AVS 45th International Symposium
    Thin Films Division Monday Sessions
       Session TF-MoP

Paper TF-MoP5
Optical Properties of the Ge:Sb:Te System

Monday, November 2, 1998, 5:30 pm, Room Hall A

Session: Thin Films Poster Session
Presenter: J. Gonzalez-Hernandez, CINVESTAV-IPN, Mexico
Authors: E. Garcia-Garcia, Univ. Autonoma de Queretaro, Mexico
A. Mendoza, Univ. Autonoma de Puebla, Mexico
G. Martinez-Montes, Univ. Autonoma de Puebla, Mexico
Y.V. Vorobiev, CINVESTAV-IPN, Mexico
J. Gonzalez-Hernandez, CINVESTAV-IPN, Mexico
B.S. Chao, Energy Conversion Devices
Correspondent: Click to Email
Stoichiometric compositions of the Ge:Sb:Te system are commercially used for optical data storage. In this work, we have measured using ellipsometry, the optical constants (n, k) in the range of 1.4 to 6 eV in all the stoichiometric composition in the Ge:Sb:Te system. It is known that the amorphous phase of these compositions undergoes an amorphous-to-crystalline transition at temperatures in the range from 140-160 °C depending on Sb concentration. The crystalline structure of this phase is the fcc. Heat treatments at temperatures above the mentioned range produce a new crystalline-to-crystalline transition from the fcc to the hexagonal phase. The n values for the amorphous and crystalline fcc phase are not so different and both decrease from a value of about 5 to 1.4 eV to a value of 1 at 6 eV. In general, this phase transition produces an increase in the values of k in the whole energy range. The observed changes in n and k in the hexagonal phase are more complex due to the increase in the free charge density and will be discussed in the extended presentation.