Ion Beam Modification Of Materials Research Articles

Recent research progress in the field of ion beam modification of materials in the Department of Technical Physics at Peking University

离子束改性技术能够实现元素的掺杂、材料表面结构和形貌的调控，是一种清洁、高效的表面改性技术，并且已经成为表面物理研究中的独特技术。为了推动“双碳“目标的实现，北京大学技术物理系核技术应用团队将离子束改性技术与新能源材料、柔性光电材料和二维材料相结合，围绕高性能新能源材料的开发和结构改性机制开展了深入地研究，提出全新的材料改性策略，取得了原创性成果。团队针对摩擦起电材料、催化材料、碳基材料和纳米多孔材料，通过离子束辐照精确调控材料的微观结构，从而大幅度提高其宏观性能，制备出高性能新能源材料和器件，促进了新能源技术的发展，并揭示其内在机制，为新能源材料的制备提供了示范性工作，也为传统离子束技术应用开拓了新的领域。

Effect of chemical bonding on ionization of nanoscale carbon and DNA upon proton irradiation

The separation of positive and negative charges under ion irradiation leads to ionization of the material. This ionization mechanism is closely related to DNA or tissue damage during ion beam therapy, enhancement of plasma oscillations driven by high-energy particles and the ion beam material modification. Here, we explore the effect of chemical bonding on the initial physical stage of ionization of target materials by building material models with different bonding states and using real-time time-depended density functional theory. By building the double layer carbon nanotubes, self-assembly bilayer graphene and DNA double helix, and tracking the evolution of nonadiabatic energy transfer, electronic stopping power, atomic force and charge populations on an attosecond scale, we find that the occupied covalent bond can rapidly conduct the excited electrons and the π-π interaction between molecular layers effectively blocks the backflow of excited electron, resulting in the ionization. In particular, the H-bond transfers a small number of excited electrons and suppresses the charge oscillations during ionization, ultimately leading to the ebb-and-flow ionization mechanism in DNA molecule. These results provide an understanding of the ionization mechanism of materials under ion beam irradiation for ionization control in radiotherapy, ion beam material modification and plasmon-enhanced applications.

Electrostatic accelerator facilities and their applications at Peking University

<p indent="0mm">Electrostatic accelerators are powerful tools in many research fields, such as nuclear physics, materials science, and archaeology. Three electrostatic accelerators, the 1.7 MV tandem, the single stage Van de Graaff with a terminal voltage of 4.5 MV, and the EN tandem with a terminal voltage of 6 MV, were installed in 1980s and have been put into operation since the early 1990s at Peking University. The 1.7 MV tandem accelerator is equipped with a radio frequency charge exchange negative ion source and a cesium sputtering negative ion source, which can produce most of the ions from H to Au. It accelerates the ions to energies from several hundreds of keV to several MeV. The accelerator is used for ion irradiation, ion beam modification of materials, as well as ion beam analysis (IBA), such as Rutherford backscattering spectroscopy (RBS) and channeling. Many significant achievements have been made by using the ion irradiation beamline, especially in the research of nuclear materials. The superlattice steel containing a high density of B2-ordered Ni(Al, Fe) superlattice nanoprecipitates (NPs) was irradiated with <sc>6 MeV</sc> Au ions at different high temperatures. The superlattice steel exhibits extraordinary radiation tolerance, namely, zero void swelling at 400–600°C under an average radiation damage of up to <sc>2350 dpa,</sc> outperforming most of the other steels studied to date. This paper demonstrates a counterintuitive strategy to enhance the radiation resistance of metallic materials by simply ordered superlattice NPs. For the 4.5 MV electrostatic accelerator, the isotope ions of hydrogen or helium can be produced in the energy range of <sc>0.7–3.8 MeV,</sc> and continuous or pulsed quasi-monoenergetic neutron fields <sc>(0.03–7 MeV,</sc> <sc>14–19 MeV)</sc> can be generated by ion beam bombarding targets. The neutron fields have applied it to measure (n, α) reaction cross section. Based on the 4.5 MV electrostatic accelerator, a total-IBA system has been established. Total-IBA can obtain self-consistency results through analyzing spectra of different emission particles, without massive modification of equipment. RBS-nuclear reaction analysis (NRA)-particle-induced X-ray emission analysis (PIXE) integrated IBA experiment was carried out to study a Fe-based alloy. The incident particle is ³He⁺ under <sc>3.0 MeV.</sc> The integrated charge is obtained by fitting the RBS spectrum. The content and depth distribution of C element can be determined by analyzing the NRA spectrum. The signal of O element can also be observed in the NRA spectrum, and its depth distribution can be obtained by fitting RBS. More than ten trace elements are analyzed by PIXE, and P has the lowest content, which is <sc>158.2 ppm.</sc> The 6 MV EN tandem accelerator, which has supported much basic and application research at Peking University, was transferred from Oxford University, UK. It is suitable for accelerator mass spectrometry (AMS), ion irradiation and ion beam analysis. The accelerator can also be applied for detector calibration. CR-39 nuclear track detectors were irradiated by <sc>3–8 MeV</sc> mono-energetic protons and <sc>6–30 MeV</sc> mono-energetic carbon ions, which were produced by the 6 MV tandem accelerator. The relationships between particle energy and orbital diameter in CR-39 detectors are established. These data on CR-39 detectors will be useful for identifying reaction products in laser-plasma experiments with complex conditions. With the technique development such as modern ion beam analysis technology and multi-beam to one target, more attractive applications are expected.

