A thyristor memory cell includes a semiconductor cathode, a first un-doped semiconductor feature connected to the semiconductor cathode, a second un-doped semiconductor feature connected to the first un-doped semiconductor feature, a semiconductor anode connected to the second un-doped semiconductor feature, and a gate feature disposed on the first un-doped semiconductor feature or the second un-doped semiconductor feature. Among the semiconductor cathode, the first un-doped semiconductor feature, the second un-doped semiconductor feature and the semiconductor anode, the semiconductor anode has the highest bottom edge of conduction band, followed by the first un-doped semiconductor feature, the second un-doped semiconductor feature and the semiconductor cathode in the given order; and the semiconductor anode has the highest top edge of the valence band, followed by the first un-doped semiconductor feature, the second un-doped semiconductor feature and the semiconductor cathode in the given order.

The present disclosure relates to semiconductor structures and, more particularly, to vertically stacked diode-trigger silicon controlled rectifiers and methods of manufacture. The structure includes: a silicon controlled rectifier in a trap rich region of a semiconductor substrate; and at least one diode built in polysilicon (gate material) and isolated by a gate-dielectric.

A transient voltage suppressing (TVS) device formed in an epitaxial layer of a first conductivity type supported on a semiconductor substrate. The TVS device further comprises a plurality of contact trenches opened and extended to a lower part of the epitaxial layer filled with a doped polysilicon layer of a second conductivity type wherein the trenches are further surrounded by a heavy dopant region of the second conductivity type. The TVS device further includes a metal contact layer disposed on a top surface of the epitaxial layer electrically connected to a Vcc electrode wherein the metal contact layer further directly contacting the doped polysilicon layer and the heavy dopant region of the second conductivity type.

A transient-voltage suppressing (TVS) device disposed on a semiconductor substrate including a low-side steering diode, a high-side steering diode integrated with a main Zener diode for suppressing a transient voltage. The low-side steering diode and the high-side steering diode integrated with the Zener diode are disposed in the semiconductor substrate and each constituting a vertical PN junction as vertical diodes in the semiconductor substrate whereby reducing a lateral area occupied by the TVS device. In an exemplary embodiment, the high-side steering diode and the Zener diode are vertically overlapped with each other for further reducing lateral areas occupied by the TVS device.

An integrated circuit includes an NMOS SCR in which a p-type body well of the NMOS transistor provides a base layer for a vertical NPN layer stack. The base layer is formed by implanting p-type dopants using an implant mask which has a cutout mask element over the base area, so as to block the p-type dopants from the base area. The base layer is implanted concurrently with p-type body wells under NMOS transistors in logic components in the integrated circuit. Subsequent anneals cause the p-type dopants to diffuse into the base area, forming a base with a lower doping density that adjacent regions of the body well of the NMOS transistor in the NMOS SCR. The NMOS SCR may have a symmetric transistor, a drain extended transistor, or may be a bidirectional NMOS SCR with a symmetric transistor integrated with a drain extended transistor.

An apparatus can include a first circuit that is configured to provide electrostatic discharge (ESD) protection against an ESD pulse applied between a first node and a second node. The first circuit includes a series stack of bipolar transistors that are configured to shunt current between the first and second nodes in response to the ESD pulse; and a diode connected in series with the stack of bipolar transistors and configured to lower a snapback holding voltage of the first circuit when shunting current between the first and second nodes.

A transient-voltage suppressing (TVS) device disposed on a semiconductor substrate including a low-side steering diode, a high-side steering diode integrated with a main Zener diode for suppressing a transient voltage. The low-side steering diode and the high-side steering diode integrated with the Zener diode are disposed in the semiconductor substrate and each constituting a vertical PN junction as vertical diodes in the semiconductor substrate whereby reducing a lateral area occupied by the TVS device. In an exemplary embodiment, the high-side steering diode and the Zener diode are vertically overlapped with each other for further reducing lateral areas occupied by the TVS device.

An ESD protection device comprising an SCR-type circuit including a PNP transistor and NPN transistor incorporates a Zener diode which permits the circuit to operate at comparatively low trigger voltage thresholds. Zener diode breakdown voltage is controlled by doping levels in a doped area of an N-type well. One or more diodes connected in series between the SCR circuit and the input/output terminal of the device advantageously raises the snapback voltage of the SCR circuit. The use of nitride spacers between doped regions instead of gate oxide technology significantly reduces unwanted leakage currents.

A transient voltage suppressing (TVS) device formed in an epitaxial layer of a first conductivity type supported on a semiconductor substrate. The TVS device further comprises a plurality of contact trenches opened and extended to a lower part of the epitaxial layer filled with a doped polysilicon layer of a second conductivity type wherein the trenches are further surrounded by a heavy dopant region of the second conductivity type. The TVS device further includes a metal contact layer disposed on a top surface of the epitaxial layer electrically connected to a Vcc electrode wherein the metal contact layer further directly contacting the doped polysilicon layer and the heavy dopant region of the second conductivity type.

Methods to forming trigger-voltage tunable cascode transistors for an ESD protection circuit in FinFET IC devices and resulting devices. Embodiments include providing a substrate including adjacent first-type well areas, over the substrate, each pair of first-type well areas separated by a second-type well area; providing one or more junction areas in each first and second type well area, each junction area being a first type or a second type; forming fins, spaced from each other, perpendicular to and over the first and second type junction areas; and forming junction-type devices by forming electrical connections between the first and second type junction areas in the first-type well areas and the substrate, wherein a first-stage junction-type device in a first-type well area includes stacked first and second type junction areas, and wherein the first-stage junction-type device is adjacent a second-type well area including first and second type junction areas.