J. Gonzalez-hernandez et al., Temperature dependence of structure and electrical properties of germanium-antimony-tellurium thin film, J VAC SCI A, 18(4), 2000, pp. 1694-1700
The interest in the study of Ge:Sb:Te thin films is due to their use as opt
ical and electrical memory materials. Both of these applications are based
on the structural change from the amorphous to the crystalline state. Thus,
understanding of the mechanism of crystallization in this material is impo
rtant from basic and technological points of view. In this work we have stu
died the kinetics of the crystallization of Ge:Sb:Te films prepared by ther
mal evaporation. For that, in situ resistance and capacitance measurements
during heating were used. The transformation kinetics from the amorphous to
the crystalline state were analyzed using the Kissinger model, from which
the activation energy of the crystallization process is obtained. Using x-r
ay diffraction, Raman spectroscopy and optical microscope measurements, we
have observed that during heating at; different heating rates, crystallizat
ion of the film is accompanied by the segregation of micrometric inclusions
formed by amorphous tissue, perhaps some segregated impurities and crystal
line tellurium particles. The number and size of these inclusions depend on
the heating rate. From our measurements we found that the capacitance meas
urements is a sensitive method by which to analyze the crystallization proc
ess in thin films. It provides additional information not obtained using ot
her methods. (C) 2000 American Vacuum Society. [S0734-2101 (00)05404-X].