W-Cu sputtered thin films grown at oblique angles from two sources: Pressure and shielding effects
Résumé
wo series of W-Cu thin films were developed by the GLAD co-sputtering technique. The films were produced with two separated W and Cu targets. Both targets were focused on the centre of the substrate and were simultaneously sputtered using opposite and oblique angles of 80° from the substrate normal. In the first series, the W and Cu target currents were inversely changed from 50 to 140. mA in order to tune the elemental concentrations and the microstructure. For the second series, a shield was added between W and Cu targets, perpendicularly to the substrate surface in order to prevent the cross-contamination of the targets. The target currents were varied similarly to the first series. Two argon sputtering pressures were used (0.42 and 1.0. Pa) in each series, with and without the shield.Microstructure showed a tuneable inclined columnar microstructure, which become normal to the substrate at high pressure. The crystallographic structure was not significantly influenced by the shield implementation but rather by the sputtering pressure. The W/Cu atomic concentration ratio varied between 0.2 and 5.5 as a function of the sputtering pressure and target currents and an anisotropic chemical composition was measured inside the columns. The wide range of DC electrical resistivities (3.6×10⁻⁷ to 5.7×10⁻⁵ Ωm) was discussed considering W and Cu target currents, high and low sputtering pressures and the use of a cross-contamination shield. The role of the microstructure was clearly shown since significantly higher resistivity was obtained at high pressure, as a function of the W/Cu atomic concentration ratio.
W-Cu sputtered thin films grown at... (PDF Download Available). Available from: https://www.researchgate.net/publication/320080270_W-Cu_sputtered_thin_films_grown_at_oblique_angles_from_two_sources_Pressure_and_shielding_effects [accessed Apr 09 2018].