| 摘要 |
PURPOSE:To restrict parasitic thyristor effect thereby securing memory by providing a high-impurity region whose conductive direction is the opposite to a base of P- ROM that is made by shortcircuiting due to a selective destruction of a base-emitter junction in a bipolar transistor. CONSTITUTION:Two or more P-type bases are formed in an N-type epitaxial layer 3 being provided on a P-type semiconductor substrate 1, then an N-type emitter is formed in each base to compose two or more NPN transistors which share the N- type layer 3 as a common collector. A P-type separation region 4 separates a transistor used for a peripheral circuit E1-B1-C1 from transistors used for memory elements. Then an N-type high-impurity channel stopper 5 is installed on the N-type collector between the adjoining two P-type bases B2, B3 of the transistors used for memory elements E2-B2-C1, E3-B3-C2. By so doing, current increase rate between the two adjoining bases in parasitic lateral transistors is reduced, thereby preventing the parasitic thyristor effect. |
