Emitter switched thyristor without parasitic thyristor latch-up susceptibility

A semiconductor switching device comprising:

• an emitter switched thyristor having an anode region, a first base region, a second base region, and a floating emitter region of first conductivity type in said second base region;
• a cathode contact region of second conductivity type, opposite said first conductivity type, in said first base region, adjacent said second base region, said cathode contact region forming a P-N junction with said first base region;
• and
• means responsive to a first bias signal for forming an electrical connection between said floating emitter region of first conductivity type and said cathode contact region of second conductivity type.

A semiconductor switching device comprising:

• a semiconductor substrate;
• an emitter switched thyristor in said semiconductor substrate, said thyristor having an anode region, a first base region, a second base region, and a floating emitter region of first conductivity type in said second base region, said floating emitter region being located at a face of said semiconductor substrate;
• a cathode contact region of second conductivity type in said semiconductor substrate, said cathode contact region forming a P-N junction with said first base region;
• a field effect transistor of second conductivity type at said face, electrically connected between said cathode contact region and said second base region, said field effect transistor having an active region in said first base region and a source region of second conductivity in said first base region, adjacent said cathode contact region;
• and
• a metal strap at said face, electrically connecting said source region of said first field effect transistor to said floating emitter region.

A semiconductor switching device comprising:

• a semiconductor substrate;
• an emitter switched thyristor in said semiconductor substrate, said thyristor having an anode region, a first base region, a second base region, and a floating emitter region of first conductivity type in said second base region;
• a cathode contact including a cathode metallization layer on said substrate and a cathode contact region of second conductivity type in said first base region adjacent said floating emitter region, said cathode contact region forming a P-N junction with said first base region;
• means, in said first base region and responsive to a first turn-off bias signal, for extinguishing conduction between said cathode contact region and said floating emitter region in sa first direction to thereby prevent parasitic thyristor conduction in said first base region, between said cathode contact region and said anode region;
• and
• turn-on gating means responsive to a turn-on bias signal for electrically connecting said floating emitter region to said first base region and providing conduction between said floating emitter region and said first base region in a second direction.