| 摘要 |
PURPOSE:To obtain the buried layer formed substrate having the least defect and dislocation by a method wherein a diffusion source is formed by oxidizing an As implanted-and-doped polycrystalline Si, a buried layer is formed by diffusion in the Si substrate through the intermediary of a thin oxide film and then an epitaxial layer is grown thereon. CONSTITUTION:For example, a thermal oxide film 5 of approximately 300-500Angstrom is formed on the buried layer forming region on the Si substrate 1 by providing an aperture on a thick oxide film 4. Then, a polycrystalline Si layer 6 is formed on the whole surface and a high density of As ion 7 is implanted in the polycrystalline Si layer 6. Subsequently, the polycrystalline Si layer 6 is changed to an As-doped oxide film 8 by performing a thermal oxidation, a heat treatment is performed in the oxygen and nitrogen of a high temperature, and an N<+> layer 9 is diffused in the substrate 1 through an oxide film 5. Then, oxide film layers 2, 5 and 8 are removed, an N type layer 10 is epitaxially grown on the whole surface and the substrate having a buried diffusion layer 9 is constituted. Through these procedures, the density of the buried layer is uniformalized and there exists almost no defect or dislocation in the epitaxial layer. |
