| 摘要 |
PURPOSE:To improve the characteristics of a device, by forming a selective epitaxial Si layer so as to contact with a poly Si layer, whose thermal expansion coefficient is approximate to that of said epitaxial Si layer, thereby alleviating thermal stress between both layers, and preventing the occurrence of crystal defects around the epitaxial layer. CONSTITUTION:A single crystal epitaxial Si layer 10 is formed on an Si substrate (an n<+> diffused layer 2), which is exposed at a window part by a selective epitaxial method that is carried out under the conditions of specified impurity concentration, temperature and pressure. Said epitaxial Si layer becomes an n-type layer when doner impurities are doped at the time of epitaxial growing. B ions are implanted in the surface of the n<-> type epitaxial Si layer 10 and diffusion is performed. Thus a p-type layer 11, which is to become the base of an n-p-n transistor, is formed. Thereafter, selective impurity diffusion is performed in the surface of said selective epitaxial Si layer 11 by an ordinary mask step. Thus crystal defects at the interface of the epitaxial Si are decreased, and the performance of the device can be improved.
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