Depth-dependent x-ray diffraction using extremely asymmetric reflections

Investigations of semiconductor heterostructures by x-ray diffraction are c haracterized by the absence of any direct depth information in the scatteri ng profile. This paper demonstrates a new method of obtaining depth-depende nt information about heterostructures by x-ray diffraction. The distances i nvolved here are limited by the absorption of the x-rays in the material. T he absorption depth can be varied continuously for asymmetric reflections b y rotating the sample around the scattering vector. Two different methods f or this rotation as well as experimental set-ups are discussed. We present experimental results that conclusively demonstrate the usefulness of depth- dependent measurements. The data can be used directly for the improvement o f semiconductor devices.