Influence of CVD diamond growth conditions and misorientation angle on nitrogen incorporation

CVD diamonds with NV-centers (nitrogen vacancy centers) are now considered as the most promising solidstate media for the realization of component base for quantum information processing due to the unique properties of NV-center electronic transitions, which allow initialization and read-out of it`s spin state [1]. The concentration and spin properties of NV-centers depend on nitrogen concentration and therefore it is important to understand the dependence of nitrogen incorporation in delta-layers on CVD growth conditions. In this work, delta-layers (1-5 nm thick) doped with nitrogen were obtained during CVD synthesis using the unique setup for delta doping created in IAP RAS [2]. It was shown that the subsequent CVD growth with and without nitrogen addition allows obtaining a two-dimensional structure of the NV centers with a given concentration and any required depth that may be determined with an accuracy of up to 1–2 nanometers. Also the influence of substrate temperature, nitrogen flow and methane content on nitrogen incorporation was investigated by the growth of nitrogen doped layers on (100) and (111)-oriented samples. The method of delta doping in contrast to the method of ion implantation does not produce lattice defects and allows controlling the depth of the NV-center to within a few nanometers. CVD growth allows producing singlecrystal diamond of high crystalline perfection with a low content of impurities that does not vary from sample to sample. Due to the absence of lattice damage, as in the case of ion implantation, NV-centers produced by deltadoping will have better properties (e.g. higher spin coherence times). CVD diamond growth of nitrogen-doped layers was performed in the novel CVD reactor. The main features of the reactor are: 1) rapid gas switching; 2) laminar gas flow; 3) axial symmetric resonant mode – symmetric discharge; 4) slow growth of diamond (40–100 nm/h without nitrogen addition). We achieve rapid gas switching from one input gas to another by a home-made electronic switch. The residence time of our reactor is approximately 5 s. The reactor is also capable for the growth of delta-layers doped with any other impurities, such as nitrogen. It is well-known, that incorporation of impurities during CVD diamond growth is highly dependent on the substrate orientation, and could also be affected by the misorientation angle. In order to eliminate the influence of substrate, each of the experiment was performed on one sample, varying growth conditions in a one growth process, resulting in the growth of multiple thin nitrogendoped layers (see Fig. 1). Moreover, in this work we investigated the dependence of nitrogen incorporation efficiency on the misorientation angle using the (100)oriented sample with multiple facets polished at different misorientation angles.