SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF

PROBLEM TO BE SOLVED: To provide a semiconductor device superior in reliability for high-speed operation, and to provide a method of manufacturing the semiconductor device of small mobility, while increasing hysteresis is suppressed, using a High-k film. SOLUTION: The semiconductor device comprises a silicon oxynitride film formed on a silicon substrate, and a high dielectric insulating film formed on the silicon oxynitride film. The concentration of nitrogen in the silicon oxynitride film has a distribution in the film thickness direction, and the concentration is low near the interface with the silicon substrate while high near the interface with the high dielectric insulating film, relative to the average value of the concentration of the nitrogen in the silicon oxynitride film. Thus, the semiconductor device is provided, in which the increase in the hysteresis and drop in the mobility due to thermal process are small. COPYRIGHT: (C)2006,JPO&NCIPI