| 摘要 |
<p>A semiconductor device formed in a semiconductor substrate and having a gate electrode formed on the semiconductor substrate, source and drain regions are formed in said the semiconductor substrate. The source and drain regions are made of a first impurity region doped with impurities of an opposite conductivity type to that of a semiconductor substrate formed at portions adjacent to the edge of the gate electrode, a second impurity region doped with impurities of an opposite conductivity type to that of a semiconductor substrate formed at portions under the first impurity region, and a third impurity region doped with impurities of opposite conductivity type to that of a semiconductor substrate formed at portions spaced apart from the edge of the gate electrode. The impurities of the second impurity region have a diffusion coefficient larger than that of the impurities of the first impurity region. The third impurity region has a higher concentration than that of the first and the second impurity regions and in addition the impurities of the third impurity region have a diffusion coefficient smaller than that of the second impurity region.</p> |
