LAUE-CASE PLANE-WAVE TOPOGRAPHY USING SYNCHROTRON-RADIATION TO REVEAL MICRODEFECTS IN A THINNED SILICON CRYSTAL

X-ray plane-wave topography in a Laue-transmission case has been widely used to observe microdefects in otherwise perfect silicon crystals. To show the experimental effect of specimen thickness, plane-wave topographic observations were conducted before and after the stepwise chemical etching of the specimen crystal. The observations showed a heightening of the strain sensitivity when reducing the specimen thickness to less than several times the extinction distance of the relevant diffraction. The thickness eff ect was interpreted through X-ray dynamical diffraction theory for distorted crystals (Takagi-Taupin theory). The computer simulations of the diffraction theory proved that correlations exist amongst the divergence of the incident X-ray beams, the crystal thickness, and the quantity of the minute strain.