Abstract

With the increasing demand of the cost effective optical recording system, the optical media based on the phase-change phenomena have attracted an extensive research interest. One of the commonly used recording material for the phase-change optical disk is Ge-Sb-Te (GST) alloys which show a reversible phase transformation between the crystalline and the amorphous, thus the corresponding reflectivity change.^[1,2] It has been reported that GST-alloys near to the stoichiometric compound are suitable for high speed application while other alloys like In-Sb-Te and Ag-In-Sh-Te are reported to be appropriate for low -speed applications.^[3,4] The main purpose of this research is to study the feasibility of GST-alloys for the blue wavelength region for both high density recording and linear velocity applications. Variation of the complex refractive indices with Sb-addition in GST-alloy and their wavelength dependence were studied in the present research by using spectroscopic ellipsometry (SE) and atomic force microscopy (AFM). The reflectivity spectra of GST with different chemical compositions were calculated using these optical constants, and compared with the measured spectra.

© 1998 Optical Society of America