Cathode assembly for GTO thyristor

摘要

A cathode arrangement for a GTO thyristor has a planar emitter zone (2) embedded in a base layer (1), a gate electrode (4) contacting the base layer (1), a metal emitter electrode (13) provided on the emitter zone (2), and a metal pressure plate (7) pressed on the emitter electrode surface which is at least 10-15 microns above the emitter zone surface so that the underside of the pressure plate (7) is spaced from the top of the gate electrode (4). The novelty comprises one of the following: (a) the emitter electrode (13) covers an insulating layer (8) applied on the emitter zone (2) such that it contacts the emitter zone (2) at the edge of the insulating layer (8); (b) a resistive layer, provided between the emitter zone and the emitter electrode, extends laterally from the middle of the emitter zone surface over an insulating film to the emitter zone edge where it contacts the emitter electrode; or (c) the emitter electrode comprises an electroplated metal layer.