SURFACE DIFFRACTED WAVES OF GRAZING INCIDENT X-RAYS WITH THE PERIODICALLY MODULATED AMPLITUDE. A.P. Bezirganyan and S.E. Bezirganyan, Dep. of Solid State Physics, Faculty of Physics, Yerevan State University, No.1, Alex Manoogian st., Yerevan-49, 375049 Armenia.

The surface diffracted waves are theoretically investigated versus on the azimuth and pole angles of incidence of X-rays with the wave front amplitude periodically varying along the single crystal (SC) surface. The surface waves are attenuating on both sides across the vacuum-structure boundary. The following scheme of X-ray grazing incidence diffraction (GID) is investigated: The X-ray plane wave is reflected by the diffraction grating (DG). The reflected radiation's wave front amplitude is varying periodically along the same direction, at which the reflecting elements of DG are periodically deposited. Then the reflected wave falls at grazing angles onto a SC. The diffracting lattice planes of SC are normal to the entrance surface (symmetrical Laue case). Due to modern technologies the device performing elements' thicknesses are in nanometer ranges e.g. in the integrated circuits, solid state lasers etc., and if in particular the performing elements are deposited periodically on the substrate, one may consider the device surface layer as the reflecting DG for the X-rays. The reflection function of such DG may be used for the control and monitoring of device surface elements quality. The conditions at which the reflected from DG X-ray wave field has the narrow angular spectrum are investigated in detail. The method of investigation of such modulated incident waves by the GID technique is suggested.