Local thickness measurements using reflectivity of X-rays in the dispersive angle mode

Abstract
The multiple beam interference of parallel layers and/or the Bragg peaks of multilayers are measured in the angle-resolved dispersive mode with a position sensitive proportional counter. The specimen is illuminated by a divergent X-ray beam produced by a sealed linear focus tube. The arrangement permits either to obtain spectra in a short time and to eliminate any movement during measurement. Furthermore, this configuration has the advantage of analysing a small surface area of the specimen (less than 1 mm²). Consequently, a scanning of a layer or a multilayer is possible. Both examples concerning a deposited layer and a multilayer will be given, showing variation in thickness according to the distance between the sputtering or evaporation system and the sample holder.