A MOSFET gate or a MOSFET source or drain region comprises silicon
germanium or polycrystalline silicon germanium. Silicidation with nickel
is performed to form a nickel germanosilicide that preferably comprises
the monosilicide phase of nickel silicide. The inclusion of germanium in
the silicide provides a wider temperature range within which the
monosilicide phase may be formed, while essentially preserving the
superior sheet resistance exhibited by nickel monosilicide. As a result,
the nickel germanosilicide is capable of withstanding greater temperatures
during subsequent processing than nickel monosilicide, yet provides
approximately the same sheet resistance and other beneficial properties as
nickel monosilicide.
