Formation of metal resistor and e-fuse

A method comprising:

• forming a first structure for a transistor and a second structure for a metal resistor on a semiconductor substrate, wherein said second structure includes a first source/drain silicide and a second source/drain silicide, and wherein said second structure is laterally separated from each of said first source/drain silicide and said second source/drain silicide;
• covering said second structure with a protection mask;
• replacing a sacrificial gate of said first structure with a metal gate of said transistor;
• removing said protection mask, after forming said metal gate, to expose a top of said second structure;
• forming a resistor silicide in a portion of said semiconductor substrate positioned in said second structure as said metal resistor, and laterally between said first and second source/drain silicides;
• and
• forming a first contact on said first source/drain silicide and a second contact on said second source/drain silicide, wherein said first and second contacts are electrically connected to each other through said resistor silicide.

A method comprising:

• forming a first structure and a second structure on top of a semiconductor substrate in a replacement-metal-gate (RMG) process to have, respectively, a sacrificial gate, spacers adjacent to sidewalls of said sacrificial gate, and first and second silicided source/drain regions of at least said first structure each adjacent to a respective one of said spacers;
• said first and second structures being embedded in a first dielectric layer, wherein said first and second silicided source/drain regions of said second structure are laterally separated from said first and second silicided source/drain regions of said first structure;
• covering said second structure with an etch-stop mask;
• replacing said sacrificial gate of said first structure with a replacement metal gate;
• removing said etch-stop mask to expose said sacrificial gate of said second structure;
• forming a silicide in a portion of said semiconductor substrate positioned in said second structure as a metal resistor;
• and
• forming a first contact on said first silicided source/drain region of said second structure and a second contact on said second silicided source/drain region of said second structure, wherein said first and second contacts are electrically connected to each other through said silicide.