PLDD/NHALO-assisted low-trigger SCR for high-voltage tolerant ESD protection in foundry CMOS process without extra mask

A new semiconductor-controlled rectifier (SCR) is proposed and realised in the foundry 0.18 m CMOS process for electrostatic discharge (ESD) protection. Without using an extra mask or trigger circuits, the new p-type lightly-doped-drain and n-type halo (NHALO) assisted SCR has a trigger voltage as low as 7 V and an ESD robustness exceeding 50 mA/ m to provide an effective protection. Compared with traditional LVTSCR, the new structure not only has a lower trigger voltage, but can also be more suitable for high-voltage tolerant applications without the gate-oxide reliability issue.