| 摘要 |
PURPOSE:To reduce the current of a parasitic P-N-P transistor, also reduce the current flowing into a substrate, prevent a thyristor to become conductive and also prevent latch-up by forming the high concentration N<+> diffusion region in such a depth as reaching the N<+> buried region in the periphery of a P type region which is formed within an N type epitaxial layer connected to the power source and is also connected to the input/output pad. CONSTITUTION:The N<+> diffusion region 35 which is sufficiently higher in concentration than that of an epitaxial layer 32 is formed in such a depth as reaching an N<+> buried region 34 in the periphery of a P type diffusion region 33, a region 36 is formed simultaneously with the emitter diffusion region of an N-P-N transistor in such a way as partly overlapping, then a contact window 37 is formed in order to connect an epitaxial layer 31 to the power source and wiring is carried out with a metal wiring 38. Thereby, the current amplification coefficient of the parasitic P-N-P transistor, where the P type diffusion region 33 operates as the emitter, the epitaxial layer 32 as the base and the substrate 40 as the collector, can be reduced. |
