Measuring the stress tensor in nitrogen-doped CVD diamond using solid-state quantum sensor

We measured the residual stress tensor in a nitrogen-doped chemical vapor deposition (001) diamond film. The stress tensor was evaluated from the amount of the shift in optically detected magnetic resonance (ODMR) spectra of NV center in the diamond. A confocal microscopy setup was used to observe the spatial variation of the stress tensor in the diamond film. We found that the components of the stress tensor, σxy, σyz, σzx, and σxx+σyy+σzz, of the residual stress were approximately 0.077, -0.39, -0.67 and 1.52 GPa, respectively in the x = [100], y = [010], z = [001] coordinate system. Regarding the components of the shear stress, σxy, σyz and σzx, the nitrogen-doped CVD diamond film grown in this study had mainly shear stress in the z-direction, which was the growth direction of the CVD diamond film. In addition, regarding axial stress σxx+σyy+σzz, the CVD diamond film was subjected to compressive stress. Due to this compressive stress, the volume of the CVD diamond film decreased by approximately 0.073%. We considered that nitrogen doping contributed to the decrease in volume of the CVD diamond film.