Vol. 51, Issue 2, pp. 223-233 (2021)

Abstract

The surface roughness and residual stress behavior in two types of SiN_x/SiO₂ dielectric quarter-wave stacks was investigated experimentally. A reactive pulsed magnetron sputtering system was used to prepare the SiN_x/SiO₂ multilayer thin films. The results show that SiN_x/SiO₂ quarter-wave stack with a buffer layer of MgF₂ thin film can reduce the residual stress. The effect of aging on the residual stress in two quarter-wave stacks was also studied. We found that the residual stresses in both SiN_x/SiO₂ multilayer coatings are changed from a compressive state to a tensile stress state with increasing the aging time. The root mean square (RMS) surface roughness of MgF₂/(SiN_x/SiO₂)²² and (SiN_x/SiO₂)²² quarter-wave stacks are 2.23 ± 0.22 nm and 2.08 ± 0.20 nm, respectively.