Using an SCR as ESD protection without latch-up danger

A properly designed Low-Voltage Triggering SCR has a four times better ESD performance than a conventional grounded-gate NMOST of the same width. But it does present a latch-up risk due to its low holding voltage. The holding voltage can be increased by using a larger anode-to-cathode spacing, but at very large spacings the ESD performance decreases. It is shown that a window in SCR anode-to-cathode spacing exists, for which the holding voltage is sufficiently large, while the excellent ESD protection properties are preserved. (C) 1997 Elsevier Science Ltd.