Field plates on two opposed surfaces of double-base bidirectional bipolar transistor: devices, methods, and systems

A power semiconductor device, comprising:

• first and second first-conductivity-type emitter/collector regions, located respectively on first and second surfaces of a second-conductivity-type semiconductor die;
• first and second second-conductivity-type base contact regions, located respectively on the first and second surface of the semiconductor die;
• first and second entrenched field plate structures, located respectively on the first and second surface of the semiconductor die;
• wherein the entrenched field plate structures are conductive, and are insulated from the bulk of the semiconductor die, and are vertically extended, and laterally adjoin the emitter/collector regions, and also laterally adjoin the base contact regions;
• wherein, on each of the surfaces, an emitter/collector region and a base contact region are separated by an entrenched field plate structure, the entrenched field plate structure adjoining both the emitter/collector region and also the base contact region;
• wherein the first and second emitter/collector regions, and also the first and second base contact regions, are each connected to a respectively corresponding external connection;
• and
• first and second field-limiting ring structures, located respectively on the first and second surfaces of the die;
• wherein the first field-limiting ring structure laterally surrounds the first emitter/collector region, the first entrenched field plate structure, and the first base contact region;
• and wherein the second field-limiting ring structure laterally surrounds the second emitter/collector region, the second entrenched field plate structure, and the second base contact region;
• whereby the breakdown voltage is improved under either polarity of applied voltage.