Electron energy loss spectroscopy (EELS) on 16M dynamic random access memory (DRAM) device structures is used to study locally the diffusion of oxygen in the physically vapor deposited (PVD)-Ti chemical vapor deposition (CVD)-TiN tungsten liner films. These results are correlated to the electrical contact resistance of 1000 tungsten contact chains on Nf silicon areas depending on different titanium thickness at the bottom of the contact hole and on the use of a liner anneal around 600 degrees C. It is shown that the local diffusion of oxygen tracked with the EEL spectroscopy is consistent with Auger analysis on blanked films and can explain the different electrical results of the 16 M DRAM devices. From this explanation it can be concluded that for a microelectronic processing application the use of CVD-TiN as the barrier in tungsten plug application with an air break between the PVD-Ti and CVD-TiN deposition is only acceptable if enough titanium is available to buffer the oxygen from the native titanium oxide.