Structural and optical properties of β-FeSi2 layers grown by ion beam mixing
TL;DR: In this paper, structural and optical properties of β-FeSi 2 layers produced by direct ion beam mixing of Fe/Si bilayers with Xe ions were analyzed by using Rutherford backscattering spectroscopy, X-ray diffraction, conversion electron Mossbauer spectrography, high resolution transmission electron microscopy, and photo-absorption.
Abstract: This study deals with structural and optical properties of β-FeSi 2 layers produced by direct ion beam mixing of Fe/Si bilayers with Xe ions. By irradiation of 35 nm Fe on Si, at 600 °C with 205 keV Xe to 2×10 16 ions/cm 2 , the formation of ∼105 nm single-phase β-FeSi 2 layers was achieved. Their structures were analyzed by Rutherford backscattering spectroscopy, X-ray diffraction, conversion electron Mossbauer spectroscopy, high resolution transmission electron microscopy, and photo-absorption. The structural analyses revealed that the β-FeSi 2 layers grow in the form of irregularly shaped crystal grains, with a pronounced surface morphology, but with a rather sharp silicide/silicon interface. The grains that originate from the interface are epitaxially oriented relative to the Si(100) substrate. Optical absorption, as compared with that in β-FeSi 2 layers produced by ion beam synthesis or co-sputter deposition, indicates a direct band gap of 0.92 eV. A pronounced surface roughness of the ion beam mixed layers yielded photo-absorption approximately three times higher as compared with the other two sets of samples. The band gap stays nearly constant over the temperature range from 80 to 295 K. This is tentatively assigned to a high degree of structural disorder and stress induced in the ion beam mixed β-FeSi 2 layers.
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TL;DR: A review of ion beam modifications at various solids, thin films, and multilayered systems covering wider energy ranges including the older basic concepts is given in this paper. But the results reveal that the ion-solid interaction physics provides a unique way for controlling the produced defects of the desired type at a desired location.
242 citations
01 Dec 2003-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
TL;DR: In this paper, a single specimen containing 3.0 nm thick layers of the three metals at different depths in Si, ensures a more reliable comparison of the mixing efficiencies of three systems.
Abstract: Swift heavy ion induced intermixing of thin metallic layers of Ti, Fe and W with Si has been studied. A single specimen containing 3.0 nm thick layers of the three metals at different depths in Si, ensures a more reliable comparison of the mixing efficiencies of the three systems. X-ray reflectivity and X-ray standing wave analysis has been used to obtain the concentration profile of the three metals before and after irradiation with 100 MeV Au ions. While Ti and Fe exhibit considerable mixing with Si after an irradiation fluence of 1 × 10 13 ions/cm 2 , W profile is only slightly broadened. XANES measurements under X-ray standing wave conditions have been able to differentiate between the structure of the center of a layer from that of the interfacial region. It is found that irradiation results in only a further disordering of the central as well as interfacial regions of the W layer. In contrast, the Fe layer gets completely mixed with Si and forms an amorphous silicide.
15 citations
TL;DR: In this paper, the influence of the preamorphization of the Si(100) substrates by 1.0keV Ar-ion irradiation was investigated and the mixing rate across the pre-amorphized Fe∕Si interface was, on average, 76% higher than that of crystalline Si.
Abstract: Ion-beam mixing of Fe∕Si bilayers, induced at room temperature by 100keV Ar+40, 180keV Kr+86, and 250keV Xe+132 ions, was investigated. The study focuses on the influence of the preamorphization of the Si(100) substrates by 1.0keV Ar-ion irradiation. Rutherford backscattering spectroscopy as well as scanning and transmission electron microscopies were applied for structural characterization. The mixing rate across the preamorphized Fe∕Si interface was, on average, by 76% higher than that of crystalline Si.
12 citations
TL;DR: In this article, the role of the buffer layer on the formation of β- and α-FeSi2 thin film was discussed, and the composition of the β-Si2 film can be tuned from Fe enrichment to Si enrichment by altering the radio-frequency input power applied on the Si or/and Fe target.
