| 摘要 |
PURPOSE:To maintain the impurity concentration of an element region at the optimum value and to meet the miniaturization of an element, without deteriorating element isolating perfor mance in a field region, by forming an element isolating region, and introducing second conducting type impurities in the surface of a first conducting type diffused layer, which is exposed out of the element isolating region. CONSTITUTION:A first conducting type diffused layer 12 is selectively formed in a part of a semiconductor substrate 11. An element isolating region 13 is formed on the surface of the substrate. Then second conducting type impurities are introduced in the surface of at least a part of the first conducting type diffused layer 12, which is exposed out of the element isolating region 13. The concentration of a second conducting impurities is made lower than the impurity concentration of the first conducting type diffused layer 12. Then, on a first conducting type diffused layer 14, in which the second conducting type impurities are intro duced, a gate insulating film 15 and a gate electrode 16 are formed. On the surface of the first conducting type diffused layer 12 on both sides of the gate electrode 16, second conducting type source are drain regions 17 and 18 are formed. Thus the impurity concentration directly beneath the fixed oxide film 13 is not decreased and the element isolating performance is not deteriorated. Since the impurity concentration in the surface of the element region can be maintained at the optimum value, the element characteristics can be improved. |
