Development of a Planarization Process for the Fabrication of Nanocrystalline Diamond Based Photonic Structures. Issue 21 (21st June 2019)

• Record Type: Journal Article
• Authors: Heupel, Julia; Felgen, Nina; Merz, Rolf; Kopnarski, Michael; Reithmaier, Johann Peter; Popov, Cyril
• Other Names: Becher Christoph guestEditor.; Pobedinskas Paulius guestEditor.
• Is Part Of: Physica status solidi. Volume 216:Issue 21(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-06-21
• Subjects: diamond nanopillars -- diamond photonic crystal slabs -- nanocrystalline diamond -- surface planarization; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.201900314
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : A significant reduction of the intrinsic surface roughness of nanocrystalline diamond (NCD) layers (e.g., from 25–50 nm down to ≈ 2–6 nm) is accomplished together with an adjustment of the film thickness applying a two‐step planarization process. Therefore, a spin‐on‐glass (SOG), consisting of the inorganic polymer perhydropolysilazane, is spin‐coated on top of the NCD layer. After baking, a smooth silica‐like layer covered the diamond crystallites. This planar surface is transferred to the NCD surface by a dry etching step, yielding a similar etch selectivity for the diamond and the SOG layer (etching rates of SOG:NCD ≈ 1) applying a mixture of sulfur hexafluoride and oxygen. The planarized surface of the NCD layer led to an enhancement of the uniformity of structures defined by electron beam lithography (EBL), e.g., nanopillars with various diameters as well as two‐dimensional photonic crystal slabs. Abstract : A two‐step planarization procedure for nanocrystalline diamond (NCD) films, utilizing a spin‐on‐glass (consisting of perhydropolysilazane) and subsequent O2 /SF6 plasma etching, is developed and investigated. With this process, a significant reduction of the NCD surface roughness is accomplished. The implementation of smooth NCD layers can minimize the scattering effects during e‐beam lithography and improves the quality of the fabricated nanostructures.