Review of sticking coefficients and sorption capacities of gases on titanium films

The pumping speed of a titanium sublimation pump or a sputter-ion pump using titanium cathodes is a function of many variables including the sticking coefficient and sorption capacity of gases on titanium films. Consequently, in vacuum systems employing such pumping mechanisms, the sticking coefficients and sorption capacities play a major role in determining the partial pressures at any given time of various gas species. However, the sticking coefficient data required to determine the partial pressure behavior to be expected is not conveniently available. The literature on this subject has been reviewed and the data for H2, D2, H2O, CO, N2, O2, and CO2 have been summarized. These results are presented and information related to the sorption mechanisms is discussed.