Silicon-Controlled Rectifier for Electrostatic Discharge Protection Solutions With Minimal Snapback and Reduced Overshoot Voltage

Abstract

An electrostatic discharge (ESD) protection structure constructed by the stacking of multiple anode gate-cathode gate directly connected silicon-controlled rectifiers (DCSCRs), fabricated in a 0.18-μm CMOS technology is reported in this letter. Two embedded diodes in the DCSCR dictate the turn-ON mechanism and hence give rise to a trigger voltage equal to twice the diode's turn-ON voltage. This approach enables the DCSCR to offer a diode-like transmission line pulsing IV characteristic with a minimal snapback and a SCR-like high-ESD robustness. At 25 °C, DCSCR has an acceptable nanoampere-level leakage current. Besides, it is verified that the DCSCR can significantly reduce overshoot voltage when stressed by very-fast-rising pulses. As such, an ESD clamp constructed by stacking a selected number of DCSCRs can offer a flexible trigger/holding voltage and is suitable for low and medium voltage ESD protection applications.