Analysis of the optical properties and structure of sculptured thin films from spectroscopic Mueller matrix ellipsometry

Abstract

The Mueller matrices describing oblique incidence reflection and normal incidence transmission have been measured for sculptured thin films (STFs) by glancing angle deposition with simultaneous substrate rotation. In data reduction, the 15 parameters of the (1,1)-normalized real Mueller matrix are converted to the six parameters of the (2,2)-normalized complex Jones matrix. Two computational methods yield excellent agreement in the real and imaginary parts of the complex amplitude ratios ρps and ρsp obtained in reflection (or τps and τsp obtained in transmission). Multilayer optical analysis has been developed that employs step-wise variations of the principal axis Euler angles, associated with the local uniaxial structure in successive sublayers, in order to simulate variations in the column orientation with depth into the film. Such analysis has elucidated the Bragg resonance characteristics exhibited by the optical rotation of chiral STFs.