High fluences of low energy Ge+ ions were implanted into Si matrix. We have also deposited Ge and SiO2 composite films by using the Atom beam sputtering (ABS). The as implanted/as-deposited films were irradiated by Swift Heavy Ions (SHI) with various energies and fluences. These pristine and irradiated samples were subsequently characterized by XRD and Raman to understand the crystallization behavior. Raman studies of the films indicate the formation of Ge crystallites as a result of SHI irradiation. Glancing angle X-ray diffraction results also confirm the presence of Ge crystallites in the irradiated samples. Moreover, the crystalline nature of Ge improves with an increase in fluence. Rutherford back scattering was used to quantify the concentration of Ge in SiO2 matrix and the film thickness. These detailed results have been discussed and compared with the ones available in literature. The basic mechanism for crystallization induced by SHI in these films will be presented.