Zr-V getter films for MEMS packaging

Films of Zr and Zr-V were evaporated on silicon substrates and their gettering properties were evaluated for MEMS packaging. Their microstructure was determined by SEM and TEM. The films were then activated at different temperatures at low pressure of oxidizing species under argon atmosphere. The oxygen sorption was measured after annealing by ion-beam analyses. Finally, integrations of getter films with various compositions were realized inside hermetic MEMS packages sealed at 300 degrees C. All the results showed an optimal performance for the alloy with composition Zr85V15 having a nanocrystallized structure. This work emphasizes the role of grain boundaries in the activation performance of getter films, showing that increasing the density of grain boundary enhances the getter performance until a point where an excess of grain boundaries like in a quasi-amorphous film becomes detrimental to the getter effect.