scholarly journals Thickness-dependent electrocaloric effect in mixed-phase Pb 0.87 Ba 0.1 La 0.02 (Zr 0.6 Sn 0.33 Ti 0.07 )O 3 thin films

2016 ◽  
Vol 374 (2074) ◽  
pp. 20160056 ◽  
Author(s):  
T. M. Correia ◽  
Q. Zhang
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Phase Transitions ◽  
Film Thickness ◽  
Tetragonal Phase ◽  
Sol Gel ◽  
Breakdown Field ◽  
Electrocaloric Effect ◽  
Thickness Increase ◽  
Higher Temperature

Full-perovskite Pb 0.87 Ba 0.1 La 0.02 (Zr 0.6 Sn 0.33 Ti 0.07 )O 3 (PBLZST) thin films were fabricated by a sol–gel method. These revealed both rhombohedral and tetragonal phases, as opposed to the full-tetragonal phase previously reported in ceramics. The fractions of tetragonal and rhombohedral phases are found to be strongly dependent on film thickness. The fraction of tetragonal grains increases with increasing film thickness, as the substrate constraint throughout the film decreases with film thickness. The maximum of the dielectric constant ( ε m ) and the corresponding temperature ( T m ) are thickness-dependent and dictated by the fraction of rhombohedral and tetragonal phase, with ε m reaching a minimum at 400 nm and T m shifting to higher temperature with increasing thickness. With the thickness increase, the breakdown field decreases, but field-induced antiferroelectric–ferroelectric ( E AFE−FE ) and ferroelectric–antiferroelectric ( E FE−AFE ) switch fields increase. The electrocaloric effect increases with increasing film thickness. This article is part of the themed issue ‘Taking the temperature of phase transitions in cool materials’.

THICKNESS EFFECTS ON THE EPITAXIAL NATURE OF THE SINGLE-PHASE MULTIFERROIC THIN FILMS

2009 ◽  
Vol 08 (01n02) ◽  
pp. 81-85
Author(s):  
A. HUANG ◽  
S. Y. TAN ◽  
S. R. SHANNIGRAHI
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Film Thickness ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Sol Gel ◽  
Fold Increase ◽  
Xrd Analysis ◽  
Sol Gel Process

Multiferroic Bi 0.95 La 0.05 Fe 0.7 Sc 0.3 O 3 (BLFS) thin films with different thicknesses have been prepared on (1 0 0) LaAlO 3 (LAO) substrates using a sol–gel process and annealed in N 2 ambient at 650°C for 5 min. From the X-ray diffraction (XRD) analysis, it was observed that BLFS thin films had (h 0 0)-preferred orientation for the film thickness 63, 125, 186, and 240 nm and became isotropic thereafter. The films developed in-plane epitaxial growth with respect to the substrate. The surface morphology became denser and the surface roughness increased as thickness increased up to 241 nm. The highest dielectric constant observed for the 241 nm thick BLFS film too. No prominent of the leakage current density observed for the film thickness up to 241 nm. However, two fold increase in the leakage current density observed for the film thickness 382 nm. For the BLFS films with thickness 241 nm, we observed the highest dielectric constant (ε) value of 1675 and remnant polarization (Pr) polarization value of 52 μC/cm2 using a sol–gel spin coating process.

scholarly journals Correlation of film thickness to optical band gap of Sol-gel derived Ba0.9Gd0.1TiO3 thin films for optoelectronic applications

2017 ◽  
Vol 162 ◽  
pp. 01042
Author(s):  
Yen Chin Teh ◽  
Ala’eddin A. Saif ◽  
Zul Azhar Zahid Jamal ◽  
Prabakaran Poopalan
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Band Gap ◽  
Optical Band Gap ◽  
Sol Gel ◽  
Optoelectronic Applications

Photo-induced Large Area Growth Of Dielectrics With Excimer Lamps

2000 ◽  
Vol 617 ◽  
Author(s):  
Ian W. Boyd ◽  
Jun-Ying Zhang
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Low Temperature ◽  
Leakage Current ◽  
Sol Gel ◽  
Low Dielectric Constant ◽  
Large Area ◽  
Excimer Lamp ◽  
Low Dielectric ◽  
Current Densities

