MOCVD Route to the Fabrication of Calcium Copper Titanate (CaCu3Ti4O12) Thin Films

2006 ◽  
Vol 45 ◽  
pp. 1194-1199
Author(s):  
Raffaella Lo Nigro ◽  
Roberta G. Toro ◽  
Graziella Malandrino ◽  
Ignazio L. Fragalà

CaCu3Ti4O12 (CCTO) thin films have been successfully deposited by Metal Organic Chemical Vapor Deposition (MOCVD) technique. A novel approach based on a molten multicomponent precursor source has been applied. The molten mixture consists of the Ca(hfa)2•tetraglyme, Ti(tmhd)2(O-iPr)2, and Cu(tmhd)2 [Hhfa= 1,1,1,5,5,5-hexafluoro-2,4- pentanedione; tetraglyme= 2,5,8,11,14-pentaoxapentadecane; Htmhd= 2,2,6,6-tetramethyl-3,5- heptandione; O-iPr= iso-propoxide] precursors. Film complete structural and morphological characterizations have been carried out using several techniques [X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM)].

1998 ◽  
Vol 541 ◽  
Author(s):  
C. H. Lin ◽  
H. C. Kuo ◽  
G. E. Stillman ◽  
Haydn Chen

AbstractHighly (100) textured pseudo-cubic Pb(ScTa)1−xTixO3 (x=0-0.3) (PSTT) thin films were grown by metal-organic chemical vapor deposition (MOCVD) on LaNiO3 (LNO) electrode buffered Si substrates at 650 °C. The microstructure and chemical uniformity were studied using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and nanoprobe X-ray energy dispersive spectroscopy (EDS). The temperature dependence of dielectric properties and P-E behavior were measured. A shift of Curie temperature of these PST-based thin films due to Ti addition was demonstrated, Furthermore, the pyroelectric properties of these thin films were estimated.


1997 ◽  
Vol 493 ◽  
Author(s):  
C. H. Lin ◽  
B. M. Yen ◽  
Haydn Chen ◽  
T. B. Wu ◽  
H. C. Kuo ◽  
...  

ABSTRACTHighly textured PbZrxTi1−xO3 (PZT) thin films with x= 0-0.6 were grown on LaNiO3 coated Si substrates at 600 °C by metal-organic chemical vapor deposition (MOCVD). The preferred crystalline orientation of PZT thin films with various Zr concentration were characterized by X-ray diffraction (XRD). Microstructures were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The dielectric constants, hysteresis and fatigue behavior of these thin films were also measured. The relationship between growth rate and the preferential orientation is discussed. Furthermore, the dependence of the electrical properties on Zr concentration and preferential orientation is demonstrated.


2019 ◽  
Vol 25 (6) ◽  
pp. 1383-1393
Author(s):  
Sabyasachi Saha ◽  
Deepak Kumar ◽  
Chandan K. Sharma ◽  
Vikash K. Singh ◽  
Samartha Channagiri ◽  
...  

AbstractGaN films have been grown on SiC substrates with an AlN nucleation layer by using a metal organic chemical vapor deposition technique. Micro-cracking of the GaN films has been observed in some of the grown samples. In order to investigate the micro-cracking and microstructure, the samples have been studied using various characterization techniques such as optical microscopy, atomic force microscopy, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy (TEM). The surface morphology of the AlN nucleation layer is related to the stress evolution in subsequent overgrown GaN epilayers. It is determined via TEM evidence that, if the AlN nucleation layer has a rough surface morphology, this leads to tensile stresses in the GaN films, which finally results in cracking. Raman spectroscopy results also suggest this, by showing the existence of considerable tensile residual stress in the AlN nucleation layer. Based on these various observations and results, conclusions or propositions relating to the microstructure are presented.


