| 摘要 |
PURPOSE:To prevent the defects such as stepped surface and shortcircuit etc. from happening by a method wherein, after U-type channels are filled with polysilicon without forming an Si3N4 film, the polysilicon is doped with impurity to be oxidized at low temperature. CONSTITUTION:An SiO2 film 11 and an Si3N4 film 12 are successively formed on the main surface of a semiconductor substrate 10. Later etched windows and U-type channels 14 are successively formed. An SiO2 films 15 are formed on the internal surface of the U-type channel 14 while P<+> type channel stoppers 16 are formed on the bottoms of said channels 14. Next the Si3N4 film 12 and the SiO2 film 11 are successively removed to form another SiO2 film 17 on the surface of the substrate 10. The channels 14 only are filled with polysilicon 18 and implanted with ion to dope the surface with much As and P, then the other SiO2 films 19 and 20 are respectively formed on the surfaces of the polysilicon 18 and the substrate 10 by means of oxidation at low temperature. Through these procedures, the surface of the substrate 10 may be prevented from any defects such as V-type step difference or exposed polysilicon from happening. |
