Stability of thin platinum films implemented in high-temperature microdevices

In this paper we report on structural and electrical properties of thin films of Pt with Ti, Ta, or no adhesion, which were annealed in different ambient at temperatures in the range 400–950 °C. Correlations are made between the mechanical strain and grain size values obtained from X-ray diffraction, electrical measurements, and optical microscope images of film sintering after annealing at high temperature. A method to obtain highly adhesive, patterned Pt films without adhesion layer is presented, which films show the highest reliability, in terms of structural integrity and electrical properties. Therefore this is the best option for implementation in high-temperature microdevices like microreactors and gas sensors operating at temperatures above 750 °C.