Correlation between Adhesive Strength and the Oxidized and Reduced States of Pt Films Electron Cyclotron Resonance Plasma Sputtered on SiO2

Electron cyclotron resonance plasma sputtering of Pt with an O-2/Ar gas mixture produced (111) oriented films with a surface roughness of similar to 1 nm and resistivities between 20 and 27 mu Omega cm. Continuous reduction of deposited film by Ar plasma is responsible for the formation of metallic Pt crystallites even under the presence of O-2. The Pt(111) film was more adhesive to the substrate than that of Pt(200) film that was produced by post annealing magnetron-sputtered PtOx films. The Pt(111) films composed of columnar texture domains could be reversibly reduced or oxidized through annealing in a vacuum or in an O-2 ambient, and the corresponding adhesive strength changed for one order of magnitude. The enhanced adhesion in the oxidized state was due to Pt films being softened by partial oxidation at the grain boundaries and the interface being immersed with oxygen species, which prevented chipping and cracking that are preludes to delamination. (C) 2011 The Japan Society of Applied Physics