One method to enhance electrostatic discharge (ESD) robustness of the on-chip ESD protection devices is through process design by adding an extra "ESD implantation" mask. In this work, ESD robustness of nMOS devices and diodes with different ESD implantation solutions in a 0.18-μm salicided CMOS process is investigated by experimental testchips. The second breakdown current (I t2 ) of the nMOS devices with these different ESD implantation solutions for on-chip ESD protection are measured by a transmission line pulse generator (TLPG). The human-body-model (HBM) and machine-model (MM) ESD levels of these devices are also investigated and compared. A significant improvement in ESD robustness is observed when an nMOS device is fabricated with both boron and arsenic ESD implantations. The ESD robustness of the N-type diode under the reverse-biased stress condition can also be improved by the boron ESD implantation. The layout consideration in multifinger MOSFETs and diodes for better ESD robustness is also investigated.
- Electrostatic discharge (ESD) implantation
- ESD protection
- Snapback breakdown