| 摘要 |
PURPOSE:To prevent deterioration in characteristics, by forming an insulator embedding groove in the main surface of a semiconductor substrate, and thereafter introducing oxygen or nitrogen into the semiconductor substrate at the part of the inner wall of the groove by an ion implantation method before embedding the insulator. CONSTITUTION:On an N-type silicon substrate 21, SiO2 22 is formed. Thereafter, a hole is provided only at a region, where a groove 23 is to be formed, in the SiO2 22. The groove 23 is provided in the N-type silicon substrate 21 by reactive ion etching with chlorine gas as a main component. With the SiO2 22 as a mask, nitrogen ions are introduced by an ion implantation method into the N-type silicon substrate, and a nitrogen-ion implanted layer 24 is formed. Then, a thermal oxide film 25 is formed only in the groove 23. Polycrystalline silicon 26 is embedded and flattening is performed. The thermal oxide film 25 is formed on the surface of the polycrystalline silicon 26. A P well 27 is formed in an N-channel element region. Thereafter, a gate electrode 28, an N<+> diffused layer 29, a P<+> diffused layer 30, an interlayer insulating film 31, an electrode wiring 32 and a surface protecting film 33 are sequentially formed. Thus, junction leak in the vicinity of the groove can be prevented without loosing the advantage of the element isolating method and without adding other cumbersome manufacturing processes. |
