A Chemical Vapor Deposition Diamond Reactor for Controlled Thin‐Film Growth with Sharp Layer Interfaces

Abstract

A microwave plasma reactor for diamond growth that allows for highly controllable process conditions is presented. The position of the diamond substrate within the reactor can be accurately controlled. Thus, equilibration of plasma conditions can be carried out after changes in process parameters. With this approach, sharp layer transitions among doped, undoped, and isotopically controlled diamond films can be obtained. In addition to the sample transfer, the growth temperature is maintained through a substrate heater, and a clean reactor environment is realized by a load‐lock sample exchange system. The plasma conditions are constantly monitored by optical emission spectroscopy. Using this system, the growth of nanoscopic sandwich structures is demonstrated with controlled isotopic ratios down to ≈10 nm thickness and N(V) layers below 50 nm are obtained on (001)‐oriented diamond. Growth rates and doping efficiencies depending on the used methane concentration are presented. Characterization with continuous‐wave optically detected magnetic resonance yields an average contrast of 4.1% per nitrogen vacancy (NV) orientation in layers with a thickness below 100 nm. Depending on the used methane concentration, surface morphology and NV doping homogeneity are influenced as observed by photoluminescence and atomic force microscopy measurements.

Imaging local diffusion in microstructures using NV-based pulsed field gradient NMR

“…S1 and S2. An electronic-grade, single crystal, 100-oriented diamond (2x2x0.5 mm, Element Six, Oxford, UK) which has been overgrown with a ∼ 19 ppm nitrogen-doped 12 C and 15 N isotopically enriched diamond layer with a thickness of ∼ 50 µm by the Fraunhofer Institute for Applied Solid State Physics (Freiburg, Germany) as described in Schätzle et al [47] and cut into a trapezoidal shape, which was then electron irradiated and annealed to increase the nitrogen to NV conversion rate. This particular thickness of the nitrogen doped layer was chosen, since simulations of the experimental geometry indicated this to optimize the signal to noise ratio (SNR) for our microfluidic channels [26].…”

Imaging local diffusion in microstructures using NV-based pulsed field gradient NMR

“…An electronic grade, single-crystal, 100-oriented diamond (2 mm by 2 mm by 0.5 mm; Element Six, Oxford, UK) was overgrown with a ∼19–parts per million (ppm) nitrogen-doped 12 C and 15 N isotopically enriched diamond layer with a thickness of ∼50 μm by the Fraunhofer Institute for Applied Solid State Physics (Freiburg, Germany) as described by Schätzle et al. ( 55 ). This particular thickness of the nitrogen-doped layer was chosen for an optimized SNR obtained by simulations of our microfluidic channels ( 29 ).…”

Microfluidic quantum sensing platform for lab-on-a-chip applications

“…The NV center-doped diamond micron-layer (∼50 μm, ∼19 ppm substitutional nitrogen (P1 centers)) was homoepitaxially grown on electronic grade single crystal diamonds (2.0 × 2.0 × 0.5 mm) with a bulk nitrogen concentration of <5 ppb (Element Six Technologies Limited, Didcot, United Kingdom) by chemical vapor deposition (CVD) at the Fraunhofer Institute for Applied Solid State Physics (Freiburg, Germany). 55 The diamond sample was subsequently irradiated with electrons and high-temperature annealed under ultrahigh vacuum, yielding a dense NV ensemble layer. 17 Subsequently, two sides of the diamonds were polished at a 45°angle yielding trapezoidal-shaped diamonds where the top face is 2.0 × 1.0 mm in size (MEDIDIA GmbH, Idar-Oberstein, Germany).…”