| 摘要 |
PURPOSE:To obtain a high hFE transistor by using as a base a P-well extending to an N<+> buried layer. CONSTITUTION:A P well 5 extending to an N<+> buried collector 2 is used as a substantial base, and a P diffused layer 6 is provided in a connecting portion so as to ensure an ohmic contact with a base electrode 11. The construction other than the above is the same with that of a conventional npn transistor. Although the width of a base is increased, according to this construction, the concentration of the base can be reduced by ion implantation in a small dose amount, and therefore hFE can be made high. For instance, hFE=500 can be obtained when an N epitaxial layer is 10 mum and when the amount of ion implantation into the P-well is 2mu10<13>/cm<2>. According to this construction, a P-well type transistor of high hFE is obtained, and a linear I<2>L coexistence type IC containing an npn transistor of high hFE can be manufactured with an excellent yield.
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