Al–YF3–Al (MIM) capacitors are formed by thermal evaporation under a vacuum of 2.66 × 10−3 Pa. The thickness of the dielectric film (YF3) is measured by MBI. From X‐ray diffraction studies, the structure of the film is found to be amorphous in nature. Aging, annealing, dielectric, and ac conduction studies are made for these films. It is observed that due to aging the capacitance becomes constant after about 25 days and it decreases with repeated annealing cycles. The dielectric constant for a film of thickness 136 nm at 1 kHz and at room temperature is found to be 13.58. AC conduction studies reveal that the conduction mechanism is electronic hopping. The activation energy is estimated from the slope of conductivity versus inverse absolute temperature plot to 0.509 eV.

Thin films of LiNbO3 are prepared by thermal evaporation onto well cleaned glass substrates at 2.66 x 10−3 Pa. The thicknesses of the dielectric films are measured by Tolansky technique (Fizeau fringes). The X‐ray diffractogram shows that the as deposited films are amorphous in nature. Aging and annealing effects are found to improve the dielectric properties. The capacitance and dielectric loss are measured from 303 to 463 K in the frequency range 1 to 30 kHz. The dielectric constant of a film of 80 nm thickness is found to be 8.01 at room temperature in the frequency range studied. From the ac conduction studies it is confirmed that the mechanism responsible for the conduction process in these films is electronic hopping. The intrinsic temperature coefficient of capacitance is estimated to 1500 ppm/K. Two activation energies are observed for the thermally activated process and the results are discussed.

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