Improvement in Dielectric Properties of CaCu3Ti4O12 Thin Film Over Pt(111)/Ti/SiO2/Si Substrate by Spin Coating Method

Abstract

High quality calcium copper titanium oxide (CaCu3Ti4O12, CCTO) thin film has been deposited on Pt(111)/Ti/SiO2/Si substrate by sol–gel method using the spin coating technique. The structural analysis shows that CCTO thin film belonging to the cubic crystal structure with Im3 space group. The morphological result show that the film surface are smooth, fully covered, homogeneous, crack free with existence of many pinholes. No peaks of any impurities other than CCTO are detected in the energy dispersive analysis by X-ray spectra indicating the high purity of resultant product. The absorption band of Fourier transform infrared spectra is observed in the range of 380–700 cm−1 which arises from the mixed vibrations of CuO4 and TiO6 groups prevailing in the cubic CCTO. The luminescence spectrum of CCTO thin film has a weak green and strong red emission centered at 536 and 786 nm, respectively. The effective dielectric constant of CCTO dielectric layer in Si/SiO2/Ti/Pt/CCTO/Pt thin film capacitor is found to decrease with increase in frequency. It is found that capacitor reached a high dielectric constant (er) of 1067 and a capacitance (C) of 1.192 µF at 100 kHz due to the improved oxygen vacancies of trapped electrons and also from the effect of electrode-film interface. We compare our dielectric constant to previously reported results and it is recommended to CCTO use of an attractive material for the production of miniaturized capacitor in microelectronic applications.