| 摘要 |
The present invention provides a technique for efficiently forming a high-breakdown voltage transistor and a low-breakdown voltage transistor on the same substrate while reducing the deterioration of each transistor's characteristics. At first, an insulating film is formed. The insulating film portions above the drain and source formation regions for the high-breakdown voltage transistor are thicker than those for the low-breakdown voltage transistor. Next, gates are formed on the insulating film. Then sidewalls are formed on the sides of the low-breakdown voltage transistor gate, and apertures are made in the insulating film portions above the drain and source formation regions for each transistor. When apertures are made in the relatively thick insulating film portions above the drain and source formation regions for the high-breakdown voltage transistor, etching is performed not to narrow widths of the sidewalls formed on the sides of the gate for the low-breakdown voltage transistor. Then drain and source regions are formed for each transistor by introduction of impure elements through the apertures.
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