| abstract |
[PROBLEMS] To provide a method of manufacturing a semiconductor device having gate insulating films of different thicknesses, while ensuring the reliability and thickness difference of the gate insulating films, and forming gate insulating films of different thicknesses. A method for manufacturing a semiconductor device that can be formed is provided. SOLUTION: A step of selectively introducing a halogen element or argon into an element region 14 of a silicon substrate 10 and wet oxidizing the silicon substrate 10 under reduced pressure or in an atmosphere diluted with nitrogen or a rare gas, A step of forming a silicon oxide film 24 in the element region 16 and a silicon oxide film 22 thicker than the silicon oxide film 24 in the region 14. |