Fabrication of a nanometer thick nitrogen delta doped layer at the sub-surface region of (100) diamond

In this letter, we report on the proof of a concept of an innovative delta doping technique to fabricate an ensemble of nitrogen vacancy centers at shallow depths in (100) diamond. A nitrogen delta doped layer with a concentration of ∼1.8 × 1020 cm−3 and a thickness of a few nanometers was produced using this method. Nitrogen delta doping was realized by producing a stable nitrogen terminated (N-terminated) diamond surface using the RF nitridation process and subsequently depositing a thin layer of diamond on the N-terminated diamond surface. The concentration of nitrogen on the N-terminated diamond surface and its stability upon exposure to chemical vapor deposition conditions are determined by x-ray photoelectron spectroscopy analysis. The SIMS profile exhibits a positive concentration gradient of 1.9 nm/decade and a negative gradient of 4.2 nm/decade. The proposed method offers a finer control on the thickness of the delta doped layer than the currently used ion implantation and delta doping techniques.