A Latchup-Immune and Robust SCR Device for ESD Protection in 0.25-μm 5-V CMOS Process

Based on good electrostatic discharge (ESD) robustness, silicon-controlled rectifier (SCR) device is used for on-chip ESD protection. The major concern of SCR is the latch-up issue, because of its low holding voltage. Previous papers tried to design latchup-immune SCR devices; however, those devices would cause lower ESD robustness. In this letter, a new latchup-immune and robust SCR device for ESD protection is proposed and verified in a 0.25-μm 5-V CMOS process. Through inserting one additional parasitic bipolar junction transistor into SCR device structure, this new proposed SCR can increase the holding voltage without causing degradation on its ESD robustness.