LOW-TEMPERATURE SOLID-PHASE HETEROEPITAXIAL GROWTH OF GE-RICH SIXGE1-X ALLOYS ON SI(100) BY THERMAL ANNEALING A-GE/AU BILAYERS

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-degrees-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 almost-equal-to 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.