US Patent 7701058 Undoped polysilicon metal silicide wiring

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.