| 摘要 |
P-type isolation regions, which surround an island of an n-type epitaxial layer, are formed by providing a p-type dopant at a part of the surface of a p-type silicon substrate. After growing the layer a p-type dopant is also provided at the surface of the layer opposite the part of the substrate surface where the dopant is provided. The dopants are diffused into the layer until the p-type regions meet. To inhibit diffusion of the p-type dopant during epitaxial growth, an n-type dopant having a lower diffusion coefficient than that of the p-type dopant is provided at the part of the substrate surface before providing the epitaxial layer. Formation of the isolation regions can be carried out simultaneously with the formation of p-type regions of a circuit element, for example a transistor, in the islands.
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