Thermal desorption spectroscopy (TDS) was used to study outgassing from polycrystalline SiGe (poly-SiGe), SiC and SiO2 films used for poly-SiGe-based MEMS thin film vacuum package technology. Primary desorption products were found to be H-2. H2O and CO2. The CO2 outgassing could be correlated with CF4 plasma interface cleaning used for thick SiGe PECVD, which can leave carbon at the CF4-plasma-cleaned interface. (C) 2011 Elsevier Ltd. All rights reserved.