| 摘要 |
PURPOSE:To relax an electric field spreading in the transverse direction between a source and a drain, to suppress the occurrence of an avalanche breakdown and a hot carrier, and to realize a hig-withstand-voltage and a high-speed operation by a method wherein a region coming into contact with a gate insulating film, out of a depleted region in a source-drain region, is covered with a gate electrode. CONSTITUTION:An n-type low-concentration source-drain region 3 is formed by introducing an n-type impurity into a p-type Si substrate 8 and by self-aligning with a first gate electrode 1 by making use of the first gate electrode 1 and an insulating film 5 as a mask. Then, an electric-conductive film composed of polycrystalline silicon, a silicide or the like, doped with an electric-conductive impurity of high concentration is deposited on the whole surface. After that, said electric-conductive film is etched anisotropically so that a second gate electrode 6 remains only at the side wall of the first gate electrode 1. Then, after the insulating film has been deposited again on the whole surface, an etching process is executed so that an insulating film 7 can be formed at the side wall so as to cover the second gate electrode 6. Tie film overlaps with the low-concentration source-drain region 3 by means of the second gate electrode 6. The overlapping amount can be controlled by the deposited film thickness for the second gate electrode 6 and by the overetching amount of said electric-conductive film.
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