| 摘要 |
PURPOSE:To prevent the insulating isolation oxide films from encroaching into the element region and to prevent the generation of protrusion on the boundaries between the insulating isolation oxide films and the element region by a method wherein grooves for isolation, which reach in the semiconductor substrate in a self-alignment manner, are formed between the element region and the insulating regions and a silicon nitride film is buried in the grooves. CONSTITUTION:An oxidation is performed selectively on the surface of an n-type epitaxial layer 202, and silicon oxide films 205 are formed. A side etching is performed on a silicon nitride film 203 using heat phosphoric acid and so forth to reduce the pattern in a self-alignment manner. Subsequently, a silicon oxide film 204 is removed using hydrofluoric water solution. An etching is performed on the epitaxial layer 202 by an ion-etching technique using the silicon nitride film 203 and the silicon oxide films 205 as masks to form grooves 207. Then, the silicon oxide films 205 are removed using hydrofluoric solution. Subsequently, a silicon nitride film 208 is formed on the whole surface and parts of the silicon nitride film 208 are removed by an ion-etching technique. Epitaxial layers 202B other than the epitaxial layer 202B on an element region 202A are converted into silicon oxide films 209 by performing a thermal oxida tion and the insulating isolation film is formed. |
