Indentation behavior of a Brittle Film/Brittle Substrate Composite

1994 ◽  
Vol 356 ◽  
Author(s):  
C. M. Czarnik ◽  
R. Gibala ◽  
O. Baron ◽  
M. Nastasi ◽  
T. R. Jervis
Keyword(s):  
Elevated Temperatures ◽  
Surface Film ◽  
Dislocation Motion ◽  
Force Microscopy ◽  
Atomic Force ◽  
Ordered Alloys ◽  
Load Removal ◽  
Film Substrate ◽  
Composite Hardness ◽  
Radial Cracks

AbstractSurface-film induced plasticity caused by the generation of dislocations at the film-substrate interface has been demonstrated previously for bcc metals and B2 ordered alloys deformed at low homologous temperatures. More recently, we have observed similar effects at elevated temperatures for ZrO2-coated MoSi2, which also demonstrates a film-induced reduction in hardness for microhardness tests over 25°C - 1300°C. In this investigation, 120 nm - 480 nm thick ZrO2 films were deposited on (001) single crystal MoSi2 by electron beam deposition. These composites were used to characterize the film-induced softening of MoSi2 at room temperature, where both MoSi2 and ZrO2 are brittle. Indents were made through the film into the substrate at 0.5 kgf loads using Vickers and Knoop indenters. Atomic Force Microscopy was employed to measure the geometry of Knoop indents after load removal, and to compare the results to the loaded indentation shapes. Increasing film thickness reduces the length of radial cracks in the substrate and lowers the composite hardness. The film also changes the relative amounts of deformation associated with material pileup at the surface near the edges of the indent, suggesting a change in deformation mechanism from pileup around the indenter edges to deformation by dislocation motion in the bulk.

Study of Kirkendall Effect in Ni/Ni3Al Welded Joint after the High Temperature Annealing

2007 ◽  
Vol 263 ◽  
pp. 213-218 ◽  
Author(s):  
Monika Losertová ◽  
Karla Čech Barabaszová ◽  
Jaromír Drápala ◽  
Miroslav Kursa
Keyword(s):  
Concentration Profile ◽  
Elevated Temperatures ◽  
Kirkendall Effect ◽  
Diffusion Annealing ◽  
Force Microscopy ◽  
Matano Plane ◽  
Atomic Force ◽  
Ni3al Phase ◽  
Before And After ◽  
Kirkendall Voids

The study of composition and microstructure of welded joints was performed before and after the diffusion annealing at elevated temperatures for different annealing time. The Kirkendall effect in the Ni/Ni3Al diffusion couples was observed by means of different methods, e.g. using light, scanning electron and atomic force microscopies. The study suitably completes and specifies the morphology features of Kirkendall voids at different evolution stages, i.e. at nucleation, growing and coalescence. Kirkendall voids occurred in the region between the Matano and γ/γ´interface planes. The location of the γ/γ´ interface that moved in the direction of Ni3Al phase during the annealing resulted from the Al concentration profile measured by EDAX. The Matano plane location was determined by means of Boltzmann-Matano’s method using concentration profile data. It was observed that the void size was increasing in the direction from the Matano plane to the γ/γ´ interface. The obtained results were completed by surface topography of Kirkendall voids of slightly etched specimens by atomic force microscopy (AFM).

SELF-ASSEMBLED Ge-DOTS FOR Si SOLAR CELLS

2002 ◽  
Vol 16 (28n29) ◽  
pp. 4347-4351 ◽  
Author(s):  
H. PRESTING ◽  
J. KONLE ◽  
H. KIBBEL
Keyword(s):  
Solar Cells ◽  
Open Circuit Voltage ◽  
Elevated Temperatures ◽  
Growth Conditions ◽  
Open Circuit ◽  
3 Dimensional ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
P Type

Silicon solar cells with embedded germanium (Ge) layers deposited as 3-dimensional islands in the Stranski-Krastanov growth mode have been grown by molecular beam epitaxy (MBE) to enhance the efficiency of Si thin film solar cells. The Ge-layers increase the infrared absorption in the base of the cell to achieve higher photocurrent which should overcome the loss in the open circuit voltage due to incorporation of a smaller bandgap material in the heterostructure. Up to 75 layers of Ge, each about 8 monolayers (ML) thick, separated by Si-spacer layers (9-18nm) have been deposited at rather elevated temperatures (700°C) on a standard 10Ωcm p-type Si-substrate. Island densities of 1011 cm -2 have been achieved by use of antimony (Sb) as surfactant. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) were used to characterize the growth of Ge-islands under variuos growth conditions. Photocurrent measurements exhibit a higher photo-response in the infrared regime but a lower open circuit voltage of the fabricated solar cells compared to a Si-reference cell.

