Comparison of Silicon-on-Insulator Wafer Mappings between Photoluminescence Intensity and Microwave Photoconductivity Decay Lifetime

概要

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We characterized the nonuniformities of state-of-the-art ultrathin silicon-on-insulator (SOI) wafers by photoluminescence (PL) intensity mapping and microwave photoconductivity decay ($\mu$-PCD) lifetime mapping. Both mapping techniques revealed characteristic patterns with extreme sensitivity. The PL and $\mu$-PCD mapping patterns on the substrate were almost exactly alike for all the measured wafers. There was also a strong resemblance between the two mapping patterns on the top Si layer for most wafers. A higher PL intensity region corresponded to a longer lifetime area. The quantitative relationship between the PL intensity and $\mu$-PCD lifetime was obtained not only for comparison within a wafer but also for wafer-to-wafer comparison. The mapping pattern on the substrates varied greatly depending on the wafer fabrication method. We believe that the pattern on the top Si layer originates in the distribution of microdefects such as HF defects in the layer, the variation in layer thickness, and/or the nonuniformity produced during the thermal process for surface passivation.
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2004-02-15