Effective removal of focused ion beam-induced damage in diamond nitrogen-vacancy pillar probes via inductively coupled plasma etching

Abstract Focused ion beam (FIB) milling was introduced to fabricate a diamond nitrogen-vacancy (NV) pillar on a diamond chip for a scanning magnetometry probe. However, FIB milling induces damaged residues that deteriorate the NV probe’s performance, limiting the smallest usable pillar probe’s diameter to about 1 μm. We propose a post-processing method via inductively coupled plasma (ICP) etching after FIB milling for the NV pillar probes. Their performances were examined to confirm the removal of the damaged layer at the pillar’s rim position and the improvement of Rabi contrast, T 2 time, and T 1 time after up to 25 nm of ICP etching (15 nm NV depth) on a 600 nm diameter pillar probe. These results highlight the future capability of the FIB-ICP method to fabricate high-quality scanning NV diamond pillar probes down to a few hundred nanometers in diameter, as well as having control over the depth of shallow NV centers.