| 摘要 |
A semiconductor substrate preventing a void from being generated in an epitaxial film buried in a trench. An N-type first epitaxial film and first trenches are formed on an N+-type substrate body. A P-type second epitaxial film is buried in the first trenches. An N+-type third epitaxial film having the same composition as the first epitaxial film is formed on the first and second epitaxial films to form second trenches. A fourth epitaxial film is grown on the entire interior of the second trenches. The formation of the first and second trenches and the burying of the second and fourth epitaxial films are performed in a plurality of steps. Thus, the aspect ratio of the first and second trenches when the second and fourth epitaxial films are buried can be reduced. As a result, the second and fourth epitaxial films can be buried in the first and second trenches without causing a void. |
