SiO2 and Al2O3 surfaces exposed to periodically modulated extreme ultraviolet (EUV) light ($łambda$ = 46.9 nm) have been investigated at the $μ$m scale by optical microscopy, scanning electron microscopy, scanning Auger microscopy, atomic force microscopy, and Kelvin probe force microscopy. The formation of a carbon contamination layer preserving the same periodical modulation of the EUV dose has been observed. The mechanisms of hydrocarbon molecules deposition have been studied with the help of correlation plots between the modulated Auger signal and the corresponding EUV dose. A surface-dependent secondary-electron-based model has been proposed.