Crystallization mechanism in Sb: Te thin films

The aim of this work is to study the mechanism of crystallization in Sb:Te thin films using differential scanning calorimetry (DSC), four-probe resistivity and X-ray diffraction (XRD) measurements. The DSC showed that the Sb70+x, Te30-x films with x in the range of -3 <= x <= 3 show one exothermic reaction at 110 degrees C, whereas the films with x in the range of 3 <= x <= 13 present an additional one at about 70 degrees C. XRD measurements and Rietveld analysis have shown that the first exothermal peak can be associated to the formation of crystalline Sb and the second to the process of transformation of the Sb and the remaining material into a more stable Sb2Te3 crystalline phase. Appearance of additional Sb phase decreases the crystallization temperature of Sb70+x,Te30-x films. These structural transformations are also observed in the four-probe resistivity measurements: a one-step crystallization process in the Sb70+x,Te30-x films with x in the range of -3 <= x <= 3and a two-steps crystallization process in films with x in the range of 3 <= x <= 13. The results of this investigation have shown that the amorphous-to-crystalline phase transformation in eutectic Sb:Te depended on the films composition. (C) 2006 Elsevier Ltd. All rights reserved.