A method is described to form a MOSFET with a fully silicided gate
electrode and fully silicided, raised S/D elements that are nearly
coplanar to allow a wider process margin when forming contacts to
silicided regions. An insulator block layer is formed over STI regions
and a conformal silicidation stop layer such as Ti/TiN is disposed on the
insulator block layer and active region. A polysilicon layer is deposited
on the silicidation stop layer and is planarized by a CMP process to form
raised S/D elements. An oxide hardmask on the gate electrode is removed
to produce a slight recess between the spacers. A silicidation process
yields a gate electrode and raised S/D elements comprised of NiSi.
Optionally, a recess is formed in the substrate between an insulator
block mask and spacer and a Schottky barrier is used instead of a
silicidation stop layer to form a Schottky Barrier MOSFET.