| 摘要 |
PURPOSE:To provide a switching element having high withstand voltage, by selecting impurity concentration and intervals so that depletion layers extending to a collector region, become a pinch-OFF state before the occurrence of breakdown phenomenon. CONSTITUTION:The concentration of impurities and the thickness of an epitaxial layer 2 are selected as follows: a low resistivity embedded region is not provided in a well; depletion layers are extended from a collector region 21 in the inside under an emitter region 4 toward a collector contact region 5; and a collector voltage is not directly applied to the collector region 21 in the inside. Namely, when the collector voltage is high, the depletion layers extended from a base region 3 and from a substrate 1 are contacted each other. The depletion layers are further extended and the voltage drop is generated between the collector contact region 5 and the collector region 21 in the inside by the depletion layers. Therefore, the potential of the collector region 21 in the inside becomes lower than the collector voltage by the amount of the voltage drop due to the depletion layers. Even though a high voltage is applied to the collector, avalanche breakdown in not generated at the lower part of the emitter region. |
