Stmicroelectronics(tours) Sas

Dalaf Ali

Samuel Menard

A bidirectional switch is formed in a semiconductor substrate of a first conductivity type. The switch includes first and second thyristors connected in antiparallel extending vertically between front and rear surfaces of the substrate. A vertical peripheral wall of the second conductivity type connects the front surface to the rear surface and surrounds the thyristors. On the front surface, in a ring-shaped region of the substrate separating the vertical peripheral wall from the thyristors, a first region of the first conductivity type is provided having a doping level greater than the substrate and having the shape of a ring-shaped band portion partially surrounding the first thyristor and stopping at the level of the adjacent region between the first and second thyristors.

Bidirectional switch

A bidirectional switch formed in a substrate includes first and second main vertical thyristors in antiparallel connection. A third auxiliary vertical thyristor has a rear surface layer in common with the rear surface layer of the first thyristor. A peripheral region surrounds the thyristors and connects the rear surface layer to a layer of the same conductivity type of the third thyristor located on the other side of the substrate. A metallization connects the rear surfaces of the first and second thyristors. An insulating structure is located between the rear surface layer of the third thyristor and the metallization. The insulating structure extends under the periphery of the first thyristor. The insulating structure includes a region made of an insulating material and a complementary region made of a semiconductor material.

A vertical four-quadrant triac wherein the gate region, arranged on the side of a front surface, includes a U-shaped region of a first conductivity type, the base of the U lying against one side of the structure, the main front surface region of the second conductivity type extending in front of the gate region and being surrounded with portions of the main front surface region of the first conductivity type.

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Dalaf Ali