An X-ray monochromator system using successive reflection and its application to measurements of diffraction curves of annealed GaAs wafers

To measure local lattice deformation on crystal surfaces, a monolithic monochromator system for Mo Kα₁ radiation was designed which uses successive 444 and 022 reflections from an Si crystal. The angular spread of the monochromated beam is 1.7′′ and the wavelength spread (Δλ/λ) is 1.9 × 10⁻⁵. The system has been applied to precise measurement of the Bragg-case diffraction curve from Ge and GaAs crystals with a triple-crystal arrangement. The percentage reflection and half-width of the diffraction curve at various points on semi-insulating GaAs wafers were measured before and after annealing at 1123 K, with the results that annealing processes are found to be very effective for improving the quality of the crystal.