Interferometry and Atomic Force Microscopy of Substrates for Optoelectronics Proceeded by Dry Plasma Etching

The paper describes the process of sapphire and silicon carbide substrates preparation by dry plasma etching and its characterization. The study confirms the possibility of using dry plasma etching processes for wide band gap materials treatment, since the condition of the substrate surface is an important parameter for electronic and optoelectronic devices manufacturing. Processed substrates were studied by interferometry to define the etch depth, and by atomic force microscopy to study the topography and statistical analysis of surface roughness before and after etching. The interferometry reveals the dependence of etch rate on the angle between the substrates and defocused beam of argon ions. It is also shown in low scale image that the surface damage occurs after the substrate treatment. But the common large area surface topography indicates the decreasing of roughness. In order to have purely physical etching the argon plasma was used. Thus this combination of methods allows determine optimal conditions of the substrate preparation.