| 摘要 |
PROBLEM TO BE SOLVED: To prevent deterioration in pressure resistance due to a punch through, by forming a gate insulating film and a gate electrode on a first conduction type impurity region, forming a second conduction type impurity diffusion layer with respect to the gate electrode, forming a second conduction type low-density impurity layer on an outer peripheral portion of the second conduction type impurity diffusion lager, and forming an element isolation region in a plurality of transistors. SOLUTION: A gate insulating film 11 and a gate electrode 12 having a spacer 13 on the sidewall thereof are formed on a semiconductor substrate 1. A diffusion layer 15 which is a second conduction type impurity diffusion layer is formed in a self-aligned manner with respect to the gate electrode 12. On an outer peripheral portion of the diffusion layer 15, a low-density layer 16 which is a second conduction type low-density impurity layer formed in a self-aligned manner is arranged. Then, first conduction type impurity ions are implanted in a desired region in a plurality of transistors having a P-well 7 formed on a peripheral circuit portion C, thus forming an element isolation region 23a. Thus, deterioration in pressure resistance due to a punch through may be prevented. |
