Microstructure and Residual Stresses in Al2O3 Prepared by Ion Beam Assisted Deposition

1993 ◽  
Vol 316 ◽  
Author(s):  
M. G. Goldiner ◽  
G. S. Was ◽  
L. J. Parfitt ◽  
J. W. Jones
Keyword(s):  
Residual Stress ◽  
Ion Beam ◽  
Arrival Rate ◽  
Film Stress ◽  
Amorphous Phases ◽  
Alumina Films ◽  
Compressive Stresses ◽  
Ion Beam Assisted Deposition ◽  
Rapid Transition ◽  
Film Porosity

ABSTRACTAlumina films synthesized by ion beam assisted deposition (EBAD) were characterized in terms of their microstructure and residual stress. Normalized energy per deposited atom, En, ranged from 0 to 130 eV/atom. The microstructure of PVD films (En=0) is a mixture of crystalline (γ-Al2O3) and amorphous phases and IBAD films are amorphous. Density and stoichiometry vary between 2.6 and 3.1 g/cm3 and 1.3 and 1.6, respectively. Neither are dependent on either ion-to-atom arrival rate ratio, R, or En. The film porosity is in the form of small (4-6 nm) voids of density 1017 - 1018 cm-3. Bombarding gas is incorporated with 80% efficiency to levels of 4-5 at. %. A tensile residual stress of 0.3 GPa exists in PVD films. A rapid transition to high compressive stresses occurs with increased En, with a saturation of -0.4 GPa occurring at high En There is a strong correlation between gas incorporation and residual film stress. However, no existing models are capable of providing a quantitative explanation of the results.

Mechanical Properties and Residual Stresses in Oxide/Metal Multilayer Films Synthesized by Ion Beam Assisted Deposition

1993 ◽  
Vol 308 ◽  
Author(s):  
C. E. Kalnas ◽  
L. J. Parfitt ◽  
M. G. Goldiner ◽  
G. S. Was ◽  
J. W. Jones
Keyword(s):  
Residual Stress ◽  
Critical Strain ◽  
Ion Beam ◽  
Crack Density ◽  
Multilayer Films ◽  
Compressive Stresses ◽  
Ion Beam Assisted Deposition ◽  
Small Grains ◽  
Ductile Substrates ◽  
Metal Layers

ABSTRACTFilms of Al, Al2O3 and Al/Al2O3 microlaminates were formed by ion beam assisted deposition (IBAD) at R ratios from 0.0025 to 0.5 and film thicknesses between 150 and 2600 nm. Oxide films were amorphous while metal layers were crystalline with small grains and texture for both PVD and IBAD conditions. The average stress in the oxide film is tensile at R=0 and becomes compressive, saturating at approximately 15 eV/atom. The residual stress in the Al films is tensile over all R ratios and the stress in the microlaminate roughly follows a rule of mixtures. Deformation of ductile substrates on which films had been deposited revealed that the critical strain to fracture was strongly dependent on residual stress. Large compressive stresses in monolithic films produced by ion beam assisted deposition delayed the onset of crack initiation while the presence of multiple layers, in general, lowered the crack density at saturation, suggesting a possible ductilizing effect.

Residual Stress Control by Ion Beam Assisted Deposition

1995 ◽  
Vol 396 ◽  
Author(s):  
G. S. Was ◽  
J. W. Jones ◽  
L. Parfitt ◽  
C.E. Kalnas ◽  
M. Goldiner
Keyword(s):  
Residual Stress ◽  
Functional Dependence ◽  
Ion Beam ◽  
Arrival Rate ◽  
Gas Content ◽  
Metallic Films ◽  
Amorphous Films ◽  
Tensile Direction ◽  
Ion Beam Assisted Deposition ◽  
Wide Range

