This work presents data on topographical structure, chemical surface composition, physicochemical properties and corrosion resistance of medical grade titanium after ion implantation. Pure commercial titanium has been implanted with 30 keV Na-, Ca- and P-ions at fluences of 2.0 × 1017 cm-2 and 1.5 × 1017 cm-2, respectively. Some of the samples were heat treated at 600 °C for 40 min. Atomic force microscopy (AFM) was used for surface analysis. The chemical composition was investigated using Rutherford backscattering spectrometry (RBS). Physicochemical investigations were carried out using contact angle measurements to determine the polarity of the modified titanium surfaces. Moreover, the electrokinetic zeta potentials on a physiological pH value have been determined. Finally, the corrosion resistance was examined in simulated body fluid (SBF) containing 4 g/l bovine serum albumin (BSA) using cyclic voltametry.

Considering the P-implantations, the measured depth distribution of phosphorus agrees well with calculations. For the implantation of Na and Ca, the concentration of implanted atoms in the maximum of the depth distribution is noticeably lower and the distribution extends to larger depths compared to the predictions. This finding is associated with a strong incorporation of oxygen over the whole penetration depth of the implanted ions. According to topographical and chemical changes different contact angles as well as zeta potentials have been detected for the ion implanted surfaces compared to pure titanium. The electrochemical examinations indicate that the implantation has no negative influence on the corrosion resistance in comparison to unmodified medical grade titanium. The results show that ion implantation using certain ions can be used to design tailor-made titanium surfaces from a physicochemical point of view.

Ag-SiO2 nanocomposite layers were synthesised by Ag+ implantation into thermally oxidised SiO2 layers and demonstrated to have excellent field emission (FE) properties. These nanocomposite layers can give an emission current of 1 nA at electric fields less than 20 V/μm, compared to several thousand volts per micrometre of pure metal surfaces. Their fabrication processes are fully compatible with existing integrated circuit technology. By correlating the FE results with other characterisation techniques including atomic force microscopy, Rutherford backscattering spectroscopy and transmission electron microscopy, it is clearly demonstrated that there are two types of field enhancement mechanisms responsible for the excellent FE properties of these cathodes. Firstly, the electrically conductive Ag nano-clusters embedded in the insulating SiO2 matrix give rise to a local electric field enhancement due to an electrical inhomogeneity effect and secondly, the dense surface protrusions provide a geometric local electric field enhancement. The FE properties of these layers are critically dependent on the size and distribution of the Ag clusters, which can be controlled by the Ag dose and modified by the post-implantation pulse annealing with a high power KrF Excimer laser operating at 248 nm.

Polyimide films are widely used in various industrial fields. Some typical products are flexible printed circuits (FPCs), flexible displays, and electronic papers. Good adhesion between metal thin films and polyimide films is required for their long lifetime. Ion beam irradiation to the polyimide films modifies the chemical compositions, the chemical states, and the surface nanomorphology. These modifications are potential techniques to improve the adhesion. In this study, the authors employed a linear ion source, which is able to irradiate ion beam on large surfaces homogeneously. The linear ion source is desirable for industrial usage because of its high productivity. The aim of this work was to investigate the effect of modification using the linear ion source. The chemical states of the interface were characterized using x-ray photoelectron spectroscopy (XPS). The surface nanomorphology was investigated by atomic force microscopy (AFM). The performance of the modification system will be discussed, and the characteristics of the modified polyimide will be investigated in detail.

Uniform keV ion irradiation causes a morphological instability known to result in the spontaneous formation of topographic ripple and dot patterns. The degree of order of these patterns, which has important implications for non-lithographic patterning applications, varies markedly with fabrication conditions. We investigate the influence of systematic variations of fabrication conditions, including current density, ion fluence and ion energy, on the degree of order of argon ion bombarded Si(111) surfaces. For quantifying order in sputter rippled topographic images, we develop an algorithm that evaluates the density of topological defects, such as ripple bifurcations and terminations, and suitably normalizes the result in order to present a scalar figure of merit: the normalized defect density. We discuss fabrication conditions that lead to extremely well ordered dot and ripple patterns upon irradiation.

