Charged device model electrostatic discharge protection for integrated circuits

摘要

A charged-device model (CDM) electrostatic discharge (ESD) protection for complementary metal oxide semiconductor (CMOS) integrated circuits such as input/output (I/O) circuits. A CDM ESD clamp device is disposed on an output buffer or an input stage of the CMOS circuit in order to clamp the CDM ESD overstress voltage across the gate oxide during a CDM ESD event. When applied to I/O circuits, a bi-directional diode string with multiple diodes is used in conjunction with the CDM ESD clamp device. During the CDM ESD event, CDM charges (CDM Q) originally stored in the common substrate are discharged through the desired CDM ESD clamp device so as to protect all functional devices in the input, output or I/O circuits, and effectively improve the CDM ESD level in integrated circuit (IC) products.