Process for producing dielectric insulating thin film, and dielectric insulating material

A method for producing a dielectric insulating thin film, comprising:

• a step (A) of making a substrate having a hydroxyl group in its surface or having a hydroxyl group introduced into its surface, adsorb a metal compound having a functional group capable of reacting with a hydroxyl group for condensation and capable of forming a hydroxyl group through hydrolysis,
• a step (B) of removing the excessive metal compound from the substrate surface,
• a step (C) of hydrolyzing the metal compound to thereby form a metal oxide layer having a hydroxyl group in the surface thereof,
• a step (D) of treating the above-mentioned layer according to any one treating method selected from the group consisting of oxygen plasma treatment, ozone oxidation treatment, firing treatment and rapid thermal annealing treatment to thereby obtain a dielectric insulating thin film;
• and
• which further comprises, between the step (C) and the step (D), a step (G) of making the hydroxyl group in the surface of the metal oxide layer formed in the step (C) adsorb a rare earth metal ion, and a step (H) of removing the excessive rare earth metal ion from the surface of the metal oxide layer and hydroxylating the adsorbed rare earth metal ion to thereby form a rare earth metal layer.