| 摘要 |
PURPOSE:To protect an integrated circuit from a surge by a method wherein the second diffusion layer containing the first conductive type impurities is formed within the first diffusion layer containing the second conductive type impurities to be provided on the first conductive type substrate. CONSTITUTION:A diffusion layer 1 containing the second conductive type impurities, which are in complementary relation with the first conductive type, are provided on the first conductive type semiconductor substrate. The diffusion layer 5 containing the first conductive type impurities are formed within the diffusion layer 1. When a negative surge voltage is added, as a surge current runs on the low impurity density part which is pinched between a substrate 2 and a diffusion layer 5, a depletion layer is expanded sufficiently, and the current path is narrowered, thereby enabling to obtain a large protective resistance. |
