Structural alteration and mechanical property enhancement of tungsten nitride films by addition of Copper

Abstract

In the current study, the alteration in different properties of WNCu films due to variation of Cu content was studied. The films were deposited using RF/DC reactive magnetron co-sputtering and the Cu content was varied by varying the RF power supplied to Cu target, such as 5 W, 10 W, 20 W, and 30 W keeping the power to W target constant. GIXRD shows the existence of a dominant Face Centred Cubic (FCC) W2N phase. Plane view FESEM represents eventual densification and agglomeration of the grains with respect to increasing Cu power whereas cross-sectional FESEM shows columnar growth to nanocrystalline formation of the films with increasing Cu content. Thermo Gravimetric Analysis (TGA) shows the increase in mass percentage with respect to temperature at higher Cu power films. Amongst all the films, the maximum hardness (H), elastic modulus (Er), elastic recovery (We), and resistance to plastic deformation (H3/E2) were obtained to be 24.90 +/- 1.12 GPa, 263.54 +/- 7.24 GPa, 64.69 +/- 1.37% and 222.3 +/- 42.2 MPa respectively for WNCu 10 W films.