Bidirectional static switch responsive in quadrants Q4 and Q1
A monolithic bidirectional switch formed in an N-type semiconductor substrate, including, in a first area, a first vertical thyristor adjacent to a second vertical thyristor; a triggering area arranged on the front surface side, apart from the first area, including a P-type well in which is formed an N-type region; a first metallization covering the rear surface; a second metallization on the front surface layers of the first and second thyristors; a third gate metallization on said well; on the rear surface side, an additional P-type region and an insulating layer interposed between this additional region and the first metallization, the additional region extending under the triggering area; and a fourth metallization on the region.
1. A monolithic bidirectional switch formed in a semiconductor substrate of a first conductivity type having a front surface and a rear surface, including:
in a first area, a first main vertical thyristor having a rear surface layer of the second conductivity type, adjacent to a second main vertical thyristor having a rear surface layer of the first conductivity type;
a triggering area arranged on the front surface side, apart from the first area, this triggering are including a well of the second conductivity type in which is formed a region of the first conductivity type;
a first main electrode metallization, covering the rear surface;
a second main electrode metallization on the front surface layers of the first and second thyristors;
a third gate metallization on said well;
on the rear surface side, an additional region of the second conductivity type and an insulating layer interposed between this additional region and the first rear surface metallization, said additional region extending under the triggering area and partially under the first area and being separated from rear surface layers of the first and second thyristors; and
a fourth metallization on said region.
2. The bidirectional switch of claim 1 , including a peripheral wall of the second conductivity type extending from the rear surface to the front surface.
3. The bidirectional switch of claim 1 , wherein, in operation, the fourth metallization is connected to the voltage of the rear surface metallization.
4. The bidirectional switch of claim 3 , wherein said well, in top view, encircles the first area, said region extending on one side only of the first area, on the side of the first thyristor.
5. The bidirectional switch of claim 3 , wherein at the periphery of the first area is arranged a lightly-doped layer of the second conductivity type separated from the rest of the structure by a sufficiently broad area of the substrate to withstand the desired breakdown voltage of the component, this sufficiently broad area being divided in two parts by a stop-channel ring.