Patent ID: 7898015

Claim:
An insulating film comprising a composition comprising: a first metal element as a core metal of the composition; oxygen of 33.3 atomic % or above; fluorine of 33.4 atomic % or below; and one element which is either a second metal element or nitrogen, wherein an amount of the fluorine is expressed as [F] in atomic %, an amount of the one element is expressed as [X] in atomic %, and a valence number difference between the first metal element and the second metal element or between oxygen and nitrogen is expressed as k (absolute number), when the one element is the second metal element, the first metal element is a quadrivalent metal element comprising one of Hf, Zr and Ti, and the second metal element is a trivalent metal element comprising one of La, Al, Sc, Y, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, an amount of which is expressed as [trivalent element] in atomic %, then [X]=[trivalent element] and k=1, when the one element is the second metal element, the first metal element is the quadrivalent metal element, and the second metal element is a divalent metal element comprising one of Mg, Sr, Ba, and Ca, an amount of which is expressed as [divalent element] in atomic %, then [X]=[divalent element] and k=2, when the one element is the second metal element, the first metal element is the trivalent metal element, and the second metal element is the divalent metal element, an amount of which is expressed as [divalent element] in atomic %, then [X]=[divalent element] and k=1, when the one element is nitrogen, an amount of which is expressed as [N] in atomic %, then [X]=[N] and k=1, and the amounts of [X] and [F] in the insulating film satisfy a relationship of {k*[X]-[F]}/2≦8.4 atomic % and a concentration distribution shape of k*[X] substantially matches the concentration distribution shape of [F].