the average kinetic energy and flux of the deposited species depend on the sputter-gas pressure through collisions with gas atom.
Futhermore, if the target contains heavier elements, there is a signigicant probability that the sputter gas ions will be reflected as neautral atom. By increasing the sputter-gas pressure, a higher flux of reflected neautral will eventually hit the growing film and thereby effect the composition and film structure. Additionally, a higher flux of bommarding Ar ion from the plasma may arise as a result of increase sputter gas pressure if the substrate is kept at a floting potential or negatively bias