Comparative Study of Amorphous and Crystalline (Ba, Sr)TiO₃ Thin Films Deposited by Laser Ablation

Abstract

(Ba0.5Sr0.5)TiO3 thin films (200-300 nm) were deposited on Pt-coated Si substrates by laser ablation at 500 and 650°C. The leakage currents of crystalline films grown at 650°C were found to be higher than those of amorphous films grown at 500°C. The crystalline thin films showed higher surface roughness than the amorphous films as measured by atomic force microscopy (AFM). A columnar grain structure was observed for crystalline films with a grain size of 20-30 nm by transmission electron microscope (TEM) analysis. These factors may be responsible for high leakage currents of crystalline films. Constant current injection measurements for Au/(Ba0.5Sr0.5)TiO3/Pt capacitors showed that electron trapping states near the top electrode interface were higher in number than at bottom electrode interface. This may be due to the presence of reactive sites on the surface of deposited films as observed by X-ray photoelectron spectroscopy (XPS) measurements.

Electrical and optical properties of PZT ferroelectric films fabricated by the PVP-assisted sol-gel method

“…The dielectric loss of 1 μm-thick PZT film at 100 kHz was 0.05 and the dielectric constant was calculated as 223. The relatively lower dielectric constant measured in this work could be due to the small grain of the film [5]. Figure 5 shows the typical P-E hysteresis loop of PZT films with Au/PZT/Pt configuration measured by TF Analyzer2000 standardized ferroelectric test system.…”

Structural and dielectric studies of Co doped MgTiO3 thin films fabricated by RF magnetron sputtering

“…37 Usually the leakage current density depends on the grain sizes, the average crystallinity, and the rms surface roughness. 47,48 We attribute that the decrease in leakage current density with increase in OMP is due to the lower rms surface roughness and more structured grain boundaries in the MCT thin films. In the present case the value of slope for the leakage current versus electric field curves are close to unity (1.08 for 50% OMP and 1.12 for 75% OMP), which indicates that the leakage mechanism is considered to be due to ohmic conduction.…”

Thickness dependence on structural, dielectric and AC conduction studies of vacuum evaporated Sr doped BaTiO3 thin films

“…A detailed survey of the literature reveals that even though some work on dielectric properties has been carried out to prepare thin film of strontium doped barium titanate such as sol-gel method [7,8], r.f. -sputtering [9], pulsed laser ablation [10] and metalorganic chemical vapor deposition [11]. No work is found in the literature about to preparation of thin films by vacuum evaporation method using glass substrate.…”