Ion irradiation and modification: The role of coupled electronic and nuclear energy dissipation and subsequent nonequilibrium processes in materials

Understanding material responses to energy deposition from energetic charged particles is important for defect engineering, ion-beam processing, ion-beam analysis and modification, geologic aging, space exploration, and nuclear applications. As an incident ion penetrates a solid, its energy is transferred to electrons and to atomic nuclei of the solid. Much of this electronic energy deposition is subsequently transferred to the atomic structure via electron–phonon (e–ph) coupling, leading to local inelastic thermal spikes in which energy dissipation is influenced by the local environment. In addition, intense ionization can lead to high densities of localized electronic excitations in wide-bandgap materials and ceramics that can affect defect dynamics and atomic mobility. Specifically, energy exchange between electrons and atomic nuclei, along with localized electronic excitations, can lead to substantial competitive (ionization-induced annealing), additive (both electronic and nuclear energy depositions contributing to damage production), and synergistic (more damage than the sums of separate damage processes) effects. Although nonmonotonic effects of the e–ph coupling strength and athermal processes are demonstrated for pre-existing defects and residual damage during ion–solid interactions, there is limited understanding of when such electronic effects must be considered in atomic-scale models of damage production and evolution in a broad variety of materials. Complex ceramics and chemically disordered solid solution alloys with different constituent elements allow a systematic evaluation of defect dynamics and irradiation performance with increasing complexity. Current knowledge regarding tuning of bonding characteristics and chemical disorder to control atomic-level dynamics is reviewed. Although a lack of fundamental understanding obstructs the advancement of reliable predictions for ion beam material modification, it highlights challenges and opens research opportunities. Insights into the complex electronic and atomic correlations with extreme energy deposition will strengthen our ability to design materials and predict ion-irradiation-induced damage in a radiation environment, and they may pave the way to better control fundamental processes and design new material functionalities for advanced technologies.

An atomic force microscope integrated with a helium ion microscope for correlative nanoscale characterization

In this work, we report on the integration of an atomic force microscope (AFM) into a helium ion microscope (HIM). The HIM is a powerful instrument, capable of imaging and machining of nanoscale structures with sub-nanometer resolution, while the AFM is a well-established versatile tool for multiparametric nanoscale characterization. Combining the two techniques opens the way for unprecedented in situ correlative analysis at the nanoscale. Nanomachining and analysis can be performed without contamination of the sample and environmental changes between processing steps. The practicality of the resulting tool lies in the complementarity of the two techniques. The AFM offers not only true 3D topography maps, something the HIM can only provide in an indirect way, but also allows for nanomechanical property mapping, as well as for electrical and magnetic characterization of the sample after focused ion beam materials modification with the HIM. The experimental setup is described and evaluated through a series of correlative experiments, demonstrating the feasibility of the integration.

