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Journal ArticleDOI

Growth of β-FeSi2 films via noble-gas ion-beam mixing of Fe/Si bilayers

16 Oct 2001-Journal of Applied Physics (American Institute of Physics)-Vol. 90, Iss: 9, pp 4474-4484
TL;DR: A detailed study of the formation of β-FeSi2 films by ion-beam mixing of Fe/Si bilayers with noble gas ions is presented in this paper, where the structures were analyzed by Rutherford backscattering spectroscopy, x-ray diffraction, conversion electron Mossbauer spectrograph, elastic recoil detection analysis, cross-section high resolution transmission electron microscopy, and energy dispersive x-rays spectroscope.
Abstract: A detailed study of the formation of β-FeSi2 films by ion-beam mixing of Fe/Si bilayers with noble gas ions is presented. Fe films of 35–50 nm deposited on Si (100) were irradiated with 80–700 keV Ar, Kr, or Xe ions in a wide temperature interval, from room temperature to 600 °C. The structures were analyzed by Rutherford backscattering spectroscopy, x-ray diffraction, conversion electron Mossbauer spectroscopy, elastic recoil detection analysis, cross-section high resolution transmission electron microscopy, and energy dispersive x-ray spectroscopy. Already after Xe irradiation at 300 °C the whole Fe layer is transformed to a mixture of Fe3Si, e-FeSi, and β-FeSi2 phases. At 400–450 °C, a unique, layer by layer growth of β-FeSi2 starting from the surface was found. A full transformation of 35 nm Fe on Si to a 105 nm β-FeSi2 layer was achieved by irradiation with 205 keV Xe to 2×1016 ions/cm2, at a temperature of 600 °C. The fully ion-beam grown layers exhibit a pronounced surface roughness, but a sharp in...
Citations
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Journal ArticleDOI
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

Journal ArticleDOI
TL;DR: In this article, the existence of amorphous semiconducting FeSi2, having a direct band gap of 0.88 eV, was demonstrated by ion beam mixing of 50 nm Fe on Si(1/0/0), with 120 keV Ar8+ ions, at 300 °C.
Abstract: The existence of amorphous semiconducting FeSi2, having a direct band gap of 0.88 eV, is demonstrated. It was synthesized by ion beam mixing of 50 nm Fe on Si(1 0 0), with 120 keV Ar8+ ions, at 300 °C. Rapid diffusion of Si to the surface is assigned to be the dominating process that results in the formation of amorphous FeSi2 phase. Other synthesis techniques should be possible for fabrication of this material, and it could be applied in large area electronics.

27 citations

Journal ArticleDOI
TL;DR: In this article, a 20nm 57 Fe layer was interlayed between Fe and Si wafers in order to monitor interface mixing and phase formation by means of Moessbauer spectroscopy, which correlated with relaxation of the as-deposited stress and uniaxial magnetic anisotropy.
Abstract: Modifications of Ni/Si and Fe/Si bilayers induced by swift heavy ions were studied in the regime of pure electronic stopping. Polycrystalline films, 65–75 nm thick, were deposited via electron evaporation (Ni) or pulsed laser deposition (Fe) onto Si wafers and irradiated at ⩽300 K with 350-MeV Au 26+ ions to fluences of up to 5 × 10 15 ions/cm 2 . The samples were analyzed by Rutherford backscattering spectroscopy, X-ray diffraction and the magneto-optical Kerr effect. In the Fe/Si samples, a 20 nm 57 Fe layer was interlayed between nat Fe and Si in order to monitor interface mixing and phase formation by means of Moessbauer spectroscopy. In both systems, a high mixing rate of ≈60 nm 4 was found, correlated with relaxation of the as-deposited stress and uniaxial magnetic anisotropy. At higher fluences, full interdiffusion gives rise to amorphous silicide phases, build-up of stress and loss of magnetic texture.

