In a method and an apparatus for forming metal oxide on a substrate, a source gas including metal precursor flows along a surface of the substrate to form a metal precursor layer on the substrate. An oxidizing gas including ozone flows along a surface of the metal precursor layer to oxidize the metal precursor layer so that the metal oxide is formed on the substrate. A radio frequency power is applied to the oxidizing gas flowing along the surface of the metal precursor layer to accelerate a reaction between the metal precursor layer and the oxidizing gas. Acceleration of the oxidation reaction may improve electrical characteristics and uniformity of the metal oxide.