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  • 1
    Digitale Medien
    Digitale Medien
    Transient boron diffusion in ion-implanted crystalline and amorphous silicon (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 63 (1988), S. 1452-1463 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Boron diffusion in ion-implanted and annealed single-crystal and amorphized Si is compared to determine the effect of amorphization on the initial transient boron motion reported for single crystal. The boron was implanted at 20 keV and at doses of 1×1015 and 3×1015cm−2. The Si was either preamorphized or postamorphized to a depth of 320 nm by implantation of Si ions at three different energies. In the amorphized samples the entire boron profile was always contained within this distance. The samples were annealed by furnace or rapid thermal annealing to 900–1100 °C with or without a preanneal at 600 °C. The initial rapid diffusion transient in the tail region of the boron profile was observed in all the crystal samples. This transient was totally absent in the amorphized samples. This is manifest by careful comparison of boron concentration profiles determined by secondary ion mass spectrometry of single-crystal and amorphized samples after annealing. For anneals where significant motion occurs, the profiles of the amorphized samples could be fit with a computational model that did not include anomalous transient effects. It is proposed that excess interstitials cause the transient diffusion in the case of the crystalline samples. The source of interstitials is believed to be provided by the thermal dissolution of small clusters that are formed by the implantation process. They exist for only a short time, during which they enhance the boron diffusion. Since there is no enhanced diffusion in the amorphous region that regrows to single crystal, apparently interstitial clusters are neither produced by nor do they survive the regrowth process in that region. In addition, the interstitials generated by the damage beyond the amorphous-crystalline boundary are prevented from entering the regrown region by the dislocation loops formed at that boundary which act as a sink consuming the interstitials diffusing toward the surface.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.339926
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  • 2
    Digitale Medien
    Digitale Medien
    Diffusion of Sb, Ga, Ge, and (As) in TiSi2 (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 63 (1988), S. 5335-5345 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Gallium, Sb, and Ge were implanted into thick (about 400 nm) layers of TiSi2 prepared by metal-silicon reaction. The diffusion of the implanted atoms was analyzed by means of secondary ion mass spectrometry. Gallium was introduced because a former study had shown that the usual p-type dopant B does not diffuse in TiSi2. Germanium was used in lieu of a Si tracer. Its diffusion characteristics are compared to those of P and As (as well as Si) which had been investigated previously. Germanium and Ga diffuse readily above 600 °C, but Sb does not. Its diffusion appears to be limited to grain-boundary effects. Accumulations of the diffusing atoms are observed (except for Sb) at the silicide-silicon interface. These are due to kinetic effects, namely fast diffusion at grain boundaries and interfaces, rather than to real adsorption which is an equilibrium condition. Because diffusion in intermetallic compounds has been shown to be significantly affected by variations in stoichiometry, experiments were conducted with films implanted not only with foreign atoms but with Ti as well. These did not lead to significantly different observations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.340399
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  • 3
    Digitale Medien
    Digitale Medien
    The diffusion of elements implanted in films of cobalt disilicide (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 2973-2980 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The diffusion of several elements implanted into layers of CoSi2 with a nominal thickness of 800 nm, grown by metal-silicon reaction, has been studied by secondary ion mass spectroscopy. Boron has by far the highest mobility. It is totally homogenized by heat treatment for 0.5 h at 800 °C; it displays evidence of grain-boundary diffusion at 400 °C and of lattice diffusion at 450 °C. The next group of elements, gallium, phosphorus, and germanium (used as a tracer in lieu of a silicon isotope) diffuse distinctly less rapidly, and remain nonhomogenized after annealing at 800 °C. The lattice diffusion of arsenic and antimony is not detectable (by the means presently used), even after heat treatment at the same relatively high temperature. Low-temperature effects, and effects far away from the implanted region, are dominated by grain-boundary diffusion. The lattice diffusion increases from boron to phosphorus and germanium, with activation energies determined to be 2.0 and 2.7 eV for boron and phosphorus, respectively. The results are discussed by comparison with those previously obtained with TiSi2.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.341560
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  • 4
    Digitale Medien
    Digitale Medien
