Influence of the elemental composition and crystal structure on the vacuumproperties of Ti-Zr-V nonevaporable getter films

Nonevaporable thin film getters based on the elements of the fourth and fif th columns of the periodic table were deposited by sputtering. Among the so me 20 alloys studied to date, the lowest activation temperature (about 180 degreesC for a 24 h heating) was found in the Ti-Zr-V system with a well-de fined composition range. Characterization of the activation behavior of suc h Ti-Zr-V films is presented. The evolution of the surface chemical composi tion during activation is monitored by Auger electron spectroscopy and the functional properties are evaluated by pumping speed measurements. The pump ing speed characteristics are quite similar to those already measured for c ommercially available nonevaporable getter materials, except for the much l ower saturation coverage for CO. This inconvenience, which is due to the sm ooth surface structure of these films, can be counteracted by increasing th e roughness of the substrate. (C) 2001 American Vacuum Society.