In situ electrical characterization of Y_xTi_y getter thin films during thermal activation

Transition metals alloys are the most studied getter films for wafer-level vacuum packaging of MEMS. In this work we investigated yttrium and Y_xTi_y alloys films that could possibly overcome the limitations of usual getter materials, i.e. reversible sorption of hydrogen and low sorption ability for hydrocarbon gases. As a preliminary step towards this objective, properties of (co-)evaporated yttrium and Y_xTi_y films were analyzed by SEM, EDS, XPS and in-situ sheet resistance measurements before, after and/or during annealing in vacuum. As deposited and annealed films have a small grain size and a columnar structure. It is shown that yttrium and Y_xTi_y films can be activated after 1 hour of annealing in vacuum at 250 °C if the Y-content is larger than ∼9 %. These results are promising for the use of Y-based films as low temperature getters for vacuum packaging. (paper)