To investigate the size-effect of reactive clusters on sputtering processes, we performed molecular dynamics (MD) simulations of reactive cluster ions with various sizes impacting on solid targets. Various sizes of fluorine clusters, (F2)30, (F2)300 and (F2)3000, were irradiated on a Si(100) target at the same total incident energy of 6 keV. These clusters were irradiated on the same target one after another in order to reproduce real experimental conditions such as the accumulation of fluorine atoms in the target. The MD simulations of sequential cluster impacts enabled to perform various statistical analyses regarding the sputtered particles. The study of cluster size distributions showed that the sputtering process by reactive cluster ion impact has similarity with the emission from quasi-liquid materials excited to hyper-thermal conditions by ion bombardment. However, the major sputtered particles were different with each other; Si for (F2)30 (100 eV/atom), SiF2 for (F2)300 (10 eV/atom), and SiF3 for (F2)3000 (1 eV/atom). At the impact of a large size cluster with low incident energy, a large number of Si-F bondings were generated at the cluster-target interface surface, which enhances formation of volatile SiFx compounds with many fluorine atoms. In contrast, a small cluster with high kinetic energy-per-atom could cause the formation of numerous energetic surface atoms at the near surface region, which could be sputtered without being well fluoridated.

The projects of a new generation of nuclear plants with improved yield and drastical reduction of waste production make necessary the development of materials able to withstand high temperature (1000-1200°C) in normal conditions. New materials such as the refractory transition metal carbides are then considered. These materials have a ceramic-like, brittle behaviour. Their mechanical properties might be improved by decreasing the particles size at a nanometer level. The behaviour under irradiation of such nano-sized materials have then to be compared with classical micro-sized ones. High density, nano-sized materials have been obtained by two different sintering techniques. In order to simulate neutron irradiation, the samples were irradiated with low energy heavy ions. Consequently, the damaged material has a low thickness (100-200 nm), requiring surface analysis methods. Here, the grazing incidence X-ray diffraction method is used. From a Rietveld analysis of the diffraction patterns, the micro-sized materials show a linear volume swelling in the range 20-40 dpa in the Zr sublattice. Nano- and micro-sized materials both show high internal distortions.

Carbon nanotubes (CNTs) are one of the possible building blocks for electronic devices in the transition phase from traditional silicon-based microelectronics towards the few-nanometer regime. Remaining problems in integrating CNTs to the existing technology is the low reactivity of the CNT walls which leads to low conductance between CNTs and the other components. Because recent studies have shown that ion irradiation can be used to modify both the electrical and structural properties of CNTs, we propose that it could also be possible to use ion irradiation with low energies to enhance the conductance of these connections. We have used classical molecular dynamics simulations with empirically fitted potentials to examine this possibility by irradiating a single-walled carbon nanotube (SWCNT) on a silicon substrate at room temperature. The nanotube was deposited over a trench created to the silicon substrate so that the nanotube was partly suspended. Low irradiation doses and low energies (0.2 keV − 1.2 keV) were used to ensure that the irradiated CNT will not be destroyed. The simulations were carried out for silicon, carbon and neon ions. Our simulations indicate that ion irradiation will increase the number of covalent bonds between the CNT and the Si substrate. When the irradiation dose and energies are low, the damage caused to the SWCNT atomic network can be tolerable when compared to the improvement in the conductance of the contact regions. Furthermore, as the CNTs have high ability to heal the irradiation-induced damage, it is possible that the irradiation will not have a significant negative effect to the conductivity of the CNT in a system of this type.

Single crystal germanium (Ge) surfaces were irradiated with 100 keV Ga ions at room temperature at doses up to 3×1017 cm-2 and were observed by a scanning electron microscope (SEM) and an atomic force microscope (AFM). It is found that the Ga-irradiated regions swelled and nano-porous structures were formed on the surface after the Ga irradiation up to a dose of about 2×1017 cm-2, but the region was etched by the Ga irradiation for larger doses. The atomic composition of the swelled and etched surfaces was investigated by an Auger electron spectroscopy (AES), but no Ga signal was observed, indicating that the precipitation of Ga did not influence on these characteristics of the Ga-irradiated Ge surfaces. To investigate the water resistance of such nano-porous structures, the sample was dipped in water up to 10 hours, and the surface was observed using SEM and AFM. It is found that the swelled structures were maintained, but the etched region formed by larger-dose irradiation was partially peeled off. This indicates that the nano-porous structures can be used under water environments as a functional surface, such as filters, and deep etching can be performed by larger dose irradiations and dipping the sample in water.

An overview of the present state of high energy focused ion beam (HEFIB) system technology, nanoprobe system design and specific ion beam writing applications will be presented. In particular, the combination of P-beam, heavy-ion writing and ion implantation to produce microstructures in resists and silicon will be demonstrated.

Heretofore, the development of HEFIB technology worldwide has progressed through a series of developments at independent research facilities, each having relatively narrow and mostly isolated, research purposes. However, a complete, versatile HEFIB nanoprobe system capable of both analysis and modification will require the combination of several component systems, each with specialized technology, and significant advances in the design of a complete system can only be expected from an effort that includes a coordinated development of the component parts.

