Roles of ion irradiation for crystalline growth and internal stresses in nickel films onto silicon substrates prepared by the ion beam and vapor deposition method
01 Nov 1997-Journal of Vacuum Science and Technology (American Vacuum Society)-Vol. 15, Iss: 6, pp 3086-3092
TL;DR: The role of ion irradiation for crystalline growth and internal stresses in Ni films prepared by the ion beam and vapor deposition method was studied in this article, where Ni films were prepared on Si-100-wafers by evaporation of Ni metal and simultaneous irradiation with inert gas ions, Ne, Ar, Kr, and Xe The energies of inert gas ion were changed in the range of 5 −100 keV Transport ratios of vaporized Ni atoms to inert gas atoms to substrates were kept at 15 Ion beam current densities and ion irradiations directions were fixed
Abstract: The roles of ion irradiation for crystalline growth and internal stresses in Ni films prepared by the ion beam and vapor deposition method were studied Ni films were prepared on Si〈100〉 wafers by evaporation of Ni metal and simultaneous irradiation with inert gas ions, Ne, Ar, Kr, and Xe The energies of inert gas ions were changed in the range of 05–100 keV Transport ratios of vaporized Ni atoms to inert gas ions to substrates were kept at 15 Ion beam current densities and ion irradiation directions were fixed at 40 μA/cm2 and perpendicular to the substrate surface, respectively From the x-ray analyses, crystallinities and preferred orientation were changed by ion irradiation conditions On the other hand, internal stresses were also changed from compressive to tensile depending on ion energies and ion species It is understood that the variations of crystalline growth and internal stresses in Ni films were caused by the difference of nuclear and electronic energy transfer abilities of irradiating ionsThe roles of ion irradiation for crystalline growth and internal stresses in Ni films prepared by the ion beam and vapor deposition method were studied Ni films were prepared on Si〈100〉 wafers by evaporation of Ni metal and simultaneous irradiation with inert gas ions, Ne, Ar, Kr, and Xe The energies of inert gas ions were changed in the range of 05–100 keV Transport ratios of vaporized Ni atoms to inert gas ions to substrates were kept at 15 Ion beam current densities and ion irradiation directions were fixed at 40 μA/cm2 and perpendicular to the substrate surface, respectively From the x-ray analyses, crystallinities and preferred orientation were changed by ion irradiation conditions On the other hand, internal stresses were also changed from compressive to tensile depending on ion energies and ion species It is understood that the variations of crystalline growth and internal stresses in Ni films were caused by the difference of nuclear and electronic energy transfer abilities of irradiating
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TL;DR: In this paper, the origin of the preferred orientation (PO) of sputter-deposited nitrides is investigated in the context of surface diffusion and grain growth processes.
Abstract: Texture control of sputter-deposited nitride films has provoked a great deal of interest due to its technological importance. Despite extensive research, however, the reported results are scattered and discussions about the origin of preferred orientation (PO) are sometimes conflicting, and therefore controversial. The aim of this study is to acquire a clear perspective in order to discuss the origin of PO of sputter-deposited nitrides. Among nitrides, we focus on titanium nitride (TiN), aluminum nitride (AlN), and tantalum nitride (TaN), which are three commonly used nitrides. First, we collected reported experimental results about the relation between operating conditions and PO, because PO is considered to be determined by film formation processes, such as surface diffusion or grain growth, which is affected by operating conditions. We also collected reported results about such PO-determining processes. Then, we categorized the PO-determining processes into an initial stage and a growth stage of film d...
108 citations
TL;DR: In this article, the effects of ion irradiation during deposition on columnar growth of thin films prepared by ion-beam-assisted deposition were studied, and the experimental results showed that every Cr film had a columnar structure regardless of ion-irradiation conditions.
Abstract: The effects of ion irradiation during deposition on columnar growth of Cr thin films prepared by ion-beam-assisted deposition were studied. Cr films were prepared by evaporation of Cr metal and simultaneous irradiation of Ar ions onto Si 〈100〉 wafers. The energies of Ar ions were varied over the range of 0.5–20.0 keV, and the transport ratios of irradiating Ar ions to depositing Cr atoms, TR(Ar/Cr), to the substrates were also varied between 0.01 and 0.20. Vaporized Cr atoms were deposited onto substrates at an angle of 45° from the substrate normal and Ar ions were irradiated perpendicular to the substrate surface. Si substrates were not rotated and were kept at low temperature during deposition by a water-cooling system. The experimental results showed that every Cr film had a columnar structure regardless of ion-irradiation conditions. The column size became larger with increasing ion energy and TR(Ar/Cr). The growth direction of the column tilted considerably with increasing ion energy and TR(Ar/Cr) in the cases where the Ar-ion energy was 10.0 keV or less. On the other hand, the column growth direction became perpendicular to the substrate with increasing TR(Ar/Cr) in the case where the ion energy was 20.0 keV. The difference of column growth direction due to ion irradiation conditions could be understood by considering the preferential adatom movements as well as the shadowing effect.