Thermal Stability and Analysis of Laser Deposited Platinum Films

2000 ◽  
Vol 624 ◽  
Author(s):  
G.J. Berry ◽  
J.A. Cairns ◽  
M.R. Davidson ◽  
Y.C. Fan ◽  
A.G. Fitzgerald ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Photoelectron Spectroscopy ◽  
Elevated Temperatures ◽  
Surface Composition ◽  
Direct Write ◽  
Force Microscopy ◽  
Annealing Conditions ◽  
Atomic Force ◽  
Transmission Electron ◽  
Induced Decomposition

ABSTRACTAs the trend towards device miniaturisation continues, surface effects and the thermal stability of metal deposits becomes increasingly important. We present here a study of the morphology and composition of platinum films, produced by the UV-induced decomposition of organometallic materials, under various annealing conditions. The surface composition of the metal deposits was studied by X-ray photoelectron spectroscopy, both as-deposited and following thermal treatment. In addition, the morphology of the surface was studied by atomic force microscopy which enabled the investigation of film restructuring. These studies were performed over a range of temperatures up to 1000°C in air and up to 600°C in reducing environments. Complementary information regarding the film morphology has been obtained from transmission electron microscopy. The data has been used to provide an insight into the effects of elevated temperatures on metal films deposited by a direct write method

Comparison of the Microstructure of AlN Films Grown by MOCVD and by PLD on Sapphire Substrates

1996 ◽  
Vol 449 ◽  
Author(s):  
Yun-Xin Li ◽  
Lourdes Salamanca-Riba ◽  
V. Talyan ◽  
T. Venkatesan ◽  
C. Wongchigul ◽  
...  
Keyword(s):  
Low Density ◽  
Full Width ◽  
High Crystalline Quality ◽  
Rocking Curve ◽  
X Ray ◽  
Force Microscopy ◽  
Sapphire Substrates ◽  
Atomic Force ◽  
Film Substrate ◽  
Microscopy Images

ABSTRACT(0001) aluminium nitride thin films were grown epitaxially on (0001) Sapphire substrates by MOCVD at 1200° C and PLD at 800° C. Both films have the same epitaxial growth relationship: (0001)AlN//(0001)Sap, and the same in-plane relationship which shows a 30° rotation between A1N and Sapphire: [ 12 10]AlN//[0 110]Sap and [10 10]AlN //[ 2110]Sap. The full width at half maximum (FWHM) of x-ray rocking curve of the MOCVD A1N film was 0.16° and PLD A1N film was 0.2°. Films grown by both MOCVD and PLD showed high crystalline quality. HRTEM images showed that these films are single crystalline with very low density of defects.Dislocations in the film parallel to the film / substrate interface were observed in both A1N films. Atomic force microscopy images showed that the MOCVD films have flatter and larger terraces than the PLD films. The PLD technique for A1N growth needs to be improved further. But both films have a surface roughness of approximately 100nm.

The Dynamics of Mgo Surface Faceting

1997 ◽  
Vol 3 (S2) ◽  
pp. 741-742
Author(s):  
Svetlana V. Yanina ◽  
Matthew T. Johnson ◽  
C. Barry Carter
Keyword(s):  
Elevated Temperatures ◽  
Film Growth ◽  
Heat Treatments ◽  
Santa Barbara ◽  
Contact Mode ◽  
Force Microscopy ◽  
Minimal Sample ◽  
Atomic Force ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

The {001} surface of magnesium oxide (MgO) has been the focus of numerous studies, which were prompted by the importance of MgO for its use as a substrate for thin film growth and also as a chemical catalyst. In the present work, atomic force microscopy (AFM) was used for studying the dynamics of surface processes of MgO which occur at elevated temperatures. AFM was chosen, in part, because it allows for imaging of topographical details at the atomic level with minimal sample preparation. Additionally, because the surface morphology of the same area was traced through a series of heat treatments, scanning electron microscopy analysis would be difficult because no conductive coating could be used (such a coating may have altered the surface between subsequent heat treatments).AFM images were recorded in contact mode, in air, on a Nanoscope III (Digital instruments, Santa Barbara, CA) using Si3N4 cantilevers (Ultralevers, Park Inst., Sunnyvale, CA) with a nominal applied force of 10-15 nN.

