Optically triggered lateral thyristor with auxiliary region

A later thyristor which is optically fired comprising a chip of semiconductor material having a pn junction-receiving layer of one conductivity type and of a given resistivity;

• a first emitter region of an opposite conductivity type and a base region of said opposite conductivity type each formed into said layer and laterally spaced from one another;
• a second emitter region of said one conductivity type formed in and totally contained within said base region and extending therein from a surface of said layer;
• first and second electrodes connected to said first and second emitter regions, respectively, and readiation means for illuminating at least a portion of said layer for turning on said thyristor;
• an auxiliary region of said opposite conductivity type extending only part way into said layer and laterally spaced from and surrounding said base region;
• and means for resistively connecting in permanent fashion said auxiliary region to said second electrode.

A lateral thyristor which is optically fired comprising a chip of semiconductor material having a pn junction-receiving layer of one conductivity type and of a given resistivity;

• a first emitter region of an opposite conductivity type and a base region of said opposite conductivity type each formed into said layer and laterally spaced from one another;
• a second emitter region of said one conductivity type formed in and toally contained within said base region and extending therein from a surface of said layer;
• first and second electrodes connected to said first and second emitter regions, respectively, and radiation means for illuminating at least a portion of said layer for turning on said thyristor;
• an auxiliary region of said opposite conductivity type extending only part way through said layer and laterally spaced from and surrounding substantially the full lateral periphery of said base region;
• and means for resistively connecting in permanent fashion said auxiliary region to said second electrode;
• said base region having an elongated shape terminating at said layer;
• said second emitter regio comprising at least one elongated rectangular shape contained within said base region;
• said first emitter region having a digitated pattern, the entirety of said elongated base region being situated between adjacent fingers to said digitated first emitter pattern.

A lateral thyristor which is optically fired comprising a chip of semiconductor material having a pn junction-receiving layer of one conductivity type and of a given resistivyt;

• a first emitter region of an opposite conductivity type and a base region of said opposite conductivity type each formed into said layer and laterally spaced from one another;
• a second emitter region of said one conductivity type formed in and totally contained within said base region and extending therein from said layer;
• first and second electrodes connected to said first and second emitter regions, respectively, and radiation means for illuminating at least a portion of said layer for turning on said thyristor;
• an auxiliary region of said opposite conductivity type extending only part way into said layer and laterally spaced from and surrounding substantially the full periphery of said base region;
• means for resistively connecting in permanent fashion said auxiliary region to said second electrode and a guard ring of said opposite conductivity type formed into said layer and being disposed symmetrically between and laterally spaced from said first emitter and auxiliary regions;
• said guard ring being out of contact with said first and second electrodes and floating electrically with respect to said electrodes.

An optically triggered thyristor comprising, in combination:

• a substrate of semiconductor material of one conductivity type and of a given resistivity;
• at least first and second elongated, spaced, and parallel base regions of an opposite conductivity type extending into the layer of the substrate;
• respective auxiliary regions of said opposite conductivity type extending only part way into the layer of said substrate and respectively laterally spaced from and surrounding substantially the full lateral peripheries of said base regions;
• respective first emitter regions of said one conductivity type extending into said layer of at least first and second parallel base regions and being completely contained within their said respective base regions;
• respective elongated second emitter regions of said opposite conductivity type extending into said substrate and respectively disposed on opposite elongated sides of, laterally spaced from, and situated parallel to each of said parallel base regions;
• said base region being situated between respective second emitter regions;
• a first electrode connected to said first emitter regions;
• a second electrode connected to said second emitter region;
• means for resistively connecting in permanent fashion said auxiliary regions to said first electrode;
• said radiation generating means energizable to generate minority carriers in said substrate which act as a base drive to turn on said thyristory when appropriate bias voltages are applied to said first and second electrodes.