The aim of this work is to study the influence of the Ge content on the 113 defects formed, after a (35 keV, 1 × 1015 Ge+/cm2) preamorphization step followed by annealing at 680 °C, in relaxed SiGe alloys. For that, plan-view Transmission Electron Microscopy (PTEM) under appropriate imaging conditions was used to study the 113 defects evolution as a function of the Ge content. Experimental results show that, increasing the Ge content results in a net reduction of both the density and the size of the 113 defects. Results analysis was performed in the framework of the "excess interstitials" model which describes perfectly the observed decrease of the 113 defects density in Si. Moreover, through a confrontation between the TEM observations and the predictions of this model, we show that the density of the interstitials contained in the defects (deduced from PTEM images) is a quasi linear function of the density of excess interstitials generated during the preamorphization step beneath the c/a interface, as calculated by the SRIM code. We conclude that collisional arguments can appropriately explain the observed evolution of the 113 defects density as a function of the Ge content. Meanwhile, the observed reduction of the 113 defects size with the Ge content, may be ascribed to a decrease of the transport capacity DiCi*, responsible for the defects growth. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.