to the target that optimize film properties such as thickness uniformity and minimum stress the process window or latitude for achieving one film property for.