| 摘要 |
A breakover diode comprises a thyristor formed by an anode region (12), an anode base region (11), a cathode base region (15) and a cathode region (18) disposed between anode and cathode electrodes (13,21), and a trigger region (16) of the same conductivity type as the anode base region (11) but of substantially higher carrier concentration. The trigger region (16) forms junctions with the anode base region (11) and with the cathode base region (15): the latter junction breaks down at a low voltage, to switch on a pilot thyristor section (B), which then switches on the main thyristor section (C). The device achieves a low breakdown voltage without the need for a high carrier concentration throughout the anode base region (11). <IMAGE>
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