Metal-induced lateral crystallization of germanium thin films

Abstract

Recent advances in polycrystalline Ge layers formed through solid-phase crystallization have demonstrated carrier mobilities superior to those of single-crystal Si. In this study, we thoroughly examined the phenomenon of metal-induced lateral crystallization in Ge, a topic that had garnered significant attention in Si research and had shown promise in improving the performance of thin-film transistors. Of the 24 metals tested (Au, In, Bi, Pb, Ga, Ag, Al, Sn, Zn, Sb, Fe, Nb, Mg, Mn, Co, Cr, Mo, Zr, Cu, Ni, Pd, Ta, Ti, and W), 20 were found to promote the low-temperature (<400 °C) lateral growth of Ge layers on glass. Based on the reaction type (eutectic or compound), reaction temperatures, diffusion coefficients, and domain matching analyzed using a materials informatics method, the growth morphology was categorized into three types: alloy, dendrite, and uniform. The knowledge of metal-induced growth obtained in this study has broad implications for a variety of materials and holds potential for developing the next generation thin-film devices with common and inexpensive substrates.