| Thin film getter, as key functional materials for attaining and maintenance of vacuum level, has been widely used in ultrahigh vacuum systems, evacuated flat plate solar collector, micro-electron-mechanical-system and become one of the essential technical solutions for maintaining high reliability, stability and long life span for most of vacuum devices. Zr-Co-RE getter materials demonstrate advantages in low activation temperature, adsorbing wide range of active gases, small H2adsorbing pressure, and better environmental safety. In this paper, we studied proper process conditions and key effects for Zr-Co-RE thin film, low temperature activation characteristic and structure changes, measured gas sorption speed and quantity by constant pressure method, uncovered relationships between structure and properties, and proposed several effective ways to continuously improve the sorption capability of thin film getters which show as follows.The structure and morphology of Zr-Co-RE getter films are influenced by preparation conditions as sputtering power, deposition pressure, substrate surface, etc. The crystalline size of thin film getter is about1-3nm. Both the deposition rate and crystalline size grow with the increase of sputtering power. The morphology of thin film getter changes regularly with increasing of deposition pressure that has less effect on deposition rate. The substrate type affects adhesive force of thin films much but crystalline size little. The atomic shadowing effect and the mobility of deposited atoms are key factors to determine the morphology of as-deposited getter films on which low sputtering power, high deposition pressure, glancing angle and etched substrate produces continuous growing nano-columnar structures. Zr-Co-RE films can be activated at300℃and exhibit growth of crystalline. More Zr and Zr3Co phases appear over the extension of activation time. The second activation creates the irreversible structure modification and decline of sorption activity. The single-layered, bi-layered and tri-layered Zr-Co-RE getter films exhibit a sorption speed in1～100cm3·s-1·cm-2by activation at300℃for30min. While the bi-layered film shows a sorption speed10times larger than that of the single-layered film and3.5times of the tri-layered film with a sorption quantity over80Pa·cm3·cm-2in3hours. The surface structure and adhesive layer have effects on sorption performance. The bi-layered getter films deposited on surface treated substrates have large amounts of interfaces and gaps as the rapid infiltration and diffusion approaches for adsorbed gases, exhibiting a stable plateau in sorption quantity range of0～200Pa·cm3·cm-2. The activation degree of thin film getters improves with increasing activation temperature or time, especially by utilizing copper substrate, the initial sorption speed was elevated from69cm3·s-1·cm-2to269cm3·s-1·cm-2with3.5times of increase in sorption quantity. The sorption capacity of the rough getter film is estimated to3665Pa·cm3·cm-2.In summary, this paper provides a solution for designing new generation non-evaporable thin film getters, efficient preparation method and application for micro-vacuum packaging areas. |
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