ABSTRACT
Using X-ray diffractometry we have measured rocking curves and the absolute reflectivity of graded and non-graded Si1-xGex crystals, which have been grown by the Czochralski technique at the Institute of Crystal Growth Berlin-Adlershof. Our measurements indicate that the crystal quality is very close to those of pure, commercially available Si crystals. The specimens were mounted on a moveable sample holder, which can be translated in all three room directions. We could therefore measure the Ge concentration on all points of the sample surface and could detect local lattice imperfections. We also discuss the properties and the accuracy of the used X-ray diffractometer and present a method to eliminate systematic errors like surface curvatures of the specimen which is important for the calculation of the true lattice parameter variation in the Si1-xGex crystals.