17 citations
TL;DR: In this paper, the effect of the nitrogen ion beam energy on mechanical properties and residual stresses was studied by changing the ionbeam energy from 0.2 to 1.5 keV, resulting in a different film microstructure.
Abstract: Aluminum nitride (AlN) thin films were prepared by the ion beam assisted deposition method. The effect of the nitrogen ion beam energy on mechanical properties and residual stresses was studied by changing the ion beam energy from 0.2 to 1.5 keV, resulting in a different film microstructure. Mechanical properties were examined by a nano-indentation method and residual stresses were evaluated from the film curvature measured by an optical cantilever system. All of the films were found to be in a compressive stress state, the value of the stress decreasing with the ion beam energy. It was also observed that the films became soft and plastic with increasing ion beam energy. To study the effect of thermal treatment on the relaxation of residual stresses, films prepared with the ion beam energies of 0.2 and 1.5 keV, which show a columnar and a granular structure, respectively, were annealed in nitrogen at 500 °C. It was found that the granular structure film is relaxed more easily than the columnar structure film.
12 citations
TL;DR: In this paper, the influence of ion irradiation on morphologies and preferred orientations of thin films prepared by ion-beam and vapor deposition was studied, and the results showed that the preferred orientation to the substrate normal changes from random to 〈100〉 orientation with increasing of ion energy.
Abstract: The influences of ion irradiation on morphologies and preferred orientations of Cr thin films prepared by ion-beam and vapor deposition were studied. Cr films were prepared onto Si 〈100〉 wafers by evaporation of Cr and simultaneous irradiation with Ar ions. The energies of Ar ions were changed in the range of 0.5–20.0 keV, and transport ratios of irradiated Ar ions to vaporized Cr atoms, Ar/Cr, to the substrates were kept at 0.033. Vaporized Cr atoms were deposited onto substrates at an angle of 45° and Ar ions were irradiated normal to the substrates. Si substrates were kept at low temperature during deposition. The experimental results show that the morphologies and the preferred orientations were varied due to the change of ion irradiating energy though other conditions were constant. Every Cr film takes a clear columnar structure. The column widths of Cr films are augmented with increase of ion energy. The columnar growth direction turns toward the deposition direction with increase of ion energy up to 5.0 keV. With further increase of ion energy the direction changes to perpendicular to the substrate, parallel to the direction of the ion irradiation. The preferred orientation to the substrate normal changes from random to 〈100〉 orientation through 〈110〉 and 〈100〉 orientation with increasing of ion energy. The reasons were understood as the mixed effects of nuclear and electronic energy transfers due to the collisions between Cr atoms and irradiated Ar ions.
10 citations
TL;DR: In this article, the growth of epitaxial Co layers on Fe(001) by simultaneous thermal evaporation of Co atoms and ion bombardment with low-energy (300-1000 eV) Ar ions has been investigated for a wide range of ion/atom flux ratios (up to 0.5) and compared with growth by a purely thermal deposition procedure.
3 citations
References
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TL;DR: It is well known that metallic films deposited electrolytically are in many cases liable to peel off if deposited to any considerable thickness as discussed by the authors, especially if it does not adhere very tightly to the body on which it is deposited.
Abstract: It is well known that metallic films deposited electrolytically are in many cases liable to peel off if deposited to any considerable thickness. This is the case with nickel which, when deposited over a certain thickness, will curl up into beautiful close rolls, especially if it does not adhere very tightly to the body on which it is deposited. For example, if a piece of glass is silvered by any of the usual silvering solutions, and then nickel is deposited on the silver, it is found that the nickel and silver peel off the glass in close tight rolls almost at once. In ‘Practical Electro-Chemistry,' by Bertram Blount, reference is made on pp. 114 and 272 to the tendency of nickel to peel off, and it is stated that it “will peel—spontaneously and without assignable cause” (p. 272), but that a thick coating can be obtained by keeping the solution at between 50° and 90°C. The late Earl of Rosse tried, about 1865, to make flat mirrors by coating glass with silver chemically, and then electroplating with copper; but he found that, owing to the “contraction” of the copper film, it became detached from the glass. I have had the' same experience in protecting silver 61ms in searchlight reflectors by a film of electro-deposited copper, it being found that if the film of copper is more than 0.01 mm. thick peeling is apt to take place.
4,477 citations
TL;DR: In this paper, a generalized expression for ν has been derived for arbitrary orientations of cubic semiconductor crystals, and the variation of E, ν, and E/(1−ν) for directions within the important {111, {100, and {110} planes is examined.
