| 摘要 |
<p>PROBLEM TO BE SOLVED: To suppress a short-channel effect and increase speed and performance and improve reliability by forming a second impurity layer MDD region with medium concentration formed to a second depth that is further deeper than a first depth around the surface of a semiconductor substrate. SOLUTION: A second conductivity impurity is ion-implanted so that it is self-aligned to the edge of a first spacer 18, and a second impurity layer with medium concentration, namely an MDD region 24, having a second depth that is deeper than a first depth is formed around the surface of a semiconductor substrate 10. At this time, the MDD region 24 is formed so that the side diffusion region does not overlap with a gate electrode 14. Also, the vertical junction depth of the MDD region 24 is diffused deeper than that of an LDD region 22. In this manner, parasitic resistance can be reduced as compared with a case where the vertical junction depth of the MDD region 24 is formed to that of the LDD region 22, thus allowing relatively larger amount of current to flow and increasing the saturation current of the drain.</p> |