Inductance Investigation of YBa2Cu3O7−δNano-Slit SQUIDs Fabricated With a Focused Helium Ion Beam

Focused helium ion beam material modification is ideally suited for the fabrication of YBa2Cu3O7−δ (YBCO) Josephson junctions and superconducting feature sizes down to the nanoscale. We report the fabrication and measurement of YBCO nano-slit SQUIDs and study how scaling the dimensions of the SQUID body and electrodes influences the electrical properties. Sixteen nano-slit SQUIDs with different width and length were fabricated from a single-layer 25-nm-thick YBCO film. The experimental results yield an estimation of the sheet inductance to be ∼4 pH/□ and a penetration depth of ∼180 nm. The temperature dependence of the inductance agree well with an impurity scattering model, indicating that the T C of the film was ∼82 K, and the ratio between geometric inductance and kinetic inductance at 0 K was ∼0.8. These results provide solid basis for the design of high-performance, high- T C micro-SQUID magnetometers.

Status of Ion Beam Modification and Analysis of Materials at STU MTF

Abstract The new Ion Beam Centre (IBC) equipped with 6 MV tandem ion accelerator and 500 kV ion implanter systems was built at the Slovak University of Technology, Faculty of Materials Science and Technology (STU MTF). The facility provides Ion Beam Modification of Materials (IBMM) and Ion Beam Analysis (IBA), which includes Rutherford Backscattering Spectrometry (RBS), Particle Induced X-ray Analysis (PIXE), Elastic Recoil Spectrometry (ERDA) and Nuclear Reaction Analysis (NRA). Presented are selected experimental procedures carried out in the IBC during the first year of operation. They present examples of a typical IBA performed, such as thin film characterisation in nm to tens of µm range, elemental depth profiles and sensitivity to the light elements enhancement by non-Rutherford cross-section regime application along with the crystalline sample channelling spectra and boron content measurement.

A new ion-beam laboratory for materials research at the Slovak University of Technology

An ion beam laboratory (IBL) for materials research has been commissioned recently at the Slovak University of Technology within the University Science Park CAMBO located in Trnava. The facility will support research in the field of materials science, physical engineering and nanotechnology. Ion-beam materials modification (IBMM) as well as ion-beam analysis (IBA) are covered and deliverable ion energies are in the range from tens of keV up to tens of MeV. Two systems have been put into operation. First, a high current version of the HVEE 6MV Tandetron electrostatic tandem accelerator with duoplasmatron and cesium sputtering ion sources, equipped with two end-stations: a high-energy ion implantation and IBA end-station which includes RBS, PIXE and ERDA analytical systems. Second, a 500kV implanter equipped with a Bernas type ion source and two experimental wafer processing end-stations. The facility itself, operational experience and first IBMM and IBA experiments are presented together with near-future plans and ongoing development of the IBL.

Wide area scanning system and carbon microbeams at the external microbeam facility of the INFN LABEC laboratory in Florence

Recently, developments have been made to the external scanning microbeam of INFN-LABEC laboratory in Florence. A new system for mechanical sample scanning was implemented. This system allows us to acquire large maps (up to 20×20cm2), of great interest in the Cultural Heritage field.In parallel, the possibility of using carbon microbeams for experiments, such as, for example, ion beam modification of materials and MeV Secondary Ion Mass Spectrometry, has been investigated.As a test application, Particle Induced X-ray Emission with carbon microbeams has been performed on a lapis lazuli stone.First results for both wide area imaging and external carbon microbeams are briefly reported.

Modification, Synthesis, and Analysis of Advanced Materials Using Ion Beam Techniques

Energetic ion beams are employed for the synthesis, modification, and analysis of advanced, technologically important materials, and many novel applications have emerged over the past several decades. The evolution of the field over this period is recorded in a broad range of conferences that are dedicated to particular aspects of ion-beam modification or analysis of materials, including international conferences on ion beam modification of materials (IBMM), ion beam analysis (IBA), surface modification of materials by ion beams (SMMIB), and so forth. This special issue aims to present some of the latest results in the field.

Xenon nano-beams for materials research

The advantage of focused Xe+ beams over other rare gas species have been investigated [Zhukov, V.; Kalbitzer, S. Russ. Microelectron. 2011, 40(1), 17–24]. In particular, the higher operation temperature of a super-tip gas field ion source for xenon ions is one outstanding technical feature. The properties of focused Xe+ beams are estimated with special reference to optimised ion-optical transport systems. Applications to both ion beam materials modification and ion beam materials analysis are outlined.

