Retrograde melting (melting upon cooling) is observed in silicon doped with 3d transition metals, via synchrotron‐based temperature‐dependent X‐ray microprobe measurements. Liquid metal‐silicon ...droplets formed via retrograde melting act as efficient sinks for metal impurities dissolved within the silicon matrix. Cooling results in decomposition of the homogeneous liquid phase into solid multiple‐metal alloy precipitates. These phenomena represent a novel pathway for engineering impurities in semiconductor‐based systems.
Metallic impurities can have a severe negative impact on the electrical properties of multicrystalline silicon. Understanding how metal impurities evolve over the course of solar cell processing is ...essential to determining their impact on final device performance, and further engineering these defects into their least detrimental configuration. Herein we present a summary of the results of several recent investigations into the evolution of metallic impurities during solar cell processing, including the types and nature of impurities present after ingot crystallization; the effectiveness of phosphorous diffusion at removing and passivating different types and levels of metallic impurities; and the relationship of the hydrogen passivation step to metal impurities, as observed in synchrotron investigations of solar cells material.
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