N-Type Extended Drain Silicon Controlled Rectifier Electrostatic Discharge Protection Device for High-Voltage Operating Input/Output Applications

Abstract

An electrostatic discharge (ESD) protection device, the so-called N-type extended drain silicon controlled rectifier (NEDSCR) device, was analyzed for high-voltage input/output (I/O) applications. A conventional NEDSCR device shows typical silicon controlled rectifier (SCR)-like characteristics with a high current immunity level. However, its extremely low snapback holding voltage and low on-resistance cause a linearity problem in the current immunity level, which obstructs adopting this device as an ESD protection device. Moreover, it may cause a latch-up problem during a normal operation. Our simulation analysis results that these disadvantageous NEDSCR device characteristics are cured by appropriate junction/channel engineering. Adding a P-type counter pocket source (CPS) implant enclosing source N+ diffusion is proven to increase the snapback holding voltage and on-resistance of the NEDSCR device, realizing an excellent ESD protection performance and a high latch-up immunity. Since the CPS implant technique does not change avalanche breakdown voltage, this methodology does not reduce available operation voltage and is applicable regardless of the operation voltage.