| 摘要 |
PROBLEM TO BE SOLVED: To attain prevention of a leakage current, increase in a punch-through margin and increase in a current drive capability. SOLUTION: A semiconductor memory device having a transistor structure is formed differently from a cell array region, a core region and a peripheral circuit region. That is, a source/drain of a transistor(TR) of the cell array region consists of an impurity region 106 with a low concentration, a source/ drain of a TR of the core region consists of an impurity region 112 with a high concentration and an impurity region 108 with a low concentration formed by the same doping agent, and a source/drain of a TR of the peripheral circuit region consists of the impurity region 112 with a high concentration and the impurity region 106 with a low concentration formed by different doping agents. The doping agent forming the impurity region 108 with a low concentration in the core region especially has a lower degree of diffusion than that of the doping agent to form the impurity region 106 with a low concentration in the peripheral circuit region. |
