Implementation of initial-on ESD protection concept with PMOS-triggered SCR devices in deep-submicron CMOS technology

In order to enhance the applications of SCR devices for deep-submicron CMOS technology, a novel SCR design with "initial-on" function is proposed to achieve the lowest trigger voltage and the highest turn-on efficiency of SCR device for effective on-chip ESD protection. Without using the special native device (NMOS with almost zero or even negative threshold voltage) or any process modification, this initial-on SCR design is implemented by PMOS-triggered SCR device, which can be realized in general CMOS processes. This initial-on SCR design has a high enough holding voltage to avoid latchup issues in a VDD operation voltage of 2.5 V. The new proposed initial-on ESD protection design with PMOS-triggered SCR device has been successfully verified in a fully-silicided 0.25-μm CMOS process.