NEG thin films for under controlled atmosphere MEMS packaging

Non-evaporable getter (NEG) thin films for residual gases control in micro-electro-mechanical systems (MEMS) cavities after sealing are considered. For this study, several getters are deposited and analyzed in terms of sorption performances, microstructure and activation mechanism. Compared to single layer evaporated titanium reference, the addition of a sub-layer is shown to decrease the activation temperature of the NEG. Effective pumping of nitrogen is monitored by Residual Gas Analysis (RGA). Microstructure investigation by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) reveals no apparent modification in NEG morphology due to sub-layer addition. X-ray Photoelectron Spectroscopy (XPS) and depth profiling monitoring of NEG activation under high vacuum conditions (10−8 mbar) shows the dissolution of the NEG surface oxide in the getter bulk, along with the formation of carbide and nitride compounds. These results are in good agreement with already published results on getter alloys.