Maskless dual silicide contact formation

A method comprising:

• forming a first set of epitaxial regions corresponding to a first set of transistors;
• forming a second set of epitaxial regions corresponding to a second set of transistors;
• forming a sacrificial epitaxial layer on top of said second set of epitaxial regions;
• converting at least a top portion of said first set of epitaxial regions into a first metal silicide and said sacrificial epitaxial layer into a sacrificial silicide layer in a first silicidation process;
• removing said sacrificial silicide layer selectively, without affecting said first metal silicide, to expose underneath said second set of epitaxial regions;
• and
• converting at least a top portion of said second set of epitaxial regions into a second metal silicide.

A method comprising:

• forming a first epitaxial region in a first region of a semiconductor substrate;
• forming a sacrificial epitaxial layer on top of said first epitaxial region;
• forming a second epitaxial region in a second region of said semiconductor substrate;
• depositing a layer of a first metal element on top of said second epitaxial region and on top of said sacrificial epitaxial layer and subsequently causing said second epitaxial region and said sacrificial epitaxial layer to form a second metal silicide and a sacrificial silicide layer respectively;
• removing said sacrificial silicide layer selectively to said second metal silicide, thereby exposing underneath said first epitaxial region;
• and
• depositing a layer of a second metal element on top of said exposed first epitaxial region and on top of said sacrificial silicide layer and subsequently causing said exposed first epitaxial region to form a first metal silicide.