Interface structure and formation between gold and trimethylcyclohexane polycarbonate

1999 ◽  
Vol 14 (9) ◽  
pp. 3538-3543 ◽  
Author(s):  
C. v. Bechtolsheim ◽  
V. Zaporojtchenko ◽  
F. Faupel
Keyword(s):  
Photoelectron Spectroscopy ◽  
Elevated Temperatures ◽  
Cluster Formation ◽  
Systematic Investigation ◽  
Temperature Dependent ◽  
Cross Sectional ◽  
Force Microscopy ◽  
Metal Diffusion ◽  
Atomic Force ◽  
Transmission Electron

This paper presents the results of a systematic investigation of structure and formation of the interface between gold and trimethylcyclohexane polycarbonate, particularly concerning interface evolvement during gold evaporation and the influence of evaporation rate, substrate temperature, and subsequent annealing. The means of investigation were cross-sectional transmission electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy. Extensive metal diffusion into the polymer and cluster formation near the interface were observed at deposition rates of the order of one monolayer per minute and below. The penetration depth is strongly temperature dependent. At high evaporation rates metal aggregation at the surface prevents cluster formation inside the polymer. No diffusion into the polymer was observed from metal films deposited at room temperature after extensive annealing at elevated temperatures.

Amorphous SIC-N Coatings: Its Properties and Applications

1994 ◽  
Vol 356 ◽  
Author(s):  
Andrew L. Yee ◽  
Hockchun Ong ◽  
Fulin Xiong ◽  
R. P. H. Chang
Keyword(s):  
Optical Properties ◽  
Film Deposition ◽  
Film Stress ◽  
Force Microscopy ◽  
Wave Measurements ◽  
Substrate Adhesion ◽  
Atomic Force ◽  
Film Substrate ◽  
Pull Testing ◽  
Amorphous Sic

AbstractLaser ablation has been used to deposit a:SiC-N films from a CVD SiC target. Depositions were carried out either in vacuum or in a nitrogen ambient ranging from 10 to 100 mT. The mechanical properties of the films versus nitrogen background pressure were assessed using nanoindentation and surface acoustic wave measurements. Deflected optical beam testing, pull testing and atomic force microscopy were used to determine film stress, film-substrate adhesion and film roughness, respectively. The optical properties were also characterized as a function of nitrogen back pressure using spectroscopic ellipsometry which determined refractive indices and predicted film compositions. Fourier transform infrared spectroscopy determined the bonding structures in the films, and finally Rutherford backscattering spectroscopy measurements were also performed. Based on the best mechanical and optical properties, the optimum film deposition conditions were obtained. It was observed that with an increase in nitrogen background pressure, oxygen content in the film, in the form of SiOx, increased significantly affecting the overall properties of the a:SiC-N films.

Epitaxial growth of PbTiO3 thin films on (001) SrTiO3 from solution precursors

1995 ◽  
Vol 10 (3) ◽  
pp. 680-691 ◽  
Author(s):  
Andreas Seifert ◽  
Fred F. Lange ◽  
James S. Speck
Keyword(s):  
Thin Films ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
Amorphous Precursor ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Heat Treated ◽  
Film Substrate

A mixed alkoxide liquid precursor was used to form epitaxial PbTiO3 thin films by spin-coating on cubic (001) SrTiO3 substrates. The films were heat-treated at temperatures between 380 °C/1 h and 800 °C/1 h. X-ray diffraction, atomic force microscopy, scanning and transmission electron microscopy were used to characterize the microstructure of the films and to evaluate the epitaxial phenomena. At ∼400 °C/1 h, a polycrystalline, metastable Pb-Ti fluorite crystallizes from the pyrolyzed amorphous precursor. At slightly higher temperatures (∼420 °C/1 h), the thermodynamically stable phase with the perovskite structure epitaxially nucleates at the film/substrate interface. A small number of epitaxial grains grow through the film toward the surface and consume the nanocrystalline fluorite grains. Coarsening of the perovskite grains leads to a reduction in mosaic spread during further heating. Pores, which concurrently coarsen with grain growth, produce a pitted surface as they disappear from within the film. At 800 °C/1 ha dense epitaxial PbTiO3 film with a smooth surface is observed. Parameters governing the formation of a- and c-domains are discussed as well as the small tilts of the domain axes away from the substrate normal.

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