Low Activation Temperature Au/Ti Getter Films for Wafer-Level Vacuum Packaging

In this work thermal diffusion of titanium through an ultrathin capping gold layer has been investigated as an alternative way to produce a getter film activated at low temperature. Ti out-diffusion from Au/Ti thin films was studied using four probe resistivity measurements, spectroscopic ellipsometry, XPS analysis, residual stress measurements, SEM cross section observation and Ion Beam Etching coupled with mass spectrometry. The results show that a titanium oxide film is growing as the titanium out diffuses and comes in contact with traces of oxidizing species in N-2 annealing gaz. The pumping capacity is large enough to integrate Au/Ti film as a low temperature getter film for wafer-level vacuum packaging.