Devices and methods to optimize materials and properties for replacement metal gate structures

A method for device fabrication, comprising:

• forming a gate structure with a sacrificial material and raised source/drain regions adjacent to the gate structure;
• processing the raised source/drain regions adjacent to the gate structure to build resistance to subsequent thermal processing;
• forming contact trenches in a dielectric layer over the raised source/drain regions;
• forming silicided regions on the raised source/drain regions in the contact trenches;
• processing the silicided regions to build resistance to subsequent thermal processing wherein the processing includes introducing impurities through the contact trenches into the silicided regions of the raised source/drain regions to reduce thermal degradation of the silicided regions;
• forming contacts in the contact trenches;
• and
• after forming the silicided regions and the contacts, removing the sacrificial material and replacing the sacrificial material with a replacement conductor.