Early Stages of Growth of BaTiO3 Thin-Films

1990 ◽  
Vol 200 ◽  
Author(s):  
M. Grant Norton ◽  
Gerald R. English ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Film Growth ◽  
Lattice Mismatch ◽  
Pulsed Laser ◽  
Surface Preparation ◽  
Thin Foil ◽  
Stages Of Growth ◽  
Early Stages ◽  
Transmission Electron ◽  
Film Nucleation

ABSTRACTBarium titanate (BaTiO3) is of interest for use in a number of thin-film applications in electronic and optoelectronic devices. For these devices the formation of epitactic films of the correct stoichiometry and phase is essential. The substrate is important during the early stages of growth in the establishment of epitaxy, factors such as lattice mismatch, surface preparation and crystallographic orientation can all affect film nucleation and growth. In this study thin-films of BaTiO3 have been formed using the pulsed-laser ablation technique. The early stages of film growth have been studied directly using transmission electron microscopy by examination of very thin films deposited onto specially prepared electron-transparent thin-foil substrates.

Observation of the early stages of heteroepitactic growth of BaTiO3 thin-films

1990 ◽  
Vol 5 (12) ◽  
pp. 2762-2765 ◽  
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Film Growth ◽  
Stoichiometric Composition ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Thin Foil ◽  
Nucleation And Growth ◽  
Small Islands ◽  
Early Stages ◽  
Transmission Electron

Thin-films of barium titanate (BaTiO3) have been deposited onto single-crystal MgO substrates using pulsed-laser ablation. The early stages of film growth have been examined using transmission electron microscopy by deposition of very thin films onto specially prepared electron transparent thin-foil substrates. The films, which were crystalline as deposited and close to stoichiometric composition, were formed by the nucleation and growth of small islands.

Microstructure of thin YBa2Cu3O7−δ films

1990 ◽  
Vol 48 (4) ◽  
pp. 8-9
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Film Growth ◽  
Weak Link ◽  
Critical Currents ◽  
Weak Links ◽  
High Tc ◽  
Fundamental Interest ◽  
Early Stages ◽  
Transmission Electron ◽  
Patterned Films

The microstructure of superconducting thin-films often strongly influences their electrical properties. The actual microstructure of the film will be dependent on the nucleation and early stages of film growth, although the substrate will also be expected to exert an influence during the early stages of growth by the establishment of epitaxy. The highest critical currents have been obtained with films grown on SrTiO3, however MgO is of fundamental interest because patterned films on MgO have been shown to possess Josephson weak-link structure. The presence of the Josephson weak-links has been correlated with the occurrence of misaligned grains in films grown on MgO. Ultra-thin films of high-Tc superconductors are of interest for understanding the properties of these materials and may also be of use in technical applications.The microstructure of ultra-thin YBa2Cu3O7−δ films prepared by pulsed-laser ablation onto (001)- oriented MgO has been studied using transmission electron microscopy (TEM) and selected-area diffraction (SAD).

Effect of Substrate on the Early Stages of the Growth of YBa2Cu3O7-δ Thin-Films

1990 ◽  
Vol 191 ◽  
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Growth Process ◽  
Critical Role ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
High Quality ◽  
Ceramic Substrates ◽  
Early Stages ◽  
Substrate Structure ◽  
Transmission Electron

ABSTRACTThe fabrication of high-quality thin-films often depends on the early stages of the growth process during which epitaxy is established. The substrate structure and orientation generally play a critical role at this stage through epitaxy and interaction or reaction. Many different materials are being used as substrates to support thin-films of the YBa2Cu3O7-δ superconductors. In this study the early stages of the growth of YBa2Cu3O7-δ thin-films have been investigated using transmission electron microscopy (TEM). Using pulsed-laser ablation, ultra-thin films were formed directly onto self-supporting, ion-thinned, single-crystal ceramic substrates. The substrates used were (001)-oriented MgO, (001)-oriented SrTiO3 and (001)-oriented LaAlO3.

Nucleation and Heteroepitaxy of YBa2Cu3O7-δ thin films

1990 ◽  
Vol 48 (4) ◽  
pp. 88-89
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Film Growth ◽  
Thin Foil ◽  
Substrate Material ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Bulk Single Crystal ◽  
Transmission Electron ◽  
Final Sample

The nucleation and heteroepitactic growth of YBa2Cu3O7−δ thin-films has been studied by transmission electron microscopy (TEM). The films were formed by pulsed-laser ablation and then observed in the TEM without further sample preparation. Direct observation of the early stages of film growth is possible due to the utilization of a new specimen-preparation technique. The films were deposited directly onto specially prepared electron-transparent substrates. The substrate material used in this study was single-crystal, (001)-oriented MgO. The thin-foil substrates were prepared from bulk single-crystal substrates in the following manner. Discs of 3mm diameter were cored, polished and dimpled to produce a final sample thickness of 10 - 20μm. The samples were ion milled to perforation using 5 kV Ar+ ions, then chemically cleaned. The cleaned foils were annealed in air at 1350°C for 10min. The annealing temperature is such that sufficient atomic mobility enables the formation of a series of steps on the surface.