20 citations

Journal ArticleDOI
TL;DR: In this paper, heavy ion-induced modifications of 65-75nm thick Ni/Si bilayers in the regime of electronic stopping (350-MeV 197 Au 26+ -ions) and nuclear stopping (400-keV Xe + -ions), were analyzed by means of Rutherford backscattering spectroscopy, X-ray diffraction and magneto-optical Kerr effect.
Abstract: We report on heavy-ion-induced modifications of 65–75 nm thick Ni/Si bilayers in the regime of electronic stopping (350 MeV 197 Au 26+ -ions) and nuclear stopping (400 keV Xe + -ions) The samples were analyzed by means of Rutherford back-scattering spectroscopy, X-ray diffraction and magneto-optical Kerr effect For both types of ions, interface mixing was observed, correlated with full relaxation of the as-deposited stress and uniaxial magnetic anisotropy For the higher fluences, full intermixing, rebuild-up of stress and loss in magnetic texture occurred It can be concluded that for both types of ion beam stopping, interface mixing and changes of magnetization occur for similar reasons

19 citations

Journal ArticleDOI
TL;DR: In this article, the ion-beam mixing (IBM) was studied by means of X-ray photoelectron spectroscopy (XPS) and factor analysis (FA).

18 citations

References
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Book
J.P. Biersack, James F. Ziegler1
01 Aug 1985
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

Journal ArticleDOI
TL;DR: Estimates of the number of arithmetic operations used by the program for any simulation to demonstrate the tradeoffs between accuracy, computation time, and algorithm sophistication are provided.
Abstract: A computer program which simulates Rutherford backscattering spectra is currently in use at Cornell University and other institutions. Straggling and detector resolution are among the effects included. Samples are considered to be made up of a finite number of layers, each with uniform composition. The emphasis in the mathematics is on accuracy beyond that of iterated surface approximation methods. Thicker layers can thus be analyzed without a net loss in accuracy. The mathematical description of the sample can then have fewer layers and fewer calculations are required. This paper provides estimates of the number of arithmetic operations used by the program for any simulation to demonstrate the tradeoffs between accuracy, computation time, and algorithm sophistication.

2,551 citations

Journal ArticleDOI
12 Jun 1997-Nature
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

Journal ArticleDOI
TL;DR: In this article, X-ray diffraction indicates the films are single-phase, orthorhombic, β-FeSi2, and single-crystal silicon wafers and with low pressure chemical vapor deposition (LPCVD) polycrystalline silicon thin films.
Abstract: Iron disilicide thin films were prepared by furnace reaction of ion beam sputtered iron layers with single‐crystal silicon wafers and with low‐pressure chemical vapor deposition (LPCVD) polycrystalline silicon thin films. X‐ray diffraction indicates the films are single‐phase, orthorhombic, β‐FeSi2. Impurity levels are below the detection limit of Auger spectroscopy. Normal incidence spectral transmittance and reflectance data indicate a minimum, direct energy gap of 0.87 eV. The apparent thermal activation energy of the resistivity in the intrinsic regime is about half of this minimum optical gap. With such a direct band gap, the material may be suitable for the development of both light‐sensitive and light‐emitting thin‐film devices within the silicon microelectronics technology.

447 citations

Journal ArticleDOI
TL;DR: In this paper, the gamma ray yield function of (p, αγ) and resonance reactions on semi-thick 19F, 23Na, 24,26Mg and 27Al targets were measured and used to calibrate the accelerating voltage and energy resolution of the new 500 kV heavy ion implanter at Gottingen.
Abstract: Gamma ray yield functions of (p, αγ) and (p, γ) resonance reactions on semi-thick 19F, 23Na, 24,26Mg and 27Al targets were measured and used to calibrate the accelerating voltage and energy resolution of the new 500 kV heavy ion implanter at Gottingen. The energy spread of the proton beam was found to vary linearly with the accelerating voltage from ΔE(200 keV) = 55 eV fwhm to ΔE(500 keV) = 105 eV; it is made up by a 0.012% high voltage ripple and the Doppler broadening of the resonances due to the thermal motion of the target nuclei. A long term stability of the proton energy of Applications of the accelerator for the remeasurement of some resonance energies and widths and for depth profiling of light implanted ions in metals by the resonance broadening method will be briefly discussed.

293 citations