Si depth profiles and contaminants in Si‐doped Al films deposited on SiO2by electron‐gun evaporation at different base pressures have been measured. The experimental techniques employed were Auger electron spectroscopy combined with ion milling for chemical analysis and depth profiling, and transmission electron microscopy for film structure studies. Auger analysis showed that at intended doping levels of 1 and 2 at.% (previously calibrated using atomic absorption spectrometry) the Al films contained 0.9 and 1.9 at.% Si, if the total Si content was averaged over the entire film thickness. However, most of the Si had migrated to the Al/SiO2interface after deposition at 300 °C and formed precipitates which nucleated at or near the Al/SiO2interface. The major film contaminants were C and O, whose concentrations were directly related to the pressure during deposition. The lowest detection limits with the Auger technique were ∼0.01 at.% (100 ppm) for both C and O, attained using a 50‐&mgr;A incident electron beam current and a scan time of <30 sec per element.