    Boron, phosphorus, and arsenic diffusion in TiSi2 (1986)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 60 (1986), S. 1634-1639 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The diffusivities of B, P, and As implanted in TiSi2 are analyzed between 500 and 900 °C by secondary ion mass spectroscopy. It is shown that P and As have high (and almost equal) diffusivities compared with B which appears immobile. This difference is presumed to be related to the very high stability of TiB2 (as compared with TiSi2) and the probable precipitation of B in the form of a titanium boride. The lattice diffusion coefficients for As and P are deduced from the diffusion profiles; they range from 10−17 to 10−14 cm2/s between 550 and 800 ° C. The activation energies are found to be, respectively, 1.8 and 2.0 eV; values close to the activation energy for the self-diffusion of Si in TiSi2, 1.8 eV. The diffusion profiles also show a high grain boundary diffusivity and an accumulation of dopant at the TiSi2–Si interface.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.337252
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  • 5
    Digitale Medien
    Digitale Medien
    Implantation damage and the anomalous transient diffusion of ion-implanted boron (1987)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 51 (1987), S. 487-489 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The effect of the implantation of silicon ions on the anomalous transient diffusion of ion-implanted boron is investigated. It is found that silicon ion fluences well below that necessary to amorphize the lattice substantially reduce the anomalous transient diffusion of subsequently implanted boron. The sheet resistance, however, is increased by the additional silicon implant. The implantation of silicon ions into activated boron layers causes additional anomalous diffusion at substantial distances beyond the range of the silicon ions. The anomalous motion is also reduced in regions where the damage is greater. The effects can be explained in terms of the generation of point defect clusters which dissolve during anneal and the sinking of point defects in the regions of high damage by the formation of interstitial type extended defects.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.98375
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  • 6
    Digitale Medien
    Digitale Medien
    Anomalous diffusion of boron implanted into silicon along the [100] direction (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 851-853 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We have observed transient enhanced diffusion of boron implanted into silicon along the [100] channeling direction and compared it with that of boron implanted in a "random'' direction. It is found that the anomalous boron displacement for the channeled implants is significantly greater than for the random counterparts. An empirical explanation for the greater displacement of the channeled implants is proposed that is related to the spatial distribution of the implanted boron and the lattice damage generated by the implantation process.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.100092
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  • 7
    Digitale Medien
    Digitale Medien
    Separation of nuclear magnetic resonance signals of internally enantiotropic protons using a chiral shift reagent. Deuterium isotope effect on geminal proton-proton coupling constants (1972)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 94 (1972), S. 3253-3254 
    Details
    ISSN: 1520-5126
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/ja00764a070
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  • 8
    Digitale Medien
    Digitale Medien
    Foreign Aid and the Business Cycle (2001)
    Oxford, UK and Boston, USA : Blackwell Publishers Ltd.
    Review of international economics 9 (2001), S. 0 
    Details
    ISSN: 1467-9396
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Wirtschaftswissenschaften
    Notizen: This paper documents empirical regularities in the foreign aid flows to developing countries over three decades. In spite of a large body of literature on foreign aid and its impact on recipients, surprisingly little is known about its business cycle characteristics. The authors show that for the vast majority of African recipients, aid flows are a major source of income that is highly volatile and, most importantly, overwhelmingly procyclical. For recipients outside of Africa, there is a similar—if somewhat less pronounced—pattern of aid procyclicality. In contrast, there is little evidence of aid procyclicality with the business cycle of donors. In light of the very high volatility of output in developing countries, the procyclicality of foreign aid flows from the recipients’ perspective raises serious questions related to their welfare and growth.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/1467-9396.00305
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  • 9
    Digitale Medien
    Digitale Medien
    APPENDIX II (1933)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of public and cooperative economics 9 (1933), S. 0 
    Details
    ISSN: 1467-8292
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Wirtschaftswissenschaften
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1467-8292.1933.tb02128.x
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  • 10
    Digitale Medien
    Digitale Medien
    Imine-enamine tautomers from hydrazine and aryl hydrazine additions to acetylenedicarboxylate (1970)
    s.l. : American Chemical Society
    The @journal of organic chemistry 35 (1970), S. 80-83 
    Details
    ISSN: 1520-6904
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/jo00826a019
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