Depth resolution of sputter profiling investigated by combined Auger-x-ray analysis of thin films

Conversion of conventional “Auger sputter profiles” into the “depth profiles” has been accomplished by detecting characteristic X-rays produced simultaneously with Auger electrons. We discuss the sputtering through the interface between GeSi films with respect to the following points: determination of the original interface position on the depth scale; asymmetry of the shape of the Auger profiles, and broadening of the interface region due to atomic mixing for different ion masses and energies (He⁺ to Xe⁺, 0.5 and 5 keV). We found that the best depth resolution of 2.5 nm is obtained for 0.5 keV Xe⁺ which increases to more than 10 nm for He⁺ at 5 keV.     

离子束混合形成氮化钛膜的摩擦和光学性能

用载能氮离子束轰击纯铁镀钛膜样品，成功地形成了金黄色氮化钛薄膜。结果表明：注入剂量为０．５×１０＾１７ Ｎ＾＋／ｃｍ＾２的混合样品表面颜色与纯金类似；氮离子束混合样品表面显微硬度及耐磨性都远优于纯铁基体，且随离子剂量的增加，混合样品的表面硬度和耐磨性也提高。     

Dynamic Monte Carlo simulation of surface composition change during sputter depth profiling

In the surface analysis methods such as X-ray photoelectron spectroscopy, Auger electron spectroscopy, or secondary-ion mass spectroscopy, sputtering processes are used for depth profiling. However, ion beam bombardment changes the surface composition and the surface structure, which deteriorates the accuracy of the surface analysis and the depth resolution. We studied the preferential sputtering in some materials consisting of two components with different mass ratio by using the dynamic Monte Carlo simulation. Dose dependence of the depth profile of composition is presented. By Ar sputtering, the surface compositions of Au_0.25Cu_0.75, Au_0.67Al_0.33, and Ni_0.5Cu_0.5 alloys changed to Au_0.28Cu_0.72, Au_0.76Al_0.24, and Ni_0.67Cu_0.33, respectively. These results agreed with the experimental data. In order to compare the effect of mass ratio on the preferential sputtering, B–C, Si–C, and W–C systems were investigated. In B–C system, preferential sputtering by 1 and 3 keV Ar ion was negligible. In W–C system, a significant preferential sputtering occurred. In Si–C system, carbon was enriched in the outermost surface layer at a fluence lower than 3×10¹⁶ ions/cm². At higher fluence, the partiality in concentration recovers because of the balance between the enrichment and the preferential sputtering.     

SIMS depth profiling of multilayer metal-oxide thin films — improved accuracy using a xenon primary ion

Multilayer thin films containing silver and copper, sandwiched in a metal oxide, have been depth profiled by secondary ion mass spectrometry (SIMS) using primary ions of differing mass, energy and chemical reactivity. These results were compared for accuracy with those obtained by Rutherford backscattering spectrometry (RBS). The use of O₂⁺ or O^? as primary ions resulted in severe distortion of the silver ion intensity distribution in the SIMS profile of a ZnO/Ag/ZnO thin film on glass; O₂⁺ bombardment at energies from 3–10 keV resulted in the detection of silver at the glass interface, while the use of O^? caused the silver to be detected closer to the outer surface than expected from RBS results. Primary beams of Ar⁺ and Xe⁺ gave progressively more accurate results for the Zn/Ag/Zn distribution; Xe⁺ at 5.0 keV energy produced profiles that agreed within 10% of RBS-derived values. The same beam conditions, used to profile a double silver layer in ZnO, resulted in some discrepancy in the position of the inner layer, compared to RBS results, and this was attributed to an enhanced sputter rate in the oxide under the outside metal film. Depth profiling of TiO₂/Cu/TiO₂ films with oxygen also resulted in significant distortion of the perceived position of the metal layer, and this was again significantly improved using Xe⁺ primary ions of 6–9 keV energy. The distorting effects of oxygen bombardment can be understood in terms of a migration of metal ions in an electrostatic field created by a charged surface. Ionization of the metallic layer is enhanced by the use of oxygen. By contrast, the use of rare gases reduces the production of ions from the metallic layer which can migrate prior to the onset of sputtering.     

ZnO thin films deposited by capillaritron ion beam sputtering deposition

ZnO thin films were deposited by capillaritron ion beam sputtering deposition. The crystalline quality, stoichiometry and photoluminescence properties of as-deposited and annealed ZnO thin films were studied. The as-deposited ZnO films show no preferred crystallographic orientations while annealed films exhibit a strong single ZnO (0 0 2) diffraction peak at 34.50°. The stoichiometry of ZnO films were found to be dependent on both beam energy and annealing conditions that the atomic percent ratio of Zn/O can be controlled between 0.95 and 1.10. ZnO films deposited with 4 keV ion beam and annealed at 800 °C in oxygen shows the lowest defect related deep level visible emission, while 80% of oxygen atoms are still located in fully oxidized stoichiometric ZnO matrixes.     

