Abstract: A semiconductor thyristor device that incorporates buried region breakdown junctions laterally offset from an emitter region. By spacing the buried regions around the emitter region, current carriers emitted from the buried regions are distributed over a large area of the emitter region, thereby providing a high current capability during initial turn on of the device. In order to achieve low breakover voltage devices, the buried regions are characterized with high impurity concentrations, with the breakdown junctions located near the surface of the chip. The low voltage thyristor device minimizes the area of high dopant concentration junctions, thus minimizing the chip capacitance and permitting high speed, low voltage signal operation.

Abstract: A semiconductor device with two epitaxial layers formed on a substrate. The middle layer of epitaxial material can be formed thin and with an appropriate doping concentration to provide a low avalanche breakdown voltage with a negative resistance characteristic. The top layer of epitaxial material is doped with the same concentration as the substrate to provide a two-terminal thyristor device with symmetrical bidirectional operating characteristics.

Abstract: A semiconductor thyristor device incorporates buried regions to achieve low breakover voltage devices, and the buried regions are offset laterally with respect to the emitter regions. The low voltage thyristor devices can be incorporated into five-pin protection modules for protecting customer circuits.

Abstract: A semiconductor thyristor device that incorporates buried regions centrally located on the chip with respect to the other semiconductor regions. By centering an upper and lower buried region, larger-area contacts can be realized, thereby increasing the current capability of the device. In order to achieve low breakover voltage devices, the buried regions are offset laterally with respect to the respective emitter regions. The low voltage thyristor devices can be incorporated into five-pin protection modules for protecting customer circuits.

Abstract: A semiconductor thyristor device (110) that incorporates buried regions (112) spaced around an emitter region (114). By spacing the buried regions (112) around the emitter region (114), current carriers emitted from the buried regions are distributed over a large area of the emitter region (114), thereby providing a high current capability during initial turn on of the device. In order to achieve low breakover voltage devices, the buried regions (112) are offset laterally with respect to the respective emitter regions (114). The low voltage thyristor device exhibits a low capacitance for operating with high speed, low voltage signals. The device capacitance is reduced by utilizing a plurality of buried regions (112), each formed having a relatively small area junction with the base region (118).

Abstract: An integrated circuit (40) providing overvoltage and overcurrent protection to a line (16). The integrated circuit (40) is constructed to provide overvoltage protection when a voltage exceeding a specified magnitude is impressed across the cathode and anode terminals (64, 66), irrespective of the gate-cathode current. A gate terminal (72) is provided to trigger the overvoltage protection device into conduction when a gate current exceeding a predefined value is carried on the line (16). The gate-cathode structure of the integrated circuit (40) includes a semiconductor resistance (74) which functions to make the gate current required for turn on higher, thereby allowing the gate-cathode terminals (64, 72) of the integrated circuit (40) too be connected in series with the line (16) to be protected.

Abstract: A four-layer low voltage thyristor device (30) in which the breakover voltage is independent of the holding current. Rather than forming a buried region (38) underlying the emitter region (42), the buried region 38 is formed laterally to the side of the emitter (42). In order to form a low breakover voltage device, the buried region (38) is required to be highly doped, but the resulting junction (40) does not approach the emitter junction (48). A low breakover voltage (5 V-12-V) thyristor can thus be realized.

Abstract: A two-terminal, bidirectional semiconductor trigger switch is provided. The trigger switch is a relatively sensitive multilayer semiconductor breakover device that switches on fully when its breakover voltage is reached. The design of the trigger switch allows its breakover voltage point to be readily adjustable during fabrication of the device.The semiconductor trigger switch is particularly suited to provide a low voltage trigger for a TRIAC. The trigger switch is connected in series with the gate of the TRIAC and mounted on the gate lead to provide a unitary, three-terminal device incorporating the TRIAC/trigger switch combination.