| 摘要 |
PURPOSE:To eliminate the reduction in the thickness of a field oxidized film in case of etching an oxidized film and to enable to utilize as a high resistance element a polycrystalline silicon layer by forming in advance a polycrystalline silicon layer under a gas phase grown SiO2 as a mask of switching diffusion. CONSTITUTION:After a silicon oxidized film 8 is formed on a polycrystalline silicon 7, a polycrystalline silicon layer 15 is suitably grown, and a gas phase grown SiO2 film 9 is thereafter grown. The region of gas phase grown film 9 to form, for example, an N type MIS semiconductor device is etched and removed. In this case, since there is the layer 15 under the film 9, a field oxidized film 6 under polycrystalline silicon is not, even if etching time of the oxidized film becomes long, etched. The polycrystalline silicon layer can be used as a high resistance element material by utilizing the fact that a small amount of impurity is implanted in case of ion implantation of forming a gate drain. |
