| 摘要 |
PURPOSE:To obtain a protective device resisting static electricity without lowering the performance of integrated circuit itself by making the dielectric strength of a P-N junction in a protective diode for an input and an output higher than service upper-limit supply voltage. CONSTITUTION:P-N junction diodes for protective diodes 5, 6 are designed so that dielectric strength is made higher than the range of service supply voltage by approximately 1V-10V. A P-N junction is formed between a P type diffusion layer 13 diffused only to an outer circumferential section and an N type diffusion layer 11 between a source and a drain in a transistor. The P type diffusion layer 13 is formed in concentration different from that of a P type diffusion layer 12 for preventing a field inversion in an integrated circuit at that time, and the dielectric strength of the diode can be determined by controlling the impurity concentration of the P type diffusion layer 13. The P type diffusion layer 12 for preventing the field inversion needs not be made different from impurity concentration for conventional inversion prevention, and has no effect on the function of the integrated circuit. A P-channel MOS integrated circuit can also be constituted similarly when polarity is changed. |
