Observation of microdefects in thin silicon crystals by means of plane-wave topography using synchrotron x-radiation

In order to observe microdefects in silicon crystals, plane-wave topography using synchrotron X-radiation has been successfully applied to thin silicon crystals. We have aimed increasing a ratio of a diffraction signal from microdefects to diffracted intensity from the matrix crystal by taking advantage of an extinction effect of X-ray dynamical intensity. Our plane-wave topography revealed that microdefects for such thin crystals always show a distinct contrast, though we have not obtained zero intensity at the background because of a long-range elastic strain. It is proposed that when silicon wafers are thinned, stress relief at the specimen surface allows a strain field to apread around microdefects to an extent which is detectable using plane-wave topography. (author)