| 摘要 |
PURPOSE:To make it possible to do precise patterning of polysilicon with impurities doped, by a method in which, after polysilicon is etched without electrically activating the impurities which are introduced into the polysilicon by means of ion-implantation, the impurities are activated. CONSTITUTION:On a thermal oxidation film 23 formed on a silicon substrate 24, undoped polysilicon is grown and phosphorus atoms are implanted therein by means of ion-implantation. An example of implantation condition into the polysilicon is 170keV and 1X10<16>atoms/cm<2>. In this way, the polysilicon 21 including electrically unactivated phosphorus atoms is formed. After patterning of the resist 22 is done thereon, the polysilicon 21 is etched so that vertical etching can be made possible in the same way as undoped polysilicon, without having side etch in the cross sectional area of the polysilicon. After the mask is removed, annealing can activate electrically the phosphorus atoms in the polysilicon. |
