| 摘要 |
PURPOSE: To reduce increasing electric field by a method wherein an intermediate layer doped to n-type is provided between an n-type base layer and a p-type base layer, and doping density of the intermediate layer is higher than that of the n-type base layer. CONSTITUTION: The cathode side is expanded by an intermediate layer 11 having n doping density higher than an n-type base layer 8 between the n-type base layer 8 and a p-type base layer 7. Preferably, the maximum of doping density of the intermediate layer 11 is within the range of about 2×10 to 8×10<14> cm<-3> . Further, preferably, a thickness of this intermediate layer 11 is within the range of 10 to 20 micron. As the result of inserting the intermediate layer 11, electric field reinforcing computation m can be limited to 1.3 (V=200V) to 1.5 (V=1000V). Further, as the result of inserting the intermediate layer 11, a static yield voltage of a p-n junction 13 is naturally reduced. When a thickness of the intermediate layer and doping density are deliberately selected, a reduction in this yield voltage can be completely accommodated within a permissible range.
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