Hydrogen sorption in yttrium-based getter thin films

Oxygen and hydrogen sorption in thermally activated yttrium-based getter thin films for MEMS vacuum packaging

“…Without annealing treatment, Y-Al, Y-Ti, Y-Zr-Al, Y-V and Y-V-Al alloys exhibit a lower amount of hydrogen than pure yttrium. As shown previously in [8], depth profiles show an hydrogen gradient from the surface to the interface and then a diffusion inside the substrate. After the annealing process, the most efficient alloys for oxygen sorption (i.e Y-Ti and Y-V-Al) show the lowest hydrogen/metal ratio.…”

“…Whatever the film composition, a global increase of oxygen content determined by NRA with annealing temperature was observed. For comparison, electrical sheet resistance has been measured and an increase with temperature is also clearly visible [8]. At 300 °C, for yttriumvanadium and yttrium-titanium based alloys, the sorption of oxygen is related to the amount of yttrium in the film: the quantity of sorbed oxygen atoms is higher in yttrium-rich alloys.…”

“…Y-Ti alloys have an hexagonal structure with a 002-peak shifting between the one of titanium and the one of yttrium, except for the Y32Ti68 which is in an amorphous state [7]. Y-Zr-Al alloys showed also an hcp crystalline structure with a 002-peak shifting between the one of yttrium (in Y rich alloy composition) and the one of zirconium, characteristic of a solid solution [8]. Y-V-Al alloys showed a broad and low intensity peak indicating a nanocrystalline structure, close to the amorphous state.…”