| 摘要 |
PURPOSE:To prevent an SiO2 film from being etched during epitaxial growth as well as to reduce defects in the periphery having vertical walls and surrounded by the isolating oxide film and by providing a thin insulating film containing no oxygen on the surface of the inner wall of the aperture and the upper face of the SiO2 film, and then forming an active region by causing Si to grow epitaxially. CONSTITUTION:An SiO2 film 2 is formed on an Si substrate 1 and provided with an aperture 3 by anisotropic etching such that the aperture has vertical walls. The upper face of the SiO2 film 2 and the internal wall faces of the aperture are covered with an insulating film containing no oxygen, e.g. with an Si3N4 film 5, such that a second aperture 6 is provided within the aperture 3 while a part of the Si substrate 1 is exposed on the bottom of the aperture. An Si layer 4 is then selectively caused to grow epitaxially within the second aperture 6. Subsequently, protruded portions of the epitaxially grown Si layer 4 and the Si3N4 film 5 on the upper face of the SiO2 are removed by polishing so as to flatten the surface and to obtain an active region 4a. In this manner, the aperture walls are not etched any way during the epitaxial growth, and therefore the verticality of the walls can be maintained. |