利用离子束技术及PECVD制备碳化硅

阐述利用离子注入、离子束增强沉积、反应离子束溅射及反应离子束辅助沉积等方法制备碳化硅薄膜的实验结果，并报道利用等离子体增强化学气相沉积技术制备可光致发光的非晶态α－ＳｉＣ：Ｈ薄膜的工作。     

Low-energy heavy-ion TOF-ERDA setup for quantitative depth profiling of thin films

Low-energy heavy-ion time-of-flight elastic recoil detection analysis (TOF-ERDA) is becoming a mature technique for accurate characterization of thin films. In combination with a small tandem accelerator (∼2 MV terminal voltage) and beam energies below 20 MeV, it is suitable for routine analysis of key materials in semiconductor technology. In this paper we discuss advantages and drawbacks of low-energy ERDA, compared to high-energy ERDA, in terms of depth and mass resolution, detection efficiency for light elements, sample irradiation damage and quantification accuracy.The results presented are obtained with the time-of-flight telescope recently developed at IMEC. The time-of-flight is measured with timing gates based on electrostatic mirrors and is acquired in coincidence with the energy signal measured by a planar Si detector.     

Sub-micron calibration for ion beam milling of thin films

Multiple beam interferometry and Rutherford backscattering spectrometry are used to extend the calibration of the amount of material removed by an ion miller to 2 nm.     

Ion beam mixing in uranium nitride thin films studied by Rutherford Backscattering Spectroscopy

Thickness, composition, concentration depth profile and ion irradiation effects on uranium nitride thin films deposited on fused silica have been investigated by Rutherford Backscattering Spectroscopy (RBS) using 2 MeV He⁺ ions. The films were prepared by reactive DC sputtering at the temperatures of ?200 °C, +25 °C and +300 °C. A perfect 1U:1N stoichiometry with a layer thickness of 660 nm was found for the film deposited at ?200 °C. An increase of the deposition temperature led to an enhancement of surface oxidation and an increase of the thickness of the mixed U–N–Si–O layers at the interface. The sample irradiation by 1 MeV Ar⁺ ion beam with ion fluence of about 1.2–1.7 × 10¹⁶ ions/cm² caused a large change in the layer composition and a large increase of the total film thickness for the films deposited at ?200 °C and at +25 °C, but almost no change in the film thickness was detected for the film deposited at +300 °C. An enhanced mixing effect for this film was obtained after further irradiation with ion fluence of 2.3 × 10¹⁶ ions/cm².     

强脉冲离子束辐照混合的RBS研究

采用卢瑟福背散射(Rutherford backscattering spectroscopy,RBS)方法对强脉冲离子束辐照Ti/Al、Al/Ti和Ni/Ti三组薄膜/衬底体系所形成的混合层进行了研究.在Ni/Ti组合中形成了厚度比离子射程大得多的、混合度较高的梯度混合层.发现熔融态混合的程度不仅取决于两材料在熔融态的表面张力的差别,而且取决于它们熔点的差异.这两个参量较接近的混合程度较好.     

Use of ion mixing to improve mechanical properties on thin metallic films

The results of experimental investigations of mechanical property variations in silver, nickel and chromium thin films during ion 120 keV irradiation are presented. The dependence of change in adhesion (peel- and scratch tests), wear resistance and friction coefficient on film thickness, ion type and irradiation dose was studied. Calculations of implanted-ion distributions, energy deposition and penetration depth of recoil atoms into the glass and silicon substrates have been performed. The results were compared to relevant data on ion mixing which helped in revealing the mechanisms responsible for property modification.     

Ion beam induced modifications in electron beam evaporated aluminum oxide thin films

Al₂O₃ thin films find wide applications in optoelectronics, sensors, tribology etc. In the present work, Al₂O₃ films prepared by electron beam evaporation technique are irradiated with 100 MeV swift Si⁷⁺ ions for the fluence in the range 1 × 10¹² to 1 × 10¹³ ions cm⁻² and the structural properties are studied by glancing angle X-ray diffraction. It shows a single diffraction peak at 38.2° which indicates the γ-phase of Al₂O₃. Further, it is observed that as the fluence increases up to 1 × 10¹³ ions cm⁻² the diffraction peak intensity decreases indicating amorphization. Surface morphology studies by atomic force microscopy show mean surface roughness of 34.73 nm and it decreases with increase in ion fluence. A strong photoluminescence (PL) emission with peak at 442 nm along with shoulder at 420 nm is observed when the samples are excited with 326 nm light. The PL emission is found to increase with increase in ion fluence and the results are discussed in detail.     

