Epitaxial Ni films were grown on Si(111) substrates to a thickness of about 500 nm by ion beam assisted deposition at room temperature. The films were grown using 25-keV-Ni ions and electron-beam evaporation of Ni at a relative arrival ratio of one ion for every 100 Ni vapor atoms. The ion beam and evaporant flux were both incident at 45° to the sample surface. Standard θ-2θ X-ray diffraction scans revealed the extent of crystallographic texture, while Ni {220} pole figure measurements identified the azimuthal orientation of Ni in the plane of the film. Films grown without the ion beam consisted of nearly randomly oriented fine grains of Ni whereas with bombardment the Ni (111) plane was found parallel to the Si (111) plane. In all the epitaxial cases the Ni [110] direction was perpendicular to the axis of the ion beam, suggesting that the azimuthal orientation of the film was determined by channeling of the ion beam down {110} planar channels in the Ni film. Additional experiments with different ions, energies, and substrates revealed their influence on the degree of epitaxy obtained.

Ge films have been grown by ion-assisted deposition on Si(100) substrates. Initial studies were conducted to determine the growth and morphology of Ge using a modified crucible arrangement and ionization chamber. It was observed that a narrow substrate temperature range existed for the deposition of smooth Ge films without ion assistance. Ionization and acceleration appear to induce additional damage to the film without improving crystalline quality.

The Microwave Multipolar Plasma (MMP) offers unique features for plasma assisted deposition by combining multipolar magnetic confinement and microwave excitation. Independent control of the plasma-surface interaction parameters (neutral flux, ion flux and ion impact energy) has led to low temperature (400–800°C) silicon epitaxial growth in pure or H2 diluted silane MMPs.

Prior to the epitaxial growth of Si, a plasma cleaning is applied to remove 0 and C atoms contaminant from the substrate surface. Ar and H2 were tested on 2 and 4 inch, (100) oriented, silicon wafers loaded “as received” and heated at the deposition temperature. The cleaning is effective in both cases giving a pure Si Auger spectrum. However, a LEED signature is only observed when operating at very low bias of the sample (low energy ions) and the lower the substrate temperature, the lower the energy allowed to obtain a LEED pattern. The cleaning process is also checked and inspected by post-deposition analyses, including TEM, RBS, SIMS and Secco etch.

Various layer thicknesses were grown according to the characterization method. Specular epitaxial films are obtained for a large range of plasma and substrate parameters. The temperature may be as low as 400°C but the best results are obtained in the 600–700°C range. Interestingly, epitaxy is lost when the ion energy is increased. These results show a compromise between ion energy and substrate temperature. One needs to work at low ion energy to enhance the surface reaction while avoiding surface damage, but the temperature has to be sufficiently high to restructure the surface. Preliminary results on intentional doping reveal further potentialities of this low energy controlled interaction for low temperature plasma processing.

In situ observations of 1.5 MeV Xe+ ion irradiated Au films at room temperature and at 150°C reveal the evolution of grain growth: the average grain size increases by the mechanisms of grain boundary migration and grain coalescence.

Transmission electron microscopy (TEM) has been used to study the precipitation of inert gases (Ar, Kr and Xe) injected into Ni at room temperature. The nucleation and size distribution of precipitates were found to be insensitive to the type of inert gas atom but dependent on gas concentration (ion fluence). The precipitate density decreases and the sizes increases with increasing gas concentration. In all cases, the inert gases precipitate as solid fcc crystals with their axes aligned with those of the host Ni lattice. For the same inert gas concentration, the lattice parameter is larger for the higher atomic mass in accord with bulk results. The lattice parameter of each type of inert gas precipitate increases with increasing gas concentration owing to the pressure relaxation that accompanies precipitate growth. This results in melting of large precipitates in accord with the behavior of bulk quantities of the gases at low temperatures.

