| 摘要 |
PURPOSE:To prevent a bonding leakage current by thermally oxidizing a film to be oxidized to become a mask for ion implanting for preventing a field from inverting as a mask in case of etching a substrate, thereby forming a field inversion preventive layer on the peripheral edge of an element separating region. CONSTITUTION:A thermal oxide film 12, a silicon nitride film 13 and a polycrystalline silicon film (film to be oxidized) 14 are accumulated on the surface of a P<-> type silicon substrate 11. A photoresist pattern 15 having a hole wider in width than the final element separating width is formed on an element forming region, and the film 14 is etched. B<+> ions are implanted to form a boron- doped layer 16. The film 14 is converted by thermal oxidation into a thermal oxide film 17, and the volume is expanded. The boron of the layer 16 is diffused to form a P type impurity region 18. A groove is formed on the substrate 11, and a P type field inversion preventive layer 20 is formed on the periphery. Films 17, 13, 12 are removed. A thermal oxide film 21 and a CVD oxide film 22 are accumulated, etched to form an element separating region. |
