Grazing incident small angle x-ray scattering: A metrology to probe nanopatterned surfaces

Grazing incident small angle x-ray scattering (GISAXS) and transmission small angle x-ray scattering studies have been carried out on periodic patterns on silicon substrates in order to determine the average morphology and arrangement of the patterned features. The GISAXS pattern exhibited rods of scattering at Bragg positions, discrete and evenly spaced, in the surface plane. The scattered intensity modulations along each rod have been compared with simulated scattering from simple geometrical patterns to obtain quantitative information on the diameter, width, height, and sidewall inclination of the pillars and gratings. The results are in good agreement with real space images obtained with SEM and demonstrate that GISAXS is a powerful technique for characterizing nanoscale arrays used in patterned media, photonics structures, and electronics structures.