Thirtieth Anniversary of Biannual International Conference on Ion Beam Modification of Materials, IBMM – From “Ion Implantation” to “Ion Beam Modification”

A review is given on the start and early years of the biannual conferences ‘Ion Beam Modification of Materials’ (IBMM), on the thirtieth anniversary of the meeting held in Budapest, 1978. Organizers of this first IBMM conference decided to broaden the scope of the previous few conferences on ion implantation to embrace side effects, like ion beam mixing, etc. also by giving a new name. The start was not free from influence of politics of the times. The scientific success, however, gave enough ammunition for the coming times to IBMM, mainly through continuous support of leading scientists of the field. Thus, it became the most important forum of studies of basics of ion beam processes. Numerous references illustrate the start and the early topics dealt with at the meetings.

Supporting routines for the SRIM code

The SRIM code is used for calculating physical quantities related to ion-beam modification of materials. This paper presents supporting routines for the SRIM code, that improve its validity, precision, and ease of use of, make a link to the formalisms used in ion-optics and generally broaden its application potential. Several routines have been merged into a single software package S3M – SRIM Supporting Software Modules. S3M enables the user to calculate beams traversing thin targets, to run SRIM with finite-emittance beams and to simulate beam-transport with scattering and collimation. It has been successfully tested and used for the simulation of beam-transport channels and ion-implantation.

Multiple ion beam irradiation and implantation: JANNUS project

JANNUS (Joint Accelerators for Nano-Science and Nuclear Simulation) is a project designed to study the modification of materials using multiple ion beams and in-situ TEM observation. It will be a unique facility in Europe for the study of irradiation effects and ion beam modification of materials, the simulation of damage due to irradiation and in particular of combined effects. The project is also intended to bring together experimental and modelling teams for a mutual fertilisation of their activities. It will also contribute to the teaching of particle-matter interactions and their applications. JANNUS will be composed of three accelerators with a common experimental chamber and of two accelerators coupled to a TEM.

587 Development of proximity based assay to detect and quantify erbB (or Her) receptor dimerization in formalin fixed-paraffin embedded tissue sections

An ion beam laboratory (IBL) for materials research has been commissioned recently at the Slovak University of Technology within the University Science Park CAMBO located in Trnava. The facility will support research in the field of materials science, physical engineering and nanotechnology. Ion-beam materials modification (IBMM) as well as ion-beam analysis (IBA) are covered and deliverable ion energies are in the range from tens of keV up to tens of MeV. Two systems have been put into operation. First, a high current version of the HVEE 6 MV Tandetron electrostatic tandem accelerator with duoplasmatron and cesium sputtering ion sources, equipped with two end-stations: a high-energy ion implantation and IBA end-station which includes RBS, PIXE and ERDA analytical systems. Second, a 500 kV implanter equipped with a Bernas type ion source and two experimental wafer processing end-stations. The facility itself, operational experience and first IBMM and IBA experiments are presented together with near-future plans and ongoing development of the IBL.

The thermodynamical process in metal surface due to the irradiation of intense pulsed ion beam

In this paper, a new simulation model of interactions between IPIB and target material was constructed, that is T-coupled fluid elastoplastic equations, considering thermal conduction of target materials. The calculation program steipib was written with C ++ language. Meantime the distributions of energy deposition of intense pulsed ion beam (IPIB) with the energy and time spectrum were studied carefully as pulsed heat sources. As the results of the thermodynamical simulation calculation for the distributions of temperature and its gradient, stresses near the surface layer, the generation and propagation of shocks and so on are given. Also important influences of pulse parameters of IPIB on the ion beam modification of materials are discussed. The radical factor, leading to surface modification by energy impinging of IPIB, is the high power density of IPIB or the high absorption power density of the target. Moreover, the energy-based modification mechanism with the main characteristics of the flash heating and the long-range interaction was explained. Especially, the strengthening effects at the backside of the thin target under the influence of some shock were predicted and proved experimentally.

