Condenser Structures Based on Barium Titanate Films Formed by Sol-Gel Method

Abstract

The objective of the work is investigation the dielectric permittivity and dielectric loss tangent of BaTiO3 films in a capacitor structure formed by sol – gel method on a Si/TiOx/Pt substrate. The basis of this capacitor is a four-layer film of barium titanate xerogel with a thickness of about 200 nm. The film was synthesized by sol-gel method at a final annealing temperature 750 °C. The problems related to the development of method of forming multilayer capacitor structures, the analysis of the morphology and phase composition of BaTiO3 film, and also the measurement of the capacitance-voltage characteristics in the frequency range 10 kHz – 2 MHz have been solved. Morphology of the films was analyzed using a Hitachi S-4800 scanning electron microscope. X-ray diffraction spectra was recorded using a DRON-3 automated diffractometer, using monochromatic CuKα radiation. Capacitance-voltage characteristics were obtained using a B1500A semiconductor analyzer. Dielectric constant and dielectric loss tangent, calculated for capacitance measurements, are changed as follows: for a bias voltage of U = 0 V, the change in ε is 232–214, and tanδ 0.022–0.16, and for a bias voltage of U = 10 V, ε occurs in the range 135–124 and tanδ from 0.02 to 0.1. The obtained frequency dependences of the dielectric constant of BaTiO3 films show a decrease in the dielectric constant in the range of 10 kHz – 2 MHz. It was found that, with a BaTiO3 film thickness of less than 100 nm, a thin-film capacitor with a lower platinum electrode is not always formed, which is probably caused by shunting of the structure.

Peculiarities of BaTiO3 in electronic and X-Ray analysis

“…The release of some light volatile elements during heating and crystallization can be explained by the crystallization of the sample. In this X-ray phase analysis [15] in the literature, a sample heated to 850 degrees can be seen in X-ray phase analysis peaks appearing at certain angles, although the peaks are very small in intensity and contrast.…”

“…Barium titanate is characterized by high values of dielectric constant (up to 104 ; 1400±250 at n.o. ); on its basis, several types of ferroelectric ceramics have been developed, used to create capacitors, piezoelectric sensors, and posistors [5][6][7][8][9][10][11][12][13][14][15].…”

Development of Technology for Obtaining Nanosized Heterostructured Films by Ion-Plasma Deposition

“…Barium titanate is characterized by high values of the dielectric constant (up to 10 4 ; 1400 ± 250 at n.o. ); on its basis, several types of ferroelectric ceramics have been developed and are used to create capacitors, piezoelectric sensors, and posistors [4].…”