Transmission Electron Microscopy studies of the vacancy ordering in YSI2-X thin films

1991 ◽  
Vol 49 ◽  
pp. 562-563
Author(s):  
F.-R. Chen ◽  
T. L. Lee ◽  
L. J. Chen
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Thin Films ◽  
Diffraction Pattern ◽  
Annealing Temperature ◽  
Lattice Mismatch ◽  
Si Substrate ◽  
Metal Thin Films ◽  
Transmission Electron ◽  
Vacancy Ordering

YSi2-x thin films were grown by depositing the yttrium metal thin films on (111)Si substrate followed by a rapid thermal annealing (RTA) at 450 to 1100°C. The x value of the YSi2-x films ranges from 0 to 0.3. The (0001) plane of the YSi2-x films have an ideal zero lattice mismatch relative to (111)Si surface lattice. The YSi2 has the hexagonal AlB2 crystal structure. The orientation relationship with Si was determined from the diffraction pattern shown in figure 1(a) to be and . The diffraction pattern in figure 1(a) was taken from a specimen annealed at 500°C for 15 second. As the annealing temperature was increased to 600°C, superlattice diffraction spots appear at position as seen in figure 1(b) which may be due to vacancy ordering in the YSi2-x films. The ordered vacancies in YSi2-x form a mesh in Si plane suggested by a LEED experiment.

Epitaxial Growth of AlN Thin Films on Silicon and Sapphire by Pulsed Laser Deposition

1995 ◽  
Vol 395 ◽  
Author(s):  
R.D. Vispute ◽  
H. Wu ◽  
K. Jagannadham ◽  
J. Narayan
Keyword(s):  
Thin Films ◽  
Electrical Resistivity ◽  
Pulsed Laser Deposition ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Breakdown Field ◽  
Transmission Electron ◽  
Uv Visible ◽  
Relationship Of

ABSTRACTAIN thin films have been grown epitaxially on Si(111) and Al2O3(0001) substrates by pulsed laser deposition. These films were characterized by FTIR and UV-Visible, x-ray diffraction, high resolution transmission electron and scanning electron microscopy, and electrical resistivity. The films deposited on silicon and sapphire at 750-800°C and laser energy density of ∼ 2 to 3J/cm2 are epitaxial with an orientational relationship of AIN[0001]║ Si[111], AIN[2 110]║Si[011] and AlN[0001]║Al2O3[0001], AIN[1 2 1 0]║ Al2O3[0110] and AIN[1010] ║ Al2O3[2110]. The both AIN/Si and AIN/Al2O3 interfaces were found to be quite sharp without any indication of interfacial reactions. The absorption edge measured by UV-Visible spectroscopy for the epitaxial AIN film grown on sapphire was sharp and the band gap was found to be 6.1eV. The electrical resistivity of the films was about 5-6×l013Ω-cm with a breakdown field of 5×106V/cm. We also found that the films deposited at higher laser energy densities ≥10J/cm2 and lower temperatures ≤650°C were nitrogen deficient and containing free metallic aluminum which degrade the microstructural, electrical and optical properties of the AIN films

Microstructure of SrTiO3 Thin Films as Single Layer and Incorporated in Yba2Cu3O7-x/SrTiO3 Multilayers

1995 ◽  
Vol 401 ◽  
Author(s):  
L. Ryen ◽  
E. Olssoni ◽  
L. D. Madsen ◽  
C. N. L. Johnson ◽  
X. Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Lattice Mismatch ◽  
Single Layer ◽  
Transmission Electron ◽  
Tilt Boundaries ◽  
Interfacial Dislocations ◽  
The Individual ◽  
Film Substrate

AbstractEpitaxial single layer (001) SrTiO3 films and an epitaxial Yba2Cu3O7-x/SrTiO3 multilayer were dc and rf sputtered on (110)rhombohedral LaAIO3 substrates. The microstructure of the films was characterised using transmission electron microscopy. The single layer SrTiO3 films exhibited different columnar morphologies. The column boundaries were due to the lattice mismatch between film and substrate. The boundaries were associated with interfacial dislocations at the film/substrate interface, where the dislocations relaxed the strain in the a, b plane. The columns consisted of individual subgrains. These subgrains were misoriented with respect to each other, with different in-plane orientations and different tilts of the (001) planes. The subgrain boundaries were antiphase or tilt boundaries.The individual layers of the Yba2Cu3O7-x/SrTiO3 multilayer were relatively uniform. A distortion of the SrTiO3 unit cell of 0.9% in the ‘001’ direction and a Sr/Ti ratio of 0.62±0.04 was observed, both in correspondence with the single layer SrTiO3 films. Areas with different tilt of the (001)-planes were also present, within each individual SrTiO3 layer.

Sign in / Sign up

Export Citation Format

Share Document