SEMICONDUCTOR DEVICE AND ITS FABRICATING METHOD

摘要

PROBLEM TO BE SOLVED: To obtain a semiconductor device where an MISFET having a thin gate insulation film and an MISFET having a thick gate insulation film exist mixedly and hot carrier resistance of the MISFET having a thick gate insulation film is enhanced. SOLUTION: The method for fabricating a semiconductor device comprises a step for forming a thick gate oxide film (thick oxide film) 14 in the first region of a substrate 10 and a thin gate oxide film (thin oxide film) 15 in the second region thereof and then oxidizing/nitriding these gate oxide films 14 and 15, a step for forming gate electrodes 1a-1d on these gate oxide films 14 and 15, and a step for forming a high oxidation/nitridation region 112 at at least a part of the interface between the thick gate oxide film (thick oxide film) 14 and the substrate 10 before or after forming the gate electrodes 1a-1d.