A method for manufacturing a transistor device is provided, the transistor device comprising a germanium based channel layer, the method comprising providing a gate structure on the germanium comprising channel layer provided on a substrate, the gate structure being provided between a germanium based source area and a germanium based drain area at opposite sides of the germanium comprising channel layer; providing a capping layer on the germanium based source and the germanium based drain area, the capping layer comprising Si and Ge; depositing a metal layer on the capping layer; performing a temperature step, thereby transforming at least part of the capping layer into a metal germano-silicide which is not soluble in a predetermined etchant adapted for dissolving the metal; selectively removing non-consumed metal from the substrate by means of the predetermined etchant; and providing a premetal dielectric layer.