| 摘要 |
PURPOSE:To flatten the surface finally by utilizing the increase of a rate through ion implantation and the variation of an etching rate through the addition of an impurity and previously etching a silicon layer with excellent controllability when executing LOCOS. CONSTITUTION:Polycrystal Si 32 is formed onto an insulator substrate 31, and the surface is coated with a SiN film 34. As Ions are implanted while using a resist pattern 35 as a mask, and an ion implantation layer 33 is formed. The ion implantation layer 33 is removed selectively through etching by utilizing a large etching rate of the layer 33. The section etched is oxidized to form a field insulating film 36, and an island of polycrystal Si 32 is formed. Lastly, the polycrystal Si is annealed by a laser, and an element is formed. The surface is flattened after LOCOS because the polycrystal Si layer 32 can be etched with excellent controllability in response to thickening through oxidation. |
