Low-temperature solid-phase heteroepitaxial growth of Ge-rich SixGe1−x alloys on Si (100) by thermal annealing a-Ge/Au bilayers

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Abstract
Heteroepitaxial layers of SixGe1−x alloys were grown on Si(100) by thermal annealing bilayers of a‐Ge/Au deposited on single‐crystal Si (sc‐Si) substrates at 300 °C. During annealing, Ge dissolves into the Au layer and then grows epitaxially to the substrate, with the final structure changing from a‐Ge/Au/sc‐Si to Au/SixGe1−x/sc‐Si. The SixGe1−x layer was found to be Ge rich (x≊0.15) from AES and STEM analysis and to be epitaxial to the Si(100) substrate from the x‐ray rocking curve and RBS channeling measurements. Stacking faults and microtwins are the major defects in the epitaxial film, as observed by cross‐sectional TEM. High‐resolution TEM analysis of the SixGe1−x/Si interface shows that the growth initiates at specific areas of the original Au/Si interface. This work demonstrates for the first time both heteroepitaxial growth and the growth of SixGe1−x alloys on Si(100) using solid phase epitaxy with an eutectic‐forming metal as the transport medium.