The feasibility of Al-based oxide precipitation in Fe–10%Cr alloy by ion implantation

This paper reports the feasibility of nano-oxide precipitate formation in Fe–Cr alloy by ion implantation synthesis. High contents of Al⁺ and O⁺ ions were implanted into thin films of high purity Fe–10%Cr alloy at room temperature and were studied by transmission electron microscopy (TEM) and atom probe tomography (APT). In contrast, to the common two-stage implantation/annealing scheme of precipitate ensemble synthesis by ion beams, cluster formation took place at the implantation stage in our study, requiring no subsequent high-temperature annealing. The post-implantation microstructural examination revealed in the as-implanted thin foil an array of precipitates with diameters in the range of 3–30?nm. The precipitate number density distribution was found to depend on the foil thickness. The precipitate enrichment with both Al and O was confirmed by the energy-filtered TEM analysis. Judging from the electron diffraction pattern and high-resolution TEM analysis, the crystal lattice of precipitates corresponds to some cubic modification of aluminium-rich oxide or pure aluminium oxide. The precipitate lattice alignment with the host matrix was revealed for at least a part of precipitates. The analysis of APT data using cluster detection algorithm indicates the presence of local zones enriched in Al and O, even in those areas of as-implanted samples where no clusters were visible by TEM.     

Ion implantation of Zn,Se and Cd in BP crystals

Ion implantation of 70 keV Zn, Se and Cd has been done in n-type BP as a function of dose and implantation temperature, and defects and lattice locations have been measured by means of channeling techniques. Crystals used were grown on Si substrates by vapor phase epitaxy. It was observed that epitaxial layers thicker than 6μm have no defects due to a lattice mismatch between Si and BP. High temperature implantation above 500°C gave high substitutional fraction of ～ 70% and low residual defects. Reordering of an amorphous layer formed by implantation below 400°C was not observed even after annealing at 900°C. The present results indicate that the effect of implantation temperature is the same with other III-V compounds such as GaAs and Gap.     

Formation,Dynamics, and Characterization of Nanostructures by Ion Beam Irradiation

Ion beam irradiation is a potential tool for phase formation and material modification as a non-equilibrium technique. Localized rise in temperature and ultra fast (～10^?12 s) dissipations of impinging energy make it an attractive tool for metastable phase formation. As a matter of fact, a major component of materials science is dominated by ion beam methods, either for synthesis of materials or for its characterization. The synthesis of nanostructures, and their modification by ion beam technique will be discussed in this review article. Formation of nanostructures using ion beam technique will be discussed first. Depending on species (e.g., mass and charge state) and energy range, there are various modes for an energetic ion to dissipate its energy. The role of the electron will also be covered in this article as a basic principle of its interaction with matter, which is same as for an ion. By using a simple reactive ion beam or electron induced deposition, a secondary phase can be nucleated by ion beam mixing techniques, either by using inert gas irradiation or reactive gas implantation on any desired substrate. Nucleation of secondary phase can also be executed by electron irradiation and direct implantation of either negative or positive ions. Post implantation annealing processes are required for the complete growth of clusters formed in most of these ion irradiation techniques. Implantation processes being inherently a non-equilibrium technique, defects always have a role to play in phase formation, amorphization, and beyond (blister formation). When implanted with large energy, even electrons, one of the lightest charged particles, also manifest these properties. Electronic and nuclear energy losses of the impinging charged particle play a crucial role in material modification. Doping a nanocluster, however, is still a controversial topic. Some light will be shed on this topic with a discussion of focused ion beam.     

Ion implantation in insulators

The modifications of insulating materials by ion implantation can be of considerable interest for many applications. If ion implantation has considerable potential for changing the properties of insulators, only a few experiments have determined the critical parameters which are important in the behaviour of the implanted layer. As a matter of fact, the ion implantation process is, by its very nature, a non-equilibrium process and, in addition, the injection of charged particles in a lattice determines a concomitant creation of intrinsic lattice defects. These defects are associated with the nuclear part of the energy loss of the particles and sometimes with the electronic one (halide compounds). The characterization of these intrinsic defects and the knowledge of their spatial distribution in the lattice are necessary because the formation or dissolution of phases precipitated in the implanted layer are strongly influenced by point or extended defects.

