| 摘要 |
PURPOSE:To blow out the fuse at comparatively low voltage by connecting the fuse in series with a diode, supplying the diode with fixed potential when the fuse is blown out, turning the diode ON, flowing currents through the fuse and melting the fuse. CONSTITUTION:The voltage of reverse bias is applied to a junction between an N<+> diffusion layer 15 biased at potential VPP and a P type well region 14 in the layer 15 and the region 14, but breakdown voltage is determined by the concentration of an impurity forming the junction, and the higher the impurity concentration is, the lower the breakdown voltage becomes. The N<+> diffusion layer 15 forms the junction together with the P type well region 14 while also forming a junction together with a P<+> diffusion layer 16. A junction section between the N<+> diffusion layer 15 and the P<+> diffusion layer 16 has the lowest breakdown voltage of the junction because the impurity concentration of the P<+> diffusion layer 16 is higher than that of the P type well region 14. The breakdown voltage of the junction reaches approximately 8V when the impurity concentration of the P<+> diffusion layer 16 and the N<+> diffusion layer 15 is brought to 1X 10<20>/cm<3> as a standard process. |
