| 摘要 |
PURPOSE:To control the characteristics of writing of a memory cell or stability to noises from a viewpoint of not a peripheral circuit but a device by partially changing the surface of a base section in a lateral transistor into an insulator and controlling the base currents of a vertical transistor according to the quantity of the surface changed into the insulator. CONSTITUTION:With an epitaxial layer 7, a bottom is isolated electrically by a P-N junction between a buried layer 6 and substrate 5, and a side surface is isolated electrically by a thick select oxide film 8. A P<+> type region under the thick select oxide film 8 is formed in order to prevent a parasitic channel. A lateral type P-N-P transistor Q1, in which a P<+> type region 9 is used as an emitter, one part of the N<-> type epitaxial layer 7 as a baselo and a P<+> type region 11 as a collector, and a vertical type N-P-N transistor Q3, in which two N<+> type regions 12a, 12b are employed as emitters and the P<+> type region 11 as the collector as a base and which contains a contact extracted from an N<+> type collector contact section 13, are each formed in the electrically isolated regions. |
