Heteroepitaxial growth of lanthanum aluminate films derived from mixed metal nitrates

1997 ◽  
Vol 12 (5) ◽  
pp. 1306-1314 ◽  
Author(s):  
Man Fai Ng ◽  
Michael J. Cima
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Linear Growth ◽  
Substrate Surface ◽  
Single Crystal Substrate ◽  
Second Phase ◽  
Heteroepitaxial Growth ◽  
Lanthanum Aluminate ◽  
Metal Nitrates ◽  
Linear Growth Model

Epitaxial lanthanum aluminate (LaAlO3) thin films were deposited on single-crystal substrates by pyrolysis of spin-on mixed nitrate precursors. The films are epitaxial without any second phase. TEM micrographs show that all of these films have pores with sizes ranging from 5 to 30 nm. Grain boundaries are not observed. Selected area diffraction shows that the films are single-crystal-like, despite the porosity. All the films are smooth and crack-free. The precursors first decompose into an amorphous mixture. Heterogeneous nucleation occurs on the lattice-matched, single-crystal substrate surface. The epitaxial films grow upward and consume the amorphous regions. The crystallization temperature of LaAlO3 is lower for thin films than for bulk samples due to nucleation on the substrate. The crystallization of LaAlO3 does not exhibit linear growth kinetics. The Johnson–Mehl–Avrami exponent of growth is between 1.4 and 1.5. This deviation from the linear growth model (n = 1) can be attributed to continuous nucleation on the substrate/film interface.

Microstructure and enhanced in-plane ferroelectricity of Ba0.7Sr0.3TiO3 thin films grown on MgAl2O4 (001) single-crystal substrate

2006 ◽  
Vol 89 (23) ◽  
pp. 232906 ◽  
Author(s):  
X. Y. Zhou ◽  
T. Heindl ◽  
G. K. H. Pang ◽  
J. Miao ◽  
R. K. Zheng ◽  
...  
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Single Crystal Substrate ◽  
Crystal Substrate

Systematic Studies on Magnetron-Sputtered Indium Nitride

1992 ◽  
Vol 242 ◽  
Author(s):  
W. A. Bryden ◽  
S. A. Ecelberger ◽  
J. S. Morgan ◽  
T. O. Poehler ◽  
T. J. Kistenmacher
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Carrier Concentration ◽  
Deposition Temperature ◽  
Inert Gases ◽  
Morphological Transition ◽  
Heteroepitaxial Growth ◽  
High Carrier Concentration ◽  
High Carrier ◽  
Nitrogen Vacancies

ABSTRACTExtensive and systematic studies on reactive magnetron sputtering of InN thin films are summarized. The films have been deposited onto several types of substrates, with variations in such process parameters as deposition temperature, partial pressures of reactive and inert gases, sputtering power and gas flows. These films have been characterized by measuring their electrical, optical, structural and morphological properties. It has been shown that epitaxial growth of InN occurs on the basal plane of single-crystal (00.1) sapphire and (001) mica substrates and on the (111) face of cubic substrates such as silicon and zirconia.Two principal problems currently limit the usefulness of thin films of InN. First, although epitaxy can be attained with the proper choice of substrate type and deposition temperature, the resulting film is an agglomerate of epitaxial grains -- not a single crystal. Second, all magnetron sputtered InN films prepared to date have low mobility and high carrier concentration (likely due to nitrogen vacancies). In an attempt to address these problems, experiments on the growth and characterization of sputtered InN films have been carried out and are discussed here with particular emphasis on seeded heteroepitaxial growth and the effects of film deposition temperature.For example, it was found early that the growth of InN on the bare surface of several crystalline substrates at growth temperatures near 350°C results in a morphological transition that causes a degradation of semiconducting properties. The predeposition of an AIN seed layer inhibits this morphological transition and stabilizes a relatively high mobility state, but a still too high carrier concentration obtains. Further progress critically depends on optimizing the seeded heteroepitaxial growth technique in conjunction with the achievement of InN films with lower density of nitrogen vacancies.

