Semi-isotropic surface etching of diamond using a Faraday cage

•Etching of single-crystalline CVD diamond using Faraday cage.•Deposition of mask on the substrate is not required.•Semi-isotropic surfaces are obtained by etching.

Etching of diamond is one of the most important process steps to realize diamond based devices. Isotropic etching in diamond yielding a high etch rate is challenging owing to its material properties. In the current study, single-crystalline diamond is etched using a Faraday cage that acts as the mask to attain semi-isotropic etching. An oxygen/chlorine plasma discharge with a pressure of 10 mTorr is used. The etching process is optimized by varying the applied plasma power, and the substrate bias together with varying parameters such as the thickness of the mask, the mask-to-diamond surface distance and the diameter of the holes in the mask. After optimization, semi-isotropic etched surface profiles up to a depth of 5 μm with an etch rate of 80 nm/min and surface roughness close to that of the unetched surface are achieved.

Graphical abstractEtching of diamond using Faraday cage and anisotropic etch technique to achieve semi-isotropic surfaces.Figure optionsDownload full-size imageDownload as PowerPoint slide