Difficulties encountered in using AES for quantitative measurements have been evaluated with three plasma deposited materials : amorphous hydrogenated silicon carbide a-SixC1-x:H; amorphous hydrogenated silicon nitride a-SiNx:H; crystallized hydrogenated aluminium nitride AlxNy:H. For a-SixC1-x:H, the values of composition x calculated from Peak/Background and Area/Background ratios are not very different for materials near to stoichiometry or rich in silicon. A divergence on results is noticed for a-SixC1-x:H films with carbon-rich contents and for a-SiNx:H films. This is attributed to broadening effects seen on the KVV peak of carbon and on both LVV and KLL peaks of silicon. The most important problem in AlxNy thin films quantitative Auger analysis is to find suitable reference samples. Available ones are silicon nitride and pure aluminium. The aluminium KLL Auger spectrum is characterized by surface and bulk plasmon loss peaks. Furthermore, the primary electrons efficiency and the emission yield is modified by changes in the solid matrix.