Reactive p DC RF sputtering with closed loop reactive gas
Therefore, the Si target was strongly oxidized and sputtering in a strongly poisoned target state, affecting formation of a porous mixture thin film. By contrast, a maximum of only 0.4% positive inhomogeneity was found for deposition in the ‘transition’ zone by employing closed-loop RMS process control. We attribute this effect to the RMS process stabilization, which results in a constant thin film through-thickness composition. Further TEM analysis of the thin films would be beneficial in explaining the exact causes of the refractive index gradients.