AbstractThe origin of residual stresses were studied in both crystalline metallic films and amorphous oxide films made by ion beam assisted deposition (IBAD). Monolithic films of AI2O3 were deposited during bombardment by Ne, Ar or Kr over a narrow range of energies, E, and a wide range of ion-to-atom arrival rate ratios, R and were characterized in terms of composition, thickness, density, crystallinity, microstructure and residual stress. The stress was a strong function of ion beam parameters and gas content and compares to the behavior of other amorphous compounds such as MoSix and WS12.2 With increasing normalized energy (eV/atom), residual stress in crystalline metallic films (Mo, W) increases in the tensile direction before reversing and becoming compressive at high normalized energy. The origin of the stress is most likely due to densification or interstitial generation. Residual stress in amorphous films (Al2O3, MoSix and WSi2.2) is initially tensile and monotonically decreases into the compressive region with increasing normalized energy. The amorphous films also incorporate substantially more gas than crystalline films and in the case of Al2O3 are characterized by a high density of voids. Stress due to gas pressure in existing voids explains neither the functional dependence on gas content nor the magnitude of the observed stress. A more likely explanation for the behavior of stress is gas incorporation into the matrix, where the amount of incorporated gas is controlled by trapping.

Synthesis of Al and Al2O3 Coatings by Ion Beam Assisted Deposition

1992 ◽  
Vol 268 ◽  
Author(s):  
C. E. Kalnas ◽  
L. J. Parfitt ◽  
A. Mashayekhi ◽  
J. W. Jones ◽  
G. S. Was ◽  
...  
Keyword(s):  
Physical Vapor Deposition ◽  
Ion Beam ◽  
Arrival Rate ◽  
Columnar Structure ◽  
Fiber Texture ◽  
Film Stress ◽  
A Value ◽  
Ion Beam Assisted Deposition ◽  
R Ratio ◽  
Columnar Grains

ABSTRACTFilms of Al and Al2O3 were formed by physical vapor deposition (PVD) and ion beam assisted deposition (IBAD) onto (100) Si, glass and graphite substrates. Ion to atom arrival rate (R) ratios for IBAD varied from 0.004 to 0.1 and film thicknesses varied from 150 to 1000 nm. The O/Al ratio of oxide films and the oxygen content of Al films decreased with increasing R ratio. Al incorporation into both types of films increased with R ratio up to a value of ∼4 at% at R=0.1. Al films were crystalline with a strong (111) fiber texture becoming more pronounced with increasing R ratio. Film morphology is characterized by large columnar grains at R=0, with a breakup of the columnar structure by R=0.04. Al2O3 films are amorphous under all deposition conditions. Average film stress for PVD Al2O3 films is tensile with a value of 0.68 GPa, becoming compressive at ∼1.3 eV/atom and saturating at a value of ∼-0.65 GPa at R=0.04. Indentation experiments of Al2O3/(100)Si with a 300 g Vickers indenter showed that the changes in crack length are consistent with a model in which the residual film stress is controlling.

Synthesis and Properties of Mo/MoSix Microlaminates Using Ion Beam Assisted Deposition

1992 ◽  
Vol 273 ◽  
Author(s):  
A. Mashayekhi ◽  
L. Parfitt ◽  
C. Kalnas ◽  
J. W. Jones ◽  
G. S. Was ◽  
...  
Keyword(s):  
Physical Vapor Deposition ◽  
Ion Beam ◽  
Arrival Rate ◽  
Fiber Texture ◽  
Film Stress ◽  
Stress Effect ◽  
Ion Beam Assisted Deposition ◽  
Maximum Value ◽  
R Ratio ◽  
Residual Stress Effect

