Method for fabricating semiconductor device

摘要

A semiconductor device is fabricated by a method comprising the steps of: selectively introducing a halogen element or argon into a device region 14 of a silicon substrate 10; and wet oxidizing the silicon substrate 10 in an ambient atmosphere which an H2O partial pressure is less than 1 atm to thereby form a silicon oxide film 22 in the device region 14 of the silicon substrate 10, and a silicon oxide film 24 thinner than the silicon oxide film 22 in a device region 16 of the silicon substrate 10. Whereby the silicon oxide film in a device region 14 with the halogen element or argon introduced can be selectively formed thick. The silicon oxide films are formed by the wet oxidation, whereby the gate insulation films can be more reliable than those formed by the dry oxidation.