Characterization of Single Crystal Epitaxial Aluminum Nitride Thin Films on Sapphire, Silicon Carbide and Silicon Substrates by X-ray Double Crystal Diffractometry and Transmission Electron Microscopy

Superconducting YBaCuO thin films have been fabricated on single-crystal MgO by the spray-pyrolysis of nitrate precursors. The effects on the superconductive behavior of processing parameters such as time and temperature of heat treatment and film thickness were investigated. The superconductive behavior was found to be strongly dependent on film thickness. Films of thickness 1 μm were found to have a Tc of 67 K while thinner films showed appreciably degraded properties. Transmission electron microscopy studies have shown that the heat treatments necessary for the formation of the superconductive phase (for example, 950 °C for 30 min) also cause a substantial degree of film-substrate interdiffusion. Diffusion distances for Cu in the MgO substrate and Mg in the film were found to be sufficient to explain the degradation of the superconductive behavior in films of thickness 0.5 μm and 0.2 μm. From the concentration profiles obtained by EDS analysis diffusion coefficients at 950 °C for Mg into the YBaCuO thin film and for Cu into the MgO substrate were evaluated as 3 × 10−19 m2/s and 1 × 10−17 m2/s, respectively.

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Characterization Of Single Crystal Epitaxial Aluminum Nitride Thin Films On Sapphire, Silicon Carbide And Silicon Substrates By X-Ray Double Crystal Diffractometry And Transmission Electron Microscopy

Advances in X-ray Analysis ◽

10.1154/s0376030800023077 ◽

1995 ◽

Vol 39 ◽

pp. 645-651

Author(s):

J. Chaudhuri ◽

R. Thokala ◽

J. H. Edgar ◽

B. S. Sywe

Keyword(s):

Thin Film ◽

Electron Microscopy ◽

Thin Films ◽

Residual Stress ◽

Transmission Electron Microscopy ◽

Silicon Carbide ◽

Defect Density ◽

Double Crystal ◽

X Ray ◽

Transmission Electron

Epitaxial AIN thin films grown on sapphire, silicon and silicon carbide substrates were studied using x-ray double crystal diffractometry and transmission electron microscopy to compare the structure, residual stress and defect concentration in these thin films. The AIN thin films was found to have a wurtzite type of structure with a small distortion in lattice parameters which results in a small residual stress of the order of 109 dynes/cm2 in the film. The strain due to lattice parameter mismatch between the substrate and film is too small to account for the residual stress present. The calculated stress from the difference in thermal expansion coefficients between the film and substrate agrees well with the experimental values. Both the x-ray and transmission electron microscopy measurements indicate a low defect density in the AIN thin film grown on 6H-SiC substrate which could be attributed to the small difference in lattice parameters between AIN and 6H-SiC. The defect density in the AIN thin film grown on other substrates were considerably higher. This is the first report of the successful growth of single crystal AIN thin films with such a low concentration of defect density.

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Characterization of diamond thin films using transmission electron microscopy

10.1117/12.216834 ◽

1995 ◽

Author(s):

Roseann Csencsits

Keyword(s):

Electron Microscopy ◽

Thin Films ◽

Transmission Electron Microscopy ◽

Transmission Electron ◽

Diamond Thin Films

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Anisotropic Behaviour of Surface Roughening in Lattice Mismatched Heteroepitaxial Thin Films

MRS Proceedings ◽

10.1557/proc-436-487 ◽

1996 ◽

Vol 436 ◽

Cited By ~ 7

Author(s):

Cengiz S. Ozkan ◽

William D. Nix ◽

Huajian Gao

Keyword(s):

Electron Microscopy ◽

Thin Films ◽

Transmission Electron Microscopy ◽

Lattice Mismatch ◽

Surface Roughening ◽

Silicon Substrates ◽

Force Microscopy ◽

Atomic Force ◽

Transmission Electron ◽

Annealing Experiments

AbstractHeteroepitaxial Si1-xGex. thin films deposited on silicon substrates exhibit surface roughening via surface diffusion under the effect of a compressive stress which is caused by a lattice mismatch. In these films, surface roughening can take place in the form of ridges which can be aligned along <100> or <110> directions, depending on the film thickness. In this paper, we investigate this anisotropic dependence of surface roughening and present an analysis of it. We have studied the surface roughening behaviour of 18% Ge and 22% Ge thin films subjected to controlled annealing experiments. Transmission electron microscopy and atomic force microscopy have been used to study the morphology and microstructure of the surface ridges and the dislocations that form during annealing.

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