The main parameters which determine the charge state and site location of the implanted atoms in insulating targets are: ionicity of the chemical bond of the lattice, electronegativity, thermal or radiation enhanced diffusion processes, and intrinsic defects. For heavily implanted insulators, phase changes of compositional type can occur which can lead to strong modifications of the physical properties of the implanted layer. In order to obtain information on the relative extent of the critical parameters of chemical implantation in insulators it is necessary to combine analysis with different techniques such as, nuclear techniques, TEM, ESR, optical spectroscopy, X-ray diffraction at glancing angle, etc.

To illustrate the effects of these parameters, typical experimental results obtained in implanted binary or ternary compounds are reported (alkali halides, silver halides, alkaline earth oxides or fluorides, transition metal oxides, natural minerals, etc.).     

Formation and microstructural investigation of Ag-Cu alloy nanoclusters embedded in SiO2 formed by sequential ion implantation

We report on the formation of alloy nanoclusters in silica by Ag/Cu ion sequential implantation. The formation of alloy nanocluster has been evidenced by optical absorption spectra, selected area electron diffraction and energy dispersive X-ray spectra. The microstructure characters of nanoclusters have been studied by high resolution transmission electron microscopy. The lattice distortion of some nanoclusters has been observed. A model has been given to explain the distortion. Some defects (partial dislocation, stacking faults) have been found in nanoclusters.     

Structure of Ion-Implanted Alloys with Long-Range Order in a Field Ion Microscope

In the present review we describe the series of investigations in which field ion microscopy is used to study the structural and phase changes in alloys with long-range order and in pure metals after ion implantation by different gas ions. It is demonstrated that ion implantation induces defects of different types spread to considerable depths from the irradiated surface that exceed many times the estimated ion mean free path. It is established that disordering and generation of various defects can be observed under irradiation of the ordered alloy surfaces. In PdCuAg alloys being supersaturated solid solutions, the irradiation provokes the intermittent decomposition. The structure of defects induced by ion implantation including disordered regions, dislocations, dislocation configurations, dislocation barriers, vacancy clusters, and segregations of one of the components is analyzed. The structure and sizes of these defects inside single cascades of displacements are determined.     

正电子慢化体的研究和进展

正电子湮没技术是一种研究材料的微观缺陷和相变的灵敏工具,在通常的正电子谱仪中,正电子能量为MeV量级,在样品中注入深度比较学（－100μm）,主要研究材料体内的平均缺陷密度,慢正电子束方法把正电子的能量降低为keV量级（而且可以调节）,注入比较浅（－μm）,所以是研究表面缺陷的探测手段,正电子慢化体是产生慢正电子的关键设备,对其研究有重要意义,文章综述了慢化体研究的历史和现状,从物理概念出发介绍使正电子慢化的四种可能方法和当今慢化体的五种几何排列方法,其中应用最广泛的是钨慢化体和百叶窗式的排列方式,效率最高的是惰性气体固体慢化体,而加电场慢化体是有待开发的高效慢化体。     

Front-end process modeling in silicon

Front-end processing mostly deals with technologies associated to junction formation in semiconductor devices. Ion implantation and thermal anneal models are key to predict active dopant placement and activation. We review the main models involved in process simulation, including ion implantation, evolution of point and extended defects, amorphization and regrowth mechanisms, and dopant-defect interactions. Hierarchical simulation schemes, going from fundamental calculations to simplified models, are emphasized in this Colloquium. Although continuum modeling is the mainstream in the semiconductor industry, atomistic techniques are starting to play an important role in process simulation for devices with nanometer size features. We illustrate in some examples the use of atomistic modeling techniques to gain insight and provide clues for process optimization.     

