| 摘要 |
PURPOSE:To prevent the local concentration of current and thus stengthen the breakdown strength by a method wherein a depletion layer is contrived to expand to the anode side by forming the anode region of a diode by the same diffusion as isolation layers. CONSTITUTION:A p<+> type diffused layer 19 is formed at the same time with the p<+> type isolation layers 4, 5 and 6. The anode electrode 14 of the diode is led out from this p<+> type diffused layer 19. When a reverse directional voltage is impressed on this diode, the depletion layer expanses to the direction of the p<+> type diffused layer 19, since the impurity concentration in the neighborhood of the p-n junction of the p<+> type diffused layer 19 is lower than that of an n<+> type region 2. Thereat, the impurity concentration of the p<+> type diffused layer 19 is larger than that of an n<-> type layer 3a; therefore the expansion of a depletion layer correponding to the impressed voltage is small, breakdown voltage becomes low, and the seat resistance in the neighborhood of the end of the depletion layer of the diffused layer 19 becomes several hundred - several thousand OMEGA/mm.<2>. Accordingly, the concentration of current to local parts is prevented. |
