High-throughput characterization of hydrogen storage materials using thin films on micromachined Si substrates

A new characterization method is proposed for the development of hydrogen storage alloys, using thin films deposited on micromachined Si cantilevers with additional layers of SiO2, Si3N4 and an adhesion layer. A sputter deposition system is used for deposition of thin films for hydrogen storage. The mechanical stress change due to hydrogenation, A sigma(H), leads to curvature changes of the film/cantilever combinations. These curvature changes are measured simultaneously on sets of cantilevers with an optical method in a gas phase hydrogenation apparatus, where the pressure can be varied from vacuum to a hydrogen pressure, p(H2), ranging between 0.105 MPa and 5.1 MPa; the temperature can be varied from 20 degrees C to 450 degrees C. Thin films of Pd, Mg. Ti, Cr, and Fe were deposited for validation experiments. Isothermal measurements of thin film/substrate combinations are presented. The results show that the method is suitable for high-throughput characterization of combinatorial thin film libraries with respect to hydrogenation properties. (C) 2007 Published by Elsevier B.V.