Patent ID: 6696730
Filing Date: 2004-02-24
Classification: H01L

Abstract:
An electrostatic discharge protection circuit for bypassing an electrostatic surge entering a semiconductor integrated circuit, the electrostatic discharge protection circuit comprising:an electrostatic discharge protection device comprising a trigger diode for triggering a thyristor with a low voltage, wherein the trigger diode comprises: an n-type cathode high impurity concentration region; a p-type anode high impurity concentration region; and an insulator section for electrically insulating a silicide layer formed on a surface of the n-type cathode high impurity concentration region from another silicide layer formed on a surface of the p-type anode high impurity concentration region; and a protection diode provided so as to produce a breakdown current in the presence of an electrostatic charge flowing through an input/output signal line, wherein: the electrostatic discharge protection device and the protection diode are arranged in parallel between the input/output signal line and a reference voltage line of the semiconductor integrated circuit; an anode and an anode gate of the thyristor provided in the electrostatic discharge protection device and a cathode of the protection diode are connected to the input/output signal line; a cathode and a cathode gate of the thyristor and an anode of the protection diode are connected to the reference voltage line; and wherein the electrostatic discharge protection device further comprises a resistor, the resistor being formed in a well, which has a conductivity type opposite to that of a substrate, between the anode of the thyristor and the cathode of the protection diode, wherein in the presence of said breakdown current the anode of the thyristor is brought to a potential higher than that of the cathode of the protection diode.