| 摘要 |
PURPOSE:To make each semiconductor layer a film thickness different from each other layer by forming an oxide film on the surface of a semiconductor layer through oxidizing again after selectively eliminating the oxide film formed on the substrate of the semiconductor layer. CONSTITUTION:SiO2 films 3a and 3b are respectively formed on a surface through thermally oxidizing polycrystalline silicon films 2a and 2b, the SiO2 film 3a is selectively eliminated by etching, and then an SiO2 film 3c is formed on a surface of the polycrystal silicon film 2a by thermally oxidizing again. In this thermal oxidation, a film thickness of the SiO2 film 3b formed on a surface of the polycrystal silicon film 2b also increases. But, because an oxidiz ing velocoty becomes up at an initial oxidation and becomes down gradually as an oxidizing time becomes longer, a film thickness of the polycrystalline silicon film 2a is thinner than that of the polycrystalline silicon film 2b. There fore, elements having a different characteristics each other can be formed with these semiconductor layers. |
