High‐TcBi‐Sr‐Ca‐Cu‐O thin films were coated with electron‐beam‐evaporated SiO2. The room‐temperature resistivity of the coated films and their superconductivity onset and zero‐resistance temperatures were not affected by the dielectric film. High‐frequency capacitance‐voltage studies did not show any modulation of space charge in the surface layer of the superconducting film. It is observed that the high‐frequency (1 MHz) capacitance of the metal‐insulator‐superconductor structure has an appreciable temperature dependence.