| 摘要 |
PURPOSE:To restrict the parasitic thyristor effect thereby securing memory by providing a channel stopper whose conductive direction is the same as a base of P-ROM that is made by short-circuiting due to a selective destruction of a base-emitter junction is 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 peripheral circuit E1-B1-C1 from transistors used for memory elements E2-B2-C2, E3-B3-C2,.... Then a P-type channel stopper 5 is installed on the N-type collector surface between the adjoining two P-type bases B2, B3 of the transistors used for memory elements. By so doing, current increase rate between the two adjoining bases in parasitic lateral transistors is reduced, thereby preventing the parasitic thyristor effect. |
