Effect of laser field and thermal stress on diffusion in laser doping of SiC

    Authors

    S. Bet; N. Quick;A. Kar

    Comments

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    Abbreviated Journal Title

    Acta Mater.

    Keywords

    SiC; chromium; laser doping; diffusion; SIMS; SILICON-CARBIDE; ENHANCED DIFFUSION; IMPURITIES; Materials Science, Multidisciplinary; Metallurgy & Metallurgical; Engineering

    Abstract

    The electromagnetic field of lasers and non-equilibrium doping conditions enable laser doping of SiC with increased dopant diffusivity. Chromium, which acts as a double acceptor, has been laser-doped in SiC wafers. A thermal model is utilized to determine the temperature distribution at various depths of the wafer and a diffusion model is presented including the effects of Fickian diffusion, laser electromagnetic field and thermal stresses due to localized laser heating on the mass flux of dopant atoms. The dopant diffusivity is calculated as a function of temperature at different depths of the wafer based on measured dopant concentration profile. The maximum diffusivities achieved in this study are 4.61 x 10(-10) cm(2) s(-1) at 2898 K and 6.92 x 10(-12) cm(2) s(-1) at 3046 K for 6H-SiC and 4H-SiC, respectively. The maximum concentration is found to be 2.29 x 10(19) cm(-3) for 6H-SiC, which is two orders of magnitude higher than the reported value (3 x 10(17) cm(-3) solid solubility limit). Published by Elsevier Ltd on behalf of Acta Materialia Inc.

    Journal Title

    Acta Materialia

    Volume

    55

    Issue/Number

    20

    Publication Date

    1-1-2007

    Document Type

    Article

    Language

    English

    First Page

    6816

    Last Page

    6824

    WOS Identifier

    WOS:000251668500015

    ISSN

    1359-6454

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