Mechanism of the film composition formation during magnetron sputtering of WTi

The WTi films were deposited by an unbalanced magnetron sputtering of a WTi (70:30 at. %) alloy target. The influence of the working gas (Ar) pressure, substrate bias, and substrate location on the composition of films was studied. The films deposited at low working gas pressures (<1 Pa) onto electrically floating substrates were largely depleted in Ti while the composition of films deposited at high argon pressure (25 Pa) was close to that of the target. The ion bombardment of the growing film resulted in a decrease of the Ti content in the films. The composition of the films deposited simultaneously onto a pair of substrates placed at the axis and at the periphery of the target did not depend on the substrate position at both low and high pressure. Further studies were carried out for a better understanding of the underlying processes affecting the film composition. Namely, the mass-resolved ion energy distribution function at the substrate position was measured for various pressures. Further, the compo...