The interactions of deuterium (D) with oxygen in Cu and Au were examined using ion implantation, nuclear-reaction analysis, and transmission electron microscopy. In Cu, the reduction of Cu2O precipitates by D to produce D20 was shown to occur readily down to room temperature, at a rate limited by the transport of D to the oxides. The reverse process of D2O dissociation was characterized for the first time below the temperature range of steam blistering. The evolution of the Cu(D)-Cu2O-D2O system was shown to be predicted by a newly extended transport formalism encompassing phase changes, trapping, diffusion, and surface release. In Au, buried 0 sinks were used to measure the permeability of D at 573 and 373 K, thereby extending the range of measured permeabilities downward by about six orders or magnitude.

The effects of Ar post-bombardment on the dissolution and reprecipitation of carbonitrides present in implanted 1020 low carbon steel are investigated using conversion electron Mössbauer spectroscopy (CEMS). The results are compared with similar experiments where samples of the same steel were post-bombarded with He. The experimental data show that the Ar is more efficient in the dissolution of precipitates and also more efficient in the precipitate retention at 450 °C, for the same peak concentration.

Pure rolled iron foils 0.025 mm thick have been implanted at two different angles of incidence and at several different temperatures. The implantation dose in each case was 5×1017 atoms/cm2. Both implanted and unimplanted foils were analyzed by transmission x-ray diffraction. Foils implanted at 320 ± 5°C exhibit peaks that correspond to the formation of several different phases of iron-nitride crystals, as observed by other investigators.[ 1,2] No such formation takes place at an implantation temperature of-20°C. We have evidence that the orientation of the iron nitride crystals is correlated with the orientation of the iron crystals.

Polycrystalline niobium was implanted with 200, 100, and 50 keV carbon ions to create a uniform distribution of carbon over a thickness of about 0.25 μm. Samples implanted with calculated carbon content of 0.6, 1.9, 5.8, and 16 atomic percent were prepared, and the uniformity of the carbon distribution with depth was confirmed by Auger electron spectroscopy analysis. Glancing-angle X-ray diffraction analysis and transmission electron microscopy were used to characterize the phases and microstructures formed. The results indicated that no detectable second phases were present except on the surfaces where an amorphous phase and many particles were formed from contamination. Despite the low equilibrium solubility limit of carbon in Nb, we have created metastable solid solutions of Nb and C with carbon contents as high as 16 at.%.

In-situ electron irradiations at 200, 300, and 1000 keV have been performed on Ni2Al3 at 100 and 300 K. At low doses, the Ni2Al3 partially disorders to a B2 structure with a lattice parameter of 0.284 nm, close to that extrapolated for β-NiAl at 60 at.% Al, the Ni2Al3 composition. The electron dose required to disorder the Ni2Al3 decreased with increasing accelerating voltage and possibly with decreasing temperature. At high doses, precipitation of aluminum from the B2 matrix occurs, along with radiation-induced sputtering and radiation-induced segregation. Lattice parameter changes for the B2 structure observed during irradiation are explained in terms of the compositional dependence of the lattice parameter of β-NiAl. The B2 structure remains stable to a dose of 6 × 1028 electrons/m2, with no amorphization detected.

CuTi was irradiated with 1-MeV electrons and Kr+ ions simultaneously at temperatures from 10 to 423 K. Retardation of Kr+-induced amorphization was observed with simultaneous electron irradiation at 295 and 423 K. The retardation effect increased with increasing irradiation temperature and relative electron-to-Kr dose rate. In contrast, simultaneous irradiation below 100 K showed an additive effect of electron- and Kr+-induced amorphization. The results can be explained by the mobility point defects introduced by electron irradiation interacting with Kr+-induced displacement cascades.

1-MeV electron irradiation of hydrogenated Zr3Al (Zr3AlH0.96) at 10K is studied. A more than 20 fold reduction in the critical dose required for complete amorphization is observed for the hydrogenated specimen as compared to the un-hydrogenated Zr3Al under identical irradiation conditions.

