Mask-less dual silicide process

A method of forming a semiconductor device, the method comprising:

• providing a substrate, the substrate having a first device region and a second device region, the first device region having a first gate stack, the second device region having a second gate stack, first source/drain regions being on opposing sides of the first gate stack, second source/drain regions being on opposing sides of the second gate stack;
• forming first stress regions in the first source/drain regions;
• forming first oxidized regions in the first source/drain regions;
• forming second stress regions in the second source/drain regions;
• forming a first dielectric layer over the first device region and the second device region;
• patterning the first dielectric layer to expose the first oxidized regions and the second stress regions;
• forming second silicide regions over the second stress regions;
• after forming the second silicide regions, removing the first oxidized regions;
• and
• forming first silicide regions over the first stress regions.

A method of forming a semiconductor device, the method comprising:

• forming a first gate stack in a first device region of a substrate and a second gate stack in a second device region of the substrate, first source/drain regions being on opposing sides of the first gate stack, second source/drain regions being on opposing sides of the second gate stack;
• forming a first mask layer over the second device region;
• forming first stress regions in the first source/drain regions;
• oxidizing a surface of the first stress regions while the first mask layer protects the second source/drain regions, thereby forming first oxidized regions;
• removing a portion of the first mask layer over the second source/drain regions;
• forming second stress regions in the second source/drain regions;
• forming an interlayer dielectric (ILD) over the first device region and the second device region, the ILD being patterned to expose the first oxidized regions and the second stress regions;
• forming a second silicide region in the second source/drain regions;
• removing at least a portion of the first oxidized regions;
• and
• forming a first silicide region in the first source/drain regions.