Interface analysis by x-ray diffraction topography

Abstract

X-ray reflection topography has been used for the analysis of cleavage surfaces of gallium arsenide epitaxial layers. The detection of a cristallographic interface is possible and this has been related to the electric probe detection. The structural nature of interface, which is different for different growth methods, is attributed to an interfacial array of dislocations with, in some cases, additional lattice strains. This is demonstrated by observations on different cleavage surfaces in the same sample. Thus the direct visualization by X-ray topography provides a non-destructive control of the quality of the growth of epitaxial layers which is essential for the improvement of devices such as Gunn Diodes.