| 摘要 |
PURPOSE:To flatten the surface of the epitaxial semiconductor layer on the surface of a substrate without using a complicate treating method by a method wherein a first epitaxial semiconductor layer is selectively formed in the recessed part of the substrate and an oxide film on the substrate surface is removed to form the second epitaxial semiconductor layer on the whole surface. CONSTITUTION:A heat treatment for diffusion is performed and n<-> diffused layers 4 are formed in part of the surface of a substrate and along the substrate surface in a recessed part 3. By this diffusion, an oxide film 5 is formed on the whole surface. Then, an epitaxial semiconductor layer 6 is formed in the recessed part 3 wherein the oxide film is not formed. With a flattening etching performed after the oxide film 5 is removed to remove the crown, the upper surface of the epitaxial layer 6 on the recessed part is made to coincide with the substrate surface other then that. A second epitaxial Si layer 8 is formed on the whole surface at a thickness of about 10mum by a normal epitaxial method, the surface is etched for flattening, an oxide film formed on the surface is performed a photo etching and isolation p-type layers 9 are formed by diffusing a boron impurity. Accordingly, the generation of the crown and the recess can be suppressed to the minimum.
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