Strain relaxation in surface nano-structures studied by X-ray diffraction methods

We study the lattice strain relaxation in pseudomorphic surface gratings us ing high resolution X-ray diffraction and elasticity theory. Symmetrical an d asymmetrical X-ray diffraction gives evidence of a non-uniform strain rel axation in the etched structures and the creation of a periodic strain fiel d deep in the substrate. The experimental findings are confirmed by an elas ticity model which describes the interaction of the different crystalline m edia. By comparing the measured with calculated diffraction maps, we determ ine the actual strain distribution in the trapezoidal grating and in the su bstrate. (C) 2000 Elsevier Science S.A. All rights reserved.