| 摘要 |
PURPOSE:To enable the reduction of quantity of encroachment as well as levelling of an oxide film isolation layer by utilizing the properties of silicon-enriched oxide film. CONSTITUTION:After an Si oxide film 12 is formed on the upper surface of an Si substrate 11, an Si nitride film 13 is grown by CVD method. After selective etching of the Si nitride film 13 in the region to be isolated, an Si oxide film is formed in a part of the substrate 11 and is then removed completely. After that, an Si-enriched Si oxide film 14 is spread by CVD method, e.g. of SiH4+CO2 group, after which oxidation is done by reactive ion etching method so as to leave the Si-enriched Si oxide film 14 only on the side parts of the projecting part of the substrate 11. In this case, the Si-enriched oxide film 14 has an effect to restrain oxidation speed in lateral direction of the single crystal Si substrate 11. Accordingly, quantity of encroachment of residual Si nitride film 13 into the lower surface is minimized and the oxide film 14 itself is lastly oxidized to become an oxide film isolation layer 15 thereby levelling the surface. |