ABSTRACTFilms of Mo, MoSix and Mo/MoSix (1.22<x<1.35) multilayers were formed by physical vapor deposition (PVD) and ion beam assisted deposition (IBAD) onto (100) Si, glass and graphite substrates. Ion to atom arrival rate (R) ratios for IBAD varied from 0.01 to 0.1 and film thicknesses varied from 200 to 1100 nm. The Si/Mo ratio decreased with increasing R ratio. The oxygen content of Mo films was greater than silicide films, but both decreased substantially with increasing R ratio. Ar incorporation increased with increasing R ratio to a maximum of 1 at% in Mo and 5 at% in MoSi1.22. Mo films exhibit a strong (110) fiber texture at low R ratios. At the highest R ratio, a tilting of the (110) fiber texture by 15° occurs, along with the development of a distinct azimuthal texture indicative of planar channeling of the ion beam along (110) planes. The microstructure of the multilayer consists of small Mo grains and an amorphous silicide. Average film stress in Mo films increases from tension to a maximum value of 0.63 GPa and becomes compressive with increasing normalized energy. The stress in the MoSix films decreases with increasing normalized energy and saturates at a compressive stress of -0.24 GPa at 25 eV/atom. Indentation fracture experiments using a Vickers indenter with a 300 g load show a fracture behavior that is consistent with a residual stress effect for the IBAD monolithic MoSix and microlaminate, but which is influenced by additional factors in the PVD microlaminate.

Synthesis and Mechanical Properties of Niobium Films by Ion Beam Assisted Deposition

1996 ◽  
Vol 434 ◽  
Author(s):  
H. Ji ◽  
G. S. Was ◽  
J. W. Jones
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Physical Vapor Deposition ◽  
Incident Angle ◽  
Ion Beam ◽  
Arrival Rate ◽  
Fiber Texture ◽  
Ion Energy ◽  
Ion Beam Assisted Deposition ◽  
R Ratio

AbstractMechanical properties of niobium thin films are studied by controlling the microstructure, texture and residual stress of the films using ion beam assisted deposition (IBAD). Niobium films were deposited onto (100) Si substrates and their microstructure, texture and residual stress were measured as a function of ion energy and R ratio (ion to atom arrival rate ratio). The grain sizes of these films ranged from 20 nm to 40 nm and no effect of ion bombardment was observed. All the films have strong (110) fiber texture, but the in-plane texture is a strong function of the incident angle, energy and flux of the ion beam. Results show that while the degree of the texture increases with increasing ion energy and flux, it is also a strong linear function of the product of the two. The residual stress of the films was measured by a scanninglaser reflection technique. As a function of normalized energy, the stress is tensile for En < 30 eV/atom with a maximum of 400 MPa at about 15 eV/atom. It becomes compressive with increasing normalized energy and saturates at - 400 MPa for En > 50 eV/atom. Both PVD (physical vapor deposition) and IBAD films have a hardness of about 6 GPa at shallow depth measured by nanoindentation. The different stress state may be responsible for the 15%difference on hardness observed between the PVD and IBAD films.

Ion Energy/Momentum Effects During Ion Assisted Growth of NbXNY Films

2002 ◽  
Vol 750 ◽  
Author(s):  
M. L. Klingenberg ◽  
J. D. Demaree ◽  
J. K. Hirvonen ◽  
R. Messier
Keyword(s):  
Residual Stress ◽  
Total Energy ◽  
Momentum Transfer ◽  
Tribological Properties ◽  
Energy Deposition ◽  
Ion Beam ◽  
Film Stress ◽  
Ion Energy ◽  
Force Microscopy ◽  
R Ratio

ABSTRACTIn a previous paper, it was shown that the tribological properties of NbxNy thin films produced by ion beam assisted deposition (IBAD) depend strongly on the beam energy and the ion-to-atom (R) ratio. This study was designed to separate ion energy vs. ion momentum effects on film stress, crystalline phase, grain size, morphology, and composition, all of which influence the tribological properties of the films. Inert ion beams (Kr, Ar, and Ne) were used in conjunction with a nitrogen gas backfill to independently control ion energy and ion momentum transfer to NbxNy films. The ion species, energies, and R ratios were chosen to create a matrix of coatings that exhibited the same total energy deposition with different momentum transfer or the same momentum transfer but different total energy deposition. The resultant films were characterized using Rutherford Backscattering Spectroscopy (RBS), x-ray diffraction (XRD), atomic force microscopy (AFM), and residual stress analysis. Crystalline phases and texture, as well as residual stress, were more closely correlated with ion momentum transfer to the coating atoms than with overall ion energy input.

