Wafer Scale N‐Doped Diamond (111) with Mainly Nitrogen Spin Bath Limited Nitrogen Vacancy Coherence Times from Heteroepitexial Growth

Diamond (111) is grown heteroepitaxially on 2″ Ir/YSZ/Si (111) wafers (YSZ=yttria‐stabilized zirconia) with a diameter of 50 mm and off‐cuts of up to 6, applying plasma‐enhanced chemical vapor deposition supported by bias‐enhanced nucleation and epitaxial lateral overgrowth. In the final growth step, a nitrogen‐doped layer (N‐Cap) is superimposed. In the N‐Cap, a preferential orientation of nitrogen vacancy (NV) centers along the surface normal is observed, which has a T coherence time of 9.3 μs, which is the highest value ever reported for heteroepitaxial diamond (111). In the meantime, the T dephasing time is 95 ns, which means that the T / T ratio is almost 100, while published ratios for homoepitaxial diamond are in the range 5–20. The total nitrogen concentration as measured by Time‐of‐Flight Secondary Ion Mass Spectrometry is determined to be 7.3 ppm, which, in combination with photoluminescence analysis, yields an NV incorporation efficiency of .