Influence of the elemental composition and crystal structure on the vacuum properties of Ti–Zr–V nonevaporable getter films

Abstract

Nonevaporable thin film getters based on the elements of the fourth and fifth columns of the periodic table were deposited by sputtering. Among the some 20 alloys studied to date, the lowest activation temperature (about 180 °C for a 24 h heating) was found in the Ti–Zr–V system with a well-defined composition range. Characterization of the activation behavior of such Ti–Zr–V films is presented. The evolution of the surface chemical composition during activation is monitored by Auger electron spectroscopy and the functional properties are evaluated by pumping speed measurements. The pumping speed characteristics are quite similar to those already measured for commercially available nonevaporable getter materials, except for the much lower saturation coverage for CO. This inconvenience, which is due to the smooth surface structure of these films, can be counteracted by increasing the roughness of the substrate.

Activation characterization of non-evaporable Ti–Zr–V getter films by synchrotron radiation photoemission spectroscopy

“…In order to upgrade and sustain the vacuum inside the cavity of vacuum-type devices, non-evaporable getter (NEG) materials, such as titanium or titanium alloys, have been widely used due to their low activation temperature, high chemical activity, large solubility, and high diffusivity for gases [1][2][3][4][5][6][7]. When the NEG materials are exposed to air, their surfaces will be covered by the reactive molecules, such as oxygen, carbon dioxide, etc.…”

Ti–Zr–V non-evaporable getter films: From development to large scale production for the Large Hadron Collider

“…The nature of the substrate does not influence the oxide dissolution process of the TiZr-V film [21]. This is not the case for morphology: such a film coated on smooth copper and stainless steel is smooth and compact, whereas on aluminium alloys and beryllium a cauliflower structure is formed.…”

“…1-a and 1-b for N 2 and H 2 on a CO charged film surface. H 2 does not affect the pumping speed of the other gases since it diffuses inside the material, while N 2 has a limited influence on the pumping of H 2 and CO as a result of its underlayer adsorption [21,32,35].…”

Deposition and characterization of TiZrV-Pd thin films by dc magnetron sputtering

“…The sorption of these gases except H2 is not reversible and it causes a progressive contamination for TiZrV film [1,8,9]. Moreover, repeated air exposure-activation cycles progressively enrich the film with reactive gases, reducing its performance and shortening its 2 / 12 operating life [10].…”