MICROCRYSTALLINITY AT SIO2 SI(001) INTERFACES - AN EFFECT OF ANNEALING/

By complemeatary use of X-ray crystal truncation rod (CTR) scattering and difference X-ray reflectivity (DXR), structural properties on ultr a-thin thermal oxides grown on Si(001) substrates were obtained. A thi n film which contains SiO2 crystallites concentrated at the SiO2/Si(00 1) interface revealed to have an interfacial thin layer characterized by high electron density. and vice versa. An effect of annealing in Ar gas has been understood consistently. The CTR scattering data indicat ed that probability of finding the crystallites in the oxide film rema ined, but the lattice constant of the crystallites increased along the direction perpendicular to the interface by the annealing. The decrea se in the density calculated by this volumetric expansion agrees well with the decrease in average density of the interfacial thin layer obs erved by the DXR measurements. (C) 1998 Elsevier Science B.V. All righ ts reserved.