Latch-Up Free CMOS by Schottky Barrier Technology

A very strict imposition on the realizable density of bulk CMOS structures is that of latch-up due to the parasitic SCR which is inherent to that technology. The four layer Shockley diode (or SCR) consists of a PNP and NPN bipolar transistor configured such that positive feedback can turn on the diode in a low voltage condition which cannot switch off without removal of applied voltages [1].