Abstract: Theoretical estimates or experimental determinations of stress fields associated with semiconductor devices are generally simplified with the aid of two elastic constants, Young's modulus E and Poisson's ratio ν. In this paper, a generalized expression for ν has been derived for arbitrary orientations of cubic semiconductor crystals, and the variation of E, ν, and E/(1‐ν) for directions within the important {111}, {100}, and {110} planes is examined. The results show that isotropic elasticity theory is exact for all directions within {111} planes and that the composite elastic constant E/(1‐ν) which frequently occurs in problems of practical interest is also invariant for all directions within {100} planes. Numerical values for the various elastic constants are tabulated for GaAs, GaP, Si, and Ge.
1,106 citations
TL;DR: In this paper, it was shown that for a given temperature, the controlling factor in the resulting thin film phase is the momentum transferred into the film per depositing boron atom.
Abstract: Ion beam assisted evaporation was used to deposit cubic and hexagonal boron nitride thin films. Boron was evaporated and bombardment was by argon and nitrogen ions. The effect of preparation conditions on the resulting phase was studied, and the relationship between the phase and the energy and momentum transferred into the film through ion bombardment was examined. It is shown that for a given temperature, the controlling factor in the resulting thin film phase is the momentum transferred into the film per depositing boron atom. At 300–400 °C a sharp threshold value of momentum‐per‐atom exists below which films are hexagonal and above which they are cubic. For 400 °C this threshold occurred at 200 (eV×amu)1/2 which is equal to 3.3×10−21 m kg s−1. Depositions performed using krypton and xenon instead of argon as the second bombarding gas confirmed this momentum‐per‐atom value. A second threshold was also observed, which was bombarding species dependent, above which either complete resputtering of the deposited material or reversion to the hexagonal phase occurred. Cubic boron nitride deposition was seen to occur in a window of momentum‐per‐atom values between these two thresholds. Using this information it was possible to grow cubic boron nitride using only nitrogen bombardment, although the window of momentum‐per‐atom values for nitrogen is very narrow. The effect of substrate temperature was studied, and it was found to be difficult to grow predominantly cubic phase films below 300–400 °C. The relationship between intrinsic stress and phase of the films is also discussed. A diagram is presented showing film phase as a function of bombardment, substrate temperature, and system chemistry. The parameter of momentum‐per‐atom is shown to combine into a single value the variables of ion beam assisted deposition: deposition rate, ion energy, ion flux, and ion species. It is suggested that, in general, for properties affected by ion bombardment the momentum‐per‐atom transferred into the film is the controlling factor. The results are shown to support momentum transfer as the dominant process in cubic boron nitride thin film formation.
317 citations
TL;DR: In this paper, the properties of carbon nitride films were studied by x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrometry (FT‐IR), ultraviolet transmission spectrography, xray diffraction, and hardness measurements.
Abstract: Carbon nitride films with the composition ratio CR(C/N)=0.5–3.0 were prepared by the ion and vapor deposition method, where carbon was evaporated on various substrates while being simultaneously bombarded with 0.5–10.0 keV nitrogen ions. The properties of the films were studied by x‐ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrometry (FT‐IR), ultraviolet transmission spectroscopy, x‐ray diffraction, and hardness measurements. The films formed at energies lower than 0.8 keV and CR(C/N)=0.6–0.7 on tungsten carbide showed the highest Knoop harness of 6400 kgf/mm2 on films with 1 μm thickness and a maximum optical band gap of 2.7 eV. X‐ray diffraction measurements demonstrated that all films have an amorphous structure. The XPS and FT‐IR studies indicated that the peak newly observed at 286.3 eV in the C‐1s1/2 XPS spectra arises from triple bonding C≡N.
185 citations
TL;DR: In this article, Nitrogen-rich films of carbon nitride were prepared for the first time on silicon wafers and tungsten carbide plates by means of the ion-assisted dynamic mixing (or ion and vapor deposition, IVD) method.
Abstract: Nitrogen-rich films of carbon nitride were prepared for the first time on silicon wafers and tungsten carbide plates by means of the ion-assisted dynamic mixing (or ion and vapor deposition, IVD) method. The thickness of the films was 1.0 µm and the composition ratio, C/N, was changed from 0.2 to 2.0. The energy of nitrogen ions also varied from 200 eV to 20 keV. The structure of films was amorphous. The Knoop hardness of films grown on WC was about 6500 for the films with atomic ratio of composition lower than C/N=1.0 and prepared by means of 200 and 500 eV beams. This hardness of the present films with 1.0 µm thickness is never obtained in films of other materials. The X-ray photoelectron spectroscopy spectra of C-1s 1/2 electrons from these films showed a larger chemical shift (286.3 eV) than that of diamond (285.8 eV), which was observed for the first time.
152 citations