The response of YBa2Cu3O7 and GdBa2Gu3O7 high temperature superconductors to particle irradiation is examined. Both ion and electron irradiations have been shown to first produce an orthorhombic-to-tetragonal transformation at relatively low doses followed by a tetragonal-to-amorphous transformation at doses roughly a factor of 10 higher. Analysis of the displacement stoichiometry that results from 120, 300, and 1000 keV electron irradiations, 400, and 500 keV O irradiations, and 300 keV helium irradiations indicate that the orthorhombic-to-tetragonal transformation is driven by O atom displacements either alone or in the presence of metal atom displacements and that the transformation to the amorphous phase is driven by displacements on the Y, Gd or other rare earth atom site.

In the last five years, the use of GeV heavy ions, such as those accelerated at GANIL, has lead to a breakthrough in the knowledge of the effects induced by the huge energy deposition which occurs during the slowing down of a swift heavy ion in matter.

The through-range microstructure of polycrystalline alumina has been examined by cross-section TEM following simultaneous implantation of 2.0 MeV Al+, 1.44 MeV O+, and 0.2 to 0.4 MeV He+ ions at room temperature to a dose of 3.1 keV/atom. The specimen remained crystalline following the irradiation, and four distinct radiation-induced defect features were observed: Network dislocations, dislocation loops, small cavities, and oblong clusters that may be aluminum colloids. The microstructure near the implanted ion region was qualitatively similar to that observed in irradiated regions far from the implanted zone.

Bulk SiC and Si3N4 have been implanted with Ti at room temperature, and subsequently vacuum heat treated between 800° and 1100°C. All specimens were backthinned by ion milling and examined in TEM. SiC becomes amorphous on implantion, and develops a fine dispersion of TiC precipitates up to 800°C. At 900°C recrystallization has begun, possibly nucleated by the TiC particles. Si3N4 shows fine TiN particles in an amorphous matrix even as implanted. This structure is retained up to 900°C. At 1000°C, regrowth of the Si3N4 apparently from the substrate begins, and the TiN particles also grow as large as 200nm.

Elastic scattering of protons with energies from 1.5 MeV to 2 MeV was used to determine the concentration of oxygen in Y-Ba-Cu-O compound, nitrogen in GaN films, and boron in B-Si glass and other materials. Proton scattering from light elements in this energy range exhibits non-Rutherford scattering cross section, which are enhanced by a factor of 3 to 6 or more relative to the Rutherford scattering cross sections. Thus the sensitivity for the light clement detection is considerably larger than that obtained by He ion scattering.

Quantitative analysis by proton scattering is discussed and compared with other methods.

A nuclear microprobe-forming system for the microscopic RBS/PIXE measurement of micro devices has been developed and installed at the Research Center for Extreme Materials, Osaka University. The use of precision quadrupole magnets and an objective collimator ensures a final spot size of less than 1μm.

The changes in friction and wear properties (i.e., tribology) of steels due to thin surface alloys formed by ion beams are surveyed, and considered in light of their microstructures. Amorphous alloys containing both Ti and C are found to give superior performance in comparison to alloys with N, B, C, P or Ti. All the amorphous layers reduce friction, but the duration of benefits and wear resistance at high loads vary with composition. By examining similar amorphous alloys with Ti alone or C alone, the critical roles played by each in resisting wear are demonstrated. Amorphous alloys with Ti and C appear to be quite hard.

Despite the advantages of laser processing for the production of wear resistant materials, laser surface melting results in tensile stresses because the melted layer shrinks during resolidification. These tensile stresses may lead to severe cracking of the material and to deleterious effects on the wear behaviour. Our basic idea presented in this paper is to convert the high tensile stresses in the laser melted surface into a compressive state after implantation. In general, neon implantation is not very effective in the reduction of wear rates. However, neon implantation into laser melted steel turns out to reduce the wear rate substantially.