Fabrication of diamond micro‐patterned structures is a technological challenge due to the outstanding hardness and chemical stability of the material. In this work, the synthetic diamond reactive ion etching (RIE) process is studied. The effects of the gas mixture and bias on the diamond etching rate are investigated. A high etching rate (up to 5 μm h−1) is achieved in SF6 based plasmas with the intensive ion sputtering. The features of protective masks on diamond samples fabrication are discussed. Etching selectivities of Al, Ni, Mo, Al2O3, and AlN as mask materials in SF6 plasma are investigated. The initial size of the mask affects its selectivity. To explain the influence of the initial mask shape on the selectivity, a semi‐empirical model of the diamond‐mask topography transformation under the ion sputtering is proposed. By setting the shape of the masks, it is possible to form diamond structures with any desirable profile using the same etching process: steep walls with 20 μm height, solid immersion lenses with 2–10 μm radii, conic figures, and developed surface. This is a relatively simple and universal method of diamond microstructures fabrication.

Single NV centers in HPHT IIa diamond are fabricated by helium implantation through lithographic masks. The concentrations of created NV centers in different growth sectors of HPHT are compared quantitatively. It is shown that the purest {001} growth sector (GS) of HPHT diamond allows to create groups of single NV centers in predetermined locations. The {001} GS HPHT diamond is thus considered a good material for applications that involve single NV centers.

Films of Ga2O3 were grown by Halide Vapor Phase Epitaxy (HVPE) on bulk heavily B-doped (001)-oriented diamond substrates using thin interlayers of Al2O3 deposited by HVPE or AlN/AlGaN deposited by metalorganic chemical vapor deposition. The growth with AlN/AlGaN was dominated by the formation of a highly conducting ɛ-phase with poor crystalline quality. For these samples, excessive leakage of Schottky diodes and of the Ga2O3/diamond heterojunction prevented meaningful electrical characterization. The film grown with the Al2O3 interlayer was mainly composed of (−201) β-Ga2O3 with an admixture of the ɛ-phase. The film had a low density of residual shallow donors, 5 × 1015 cm−3, with deep electron traps spectra consisting of the well documented centers for β-Ga2O3 near Ec 0.27, Ec 0.7, and Ec 1 eV, all of which are often ascribed to native defects or their complexes. The electrical properties of heterojunctions were mostly determined by the properties of the Ga2O3 films. Both Schottky diodes and heterojunctions showed measurable photosensitivity for 259 nm wavelength excitation, but very low photocurrent for near-UV (365 nm wavelength excitation).

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