Synchrotron-based impurity mapping

McHugo, Scott A.; Thompson, A.C.; Flink, C.; Weber, E. R.; Lamble, G. M.; Gunion, B; MacDowell, A. A.; Celestre, Richard; Padmore, H. A.; Hussain, Zakria

doi:10.1016/s0022-0248(99)00718-6

Cited by 42 publications

(37 citation statements)

References 9 publications

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“…15 More details about the operational principles and detection limits of the m-XRF technique can be found elsewhere. 15,[38][39][40] Once a metal precipitate is located, its chemical state can be determined via X-ray absorption microspectroscopy (m-XAS). The position of the X-ray beam is fixed on the precipitate while the energy of the incoming Xray beam is scanned in steps of 1 eV or less across the absorption energy edge of the impurity species of interest (e.g., Fe, Ni, Cu, etc.).…”

Section: Methodsmentioning

confidence: 99%

“…Via comparison with standard materials, one can very accurately determine the chemical state of a given impurity species. 15,17,39 The X-ray beam induced current (XBIC) is used to measure the recombination activity of defects in a method analogous to laser/light beam induced current (LBIC). The incoming X-ray beam is used to generate electronhole pairs, which are then collected by a Schottky diode 41 or a pn junction.…”

Section: Methodsmentioning

confidence: 99%

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Chemical natures and distributions of metal impurities in multicrystalline silicon materials

Buonassisi

Istratov

Pickett

et al. 2006

Progress in Photovoltaics

176

106

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We present a comprehensive summary of our observations of metal-rich particles in multicrystalline silicon (mc-Si) solar cell materials from multiple vendors, including directionally-solidified ingot-grown, sheet, and ribbon, as well as multicrystalline float zone materials contaminated during growth. In each material, the elemental nature, chemical states, and distributions of metal-rich particles are assessed by synchrotron-based analytical x-ray microprobe techniques. Certain universal physical principles appear to govern the behavior of metals in nearly all materials: (a) Two types of metal-rich particles can be observed (metal silicide nanoprecipitates and metal-rich inclusions up to tens of microns in size, frequently oxidized), (b) spatial distributions of individual elements strongly depend on their solubility and diffusivity, and (c) strong interactions exist between metals and certain types of structural defects. Differences in the distribution and elemental nature of metal contamination between different mc-Si materials can largely be explained by variations in crystal

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Chemical natures and distributions of metal impurities in multicrystalline silicon materials

Buonassisi

Istratov

Pickett

et al. 2006

Progress in Photovoltaics

176

106

View full text Add to dashboard Cite

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“…[32,33] for details). Measurement geometry was selected for the sample normal, varying between approximately 15°and 45°relative to the incoming beam, and thus the information depth (i.e., thickness of material after which the XRF signal intensity decays to 1/e, a strong function of the X-ray fluorescence energy [32]) varied between 9 and 25 lm for iron (K-edge fluorescence at 6.4 keV) and between 18 and 50 lm for copper (K-edge at 8 keV).…”

Section: Methodsmentioning

confidence: 99%

“…Once a metal impurity precipitate of interest was located, X-ray absorption microspectroscopy (l-XAS) was performed on the regions with distinct elemental composition to determine the local chemical state (see [32,33] for details). The absorption spectra allow one to determine what chemical interactions, if any, exist between individual elemental species at a given location within a metal-rich precipitate.…”

Section: Methodsmentioning

confidence: 99%

Transition metal co-precipitation mechanisms in silicon

et al. 2007

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“…These beamlines at third-generation synchrotrons are capable of detecting submicron-sized metal-rich precipitates and inclusions in mc-Si. 60 …”

Section: Other Characterization Techniquesmentioning

confidence: 99%

Infrared birefringence imaging of residual stress and bulk defects in multicrystalline silicon

Ganapati

Schoenfelder

Castellanos

et al. 2010

Journal of Applied Physics

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This manuscript concerns the application of infrared birefringence imaging ͑IBI͒ to quantify macroscopic and microscopic internal stresses in multicrystalline silicon ͑mc-Si͒ solar cell materials. We review progress to date, and advance four closely related topics. ͑1͒ We present a method to decouple macroscopic thermally-induced residual stresses and microscopic bulk defect related stresses. In contrast to previous reports, thermally-induced residual stresses in wafer-sized samples are generally found to be less than 5 MPa, while defect-related stresses can be several times larger. ͑2͒ We describe the unique IR birefringence signatures, including stress magnitudes and directions, of common microdefects in mc-Si solar cell materials including: ␤-SiC and ␤-Si 3 N 4 microdefects, twin bands, nontwin grain boundaries, and dislocation bands. In certain defects, local stresses up to 40 MPa can be present. ͑3͒ We relate observed stresses to other topics of interest in solar cell manufacturing, including transition metal precipitation, wafer mechanical strength, and minority carrier lifetime. ͑4͒ We discuss the potential of IBI as a quality-control technique in industrial solar cell manufacturing.

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Synchrotron-based impurity mapping

Cited by 42 publications

References 9 publications

Chemical natures and distributions of metal impurities in multicrystalline silicon materials

Chemical natures and distributions of metal impurities in multicrystalline silicon materials

Transition metal co-precipitation mechanisms in silicon

Infrared birefringence imaging of residual stress and bulk defects in multicrystalline silicon

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