Disclosed structures include a semiconductor controlled rectifier or bi-directional semiconductor controlled rectifier with a trigger voltage (Vtrig) that is tunable. Some structures include a semiconductor controlled rectifier with an Nwell and Pwell in a semiconductor layer, with a P-type diffusion region in the Nwell, and with an N-type diffusion region in the Pwell. Gate(s) on the well(s) are separated from the junction between the wells and from the diffusion regions. Other structures include a bidirectional semiconductor controlled rectifier with a Pwell between first and second Nwells in a semiconductor layer, with first P-type and N-type diffusion regions in the first Nwell, and with second P-type and N-type diffusion regions in the second Nwell. Gate(s) on the well(s) are separated from junctions between the Nwells and the Pwell and from any diffusion regions. In these structures, the gate(s) can be left floating or biased to tune Vtrig using gate leakage current.

The present disclosure relates to an electrostatic protection device including an SCR and a manufacturing method thereof. The electrostatic protection device includes a third N+ doped region across an N-type well region and a P-type well region, and a third P+ doped region adjacent to the third N+ doped region. Each of the third N+ doped region and the third P+ doped region has a high doping concentration. In a case that Zener breakdown occurs in a PN junction structure between the third N+ doped region and the third P+ doped region, the SCR is triggered to form a discharge current path. The present disclosure can reduce a trigger voltage of an electrostatic protection device including an SCR, and can provide electrostatic protection devices having different trigger voltages, with high stability and high robustness.

A memory structure includes a substrate, a first gate structure, a second gate structure, a third gate structure, and channel bodies separated from each other and passing through the first gate structure, the second gate structure and the third gate structure along a first direction. The first gate structure, the second gate structure and the third gate structure are disposed on the substrate, and are separated from each other along the first direction and extend respectively along a second direction and a third direction. The first gate includes first, second and third island structures respectively extending along the third direction and separated from each other along the second direction. The third gate structure includes fourth, fifth and sixth island structures respectively extending along the third direction and separated from each other along the second direction.

An IC device includes first and second CMOS structures positioned in n-type doped regions of a substrate, the first CMOS structure including a common gate terminal, first NMOS body and source contacts, and first PMOS body and source contacts, the second CMOS structure including a common drain terminal, second NMOS body and source contacts, and second PMOS body and source contacts. The IC device includes a first electrical connection from the common drain terminal to the common gate terminal, a clamp device including a diode, a second electrical connection from a cathode of the diode to the first PMOS body and source contacts, and a third electrical connection from an anode of the of the diode to the first NMOS body and source contacts, and entireties of each of the second and third electrical connections are positioned between the substrate and a third metal layer of the IC device.

Low capacitance silicon controlled rectifier (SCR) topologies for overvoltage protection are disclosed herein. In certain embodiments, an overvoltage protection circuit is connected between an RF signal pad and a ground signal pad. The overvoltage protection circuit includes a fin field-effect transistor (FinFET) SCR including a PNP bipolar transistor and an NPN bipolar transistor that are cross-coupled, a FinFET trigger circuit connected between an emitter of the PNP bipolar transistor and a base of the NPN bipolar transistor, and a linearity enhancement impedance connected between a reference voltage terminal and the emitter of the PNP bipolar transistor. In certain implementations, a FinFET diode is further included in series with the FinFET SCR with a cathode of the FinFET diode connected to the emitter of the PNP bipolar transistor.

An electronic device includes a doped semiconductor substrate of a first conductivity type. First and second doped wells are provided, separated from each other by trench isolation, within the doped semiconductor substrate. At least one first region and at least one second region are respectively located in the first and second doped wells, with each first and second region having a doping level higher than a doping level of the first and second doped wells. The trench isolation penetrates into the first and second doped wells and extends laterally between the first region and second region. A third region laterally extends between the first and second doped wells at a location under the insulating trench. The third region has a doping level lower than the doping level of the first and second doped wells.

Low capacitance poly-bounded silicon controlled rectifiers (SCRs) are disclosed herein. In certain embodiments, an SCR includes an n-type well (NW) and a p-type well (PW) formed adjacent to one another in a substrate. The SCR further includes active regions including p-type active (P+) fin regions over the NW and connected to an anode terminal of the SCR, and n-type active (N+) fin regions over the PW and connected to a cathode terminal of the SCR. The SCR further includes polysilicon gate regions over the PW and NW that serve to separate the active regions while also improving the SCR's turn-on speed in response to fast overstress transients.

Structures for a silicon-controlled rectifier and methods of forming same. The structure comprises a first well, a second well, and a third well in a semiconductor substrate. The third well is positioned between the first well and the second well. A first terminal includes a first doped region in the first well, and a second terminal includes a second doped region in the second well. The first well, the second well, and the second doped region have a first conductivity type, and the third well and the first doped region have a second conductivity type opposite to the first conductivity type. The structure further comprises a third doped region in the third well. The third doped region includes a first segment and a second segment, and the first segment is separated from the second segment by a portion of the first well and a portion of the third well.