Massachusetts Institute of Technology,
Keywords: bicrystal, TEM, HREM, CBED, AFM
Summary:A unique microstructure is obtained for molecular beam epitaxy (MBE) Al thin films on (100) Si when the substrate is heated during deposition in order to enhance surface mobility of the Al atoms. Two (110) Al variants are nucleated and within the plane of the thin film, they are rotated 90 degrees with respect to each other. Each variant's single close-packed direction is parallel to one of the two close-packed directions of the Si substrate. Moreover, the meandering boundary between the two variants contains no triple junctions. This combination of the crystallographic and geometric relationships is termed the mazed bicrystal microstructure. This talk presents the results of a comprehensive characterization study of the Al mazed bicrystal using transmission electron microscopy (TEM) techniques including high-resolution electron microscopy (HREM) as well as scanning electron microscopy (SEM) to decipher detailed understanding of the mazed bicrystal microstructure, convergent beam electron diffraction (CBED) to map the strain fields on either side of each type of grain boundary, and atomic force microscopy (AFM) multifrequency modes to image the mechanical properties of each type of grain boundary on the nanometer length scales.