Influence of the sputtering power supply and substrate outgassing on the sorption properties of Zr-Co-Ce Non-Evaporable Getter films

Highly porous Zr-Co-Ce Non-Evaporable Getter (NEG) films have been produced by magnetron sputtering from a preformed Zr-Co-Ce alloy target. The NEG performance and morphology dependence on sputtering power supply, substrate temperature during coating, and substrate material have been investigated. It has been found that DC magnetron sputtering is more efficient in the preparation of porous film with columnar structure than RF. The substrate temperature affects significantly the microstructure and the performance, and the highest hydrogen sorption speed of 97.2 cm(3).s(-1).cm(-2) is obtained for substrate temperature of 200 degrees C. X-ray diffraction studies reveal that the Zr-Co-Ce film is composed of amorphous or nanocrystalline grains with the average grain size less than 5 nm. The feature of substrate material can also affect the performance of the film, and the hydrogen sorption speed of the film can be clearly improved by substrate outgassing prior to deposition.