The HfO2 films prepared from alkoxy-derived precursor solution chemically modified with diethanolamine. The effects of UV irradiation on the HfO2 films were investigated. The UV irradiation using low pressure mercury lamp (LPML) was effective for the organics decomposition in the film and densification. The uniform and smooth HfO2 films were obtained. The refractive index of HfO2 films was enhanced.