Silicon controller rectifier (scr) with capacitive trigger

Abstract

A thyristor device includes first and second terminals, a PNPN thyristor structure including first P-region, a first N-region, a second P-region and a second N-region disposed in series between the first and second terminals, and an electrode for inducing an electric field into the second P-region. The induced electric field increases the number of charge carriers in the second P-region, and enables the device to be triggered at a lower voltage applied between the first and second terminals. The electrode includes an insulated gate, and can be connected to either the first or second terminal. The gate can include a thick field oxide layer, or a thin oxide layer to further reduce the triggering voltage. A differentiator including a capacitor connected between the first terminal and the electrode and a resistor connected between the second terminal and the electrode prevents false triggering during normal operation. A metal interconnection layer includes an anode section which is connected to the N-region and to the second terminal, and a cathode section which is connected to the P-region, the first terminal and the electrode, such that the cathode section laterally surrounds the anode section.