High-current pulse sources of broad beams of gas and metal ions for surface treatment

This paper reviews the experimental study, development, and improvement of various types of processing ion sources undertaken in association with the joint program performed in recent years by the Institute of Electrophysics and the Institute of High-Current Electronics of the Russian Academy of Sciences. The beam parameters (type and energy of ions, current density, cross-sectional area of the beam, permissible content of impurities, etc.) should meet the requirements of particular ion beam treatment conditions, while the ion source itself should be simple and reliable in operation. Technical and service characteristics of the developed ion sources permit their use for ion-beam modification of materials, preparation of surfaces and ion-assisted deposition of thin films, and in some other applications. The sources under consideration employ high-current glow discharges with a hollow cathode or in crossed electric and magnetic fields, and low-pressure arc discharges and vacuum arc. Cold cathodes enhance reliability of the ion sources when they work at a high residual gas pressure or in the reactive gas media. The repetitive pulse mode of the plasma and beam generation provides optimum conditions for stable operation of the discharge, control of the average beam current over a wide range, and formation of homogeneous large-cross-section beams. The paper describes techniques used to realize high-current discharges at a reduced pressure, methods for producing a stable, dense and homogeneous plasma in a large volume, techniques of formation of large-cross-section homogeneous beams, and also findings on the mass-charge composition of the plasma and beams produced. Some design versions of the sources are given. At voltages from 10 to 100 kV, the pulse duration of 10 to 1000 μs, and the pulse repetition rate of 1 to 500 Hz these sources provide the current density of ∼1–10 mA/cm 2 in beams having the cross-sectional area of a few hundreds of square centimeters. The achieved parameters of the sources permit their use both in commercial and research applications. The use of these sources for modification of surface properties of materials has been exemplified.

Relaxation of metals: A model based on MD calculations

The relaxation processes of copper associated with the presence of point defects such as vacancies and interstitials, have been analysed via Molecular Dynamics (MD). The accommodation of the atoms in the lattice is due to a tension field which arises from the presence of the above mentioned defects. These tension fields are calculated and expressed in terms of the effective displacement volume associated with the corresponding defect. Two main conclusions are: First, the finiteness of the tension fields, in contradiction with usual relaxation models applied in solving problems related to atomic mixing. Second, the relaxation process may be considered on average as isotropic except for very near to the surface, where the process is markedly anisotropic due to the surface itself. These results are summarised by means of an analytical expression, applicable in studies of solid relaxation and in other related problems of ion beam modification of materials.

Ion sources for ion implantation and ion beam modification of materials (invited)

Industrial applications of ion beams began in the 1970s with their application in fabrication of semiconductor devices. Since electronic characteristics of semiconductors are very sensitive to the amount of doped elements and to the species, the ion beams should be precisely mass separated. Nowadays, ion implantation is expected to be used for surface modification of materials. For this the needed beam purity is lower, but the needed dose is higher, since mechanical and/or chemical characteristics of materials, which are less sensitive to the dose, should be improved rather than electronic ones. Mass resolution by a separator may be lowered to allow mixing of some neighboring elements and in some cases mass separation may be completely eliminated. Many ion sources have been developed for such applications; however, most were used for research work. In this paper, some of the typical ion sources are reviewed from the viewpoint of future industrial use.

X-ray, XTEM and RBS analysis of recrystallized ion beam amorphized CVD Si

Ion beam modification of materials has been used for the formation of high quality single-crystal silicon (c-Si) over oxide, for high speed CMOS device applications. In the lateral solid phase epitaxy (LSPE) technique, thin c-Si layers (typically 300 nm) are formed by ion beam amorphization of a low pressure chemical vapor deposited (LPCVD) polysilicon layer over an oxidized Si wafer in which seed windows have been opened in the oxide. A c-Si layer is formed by LSPE from the single-crystal substrate up and over the thermal oxide adjacent to the oxide window for distances of up to 4 μm beyond the window boundary. We have obtained high quality 〈100〉 single-crystal silicon by conversion of polycrystalline LPCVD-Si, using rapid thermal annealing (RTA) followed by ion implantation amorphization and subsequent thermal recrystallization. Amorphization of LPCVD deposited poly-Si to a depth of 300 nm is achieved by LN 2 temperature implants of 5 × 10 14 cm −2 28Si + at 80 and 230 keV each. The crystallinity upon thermally induced recrystallization is evaluated by X-ray rocking curves, X-ray Read camera, RBS and cross-sectional transmission electron muscopy (XTEM).