| 摘要 |
PURPOSE:To form flat surface of MOS device and reduce the crystal defect and make the device compact, by a method wherein polycrystalline semiconductor region is buried in element isolation region of monocrystalline semiconductor substrate. CONSTITUTION:Si3N4 mask 2 is applied to Si substrate 1 of n type or p type and anisotropy etching is performed, and a thin groove is formed and filled with poly Si 3 by CVD method. Poly Si on the surface is removed by etching, and impurity ion is injected and diffused at a layer 5, and then the Si3N4 mask is removed. Since diffusion coefficient of Si is smaller than that of poly Si, spreading of the layer 5 is small. In this constitution, isolation between elements can be performed without stage difference or crystal defect on the substrate surface and the groove width be made thin, thereby the device is made compact. |