Ge nanocrystals embedded in an amorphous SiO2 film on Si matrix were prepared by ion implantation and subsequent annealing. Neutron transmutation doping (NTD) technique was used for doping Ge nanocrystals with As impurities. The microstructure, phase and photoluminescence of NTDed Ge nanocrystals were analyzed and compared with undoped Ge nanocrystals. A new photoluminescence peak related to As impurities was found. It is discovered that impurities are expelled from larger clusters resulted from Ge nanocrystal aggregation on the sample surface. To prevent nanocrystal aggregation and assure uniform doping of As, it is necessary to adopt appropriate implantation and annealing conditions.

The redistribution of implanted Mn ions in Si after thermal annealing is studied. P-type Si wafers were implanted with 300-keV Mn+ ions at 350°C to a dose of 1×1015 cm-2, and then annealed at 800 °C for 5 min. Ferromagnetic hysteresis loops were obtained at 10 K using a SQUID magnetometer both before and after annealing. The saturation magnetization increases by ∼2 × after the post-implant annealing, while the Mn redistributes with sharp peaks in concentration. The calculated point-defect profile created during the implantation process peaks around the Mn-depleted region, suggesting that the residual implant damage may play a role in the ferromagnetic behavior of Mn-implanted Si.

IBIC ( Ion Beam Induced Charge ) represents a powerful method to investigate the homogeneity of the response of semiconductor nuclear detectors from the point of view of charge collection efficiency ( cce ) with a spatial resolution of few microns. Polycrystalline materials like CVD diamond displayed in the past non-uniform cce maps, in which it was easy to notice the appearance of single grains. Moreover, the presence of traps in the defective regions around the grain boundaries caused strong polarization effects which in practice impeded in many cases to get reasonable cce maps. With the availability of new homoepitaxially grown CVD diamond samples the situation is now very much improved : maps are very uniform and the non-homogeneous broadening of peaks with the consequent worsening of energy resolution is extremely reduced.

In this paper, both proton and alpha microbeams of energies 3 and 4.5 MeV were used for the investigation of single crystal CVD homoepitaxial diamond, with a beam diameter spot of about 1.2 mm over scanned areas of more than 1 mm2, sampled in regions of interest from 450 um × 450 um down to 150 um × 150 um and below. The good spatial homogeneity together with a cce value of about 50 % made it possible to reach energy resolutions of 1.3 % FWHM, including a not negligible electrical noise. These values compare quite well with Si performances, which in the same conditions reached 0.85% FWHM. The stability and reproducibility of the detector was very good without any preliminary priming and polarization effects were reduced to a minimum. The detector was pushed in some cases up to 700 cps with apparently no cce losses and with only a slight worsening of energy resolution.

Indium oxide doped with tin oxide, ITO, is extensively used to fabricate transparent conductive coatings. ITO thin film on flexible substrates has been used in applications including touch panel contacts, electrodes for LCD and Plasma displays. ITO thin film can be deposited onto polymer substrates using electron-beam evaporation. Surface modification of polymer substrate improves its superficial properties, adhesion in particular, to meet specific requirements while retaining the good mechanical properties of the substrates. In this study, a system consists of a linear ion beam and an electron beam which have been developed in vacuum. The linear ion beam treats the polymer surface while simultaneously the ITO thin film is deposited onto the surface using electron-beam evaporation. We demonstrated that polymer surface treated with the ion beam has been improved. Moreover, the linear ion beam source provides good uniformity of surface treatment and is very suitable for production-scale processes. An integrated electron-beam evaporation and linear ion beam system significantly increases the chemical compatibility of a polymer surface to an over-layer.

Magnesium oxide (MgO) film is commonly used as protecting layer for alternative current plasma display panels (AC-PDPs). Low energy ion induced secondary electron emission coefficient (γ) is one of the important factors to improve performance of AC-PDPs. The aim of this study is to prepare MgO films with high γ using ion beam assisted deposition (IBAD). The film composition, density, and crystal orientation were also investigated. The results suggest that MgO films with high γ can be obtained using IBAD. On the other hand, as the assisted ion beam energy increased to more than 500eV during deposition, (200)-oriented film with low γ grew preferentially and then the γ decreased.

The Ge condensation by oxidation of SiGe/Si-on-insulator (SOI) structures enabled highly stress relaxed SGOI. However, the relaxation rate obtained in the SiGe layers on insulator (SGOI) abruptly decreased with decreasing SiGe thickness below 50 nm. In order to enhance the relaxation rate in ultra-thin SGOI, the technique combined with H+ irradiation with medium dose (5×1015 cm-2) and post-annealing (1200°C) has been developed. It was demonstrated that highly relaxed (70 %) ultra-thin SGOI with low defect density (<106 cm-2) has been realized by this technique.

