Transistor off-state leakage current induced by TiSi2 pre-amorphizing implant in a 0.20 μm CMOS process

We report on an anomalous off-state leakage current found in NMOS devices fabricated with a pre-amorphizing (PA) implant before titanium silicide formation. We present data which indicates that the leakage current is caused by channeling of the arsenic PA implant through the polysilicon gate. An angled PA implant is shown to prevent the channeling and allow the fabrication of well-behaved devices with low resistance titanium silicide.