Morphology evolution and non-uniformity removal mechanism analysis of diamond nanocone arrays by reactive ion etching

Abstract

Microstructures of diamond can be fabricated by reactive ion etching and during this process the evolution of surface morphology can affect the electric field near the microstructure. These changes in the electric field will alter the trajectory of ions, thereby affecting the number of ion bombardments on the surface regions of the microstructure. Consequently, this will affect the removal rate of the material on the microstructure surface and consequently affects the evolution of microstructure morphology. In order to understand the morphology evolution process of diamond during etching. H2 and Ar were used as the reactive gases to etch the nanocrystalline diamond (NCD) films with masks. The electric field near the microstructure and the trajectories of reactive ions was stimulated. The number of H+ and Ar+ bombardments at various regions on the diamond microstructure surface has been recorded and analyzed. By observing the cross-sectional morphology of the microstructure at different periods, the etching process of nanocones was analyzed. The study found that the microstructure of the diamond surface would gradually be etched into convex shaped and waist drum shaped and cone. By stimulating the electric field near the microstructure, it was found that the electric field distorted near the microstructure, causing the electric field lines initially perpendicular to the diamond surface to be diverted. As a result, the trajectory of the particles originally arrived perpendicularly to the diamond surface was distorted and hence they bombarded against the sidewall of the diamond microstructures. The angle between the ion trajectory and the electric field line also increased gradually.