Silicide (salicide)
Beginner
A thin layer of metal mixed with silicon on a switch’s ends and gate. It lets electricity get in and out more easily.
Novice
A metal (titanium, cobalt or nickel) is deposited and heated. It reacts only where it touches bare silicon, forming a low-resistance silicide; the leftover metal is then etched away. No mask is needed, hence “self-aligned silicide”.
Expert
Cuts sheet and contact resistance of source, drain and gate. Older flows used titanium silicide, annealed in nitrogen so the same step also formed titanium nitride.