Metal oxynitride thin film, process for producing metal oxynitride thin film, and capacitor element

A metal oxynitride thin film having a perovskite structure where octahedrons in which anions occupy six vertexes and a B site atom exists in a center share vertexes, wherein

• the metal oxynitride thin film has a composition represented by a compositional formula A1+αBOx+αNy wherein α is larger than zero and 0.300 or less, x+α is larger than 2.450, and y is 0.300 or more and 0.700 or less,
• an AO structure having a layered structure parallel to a plane perpendicular to a c-axis of the perovskite structure and having a composition represented by a general formula AO, and
• the AO structure is bonded with the perovskite structure and incorporated in the perovskite structure.