| 摘要 |
PURPOSE:To enable an LDD structure to be formed easily, by implanting a high-concentration impurity into an element with the element positioned obliquely after the formation of a gate electrode, then implanting a low-concentration impurity with the element positioned vertically and finally heat treating the ion implanted layers so as to activate them. CONSTITUTION:A gate oxide film 102 is provided on a P substrate 101, and a gate electrode 103 is formed thereon. The first ion implantation is performed with the element positioned obliquely so as to form a high-concentration N-type impurity layer 104 in the regions except the electrode portion. The element is then returned to the vertical position, and the second ion implantation is performed so as to convert a part of the high-concentration N-type impurity region into a low-concentration N-type impurity region. These ion implanted regions are heat treated to form an active high-concentration N-type impurity region 106 and an active low-concentration N-type impurity region 107, respectively. Thus, an LDD structure can be obtained.
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