Method for fabricating semiconductor device

摘要

The semiconductor device fabrication method of the present invention comprises an impurity introduction step of introducing an impurity capable of accelerating thermal oxidation selectively into a first region of the surface of a silicon substrate and an oxidation step of successively carrying out oxidation and oxynitridation for said first region and a second region where no impurity is introduced and forming insulating films with respectively different film thicknesses on the surface of said first region and the surface of said second region.