where Es is the substrate's Young modulus, νs the substrate's Poisson ratio, hs is the substrate's thickness, hf the thickness of the film and R the radius of curvature of the film after initial curvature correction. The extraction of the principal directions radii is performed by the “Gwyddion software” from the subtraction of the substrate images before and after deposition. The residual stress in the films at different N/Mo ratios is presented in Fig. 4.