| 摘要 |
PURPOSE:To complete patterning of a mask by a one-time process by a method wherein a gate electrode under a mask pattern is side-etched in an isotropic manner, an impurity having high concentration is implanted, using the mask pattern as a mask, an impurity having low concentration is implanted, employing the gate electrode as a mask and an impurity diffusion region is formed. CONSTITUTION:A gate electrode 25 under a mask pattern 26 is etched in an isotropic manner, and a side surface is etched approximately uniformly in predetermined width. An impurity having high concentration is implanted into an element formation region in the vicinity of the gate 25 through ion implantation, using the mask pattern 26 as a mask, and impurity regions having high concentration as a source 27 and a drain 28 are shaped toward the outside from a section just under the mask pattern 26. When the mask pattern 26 on a gate is removed and an N<-> type impurity having low concentration is implanted into the element formation region, employing the gate 25 as a mask, a concentration gradient is generated with separation from a section in the vicinity of the gate in an impurity diffusion region, thus forming the source 27 and the drain 28 having an LDD structure.
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