Patent ID: 7601991

Claim:
A high holding, low voltage trigger silicon controlled rectifier device having first and second terminals, the device comprising: an N-type layer on a P-type substrate; an N-type tub region having a first portion extending from a top surface of the N-type layer to a first location of the P-type substrate, a second portion extending into the P-type substrate, and a third portion extending from the top surface of the N-type layer to a second location of the P-type substrate different from the first location; adjacent P-type and N-type well regions in the top surface of the N-type layer between walls of the first portion and over the second portion the N-type tub region; spaced source and drain regions of a first conductivity type in one of the wells of a conductivity type opposite the first conductivity type, the drain region extending into the other of the wells of the same conductivity type; an insulated gate over the space between the source and drain regions; a region of the opposite conductivity type in the other well; a contact region of the first conductivity type in the other well and a contact region of the other conductivity type in the one well; and a first contact connecting the gate and the source region and forming the first terminal and a second contact connected to the region of the opposite conductivity type and forming the second terminal, wherein the P-type well region and the N-type well region both contact the N-type layer along their entire bottom surfaces.