Electrical and morphological characterization of platinum thin-films with various adhesion layers for high temperature applications

In this paper we report on the morphological and electrical properties of platinum (Pt) thin-films with Titanium (Ti) and, alternatively, Titanium dioxide (TiO2) as adhesion layers for high temperature applications. All films were sputter deposited on silicon substrates and afterwards annealed in air up to 800 A degrees C. The results show that Ti diffuses into Pt grain boundaries forming oxide precipitates (TiOx) in the Pt grain boundaries. The resistivity of Pt/Ti thin-films increased continuously with annealing temperature up to 500 A degrees C and decreases again continuously above 500 A degrees C. In contrast, TiO2 demonstrates a dense stable oxide layer after annealing. Pt/TiO2 thin-films show a continuous decrease in the sheet resistance with increasing the annealing temperature. Accordingly, TiO2 thin-film is the preferable adhesive layer for Pt over Ti thin-films for high temperature applications.