In this work, we have investigated the reaction between Zr and SiGeC alloys. Annealings have been performed in a rapid thermal annealing (RTA) furnace at temperatures ranging from 400 to 800°C for 5 min. The reaction of the metal with the alloy has been investigated by x-ray diffraction and Rutherford backscattering spectrometry. Four crystal x-ray diffraction was performed to measure the residual strain in the epilayer. The analyses indicate that the C49-Zr(Si1-xGex)2 is the final phase of the reaction. For all compositions examined (from 0% up to 33% of Ge), the C49 film has the same Ge content as in the as-deposited Si1-x-yGexCy layer and no Ge segregation has occured. In addition, this thermal treatment leads to only a small strain relaxation in the unreacted epilayer. The presence of C does not modify the reaction and it prevents any strain relaxation. Schottky barrier height measurements have been performed on p-type layers. RTA leads to a slight decrease of the barrier without any degradation of the contact. The C49 film presents a resistivity of about 80 μcm. These results indicate that Zr may be a good candidate for contacts on IV-IV alloys in terms of thermal stability.