Thickness Dependent Structural and Dielectric Properties of Calcium Copper Titanate Thin Films Produced by Spin-Coating Method for Microelectronic Devices

Calcium copper titanate (CaCu₃Ti₄O₁₂, CCTO) thin films have been deposited on platinized silicon [(111)Pt/Ti/SiO₂/Si] substrate through a sol–gel spin coating technique and annealed at 600–900°C with a variation of 100°C per sample for 3 h. The activation energy for crystalline growth, as well as optimal annealing temperature (900°C) of the CCTO crystallites was studied by x-ray diffraction analysis (XRD). Thickness dependent structural, morphological, and optical properties of CCTO thin films were observed. The field emission scanning electron microscopy (FE-SEM) verified that the CCTO thin films are uniform, fully covered, densely packed, and the particle size was found to be increased with film thickness. Meanwhile, quantitative analysis of dielectric properties (interfacial capacitance, dead layers, and bulk dielectric constant) of CCTO thin film with metal–insulator–metal (M–I–M) structures has been investigated systematically using a series capacitor model. Room temperature dielectric properties of all the samples exhibit dispersion at low frequencies, which can be explained based on Maxwell–Wagner two-layer models and Koop’s theory. It was found that the 483 nm thick CCTO film represents a high dielectric constant (ε_r = 3334), low loss (tan δ = 3.54), capacitance (C = 4951 nF), which might satisfy the requirements of embedded capacitor.