X-Ray Scattering Studies of Surfaces and Interfaces.

Available from UMI in association with The British Library. Requires signed TDF. This thesis describes the development of x-ray scattering techniques for the study of microscopic structural properties of surfaces and interfaces down to the Angstrom level. Experiments were performed using a triple-crystal x-ray diffractometer based on a rotating-anode source. The resolution function of the instrument is discussed in detail, in particular with reference to surface scattering and x-ray reflectivity measurements. Measurements are compared with a Gaussian description of the resolution function and it is found that this is accurate to better than 25%. Results from a variety of Si/SiO_2 structures show how a combination of x-ray reflectivity and crystal truncation rod measurements provide detailed information about amorphous surface films and also, probe the crystallinity at the Si/SiO_2 interface. New features in the crystal truncation rod scattering are caused by distortions in the top three monolayers of the silcon crystal. The reflectivity measurements are extremely sensitive to contaminant layers at the oxide surface and correct interpretation of the results is critically dependent upon their presence in the scattering model. The x-ray reflectivity and crystal truncation rod techniques provide complementary information when applied to the study of thin-layer single quantum well semiconductor devices, thus enabling full structural characterisation on an Angstrom scale. The lattice parameter strain can be obtained by modelling of the intensity distribution of the crystal truncation rod. The versatility of the x-ray reflectivity technique is demonstrated in characterising the photo-dissolution reaction in thin -film silver/chalcogenide samples. New information on the reaction process indicates the importance of sample preparation techniques in the manufacture of high-resolution devices by micro-lithography.