| 摘要 |
PURPOSE:To obtain a large-capacity junction capacitance structure having little leakage current by a method wherein the edges of the diffusion layer of at least one side of joined diffusion layers are prevented from being formed in the interior of the other diffusion layer. CONSTITUTION:An N-type buried layer 12 and an N-type epitaxial layer 13 are formed on a P-type Si substrate 11. A P-type isolation diffusion layer 17 is formed in the interior of this layer 13. Moreover, P-type isolation diffusion layers 14 are respectively formed at both end parts of the layer 13. A P-type base diffusion layer 15 and an N-type diffusion layer 16 are laminatedly formed in this order lying over on the layer 17 and the layer 13. For leading an electrode of an electrode of the layer 17, the layer 15 is formed in a structure that the layer 15 is extended to the outside of the layer 16 and the layer 15 is provided with an electrode. In this construction, a junction capacitance which is formed of the layer 15, the layer 17 and the layer 16 is used. By avoiding the inclusion of joined ends of the layer 16 in the layer 17 like this, soft breakdown can be prevented.
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