Development of Disordered and Ordered Nanoscale Terraced Topographies on Si Under Oblique Incidence Xe⁺ Ion Bombardment

We explored disordered and ordered nanoscale terraced topographies that develop when a solid surface is bombarded by an ion beam at oblique incidence. It is shown that a flat Si surface when bombarded with 1500 eV Xe⁺ ions at 75° off normal incidence develops a disordered terraced topography. Using a Si surface pre-patterned with 500 nm pitch lines, it is demonstrated that ordered terraced topographies with sub-nanometer roughness on the facets develop under the above conditions. Ordered terraced substrates can be used in the fabrication of EUV multilayer blazed gratings. This work was performed in tandem with theory in an effort to refine models.