| 摘要 |
PURPOSE:To eliminate the influence of the thickness of an N-type epitaxial layer on the current amplification factor of a PNP Tr by forming an N-type buried layer similar to an N-type buried layer for forming the NPN type transistor Tr on a boundary between a P-type substrate and the N-type epitaxial layer. CONSTITUTION:N-type buried layers 121, 122 are formed corresponding to a region A on a P-type substrate 11, and an N-type buried layer 13 is formed on a region B. Then, an N-type epitaxial layer 14 is formed on the substrate 11. Thereafter, N-type base diffused layers 16, 17 are formed on the regions corresponding to the regions A, B of the layer 14. An N-type emitter diffused layer 18 is formed in the layer 14, and an N-type emitter diffused layer 19 is formed in the layer 17 of the region B simultaneously with the layer 18. In this case, an N-type collector contact diffused layer 20 is further formed in the layer 14 of the region B. The current amplification factor of the PNP Tr of the substrate of the region A formed in this manner is controlled by layers 121, 123. Thus, the current amplification factor of the PNP Tr or the substrate is so controlled as not to be affected by the influence of the thickness of the layer 14.
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