Evolution of CoSi2 buried structures created by high temperature Co+ ion implantation into Si(1 0 0) during post-implantation annealing

The evolution of buried structures of cobalt disilicide, which are formed in a Si(1 0 0) matrix by 400 keV Co⁺ ion implantation at 875 K substrate temperature with subsequent rapid thermal annealing at 1275 K was studied by cross-sectional transmission electron microscopy (X-TEM). The analysis of identical samples with successive variations of the implanted doses and annealing times allows a detailed observation of the role of defects, created by the ion flux, on the process of ripening and growth of CoSi₂ precipitates. We found that transport of the implanted material along diffusive links leads to the formation of a secondary CoSi₂ distribution between the main layer and the surface. Post-implantation annealing results in the evolution of defects into dislocations, which affects the mobility and therefore the growth of CoSi₂ precipitates. Increasing the annealing time leads to the separate growth of precipitates in each layer. The result is not the formation of a single uniform buried layer because the distance between the individual layers is too large due to a screening effect, which operates during the ripening stage.     

用于材料表面改性的多功能等离子体浸没离子注入装置

详细叙述了新近研制的多功能等离子体浸没离子注入（ＰⅢ）装置，在装置设计中，考虑了等离子体产生手段、高压脉冲电源和真空抽气系统多项功能要求，把离子注入、涂敷和溅射沉积结合起来，该已实现了多种气体等离子体注入、气－固离子混合与注入、金属等离子体沉积与注入、离子束混合与离子束增强沉积等，以满足不同材料制成的不同零件对多种表面处理工艺的需要，初步应用结果证明，该装置对于改进４５号钢、Ｔｉ－６Ａｌ０－４Ｖ和     

辐射损伤对α-Fe2O3穆斯堡尔谱线形状的影响

利用离子注入产生晶体缺陷,研究其对穆斯堡尔谱线形状的影响。 关键词：     

Optical spectroscopy study of damage evolution in 6H-SiC by H_2~+ implantation

Lattice defects induced by ion implantation into Si C have been widely investigated in the decades by various techniques. One of the non-destructive techniques suitable to study the lattice defects in Si C is the optical characterization. In this work, confocal Raman scattering spectroscopy and photoluminescence spectrum have been used to study the effects of 134-ke V H_2~+ implantation and thermal treatment in the microstructure of 6 H-Si C single crystal. The radiation-induced changes in the microstructure were assessed by integrating Raman-scattering peaks intensity and considering the asymmetry of Raman-scattering peaks. The integrated intensities of Raman scattering spectroscopy and photoluminescence spectrum decrease with increasing the fluence. The recovery of the optical intensities depends on the combination of the implantation temperature and the annealing temperature with the thermal treatment from 700℃ to 1100℃. The different characterizations of Raman scattering spectroscopy and photoluminescence spectrum are compared and discussed in this study.     

Effect of ion implantation on quantum well infrared photodetectors

Ion implantation is a postgrowth processing technique which, when combined with annealing, can be used to tune the absorption wavelength of quantum well devices. We have implanted and annealed, three different quantum well infrared photodetector structures, and measured the absorption spectra of the samples by Fourier transform spectroscopy. The peak absorption wavelength shift of each structure has been calculated as a function of diffusion length by simulating the diffusion processes. We found different diffusion rates for the structures and attribute this to different numbers of as-grown defects. Our results indicate that agglomeration of single defects into defect clusters limits the ability of ion implantation to tune the wavelength of a structure with a higher number of as-grown defects. Thus, a structure with the lowest number of as-grown defects is most useful for fabricating a multi-color quantum well photodetector by ion implantation, because in this case ion implantation can enhance the diffusion rate considerably leading to large red- shift in peak absorption wavelength.     

Synthesis of nano-sized SiC precipitates in Si by simultaneous dual-beam implantation of C+ and Si+ ions

Nanometer-sized SiC precipitates were synthesized in situ in Si by simultaneous implantation of two ion beams of C⁺ and Si⁺ ions. The results of simultaneous dual-beam implantation are compared with those of sequential dual-beam ion implantation and of single-beam C⁺ ion implantation. Remarkable differences are observed regarding the content and the crystal quality of SiC precipitates as well as the defect structure of the Si substrate. The SiC precipitation during dual-beam synthesis is found to depend on the ion energy of the second beam and on the implantation mode, simultaneous or sequential. For suitable implantation conditions, simultaneous dual-beam synthesis can improve the in situ SiC formation in comparison to the single-beam synthesis. A higher density of SiC precipitates with better crystal quality was observed, whereas their size was not changed. The second ion beam enables a shift in the dynamic equilibrium of constructive and destructive processes for SiC formation. A model is proposed assuming that SiC precipitation preferentially proceeds in regions with vacancy defects. The implantation process itself creates vacancy-dominated and also interstitial-dominated regions. The balance of the local point-defect composition is shifted under the second ion beam. In this way, the conditions for SiC precipitation can be modified. Received: 18 February 2002 / Accepted: 17 May 2002 / Published online: 17 December 2002 RID="*" ID="*"Corresponding author. Fax: +49-351/260-3411, E-mail: koegler@fz-rossendorf.de     

