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

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.

1992 ◽  
Vol 268 ◽  
Author(s):  
C. E. Kalnas ◽  
L. J. Parfitt ◽  
A. Mashayekhi ◽  
J. W. Jones ◽  
G. S. Was ◽  
...  

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.


1992 ◽  
Vol 273 ◽  
Author(s):  
A. Mashayekhi ◽  
L. Parfitt ◽  
C. Kalnas ◽  
J. W. Jones ◽  
G. S. Was ◽  
...  

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.


2002 ◽  
Vol 750 ◽  
Author(s):  
M. L. Klingenberg ◽  
J. D. Demaree ◽  
J. K. Hirvonen ◽  
R. Messier

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.


1995 ◽  
Vol 396 ◽  
Author(s):  
G. S. Was ◽  
J. W. Jones ◽  
L. Parfitt ◽  
C.E. Kalnas ◽  
M. Goldiner

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.


2000 ◽  
Vol 18 (4) ◽  
pp. 1567-1570 ◽  
Author(s):  
Yoshihisa Watanabe ◽  
Nobuaki Kitazawa ◽  
Yoshikazu Nakamura ◽  
Chunliang Li ◽  
Tohru Sekino ◽  
...  

1993 ◽  
Vol 316 ◽  
Author(s):  
M. G. Goldiner ◽  
G. S. Was ◽  
L. J. Parfitt ◽  
J. W. Jones

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.


2000 ◽  
Vol 647 ◽  
Author(s):  
Shuichi Miyabe ◽  
Toshiyuki Okawa ◽  
Nobuaki Kitazawa ◽  
Yoshihisa Watanabe ◽  
Yoshikazu Nakamura

AbstractAluminum nitride (AlN) thin films were prepared by ion-beam assisted deposition method, and the influence of the nitrogen ion beam energy on their microstructure and mechanical properties was studied by changing the ion beam energy from 0.1 to 1.5 keV. Films prepared with a low-energy ion beam show a columnar structure, while films prepared with a high-energy ion beam show a granular structure. The film hardness is found to decrease with increasing nitrogen ion beam energy. It is also found that the film hardness does not change drastically after annealing in nitrogen atmosphere at 500 °C, yielding the residual stress relaxation. It is proposed that the film hardness is dependent on the film microstructure, which can be controlled with the nitrogen ion beam energy, rather than the residual stress in the films.


1999 ◽  
Vol 17 (2) ◽  
pp. 603-607 ◽  
Author(s):  
Yoshihisa Watanabe ◽  
Shingo Uchiyama ◽  
Yoshikazu Nakamura ◽  
Chunlang Li ◽  
Tohru Sekino ◽  
...  

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Hongfei Shang ◽  
Jian Li ◽  
Tianmin Shao

TiN/Ta multilayer film with a modulation period of 5.6 nm and modulation ratio of 1 : 1 was produced by ion beam assisted deposition. Microstructure of the as-deposited TiN/Ta multilayer film was observed by transmission electron microscopy and mechanical properties were investigated. Residual stress in the TiN/Ta multilayer film was about 72% of that of a TiN monolayer film with equivalent thickness deposited under the same conditions. Partial residual stress was released in the Ta sublayers during deposition, which led to the decrease of the residual stress of the TiN/Ta multilayer film. Nanohardness (H) of the TiN/Ta multilayer film was 24 GPa, 14% higher than that of the TiN monolayer film. It is suggested that the increase of the nanohardness is due to the introduction of the Ta layers which restrained the growth of TiN crystal and led to the decrease of the grain size. A significant increase (3.5 times) of theH3/E2(Eelastic modulus) value indicated that the TiN/Ta multilayer film has higher elasticity than the TiN monolayer film. TheLc(critical load in nano-scratch test) value of the TiN monolayer film was 45 mN, which was far lower than that of the TiN/Ta multilayer film (around 75 mN). Results of the indentation test showed a higher fracture toughness of the TiN/Ta multilayer film than that of the TiN monolayer film. Results of differential scanning calorimetric (DSC) and thermo gravimetric analysis (TGA) indicate that the TiN/Ta multilayer film has better thermal stability than the TiN monolayer film.


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