| 摘要 |
PURPOSE:To operate at a high speed by forming a higher density P-type impurity region than a substrate in contact with an N<+> type buried layer under the N<+> type buried layer of a memory cell. CONSTITUTION:A P<+> type diffused region 18 is formed in a P<-> type substrate 1, an N<+> type buried layer 2 is formed thereon, a P<+> type base diffused region 4 is formed on an N<-> type epitaxial layer 3, and N<+> type emitter regions 5a-5c are formed in the region 4. A P-N junction capacity of the layers 2 and 18 is formed larger than that of the layer 2 and the substrate 1 to increase a junction capacity CTS between a collector and the substrate of multi-emitter transistor of a memory cell M to strengthen against information inversion due to alpha-ray. Thus, a memory having high speed and high reliability can be obtained. |
