Impact of interface thermodynamics on Al-induced crystallization of amorphous SixGe1–x alloys

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Al-induced crystallization (AIC) of amorphous SixGe1–x (a-SixGe1–x) alloys with compositions over the entire range of the isomorphous Si–Ge system has been investigated. The crystallization progress was monitored by dedicated in situ x-ray diffraction analysis while gradually increasing the annealing temperature. Auger sputter-depth profiling was applied to investigate the occurrence of Al-induced layer exchange of the Al and a-SixGe1–x sublayers after complete crystallization. A-SixGe1–x alloys with x < 0.13 and x > 0.41 show largely different AIC behaviors with respect to crystallization rate and possible layer exchange of the Al and a-SixGe1–x sublayers upon crystallization. A thermodynamic model for AIC of a-SixGe1–x alloys is presented, which well explains these experimental observations and thereby demonstrates the dominant role of interface thermodynamics in the AIC process of amorphous semiconductors. The model can be used to predict the AIC behaviors of a-SixGe1–x alloys over the entire composition range at specified annealing temperatures.

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The authors are grateful to Mr. Reinhart Völker for preparation of specimens by magnetron sputtering, to Dipl.-Ing. Bernhard Siegle and Dipl.-Ing. Martin Noah for AES measurements, and to Dipl.-Ing. Gerd Maier for support with in situ XRD measurements.

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Correspondence to Zumin Wang.

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Niedermeier, C.A., Wang, Z. & Mittemeijer, E.J. Impact of interface thermodynamics on Al-induced crystallization of amorphous SixGe1–x alloys. Journal of Materials Research 29, 786–792 (2014).

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