Temperature-independent physical properties of electrophoretic Ti5NbO14 films for high-temperature capacitors

초록

Ti5NbO14 (T5NO) films were developed on Pt/Ti/SiO2/Si substrates by electrophoretic method by using T5NO(3-)nanosheets. The film deposited at room temperature (RT) contained organic defects, which were almost eliminated in the film annealed at 700 degrees C. The film deposited at RT revealed (100) planes with an inter-planar distance of 1.1 nm because of the existence of TBA(+) defects. However, for the films annealed at higher temperatures (>= 400 degrees C), two types of structures formed: (100) planes with 0.55 nm inter-planar distance (group-1 structure), and (100) planes with 1.42 nm inter-planar distance (group-2 structure). The dielectric constant (epsilon(r)) of the film annealed at 700 degrees C was 61 with a low dielectric loss of 1.0%. Variations in the epsilon(r), according to the film thickness, electric field, and temperature were small. This film displayed a high insulating property up to 300 degrees C with a small temperature coefficient of capacitance (-56.7 ppm/K) up to 400 degrees C.

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