The method for forming first and second metal-based materials comprises providing a substrate comprising an area made from a first semi-conductor material and an area made from a second semi-conductor material comprising germanium separated by a pattern made from dielectric material, depositing a metal layer and performing a first heat treatment in an atmosphere comprising a quantity of oxygen comprised between 0.01% and 5%. The metal layer reacts with the first semi-conductor material and the second semi-conductor material comprising germanium to respectively form the first metal-based material and the second metal-based material containing germanium.