Impact of adhesion promoters and sputter parameters on the electro-mechanical properties of Pt thin films at high temperatures

Abstract In this study the influence of film thickness, adhesion promoters such as chromium (Cr) and rutile titanium dioxide (TiO 2 ), sputtering power and substrate temperature on the electro-mechanical properties of platinum (Pt) thin films is investigated. The bilayered samples consisting of an adhesion promoter and a Pt thin film are deposited using direct current magnetron sputtering on sapphire substrates und characterized by Van-der-Pauw as well as gauge factor measurements up to 500 °C in air. Additionally, transmission electron microscopy and energy dispersive X-ray spectroscopy analysis are performed to investigate the microstructure and the chemical composition of the thin films before and after temperature loading. No substantial impact of the Pt film thickness on the electro-mechanical properties is determined. The diffusion of Cr into the Pt thin film at elevated temperatures leads to a lower gauge factor with a higher scatter range. Furthermore, higher sputtering power and substrate heating during deposition lead to a higher crystallinity of the Pt thin film and thus promote higher gauge factors.