| 摘要 |
PURPOSE:To make it possible to form a highly reliable SOI type MOSFET, in which irregularities are not present in a gate forming part, readily, by forming a gate electrode, implanting oxygen ions only in the source region and the drain region of a single crystal silicon substrate with the patterned resist mask on said gate electrode as a mask, and forming a silicon dioxide layer. CONSTITUTION:A gate electrode 6 comprising patterned polycrystalline silicon is formed on a single crystal silicon substrate 1 by using a field insulating film 7, a gate insulating film 5 are resist 8. O<+> ions (oxygen ions) are implanted with the resist 8 and the gate electrode as masks. An SiO2 layer 9 is formed at a position with a depth W of about 3,000-4,000Angstrom from the gate insulating film 5. Thereafter, a source region 4a and a drain region 4b are formed on the SiO2 layer 9 by ordinary ion implantation and annealing. There are no irregularities in the state of the gate electrode forming part at all, and the electrode forming part is flat. Thus, the reliability of the gate electrode is not decreased. |
