Defect density of a polysilicon metal silicide wiring is reduced by
employing a block of undoped polysilicon metal silicide in locations in
which dopants are not needed in the underlying polysilicon. Furthermore,
detection of presence of defects in the polysilicon metal wiring that
adversely impacts device performance at high frequency is facilitated by
employing a block of undoped polysilicon metal silicide since defects in
undoped polysilicon metal silicide is more readily detectable than
defects in doped polysilicon metal silicide. Locations wherein undoped
polysilicon metal silicide wiring is employed include areas over shallow
trench isolation.