离子束分解卤化物涂层镀膜技术的初步实验

离子束轰击化合物涂层镀膜是七十年代发展起来的一种新方法。本文叙述了用这种方法在硅片和玻璃片上形成钯膜的过程,并给出了用扫描电子显微镜和俄歇电子谱仪观察分析的结果。最后讨论了镀膜的机理和可能的应用。     

离子束混合及离子注入陶瓷材料表面改性研究概述

对离子注入陶瓷材料引起的辐照损伤和材料力学性能、摩擦学性能的改善及陶瓷基体上金属薄膜的离子束混合增强粘着研究的进展进行了综述。     

Morphological change in FePt nanogranular thin films induced by swift heavy ion irradiation

We have investigated morphology change of FePt nanogranular films (FePt)₄₇(Al₂O₃)₅₃ under irradiation with 210 MeV Xe ions. Here, electron tomography technique was extensively employed to clarify three-dimensional (3D) structure in irradiated specimens, in addition to conventional transmission electron microscopy (TEM) techniques such as bright-field observation and scanning TEM energy dispersive X-ray spectroscopy (STEM-EDX) analysis. The ion irradiation induces the coarsening of FePt nanoparticles with elongation along the beam direction. Electron tomography 3D reconstructed images clearly demonstrated that when the fluence achieves 5.0 × 10¹⁴ ions/cm², well-coarsened FePt balls have been formed on the irradiated surface, and the particles in the film interior have been deformed into rods along the ion trajectory. The alloy particles become inhomogeneous in composition after prolonged irradiation up to 1.0 × 10¹⁵ Xe ions/cm². The particle center is enriched with Pt, while Fe is slightly redistributed to the periphery.     

Control of temperature in thin samples during ion beam analysis

The ability of ion beam analytical techniques such as proton induced X-ray emission (PIXE) to determine elemental content without damaging fragile objects is a key factor in their increasing use in the analysis of art and archaeological objects In this paper, we calculate the expected temperature rise in thin, planar samples with and without radiative, conductive and convective cooling The results show that the primary emphasis must be placed on minimizing energy input to the sample, and that forced convective cooling is by far the most effective method of energy removal in materials such as paper, parchment, and fabrics     

Swift heavy ion irradiation induced texturing in NiO thin films

NiO thin films grown on Si(1 0 0) substrate by electron beam evaporation and sintered at 500 and 700 °C were irradiated with 120 MeV Au⁹⁺ ions. The FCC structure of the sintered films was retained up to the highest fluence (3 × 10¹³ ions cm⁻²) of irradiation. In the low fluence (?1 × 10¹³ ions cm⁻²) regime however, the evolution of the XRD pattern with fluence showed a wide variation, critically depending upon their initial microstructure. Though irradiation is known to induce disorder in the structure, we observe improvement in crystallization and texturing at intermediate fluences of irradiation.     

Surface modification of Pd-plated Ti alloys by ion beam mixing

Ti-Pd surface alloys were prepared by bombarding a Pd-plated Ti alloy with Xe ions. From AES-PRO, XPS-PRO and SIMS analysis it has been shown that the distribution of Pd is quite homogeneous through the thickness of the surface layer, a hardening phase, TiC, was formed in the surface layer and a TiO₂ passive film was found on the exposed surface. The average corrosion rate of the Ti-Pd surface alloy in boiling 1N H₂SO₄ is about 1/60 that of the Ti alloy substrate, and in the outer-surface region it makes three orders of magnitude improvement in the corrosion rate. There are many differences in micromorphology between the Ti-Pd surface alloy and the Ti alloy substrate after corrosion testing. Microhardness of the surface alloy increases 43% and the dry friction coefficient decreases 40% compared to the Ti alloy substrate.     

离子束混合生成银-黄铜合金混层及其摩擦性能

黄铜是工业上应用十分广泛的一种合金材料,若能改善其表面的摩擦性能,又保持基体原有的强度,将是具有实际意义的。为此,我们用离子束混合技术将银引入黄铜基体,在表面生成了润滑性能良好的银-黄铜合金混层,并对其摩擦性能、强度及与基体的结合力作了对比试验,然后用AES、SIMS、SEM以及光学显微镜对其混合状态和表面形貌作了分析和