SEMICONDUCTOR DEVICE AND ITS FABRICATING PROCESS

摘要

PROBLEM TO BE SOLVED: To provide a semiconductor device in which the resistance of the gate electrode is decreased and leak current is reduced, and to provide its fabricating process. SOLUTION: A smile oxide film 6 functioning as a gate oxide film is formed beneath the three layer polymetal gate layer 11 consisting of a doped polysilicon layer 4, a tungsten layer 5 and an SiON layer 8. The smile oxide film 6 is formed by corrosion in the vicinity of the edge of the doped polysilicon layer 4 such that the three layer polymetal gate layer 11 becomes thicker beneath the vicinity of edge than beneath the central part. The three layer polymetal gate layer 11 is not exposed but covered with an oxidation preventive film 7 composed of a material having an oxygen diffusion rate lower than that of silicon. COPYRIGHT: (C)2004,JPO