High-voltage-resistant and high-energy-density capacitor and preparation method thereof

The invention relates to a high-voltage-resistant and high-energy-density capacitor and a preparation method thereof. The high-voltage-resistant and high-energy-density capacitor comprises a substrate, a bottom electrode, a dielectric layer and a top electrode, wherein Si or SiO2/Si is taken as the substrate; the bottom electrode is a metal film, a conductive oxide film or a combination of both; the dielectric layer consists of a BaTiO3 ferroelectric film; and the top electrode is a metal film point electrode. A metal target or/and conductive oxide target is adopted, and a single target is used for depositing a metal film or a conductive oxide film, or depositing the meal film and the conductive oxide film in sequence on the substrate in a radio-frequency or direct current magnetron sputtering way; a ceramic BaTiO3 target is adopted, and a BaTiO3 layer is deposited on the bottom electrode in a radio-frequency magnetron sputtering way; and a metal target is adopted, and the top electrode is deposited in a radio-frequency magnetron sputtering way. The film capacitor prepared with the method has the advantages of small size, high voltage resistance and breakdown field strength Eb of higher than 1000kV/cm; the practical discharging energy density is not less than 10J/cm<3>; and the loss is low, and the dielectric performance is kept stable when the frequency and temperature change.