Analysis of ZnS and MgF2 layered nanostructures grown by glancing angle deposition for optical design

Abstract

This study investigated the multilayer growth and properties of ZnS and MgF2 using glancing angle deposition. We used deposition angles of 85 degrees-89 degrees for ZnS and 70 degrees-88 degrees for MgF2 to obtain the structural properties. The film properties primarily followed Tait's rule with a deposition angle of less than 87 degrees in the vapor flux. However, film growth with a vapor flux angle of 88 degrees-89 degrees followed the tangent rule. Mathematical and cross-sectional scanning electron microscopy examinations found a transition point for the growth mechanisms at 87 degrees, which comes from an extreme angle property for glancing angle deposition. We also performed mathematical derivations for the well-known empirical formula of the tangent rule and its generalized version. To stabilize the interface structure and surface roughness of multilayer structures, film growth at slightly tilted angles is recommended. Based on these results, an optical structure was designed, fabricated, and analyzed for a 550 nm wavelength pass filter on a glass substrate.