2000 ◽  
Vol 637 ◽  
Author(s):  
F. Niu ◽  
A.R. Teren ◽  
B.H. Hoerman ◽  
B.W. Wessels

AbstractEpitaxial ferroelectric BaTiO3 thin films have been developed as a material for microphotonics. Efforts have been directed toward developing these materials for thin film electro-optic modulators. Films were deposited by metalorganic chemical vapor deposition (MOCVD) on both MgO and silicon substrates. The electro-optic properties of the thin films were measured. For BaTiO3 thin films grown on (100) MgO substrates, the effective electro-optic coefficient, reff depended on the magnitude and direction of the electric field. Coefficients as high as 260 pm/V have been measured. Investigation of BaTiO3 films on silicon has been undertaken. Epitaxial BaTiO3 thin films were deposited by MOCVD on (100) MgO layers grown on silicon (100) substrates by metal-organic molecular beam epitaxy (MOMBE). The MgO serves as the low index optical cladding layer as well as an insulating layer. X-ray diffraction and transmission electron microscopy (TEM) indicated that BaTiO3 was epitaxial with an orientational relation given by BaTiO3 (100)//Si (100) and BaTiO3[011]//Si [011]. Polarization measurements indicated that the BaTiO3 epitaxial films on Si were in the ferroelectric state.


1998 ◽  
Vol 541 ◽  
Author(s):  
Nan Chen ◽  
G. R. Bai ◽  
O. Auciello ◽  
R. E. Koritala ◽  
M. T. Lanagan

AbstractSingle-phase polycrystalline PbZrO3 (PZ) thin films, 3000-6000 A thick, have been grown by metal-organic chemical vapor deposition (MOCVD) on (111)Pt/Ti/SiO2/Si substrates at ≍525°C. X-ray diffraction analysis indicated that the PZ films grown on (111)Pt/Ti/SiO2/Si (Pt/Tgi/Si) showed preferred pseudocubic (110) orientation. In contrast, PZ films grown on 150 A thick PbTiO3 (PT) template layers exhibited a pseudocubic (100) preferred orientation, and PZ films deposited on TiO2 template layers consisted of randomly oriented grains. The PZ films grown on Pt/Ti/Si with or without templates exhibited dielectric constants of 120-200 and loss tangents of 0.01-0.0. The PZ films with (110) orientation exhibited an electric-field-inducedtransformation from the antiferroelectric phase to the ferroelectric phase with a polarization of ≍34 µC/cm2, and the energy that was stored during switching was 7.1 J/cm3. The field needed to excite the ferroelectric state and that needed to revert to the antiferroelectric state were 50 and 250 kV/cm, respectively. Relationships between the MOCVD processing and the film microstructure and properties are discussed.


Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3645
Author(s):  
Liyao Zhang ◽  
Yuxin Song ◽  
Nils von den Driesch ◽  
Zhenpu Zhang ◽  
Dan Buca ◽  
...  

The structural properties of GeSn thin films with different Sn concentrations and thicknesses grown on Ge (001) by molecular beam epitaxy (MBE) and on Ge-buffered Si (001) wafers by chemical vapor deposition (CVD) were analyzed through high resolution X-ray diffraction and cross-sectional transmission electron microscopy. Two-dimensional reciprocal space maps around the asymmetric (224) reflection were collected by X-ray diffraction for both the whole structures and the GeSn epilayers. The broadenings of the features of the GeSn epilayers with different relaxations in the ω direction, along the ω-2θ direction and parallel to the surface were investigated. The dislocations were identified by transmission electron microscopy. Threading dislocations were found in MBE grown GeSn layers, but not in the CVD grown ones. The point defects and dislocations were two possible reasons for the poor optical properties in the GeSn alloys grown by MBE.


Author(s):  
Z.-R. Dai ◽  
Z.L. Wang ◽  
X.F. Duan ◽  
J. Zhang

Epitaxially grown BaTiO3 thin films have potential applications in microelectronics and integrated photonics. The ferroelectric property of this material is largely determined by the domain structure. It is believed that the structure of the substrate would have profound effect on the quality of BaTiO3 epitaxial thin films. This paper reports our studies on the pinning of 90° domain boundaries at interface dislocations.Epitaxial BaTiO3 thin films were deposited on single crystalline LaAIO3 (100) substrates at 800°C by metal-organic chemical vapor deposition (MOCVD). Cross-section specimens of the films were studied at 200 kV using an JEOL 2010 high-resolution transmission electron microscope (HRTEM).


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