| 摘要 |
PURPOSE:To realize a very fine structure with a reduced thickness of the surface insulation oxide film and a reduced distance between diffusion layers, by providing the field of a bipolar transistor with a guard ring in which the concentration of a conductive impurity is selectively increased. CONSTITUTION:A guard ring 61 acts to obstruct the formation of a channel inversion layer in the field section between a p type isolating diffusion layer 7 and a p type collector diffusion layer 81. Accordingly, even if the thickness of a surface insulation oxide film 41 is reduced for the purpose of providing a fine structure, the film is prevented from being effected adversely by parasitic MOSFET. Further, since the ring 61 is interposed between the diffusion layers 7 and 81, the effective current amplification factor of a pnp bipolar transistor TR constituted by the diffusion layer 7, an n<-> type epitaxial layer 2 and the diffusion layer 81 is decreased. In this manner, the distance between the diffusion layer 7 and the diffusion layer 81 can be decreased for the purpose of realizing a fine structure without suffering from adverse effect by a parasitic bipolar TR. |