AbstractIn this paper, UV-induced large area growth of high dielectric constant (Ta2O5, TiO2and PZT) and low dielectric constant (polyimide and porous silica) thin films by photo-CVD and sol-gel processing using excimer lamps, as well as the effect of low temperature LW annealing, are discussed. Ellipsometry, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), UV spectrophotometry, atomic force microscope (AFM), capacitance-voltage (C-V) and current-voltage (I-V) measurements have been employed to characterize oxide films grown and indicate them to be high quality layers. Leakage current densities as low as 9.0×10−8 Acm−2 and 1.95×10−7 Acm−2 at 0.5 MV/cm have been obtained for the as-grown Ta2O5 films formed by photo-induced sol-gel processing and photo-CVD. respectively - several orders of magnitude lower than for any other as-grown films prepared by any other technique. A subsequent low temperature (400°C) UV annealing step improves these to 2.0×10−9 Acm−2 and 6.4× 10−9 Acm−2, respectively. These values are essentially identical to those only previously formed for films annealed at temperatures between 600 and 1000°C. PZT thin films have also been deposited at low temperatures by photo-assisted decomposition of a PZT metal-organic sol-gel polymer using the 172 nm excimer lamp. Very low leakage current densities (10−7 A/cm2) can be achieved, which compared with layers grown by conventional thermal processing. Photo-induced deposition of low dielectric constant organic polymers for interlayer dielectrics has highlighted a significant role of photo effects on the curing of polyamic acid films. I-V measurements showed the leakage current density of the irradiated polymer films was over an order of magnitude smaller than has been obtained in the films prepared by thermal processing. Compared with conventional furnace processing, the photo-induced curing of the polyimide provided both reduced processing time and temperature, A new technique of low temperature photo-induced sol-gel process for the growth of low dielectric constant porous silicon dioxide thin films from TEOS sol-gel solutions with a 172 nm excimer lamp has also been successfully demonstrated. The dielectric constant values as low as 1.7 can be achieved at room temperature. The applications investigated so far clearly demonstrate that low cost high power excimer lamp systems can provide an interesting alternative to conventional UV lamps and excimer lasers for industrial large-scale low temperature materials processing.

Preparation and Characterization Of SrTio3 Thin Films Using ECR Plasma Assisted MOCVD

1995 ◽  
Vol 415 ◽  
Author(s):  
Joon Sung Lee ◽  
Han Wook Song ◽  
Dae Sung Yoon ◽  
Byung Hyuk Jun ◽  
Byoung Gon Yu ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Oxygen Plasma ◽  
Grain Structure ◽  
Breakdown Field ◽  
Ecr Plasma ◽  
Step Coverage

ABSTRACTSrTiO3 thin films were prepared on Si(p-type 100) and Pt/SiO2/Si substrates using ECR plasma (or without ECR plasma) assisted MOCVD. Sr(TMI-D)2 and Ti-isopropoxide were used as Sr and Ti metal organic sources, respectively. Perovskite SrTiO3 films were obtained at relatively low temperature of 500°C (using ECR oxygen plasma. Experimental results indicated that higher deposition temperature and ECR oxygen plasma increase the crystallinity, the dielectric constant and the leakage current density. The dielectric constant and the dielectric loss were 222 and 0.04, respectively, for 1234 Å thin SrTiO3 film (Sr/(Sr+Ti)=0.5). The leakage current density was 3.78 × 10−7 A/cm2 at 1.0V, and the dielectric breakdown field was 0.57MV/cm. SEM analyses showed that SrTiO3 films have a uniform and fine grain structure. In terms of step coverage, a lateral step coverage of 50% at 0.8 μm step (the aspect ratio was 1) was obtained with the thickness uniformity of ± 0.5% and the composition uniformity of ±1.2% at 4′′ wafer.

Electrochromic and Electrochemical Properties of Nickel Oxide Thin Films Prepared by a Modified Sol-Gel Method

2008 ◽  
Vol 47-50 ◽  
pp. 625-629 ◽  
Author(s):  
X.H. Xia ◽  
J.P. Tu ◽  
J. Zhang ◽  
X.L. Wang
Keyword(s):  
Thin Films ◽  
Cyclic Voltammetry ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method ◽  
Electrochemical Reversibility ◽  
Vis Spectroscopy ◽  
Ito Glass ◽  
Higher Temperature ◽  
Cv Measurements

NiO thin films were prepared on ITO glass by a modified sol-gel method in combination with a following annealing process. The XRD results show that the film annealed at 280 °C is amorphous, while the films annealed at and above 300 °C are cubic NiO phase. The electrochromic performances of the annealed films were characterized by means of UV–vis spectroscopy and cyclic voltammetry (CV) measurements. The film annealed at 280 °C exhibits a noticeable electrochromism with a variation of transmittance up to 76 % at 550 nm. The cyclic voltammetry (CV) measurements reveal that the film annealed at higher temperature has better electrochemical reversibility.

