| 摘要 |
PURPOSE:To reduce the Miller capacity between a gate electrode and source and drain regions and to decrease a capacity between the drain and the gate, by thermally oxidizing the gate electrode so that a gate oxide film is thicker at the ends thereof. CONSTITUTION:An oxide film including a side oxide film 7 covering a gate electrode 5 and an oxide film on a substrate 1 are chemically etched without any masking layer so that they are removed. The gate electrode 5 is thereby exposed totally while a gate oxide film 3 is also side etched deep from the ends of the gate electrode 5. The whole substrate 1 is reoxidized and the gate oxide film 3 is made thicker at the ends of the gate electrode 5 so as to utilize the principle of 'bird's beak' produced at the ends of a silicon nitride film during selective oxidation. Thereby, the source and drain regions 8, 9 and the gate oxide film 3 are formed thicker than the other parts and the Miller capacity is reduced. N<+>type source and drain regions 8b, 9b are formed by ion implantation with the gate electrode 5 and the reoxidized film 10 used as a mask. Accordingly, the source and drain regions 8, 9 have a DDD (Double Diffused Drain) structure, with a reduced resistance.
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