Abstract: Single-phase β- and α-FeSi2 thin films can be grown on Si(100) with and without a thin Fe buffer layer by adopting a facing target radio-frequency magnetron sputtering method. The role of the buffer layer on the formation of β- and α-FeSi2 thin film was discussed. The composition of β-FeSi2 thin film can be tuned from Fe enrichment to Si enrichment by altering the radio-frequency input power applied on the Si or/and Fe target, and the β-FeSi2 thin film has a high (202)/(220) orientation. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
5 citations
01 Apr 2007-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
TL;DR: In this paper, interface mixing of Fe/Si(1.0.0) bilayers, induced by 100 keV 40 Ar, 180 keV 86 Kr and 250 keV 132 Xe ions, either singly and multiply charged (Ar 8+, Kr 11+, Xe 17+ ), was investigated.
Abstract: Charge-state equilibration of ions moving in matter occurs within femtoseconds and when penetrating nanometer depths. Ion-beam mixing in bilayers, tens of nm thick, should therefore not depend on the charge state of the projectiles. As the experimental situation for metal/silicon bilayers irradiated with noble-gas ions of different charge-states is ambiguous, we studied interface mixing of Fe/Si(1 0 0) bilayers, induced by 100 keV 40 Ar, 180 keV 86 Kr and 250 keV 132 Xe ions, either singly and multiply charged (Ar 8+ , Kr 11+ , Xe 17+ ). No significant influence of the ionic charge-state was established for Kr and Xe ions; a slightly higher mixing rate was found for Ar 8+ than for Ar 1+ irradiation.
4 citations
References
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Book•
IBM1
TL;DR: A review of existing widely-cited tables of ion stopping and ranges can be found in this paper, where a brief exposition of what can be determined by modern calculations is given.
Abstract: The stopping and range of ions in matter is physically very complex, and there are few simple approximations which are accurate. However, if modern calculations are performed, the ion distributions can be calculated with good accuracy, typically better than 10%. This review will be in several sections:
a)
A brief exposition of what can be determined by modern calculations.
b)
A review of existing widely-cited tables of ion stopping and ranges.
c)
A review of the calculation of accurate ion stopping powers.
10,060 citations
Book•
01 Jan 1971TL;DR: Optical processes in semiconductors as mentioned in this paper, Optical Process in Semiconductors (OPP), Optical Process of Semiconductor (OPS) and Optical Process (OPI)
Abstract: Optical processes in semiconductors , Optical processes in semiconductors , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
4,630 citations
Book•
01 Jan 1975
TL;DR: Optical processes in semiconductors as discussed by the authors, Optical Process in Semiconductors (OPP), Optical Process of Semiconductor (OPS) and Optical Process (OPI)
Abstract: Optical processes in semiconductors , Optical processes in semiconductors , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
922 citations
TL;DR: In this article, a light-emitting device operating at 1.5 µm was presented that incorporates β-FeSi2 into a conventional silicon bipolar junction, which demonstrates the potential of this material as an important candidate for a silicon-based optoelectronic technology.
Abstract: Although silicon has long been the material of choice for most microelectronic applications, it is a poor emitter of light (a consequence of having an ‘indirect’ bandgap), so hampering the development of integrated silicon optoelectronic devices. This problem has motivated numerous attempts to develop silicon-based structures with good light-emission characteristics1, particularly at wavelengths (∼1.5 μm) relevant to optical fibre communication. For example, silicon–germanium superlattice structures2 can result in a material with a pseudo-direct bandgap that emits at ∼1.5 μm, and doping silicon with erbium3 introduces an internal optical transition having a similar emission wavelength, although neither approach has led to practical devices. In this context, β-iron disilicide has attracted recent interest4,5,6,7,8,9,10,11,12 as an optically active, direct-bandgap material th might be compatible with existing silicon processing technology. Here we report the realization of a light-emitting device operating at 1.5 μm that incorporates β-FeSi2 into a conventional silicon bipolar junction. We argue that this result demonstrates the potential of β-FeSi2 as an important candidate for a silicon-based optoelectronic technology.
649 citations
TL;DR: In this article, the combinatorial optimization simulated annealing algorithm is applied to the analysis of Rutherford backscattering data, which is fully automatic and does not require time-consuming human intervention.
Abstract: The combinatorial optimization simulated annealing algorithm is applied to the analysis of Rutherford backscattering data. The analysis is fully automatic, i.e., it does not require time-consuming human intervention. The algorithm is tested on a complex iron-cobalt silicide spectrum, and all the relevant features are successfully determined. The total analysis time using a PC 486 processor running at 100 MHz is comparable to the data collection time, which opens the way for on-line automatic analysis.
587 citations