| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device and the manufacturing method thereof wherein the mobility of its carriers is improved and its leakage current can be reduced. SOLUTION: An SiO<SB>2</SB>film 2 is formed as a thermal oxidation film on the surface of an Si substrate 1. Then, the SiO<SB>2</SB>film 2 is changed into an SiON film 3 by subjecting the SiO<SB>2</SB>film 2 to a heat treatment in a nitriding type gas atmosphere. As a result, a tensile stress oriented toward the side of the SiON film 3 so acts on the atoms present on the surface layer of the Si substrate 1 as to generate strains and as to lengthen the interatomic distances of the Si atoms present in the Si substrate 1. The amount of the strains can be measured by e.g., an X-ray CTR scattering method. Subsequently, an SiN film 4 is formed on the SiON film 3 by a CVD method, etc. The intensities of the tensile stresses acting on the Si substrate 1 which are caused by the change of the thickness of the SiN film 4 are made different from each other too. According to this method, since the mobility of carriers is improved by the displacements of the Si atoms, an enough mobility of the carriers can be obtained even when the concentration of nitrogen present in the vicinity of the interface between the SiON film 3 and the Si substrate 1 is made high. COPYRIGHT: (C)2005,JPO&NCIPI
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