Composition and Phase Control for Molybdenum Nitride thin Films

1994 ◽  
Vol 354 ◽  
Author(s):  
Mandar S. Mudholkar ◽  
Levi T. Thompson
Keyword(s):  
Thin Films ◽  
Energy Density ◽  
Rutherford Backscattering Spectrometry ◽  
Ion Beam ◽  
Arrival Rate ◽  
Molybdenum Nitride ◽  
Effective Energy ◽  
Film Composition ◽  
Ion Beam Assisted Deposition ◽  
Molybdenum Nitrides

AbstractMolybdenum nitrides are active and selective hydrodenitrogenation (HDN) catalysts. The catalytic properties of molybdenum nitrides were found to be dependent on the structural properties. The purpose of research described in this paper was to synthesize molybdenum nitride thin films with well defined structures and stoichiometries using ion beam assisted deposition. The films were deposited by evaporating Mo metal, and simultaneously bombarding the growing film with low energy nitrogen ions. The phase constituents of the films were determined using x-ray diffraction and the film composition was obtained by Rutherford backscattering spectrometry.The film composition and phase constituents were strong functions of the ion-to-atom arrival rate ratio, ion energy and ion angle of incidence. Differences in the film composition for different arrival rate ratios and ion angles of incidence were interpreted based on reflection and sputtering effects. Our results suggest that phase formation was governed by the effective energy density per deposited atom. Evaluation of the effective energy density per deposited atom and its physical significance in ion beam assisted deposition is discussed.

Characteristics of Alumina Diffusion Barrier Films on Hastelloy

2004 ◽  
Vol 19 (4) ◽  
pp. 1175-1180 ◽  
Author(s):  
I. Usov ◽  
P. Arendt ◽  
L. Stan ◽  
DePaula R. ◽  
H. Wang ◽  
...  
Keyword(s):  
Ion Beam ◽  
Diffusion Mechanism ◽  
Barrier Films ◽  
Alumina Films ◽  
Ion Beam Assisted Deposition ◽  
Transmission Electron ◽  
Before And After ◽  
Wide Interface ◽  
Secondary Ion

The diffusion behavior of elements constituting Hastelloy C-276 (C, Si, Mn, Co, W, Fe, Cr, Mo, and Ni) in alumina films was investigated using secondary ion mass spectroscopy. The films were deposited by ion-beam-assisted deposition and annealed in vacuum over a temperature range of 500–1000 °C. Characterization of film microstructure was performed using transmission electron microscopy and selected area diffraction analyses. The films were predominantly amorphous with alumina nanocrystallites nonuniformly dispersed throughout the volume both before and after annealing. A relatively wide interface region between the Hastelloy substrate and alumina film was formed in the as-deposited sample due to ion beam mixing. No diffusion of any of the substrate elements was observed after annealing, except for Mn, Cr, and Ni. The impurity depth distributions consisted of two components, which differed by several orders of magnitude with respect to diffusion coefficient and solubility. Activation energies and temperature dependencies of the diffusion coefficients were determined, and a diffusion mechanism was discussed.

Mechanical properties and residual stress in AlN films prepared by ion beam assisted deposition

2000 ◽  
Vol 18 (4) ◽  
pp. 1567-1570 ◽  
Author(s):  
Yoshihisa Watanabe ◽  
Nobuaki Kitazawa ◽  
Yoshikazu Nakamura ◽  
Chunliang Li ◽  
Tohru Sekino ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Ion Beam ◽  
Ion Beam Assisted Deposition
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