Articles you may be interested inTemperature-dependent energy storage properties of antiferroelectric Pb0.96La0.04Zr0.98Ti0.02O3 thin films Appl. Phys. Lett.

The structural, electrical and optical properties of RF sputtered In2O3 : Sn (ITO) thin films and the effect of post-deposition annealing have been studied. The thickness ranges from 225 to 862 nm. X-ray diffraction, scanning electron microscopy (SEM) and atomic force microscopy (AFM) experiments were performed to study the structure and the surface morphology of these samples. We found that thinner films have a ⟨100⟩ texture and as the film grows the preferred orientation changes from ⟨100⟩ to ⟨111⟩. The lattice parameters are found to be larger than the bulk value, indicating that the samples are under a tensile stress. The grain size increases with increasing thickness. SEM images show a dense granular structure with grains having different shapes and sizes. From AFM images, the average surface roughness (rms) was estimated to be 3.89 nm. The energy gap was found to decrease from 3.65 to 3.50 eV as t increases from 225 to 866 nm. Annealing experiments were done, in the air, at temperature T in the 100–500 °C range. We found that the ⟨111⟩ texture becomes stronger after the annealing treatment. A large increase of the grain size with increasing T is observed. The lattice constant decreases with T to become closer to the bulk value, i.e. annealing seems to relieve the stress present in the as-deposited films; T = 400 °C seems to be the best temperature to obtain practically a stress free sample. We observe a large decrease in the electrical resistivity ρ after annealing. The lowest ρ value (16 × 10−4 Ω cm) was noted in the 699 nm thick sample annealed at 500 °C. The decrease of ρ seems to be the consequence of a larger grain size and a stronger ⟨111⟩ texture.

The problem of electromechanical film characterization, and, in particular, the determination of the piezoelectric activities of thin films deposited on substrates, is of fundamental importance in the development of structures for microelectromechanical system (MEMS) applications. The design and the architecture of the piezoelectric MEMS are directly related to the mechanical and the piezoelectric performances of the material. In this article, we present and compare some results obtained on different experimental setup for the determination of the d33 coefficient. We have optimized the experimental conditions using a laser Doppler vibrometer. The main problem is the contribution of the bending effect of the substrates on the d33 coefficient, which is an intrinsic property of the film. We show that the d33 values are directly related to parameters such as the top electrode diameter and the substrate holder. The results are in agreement with those obtained with the conventional double beam interferometer used to account for substrate bending.

In this letter, two organic thin-film transistors with SiO2 and ferroelectric PbZrTiO3 (PZT) gate insulator are compared. The fabrication of the devices is described and their electrical properties estimated. The PZT-based devices show better performance: Low driving voltage, high Ion/Ioff ratio, etc. Moreover, a memory effect is reported in correlation with ferroelectric properties of PZT thin films.

Articles you may be interested inTemperature-dependent energy storage properties of antiferroelectric Pb0.96La0.04Zr0.98Ti0.02O3 thin films Appl. Phys. Lett.

No abstract

Ion beam etching of sputtered Pb(Zr x ,Ti 1Ϫx )O 3 ͑PZT͒ with x equal to 0.54 thin films grown on Pt/Ti/SiO 2 /Si substrates has been performed using pure Ar gas. The etch rate dependence on the process parameters ͑current density, acceleration voltage, gas pressure͒ has been investigated. The PZT etch rate can reach 600 Å/min with acceleration voltage of 1000 V and current density of 1 mA/cm 2 . Selectivity ratios between PZT and masks of various natures ͑photoresist, Pt, Ti͒ have been evaluated to determine a pertinent material for etching mask. According to our etching conditions, titanium seems to be the best candidate. We evaluated the PZT surface damage by contact mode atomic force microscopy. It appears that the roughness increases after ion bombardment, and that the grain boundary zone is preferentially etched. For some etching parameters, we also observed electrical damage. Carrying out C(V) and hysteresis loops P(E) measurements before and after etching have provided evidence of degradation. We noted a large decrease in permittivity after the etching process irrespective of the current density and acceleration voltage. Ferroelectric damage was illustrated by a large increase in the average coercive field. For each of the electrical properties under study, the same behavior has been observed after etching: the increase of damage was obtained as a function of the current density and acceleration voltage. The evolution of electrical properties when the PZT layer is protected by a metallic mask has also been studied. We observed very slight variations in the electrical properties.

No abstract