The orientation polarization (positive and negative) of the Si—N bonds and the Si—O bonds is canceled, thereby enabling to minimize the polarization in a capacitive insulating film. As a result, a silicon oxynitride film with a small voltage secondary coefficient is formed, and is applied as a capacitive insulating film for use in a MIM capacitor. Specifically, the refractive index “n” of the silicon oxynitride film satisfies 1.47≦n≦1.53, for light with a wavelength of 633 nm.