| 摘要 |
PURPOSE:To decrease the parasitic capacity of a semiconductor layer directly beneath a bonding pad, by providing an electrode taking out metal film at least at the upper of an innermost field limiting ring, and forming an active semiconductor region at a place shallower than the field limiting ring. CONSTITUTION:A part of an inner field limiting ring (FLR) 50a is protruded to the inner side. At the upper part of this part, bonding pads 46a and 47a are formed through an insulating film 45. The FLR 50a is formed as an island region independent of a p-type semiconductor layer 43 and not connected to the bonding pads 46a and 47a electrically. Therefore, the collector-base junction capacity becomes small, and the switching speed becomes high. The same bias as that for the base is applied to the bonding pads formed on the FLR 50a. Therefore, the pads operate as field plates, and reliability is improved. The bonding pads are not extended to outermost FLR 50b so that the pads are operated as the field plates.
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