| 摘要 |
PURPOSE:To obtain a gate oxide film and a capacitance-generating insulator film thick and uniform in thickness as desired by a method wherein a thick SiO2 film is formed on the surface of a substrate and then a thinner insulator film is formed by an intermediate process. CONSTITUTION:A field oxide film 2 and then a relatively thick SiO2 film 3' is formed on the surface of a P type Si substrate 1. Ion implantation is effected for the formation of a P<+> region 5 with a photoresist film 7' serving as a mask. Next, a part of the SiO2 film 3' located on the P<+> region 5 is removed, and a thin SiO2 film 3, Si3N4 film 4 are formed for the formation of a capacitance- generating dielectric lamination. Further, another ion implantation is performed with a photoresist film 7'' serving as a mask for the formation of an N<+> region 6. Then, a mask is applied onto the region 5, etching is effected for the removal of the SiO2 film 3' resulting in the exposure of the substrate 1, and a gate oxide film 9 is formed by a thermal oxidation process. After this, N<+> layers for a source 10 and drain 11, a gate electrode 12 and capacitance electrode 13 both composed of poly-Si are formed. |
