Snapback clamp having low triggering voltage for ESD protection

摘要

An SCR device having a first P type region disposed in a semiconductor body and electrically connected to anode terminal of the device. At least one N type region is also disposed in the body adjacent the first P type region so as to form a PN junction having a width Wn near a surface of the semiconductor body. A further P type region is also disposed in the body to form a further PN junction with the N type region, with the junction having a width Wp near the body surface, with Wp being at least 1.5 times width Wn. A further N type region is provided which is electrically connected to a cathode terminal of the device and forming a third PN junction with the further N type region.