Dynamic triggering characteristics of SCR-type electrostatic discharge protection circuits

Experimental dynamic triggering characteristics of various SCR ESD protecti on circuits have been compared. These circuits include diode-chain-triggeri ng SCR (Silicon Controlled Recitfier). low-voltage zener diode trigger SCR and gate-coupled low-voltage trigger SCR circuits. The magnitude of turn-on time, from the instant the SCR subjected to an electrostatic discharge (ES D) pulse to latch in a clamped state. strongly depends upon the type of ESD circuits. The temporal electrical response of the circuits to an ESD-like pulse in general can be divided into three regions: the delay region (I), t he triggering region (II), and the holding region (III). Experimental resul ts of diode-chain-triggering SCRs show that it is hard to distinguish phase I and phase II if the ESD overvoltage is high, however if the ESD overvolt age is slightly higher than the dynamic trigger voltage. then the above thr ee regions can be clearly seen. This paper improves the understanding of th e temporal development of ESD transient during the triggering process of SC R-type ESD protection circuits. (C) 2001 Elsevier Science Ltd. All rights r eserved.