Polarization conversion effect in obliquely deposited SiOx films

Abstract

Structural anisotropy of the SiOx films and nc-Si-SiOx light emitting nanostructures, prepared by oblique deposition of silicon monoxide in vacuum, has been studied using the polarization conversion (PC) effect. For this purpose, a simple method of PC investigation with usage of a standard null-ellipsometer is proposed and tested. This method is based on the analysis of the azimuthal angle dependence of the offdiagonal elements of the Jones matrix. The electron microscopy study shows that obliquely deposited SiOx films have a porous (column-like) structure with the column diameter and inclination depending on the deposition angle. Polarimetric investigations revealed that both in-plane and out-of-plane anisotropy was present, which is associated with the columnar growth. The correlation between the PC manifestations and the scanning electron microscopy results is analyzed. It was found that the tilt angle of columns in obliquely deposited SiOx is smaller than that predicted by the “tangent rule” and “cosine rule” models, and depends on the crystallographic orientation of Si substrate. It is concluded that the proposed method is effective non-destructive express technique for the structural characterization of obliquely deposited films.