An antifuse structure was analyzed using scanning electron microscope imaging and focused ion beam image slicing to generate a form of three-dimensional microscopy. This method reveals nanometer scale features that could not be easily imaged using a single focused ion beam cross-section. A novel end-point detection technique has been developed to control the thickness of the slice to about 2 nm. Voxel imaging and interpretive three-dimensional reconstruction was used to resolve volumes as small as 2 cubic nm3. It was determined that the fusing region for an antifuse is a complex mixture of material phases with an elliptical volume approximately 75 nm in diameter.

Recently many groups have started studies of formation of zinc-oxide (ZnO) nanoparticle (NP) in transparent insulators, such as silica glass, sapphire, etc, using ion implantation techniques. In the early half of this article, we shortly review recent activities of ZnO NP formation using ion implantation combined with thermal oxidation. Some groups succeeded but the others did not. Even if they succeeded in the formation of ZnO nanostructures, one reported that they were in the shape of thin film and another reported the NP form. Based on our recent experimental results, we point out the importance of the oxidation temperature and the peculiar shapes and depth profiles of ZnO formed.

This work presents data on damage evolution, volume expansion and etching behavior of LiNbO3 irradiated with Ar+-ions as a function of irradiation and etching conditions. Single crystals of x- and z-cut LiNbO3 were irradiated at room temperature and 15 K using Ar-ions with energies between 60 and 600 keV and ion fluences between 5 × 1012 and 1 × 1015 cm-2. The damage formation investigated with RBS channeling analysis depends on the crystal cut as well as on the irradiation temperature. Irradiation of z-cut material at 300 K causes complete amorphization at 0.4 dpa (displacements per target atom). In contrast 0.27 dpa are sufficient to amorphize the x-cut LiNbO3. Irradiation at 15 K reduces the number of displacements per atom necessary for amorphization to 0.18 dpa. To study the etching behavior ∼500 nm thick amorphous layers were generated via multiple irradiations with Ar+-ions. Etching was performed in HF-solution of different concentration and at different temperatures. The influence of the irradiation and etching conditions on damage formation and etching of LiNbO3 is discussed. In conclusion, negligible etching of the perfect crystal, high etching rates and high contrast of Ion Beam Enhanced Etching (IBEE) allow the realization of high aspect ratio microstructures in LiNbO3.

In situ observations in a transmission electron microscope (TEM) were used to study ion-beam enhancement of second-phase precipitation in Zr-Fe nanocrystalline thin films. The free-standing films were prepared by co-sputter deposition with an Fe content of 1.2 at%. TEM diffraction analysis showed that only the hcp Zr crystal structure was present in the as-deposited films. No second phases were detected, although Rutherford Backscattering Spectroscopy (RBS) confirmed a Fe content beyond the solubility limit of Fe in Zr (of the order of ppm). This means the thin films were Zr solid solutions supersaturated with Fe. Heat treatment in the absence of irradiation was observed to cause precipitation of the Zr2Fe intermetallic phase, but only above 673 K. The same second-phase precipitation can occur at lower temperatures in the presence of ion irradiation. Samples were irradiated in-situ at the Intermediate Voltage Electron Microscope (IVEM) at Argonne National Laboratory with Kr ions to fluences in excess of 1016 ion/cm2, at temperatures ranging from 50 to 573 K. Second phase precipitation was detected by electron diffraction patterns and by dark field imaging comparing regions exposed to the beam with regions protected from the beam by the TEM support grid. Precipitation of Zr2Fe intermetallic phase was observed at all irradiating temperatures above room temperature. In the bulk, this phase is thermodynamically metastable in the range of temperatures investigated (relative to the orthorhombic Zr3Fe intermetallic phase). The kinetics of the irradiation-enhanced second-phase precipitation was followed by recording the diffraction patterns at regular intervals. The dose to precipitation was found to decrease with increasing irradiation temperature.

The application of nanocrystalline material for data-storage applications requires control over the in-plane and out –of-plane NanoCrystal (NC) orientation. In order to attempt to control the out-of-plane orientation of NCs introduced by the irradiation of Ni-P material with Ga+ ions, this processing has been completed upon material under tensile and compressive strains. The orientations of NCs nucleated have been compared to those introduced into the same material without the application of an external strain. Samples introduced under no external strain have previously been shown to be oriented with <111> parallel to the irradiated plane normal and <110> parallel to the irradiation direction. In this work, NCs nucleated under tensile strains in excess of ≈2 × 10-3 have been oriented with <112> parallel to the irradiated plane normal and <111> parallel to the applied stress direction, although <110> is still parallel to the irradiation direction. NCs formed under tensile strains lower than this critical value, as well as those formed under the compressive strain values tested, have been formed in the same orientation as those formed without the application of an external strain.