| 摘要 |
PURPOSE:To prevent a high field effect from occurring locally in the vicinity of a drain even if fineness is promoted and to upgrade reliability, by decreasing thickness of a gate insulating film in the direction of the drain from a source in a MOS type field effect transistor with the source and the drain. CONSTITUTION:While a substrate 1 is thermally oxidized, a gate insulating film 3 is formed between the substrate 1 and a silicon nitriding film 2 so that its film thickness is gradually decreased in the direction of a drain region. Thereafter, a resist pattern is formed on a polycrystal sllicon film 4, and a polycrystal silicon film 4a is made to remain on a gate insulating film 3a changed in film thickness and on this insulating film 3 by an anisotropic etching. Next, a source 5 and a drain 6 are formed in a state of self matching to the gate insulating film 3a. Successively, after a silicon oxidizing film 7 is piled on the whole surface, wiring materials 10 and 11 are buried in contact holes 8 and 9. Even if fineness is promoted in this manufactured MOS type field effect transistor, a high field effect can be prevented from occurring locally in the vicinity of the drain.
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