Selective dual silicide formation

A method, comprising:

• performing, in a first processing chamber and under an at least partial vacuum, a pre-clean operation to clean a top surface of a p-type source/drain region of a semiconductor device and to clean a top surface of an n-type source/drain region of the semiconductor device;
• transferring, after performing the pre-clean operation, the semiconductor device to a second processing chamber while maintaining the at least partial vacuum;
• forming, in the second processing chamber and under the at least partial vacuum, a p-type metal silicide layer on the top surface of the p-type source/drain region;
• transferring, after forming the p-type metal silicide layer, the semiconductor device to a third processing chamber while maintaining the at least partial vacuum;
• and
• forming, in the third processing chamber and under the at least partial vacuum, an n-type metal silicide layer on the top surface of the n-type source/drain region.

A method, comprising:

• providing a flow of a ruthenium (Ru) precursor into a processing chamber,
• wherein the ruthenium precursor bonds to germanium (Ge) sites of a p-type source/drain region on a substrate and resists bonding to silicon (Si) sites of an n-type source/drain region on the substrate as a result of a greater dissociation energy, of a first ligand of a plurality of ligands of the ruthenium precursor, for silicon relative to a dissociation energy of the first ligand for germanium;
• and
• providing a flow of a reactant gas into the processing chamber,
• wherein the reactant gas disassociates a second ligand of the plurality of ligands from the ruthenium precursor such that ruthenium of the ruthenium precursor remains bonded to the Ge sites, which results in formation of a ruthenium silicide (RuSi) layer on the p-type source/drain region.