| 摘要 |
PURPOSE:To restrain the oxidation in the parallel direction with the surface of substrate from advancing by a method wherein an insulating film, a semiconductor layer, an oxidation preventive film are successively formed and then a part of oxidation preventive film and semiconductor layer is selectively removed to be utilized as a mask for thermal oxidation. CONSTITUTION:The surface of P type silicon substrate 1 is thermal-oxidized to form an extremely thin SiO2 film 2 while the film 2 is successively coated with a polycrystalline silicon film 8 and an Si3N4 film 3. Firstly photoresist 9 is formed on the film 3 to etch the film 3 and then the film 8 is etched down to specified film thickness. Secondly the photoresist 9 is removed and the substrate 1 is ion-implanted with P type impurity utilizing the film 3 as a mask. |
