APPLICATION OF HIGH-RESOLUTION X-RAY-DIFFRACTOMETRY TO THE STRUCTURALSTUDY OF EPITAXIAL MULTILAYERS ON NOVEL INDEX SURFACES

The applicability of high-resolution X-ray diffractometry (HRXRB) to t he structural characterization of epitaxial structures on arbitrarily oriented surfaces is shown. This technique was used to study piezoelec tric InGaAs/GaAs multiquantum well and superlattice p-i-n photodiodes grown on (001) and (111)B GaAs. The structural information obtained by HRXRD was important for understanding the optoelectronic behaviour of the diodes, since the strain-induced piezoelectric field strongly aff ected their characteristics. The interpretation of the HRXRD experimen ts was possible thanks to a simulation model developed in our laborato ry which allows the calculation of any symmetric or asymmetric reflect ion on an arbitrarily oriented substrate. We also show some examples o f the asymmetric distortion of the strained unit cells owing to the su bstrate misorientation. (C) 1997 Elsevier Science Ltd.