MEASUREMENT OF INTERDIFFUSION BY HIGH-ANGLE HOLLOW CONE ILLUMINATION

High angle hollow cone darkfield or Z-contrast imaging is used to supr ess dynamical contributions like bend or extinction contours to electr on imaging. Using a multiple scattering model it is possible to interp ret image intensities quantitatively and to analyze specimen compositi on on a nanometer scale without specialized detectors like energy-ener gy-loss spectroscopy or energy dispersive spectroscopy, This method is practically tested on the interdiffusion of Cu-Au couples. Measured t hin film interdiffusion coefficents, are comparable to literature data of the bulk diffusion coefficent in this system. (C) 1997 American In stitute of Physics.