| 摘要 |
PURPOSE:To increase the degree of integration by preventing the punch through that will be caused at the corner of the diffused layer without occupying margin and also without decreasing the impurity concentration of the substrate. CONSTITUTION:In the case the impurities are diffused in the semiconductor substrate, the extension of the diffusion at the corner depends largely on the ratio between the concentration of the surface of the impurity layer and the concentration of the substrate. It is especially large at the corner of a P-well layer of CMOS. Therefore, the sufficiently large margin has been given in the conventional devices and the degree of integration has been hampered. Now the configuration of a mask 4 is improved so that the corner 21 of an N<+> layer 3 is diagonally cut out. In this constitution, since the distance between the P well 2 and the N<+> layer 3 at the corner is broadened, said distances at the corner and the sides are uniformly averaged, and the punch through can be perfectly prevented. Since the distance between the N<+> layer mask 4 and the P well mask 5 can be shortened, the IC can be advantageously miniaturized. In this constitution, the concentration of the impurities in the substrate need not be decreased. |
