| 摘要 |
PURPOSE:To realize high withstand voltage and high ASO, by making a pnpn four-layer structure, and making the sum of current amplification factors in a pnp transistor region and in an npn transistor region less than 1. CONSTITUTION:Four semiconductor layers of pnpn constituted of, for example, a p-emitter layer 1, an n-base layer 2, a p-base layer 3 and an n-emitter layer 4 are provided. Each impurity concentration of the four semiconductor layers of pnpn is constituted in the manner in which the sum of current amplification factor, (alpha1+alpha2), is made smaller than 1, where alpha1 and alpha2 are as follows; alpha1 is a current amplification factor of transistor action appearing in a pnp lamination part, and alpha2 is a current amplification factor of transistor action appearing in an npn lamination part. Thereby, a wide ASO (safety operation region) with high withstand voltage can be easily obtained, and sufficiently high performance can be exhibited in the application to a current type inverter and the like.
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