Homoepitaxial Alignment of SrTiO3 Thin Films Prepared by Metallo-Organic Decomposition.

1991 ◽  
Vol 249 ◽  
Author(s):  
Gabriel Braunstein ◽  
Gustavo R. Paz-Pujalt
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Solid Phase ◽  
Single Crystal Substrate ◽  
Layer By Layer ◽  
Extrinsic Factors ◽  
Ion Channeling ◽  
Random Nucleation ◽  
Crystal Substrate ◽  
Organic Decomposition

ABSTRACTWe demonstrate the homoepitaxial growth of SrTiO3 prepared by the method of metallo-organic decomposition (MOD). Thin films of SrTiO3 are prepared by spin-coating and thermal decomposition of a solution of metallo-organic compounds, on single crystal, <100> oriented, SrTiO3 substrates and subsequently heat treated at temperatures ranging from 650°C to 1100°C for 30 minutes. Heat treatment at 1100°C results in the formation of single-crystal SrTiO3, perfectly aligned with respect to the underlying substrate.Ion-channeling analysis shows that the transformation to singlecrystal material proceeds epitaxially from the coating-substrate interface towards the surface of the sample. Transmission electron microscopy (TEM) studies of partially regrown samples reveal two distinct phases: an epitaxially aligned single-crystal phase, adjacent to the substrate, and a polycrystalline phase on top. On the basis of these observations, it is proposed that the crystallization of the MOD films involves the competition between two processes: layer-by-layer solid phase epitaxy and random nucleation and growth of crystallites. Layerby- layer epitaxy is the predominant crystallization mechanism unless it is inhibited by extrinsic factors like the contamination of the interface between the MOD film and the single-crystal substrate.

Enhanced in-plane ferroelectricity in Ba0.7Sr0.3TiO3 thin films grown on MgO (001) single-crystal substrate

2005 ◽  
Vol 86 (21) ◽  
pp. 212904 ◽  
Author(s):  
D. Y. Wang ◽  
Y. Wang ◽  
X. Y. Zhou ◽  
H. L. W. Chan ◽  
C. L. Choy
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Single Crystal Substrate ◽  
Crystal Substrate

Epitaxy, microstructure, and processing-structure relationships of TiO2 thin films grown on sapphire (0001) by MOCVD

1993 ◽  
Vol 8 (10) ◽  
pp. 2634-2643 ◽  
Author(s):  
H.L.M. Chang ◽  
T.J. Zhang ◽  
H. Zhang ◽  
J. Guo ◽  
H.K. Kim ◽  
...  
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Film Growth ◽  
Growth Parameters ◽  
Substrate Surface ◽  
Growth Conditions ◽  
Organic Chemical ◽  
Tio2 Thin Films ◽  
Growth Plane ◽  
Deposited Films

TiO2 thin films have been deposited on sapphire (0001) substrates under various conditions by metal-organic chemical vapor deposition. The structural properties of the deposited films were characterized by x-ray diffraction and transmission electron microscopy. The important growth parameters were found to be the deposition temperature and the deposition rate. The ranges studied for the two parameters were 400 to 850 °C and 10 to 120 Å/min, respectively. Depending on the growth conditions, most of the deposited films were either single-phase anatase or rutile, or a mixture of the two. These films were all epitaxial, but none of them were single-crystal films. Three distinct epitaxial relationships were observed between the films and the substrates, and, depending on the growth conditions, a deposited film can contain one, two, or all three of them. The fact that the films we obtained, although epitaxial, were never single crystal is explained based on the consideration of the difference in the rotational symmetries of the substrate surface and the film growth plane. We believe that it should be generally true that, in heteroepitaxial growth, a true single-crystal film can never be obtained as long as the point symmetry group of the substrate surface is not a subgroup of that of the film growth plane.

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