| 摘要 |
<p>1376480 Semi-conductor devices SIEMENS AG 24 Nov 1972 [3 March 1972] 54484/72 Heading H1K The emitter electrode 5 of a thyristor shorts the emitter region 1 to the base region 2 at a location adjacent a further region 11 of the same conductivity type as the emitter region 1, which region 11 is shorted to the base region 2 by the control electrode 6, and is located between the control electrode 6 and the emitter region 1. In the blocking direction the presence of the region 11 avoids destructive avalanche break-down of the emitter junction 8, while in the conducting direction it ensures that most of the firing current from electrode 6 passes through the emitter region 1 rather than passing directly to the emitter electrode 5. The invention is particularly useful in thyristors having a central relatively low resistivity zone 10 of the second base region 3. There may be a plurality of the regions 11 symmetrically disposed about the circular base electrode 6 and projecting into corresponding recesses in the inner periphery of the annular emitter region 1. The emitter region 1 may be an auxiliary emitter located within a larger annular main emitter region (22), Fig. 5 (not shown). In this case outward projections (18) of the auxiliary emitter region (1), corresponding to the regions (11), extend towards portions of the main emitter region (20) shorted to the base region (2).</p> |
