| 摘要 |
PURPOSE:To improve a rate of integration of a CMOS integrated circuit without causing a latch-up phenomenon by separating elements securely. CONSTITUTION:A silicon oxide film 2 as a buffer is formed by oxidizing a surface of a silicon substrate 1 and an SiN film 3 is formed on it. After the surface of the SiN film 3 is patterned by a photoresist 4 or the like, grooves 5 are formed in the substrate 1 by isotropic etching. A silicon oxide film 6 as a buffer is formed by oxidizing the inside surface of the groove 5. After a thin SiN film 7 is formed on the substrate, grooves 8 are further formed in the substrate 1 by etching the bottoms of the grooves 5. By oxidizing the exposed substrate 1, an oxide domain 9 is formed to separate an element forming domain 1'. The SiN films 3 and 7 are removed and the grooves 8 are filled with oxide films 10. With this constitution, the element forming domain 1' is completely separated from the substrate 1 by the oxide domain 9. |
