Implementation of smooth nanocrystalline diamond microstructures by combining reactive ion etching and ion beam etching

摘要

AbstractDue to its extraordinary properties diamond can be used as mold in a hot embossing process which allows the replication of micro-optical structures. For this application a low surface roughness is indispensable. We investigated the ability of ion beam etching (IBE) to smooth defined rough areas after reactive ion etching (RIE). Simulations based on the influence of the angle dependence of the ion beam etch rate showed the suitability of this approach.Different surface qualities were achieved for nanocrystalline diamond films by RIE with three different oxygen-argon gas mixtures and etch depth, respectively. SEM images displayed the expected increase of surface roughness with the oxygen share of the gas mixture and the achieved etch depth.No masking layers were employed during ion beam post-processing. The comparison of different AFM images confirm that this process enlarged the etch depths corresponding to the initial surface roughness until the rough areas are smoothed completely. With increasing surface roughness the expenditure of time necessary to reach saturation rose. Etch rates measured for reactive ion etching were 5 to 6 times higher than the etch rate measured for IBE. Simply comparing the etch time the combination of RIE and IBE is up to four times faster than only employing IBE for the fabrication of structures despite using low RIE plasma powers.Graphical abstractDisplay OmittedHighlights?Smoothing of rough areas after reactive ion etching (RIE) by ion beam etching (IBE)?IBE post-processing is easy to employ because no masking layers are used.?Initial surface roughness determines duration of IBE and step heights increase.?RIE with post-processing by IBE is considerably faster than employing IBE only.]]>