| 摘要 |
PURPOSE:To prevent a short channel effect, punch-through currents, etc. effectively by implanting ions into an ion implantation region for the second time through self-alignment. CONSTITUTION:A field oxide film 2 and a gate oxide film 2' are each formed onto a silicon substrate 1 in 7,000Angstrom and 200Angstrom . Polysilicon 3 to which phosphorus is doped is deposited on the whole surface in thickness of 2,500Angstrom , and an SiO2 film in 10,000Angstrom is shaped. A resist pattern 5 in which an opening is bored in a gate forming region is shaped. The SiO2 film is directional dry-etched, and As ions are implanted while using an SiO2 pattern in which the resist pattern is left as a mask to obtain an ion implantation region 6. A W film 7 is shaped in thickness of 1mum. SiO2 is removed, polysilicon is etched while employing a W pattern as a mask, B ions are implanted, and ion implantation regions 8 are aligned with an As-ion implantation region and formed. |
