Surface Effects in Uniaxially Stressed Crystals: The Internal Strain Parameters of Silicon and Germanium Revised

摘要

All previous determinations of internal strain parameters have been based on the measurement of the intensity of ''forbidden'' X-ray reflections as a function of uniaxial stress, with the stress taken as the quotient of applied force and the cross-sectional area of the crystal. We report here the results of monitoring directly several interplanar spacings in the regions of the surface where the X-ray diffraction actually occurs. Values 35% larger than those calculated from the mean stress were found consistently for both silicon and germanium. Together with support from a re-examination of the data on which previous values were based these investigations lead to revised values of the internal strain parameters. (ERA citation 12:027935)