Preparation and Characterization of (Sr1−xTix)O3 and (Ba1−xSrx)TiO3 Thin Films using ECR Plasma Assisted MOCVD

1996 ◽  
Vol 433 ◽  
Author(s):  
Kwangsoo No ◽  
Joon Sung Lee ◽  
Han Wook Song ◽  
Won Jong Lee ◽  
Byoung Gon Yu ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Electrical Properties ◽  
Dielectric Loss ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Breakdown Field ◽  
Carrier Gas ◽  
Ecr Plasma

AbstractBa(TMHD)2, Sr(TMHD)2 and Ti-isopropoxide were used to fabricate the (SrxTi1 x)O3 and (Ba1 x Srx)TiO3 thin films. The decomposition and degradation characteristics of Ba(TMHD)2 and Sr(TMHD)2 with storage time were analyzed using a differential scanning calorimeter (DSC). The thin films were fabricated on Si(p-type 100) and Pt/SiO2/Si substrates with Ar carrier gas using ECR plasma (or without ECR plasma) assisted MOCVD. Experimental results showed that the ECR oxygen plasma increased the deposition rate, the ratio of Sr/Ti, the dielectric constant and the leakage current density of the film. The dependency of the crystallinity and the electrical properties on the Sr/Ti ratio of films were investigated. However, almost of the films deposited with Ar carrier gas had slightly high dielectric loss and high leakage current density and showed non-uniform compositional depth profiles. NH3 gas was also used to decrease the degradation of the MO-sources. Mass spectra in-situ monitoring of source vapors in ECR-PAMOCVD system were obtained. By introducing NH3 as a carrier gas, a significant improvement was achieved in the volatility and the thermal stability of the precursors, and the vaporization temperatures of the precursors were reduced compared to Ar carrier gas. The uniform compositional depth profile, less hydrogen and carbon content and the good electrical properties of (SrxTi1−x)O3 thin films were obtained with NH3 carrier gas. The (Ba1−xSrx)TiO3 thin film were fabricated to have very fine and uniform microstructure, the dielectric constant of 456, the dielectric loss of 0.0128, the leakage current density of 5.01 × 10−8A/cm2 at 1V and the breakdown field of 3.65MV/cm.

Characterization of MgZnO Thin Film for 1 GHz MMIC Applications

2013 ◽  
Vol 832 ◽  
pp. 310-315
Author(s):  
R. Ahmad ◽  
M.S. Shamsudin ◽  
M. Salina ◽  
S.M. Sanip ◽  
M. Rusop ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Dielectric Constant ◽  
Loss Tangent ◽  
Integrated Circuit ◽  
Annealing Temperature ◽  
Dielectric Material ◽  
Sol Gel ◽  
Size Reduction ◽  
High Frequencies

MgZnO thin films are proposed as a new dielectric material for 1 GHz monolithic microwave integrated circuit (MMIC) applications. The high permittivity of this material enables size reduction; furthermore this can be fabricated using a low cost processing method. In this work, MgZnO/Pt/Si thin films were synthesized using a sol-gel spin coating method. The samples were annealed at various temperatures with the effects on physical and electrical properties investigated at direct current (DC) and high frequencies. The physical properties of MgZnO thin film were analyzed using X-Ray diffraction, with the improvements shown in crystalline structure and grain size with increasing temperature up to 700 °C. DC resistivity of 77 Ωcm at higher annealing temperature obtained using a four point probe station. In order to prove the feasibility at high frequencies, a test structure consisting of a 50 Ω transmission line and capacitors with 50 × 50 μm electrode area were patterned on the films using electron beam lithography. The radio frequency (RF) properties were measured using aWiltron 37269Avector network analyzer andCascade Microtechon-wafer probes measured over a frequency range of 0.5 to 3 GHz. The dielectric constant, loss tangent and return loss, S11improve with the increment annealing temperature. The dielectric constant was found to be 18.8, with loss tangent of 0.02 at 1 GHz. These give a corresponding size reduction of ten times compared to conventional dielectrics, silicon nitride (Si3N4). These indicate that the material is suitable to be implemented as a new dielectric material for 1GHz MMIC applications.

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