Surface relief gratings of 3200-Å-period fabrication techniques and influence on thin-film growth

As part of a project to study the effects of surface relief steps on thin-film nucleation and growth, a technology for fabricating 1000-Å-linewidth surface relief gratings with control of sidewall profiles to a resolution of the order of 100 Å is under development. Laser holographic lithography and ion beam etching are used to produce gold gratings on 0.9-μm-thick polyimide membrane masks. Next, these masks are replicated using CuL or CK x-ray lithography, thereby producing high aspect ratio relief gratings in PMMA having well-defined vertical sidewalls. Surface relief structures are then produced on substrates by liftoff, ion beam etching, or reactive ion etching using the PMMA relief gratings. Such structures were decorated with gold nuclei using ion beam sputter deposition. The decoration experiments indicated a periodic variation in nuclei density and showed that the smoothness of the grating edges is of the order of 100 Å.