A method for forming germano-silicide contacts atop a Ge-containing layer
that is more resistant to etching than are conventional silicide contacts
that are formed from a pure metal is provided. The method of the present
invention includes first providing a structure which comprises a
plurality of gate regions located atop a Ge-containing substrate having
source/drain regions therein. After this step of the present invention, a
Si-containing metal layer is formed atop the said Ge-containing
substrate. In areas that are exposed, the Ge-containing substrate is in
contact with the Si-containing metal layer. Annealing is then performed
to form a germano-silicide compound in the regions in which the
Si-containing metal layer and the Ge-containing substrate are in contact;
and thereafter, any unreacted Si-containing metal layer is removed from
the structure using a selective etch process. In some embodiments, an
additional annealing step can follow the removal step. The method of the
present invention provides a structure having a germano-silicide contact
layer atop a Ge-containing substrate, wherein the germano-silicide
contact layer contains more Si than the underlying Ge-containing
substrate.