AN X-RAY-SCATTERING STUDY OF LATERALLY MODULATED STRUCTURES - INVESTIGATION OF COHERENCE AND RESOLUTION EFFECTS WITH A GRATING

An X-ray scattering experiment at small angle of incidence from the la terally modulated structure of a grating is reported. The attention is mainly focused on the determination of the linewidth of the different diffracted orders observed in transverse scans parallel to the surfac e of the grating. It is shown that the width of the different orders d ecreases when the incident angle increases and that the evolution of t he width is consistent with the evolution of the instrumental resoluti on. It is also shown that if the spatial coherence of the beam is defi ned by the angular apertures of the incident and outgoing beams a iden tical behavior is expected at least when the diffracted orders are wel l separated.