The concentration of nitrogen of4 ppm gives the diamonds yellow color of saturation in the range of grade Z .This nitrogen content can be considered as a moderate doping level for CVD diamonds. A
heavily doped CVD diamonds may take up to tens of ppm of dispersed nitrogen. Much lower maximum concentration of nitrogen which can be achieved in CVD diamonds, as compared with HPHT-grown diamonds, is the consequence of much lower temperature and pressure the CVD diamond grow at. It is known, that the equilibrium concentration of dispersed nitrogen in diamond lattice strongly increases with temperature and pressure.