Ordering of gas bubbles during light ion gas implantation

There have been interesting observations about ordering of microstructures during irradiation. The formation of void lattices is amongst the better known examples. Ordering has also been observed in small gas filled bubbles formed during low energy light ion implantation in the energy range 30–100 keV. The basic underlying mechanism for ordering of gas bubbles has not been clearly understood so far. We identify in this paper a basic instability in the growth kinetics of such bubbles which can develop during irradiation. This instability is shown to be associated with the interstitial production due to the high pressure inside these bubbles and their differential bias due to the strain field interactions with vacancies and interstitials. It is shown that such an instability leads to a selection of a wavelength scale which agrees with the observed lattice parameter.     

Low energy ion assisted atomic assembly of metallic superlattices

Metallic superlattices with planar, unalloyed (unmixed) interfacial structures are difficult to fabricate by all conventional vapor deposition methods. Molecular dynamics simulations have been used to explore the ways in which inert gas ions can be used to control the atomic assembly of a model Cu/Co metallic super lattice system. High energy, high atomic weight ions are shown to smooth rough interfaces but introduce undesirable intermixing at interfaces. Light ions with very low energies fail to flatten the rough surfaces that are naturally created during deposition at ambient temperature where surface atom mobility is kinetically constrained. The optimum energies for achieving the lowest combination of interfacial roughness and interlayer mixing have been found for each inert gas ion species and the key mechanisms of surface structure reorganization activated by ion impacts have been identified over the range of ion masses and energies studied. Optimum ion energies that maximize the interface structural perfection have been identified.     

Field ion microscopy of ion-implanted alloys

In this review we describe research in which field ion microscopy is used for the first time for a precision investigation of the structural and phase changes that occur in the surface layers of ordered and aging alloys as a result of implantation with ions of different gases. It is established that when ordered and aging solid solutions are irradiated with gas ions with an energy of 15–40 keV and doses of 10¹³–10¹⁸ ion/cm² a structural phase transition occurs in the surface volume of the alloys. Radiationally disordered zones in the case of order-disorder transitions and ordered zones in the case of the reverse transition are detected and their dimensions are found. The atomic structure of the defects formed due to ion implantation are studied, these include radiationally disordered regions, dislocation configurations, dislocation loops and barriers, and also complexes of these defects localised in small volumes, and the segregation of atoms of one of the components. The structure of these defects in regions of single cascades of atomic displacements, their dimensions and mutual arrangement and their crystal-geometric characteristics are determined.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii. Fizika, No. 5, pp. 41–58, May, 1994.     

A model of melting of rare gases within bubbles of crystalline metal matrix

Abstract

On the basis of experimental results obtained in the present and some other works a model of melting of rare gas solids within bubbles formed in a crystalline metal matrix as a result of ion implantation is proposed. Rare gas solid is supposed to melt on heating at the expense of the bubble volume expansion by emission of a dislocation loop. On this basis the melting temperature can be estimated as one which is enough to provide for a pressure inside a bubble sufficient for the initiation of the dislocation loop punching. Values of melting temperatures obtained in this way are in good agreement with available experimental data.     

离子注入结合离子交换技术制备KTiOPO4光波导特性研究

用离子注入结合离子交换技术形成了 KTiOPO₄ 平面光波导,研究了离子注入对离子交换波导结构的影响.使用棱镜耦合法测量了波导特性,结果显示形成了表面折射率升高的多模波导,通过背散射技术研究了离子交换后的 Rb 离子分布.实验表明,注入离子导致样品晶格损伤,在 2.8 μm处对离子交换形成了阻挡层,阻止了交换向KTP晶体的更深处进行.