| 摘要 |
PURPOSE: To provide a semiconductor device reducing the dispersion in the threshold voltage due to the fluctuation in the film thickness of a silicon layer and the manufacturing method thereof. CONSTITUTION: The semiconductor device is composed of the six steps mentioned as follows: i.e., the first step of forming an element isolation field oxide film 4 (a) on an SOI structured wafer 10000Åof mean thickness of a silicon layer 3 successively formed of a buried oxide film 2 and a single crystalline silicon layer 3 on a high resistant silicon substrate 1, the second step of growing an oxide film 5 for ion-implanting threshold value voltage adjusting BF2 <+> in the silicon layer 3 (b), the third step of ion-implanting (P<+> ) in the silicon layer 3, (c). The forth step of implanting phosphorus (P<+> ) in the part deeper than the thin thickness of the silicon layer 3 so as to thrust through the thin film thickness part of the silicon layer 3 for making a pierced part therein, the fifth step of forming a gate electrode 6 of N type polysilicon on a gate oxide film 5' and the sixth step of forming an N<+> diffused layer to be source.drain of N channel type MOS-FET for the formation of the part opposing to the gate electrode 6 to be a body part 8 through the intermediary of the gate oxide film 5'.
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