Treatments by femtosecond Ti-sapphire laser (wavelength is 800 nm, pulse duration is <30 fs) and nanosecond KrF excimer laser (wavelength is 248 nm, pulse duration is 25 ns) were performed to study the impact of laser fluence, pulse duration and energy of photons on the process of chemical and structural reconstructions in GeOx and GeO2:Ge heterolayers. The solid GeOx films are metastable and decompose into two phases - Ge and GeO2. Nanosecond KrF laser irradiation produces significant shrinkage of GeOx films and GeO2:Ge heterolayers caped by thin SiNxOy or SiO2 films. Pulse annealing by both types of lasers stimulate as the process of nanoclusters forming and crystallization of initial amorphous Ge-nanoclusters in the GeO2 matrix. The possibility to use the solid germanium monoxide (GeO(s)) and GeO2:Ge heterolayers (without cap layers) as nano-resist in laser nanolithography was demonstrated. The new nanostructured material was formed - the layers of nanofoam GeO2 which can be obtained only with application of femtosecond laser pulse treatments.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.