1994 Volume 58 Issue 5 Pages 576-583
The crystallization processes of amorphous Sb-Se thin films were studied in detail mainly by calorimetry and mean time for crystallization at room temperature was estimated. Amorphous Sb100−x-Sex thin films (X=20∼65 at%) were deposited on glass plates and Polymethyl-Methacrylate (PMMA) substrate using two-point electron beam deposition and RF magnetron sputtering techniques. The crystallization process of amorphous Sb-Se thin films have been investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). An activation energy for the crystallization is estimated by Kissinger’s plot and Johnson-Mehl-Avrami (J.M.A) equation. The crystallization temperatures were found to be proportional to the Se concentration (Se≤60 at%) and those of Sb40Se60(Sb2Se3) and Sb67Se33(Sb2Se) films were estimated to be 220°C and 195°C respectively by DSC measurements (heated at a scanning rate of 10°C/min). An activation energy for the crystallization in an Sb67Se33(Sb2Se) film is estimated to be (2.85±0.02)×105 J/mol by Kissinger’s plot (from the analysis of the DSC data on the continuous heating) and (2.78±0.02)×105 J/mol by J.M.A equation (from the analysis of the DSC data on the isothermal annealing), and its reaction order is n=5∼6 and the frequency factor is ν=1.61×1029 (s−1). It was concluded that the amorphous Sb67Se33(Sb2Se) thin film is sufficiently stable at room temperature for practical use. The mean time for 10% crystallization was estimated to be about 100 years at 100°C. The structure of the crystalline Sb67Se33(Sb2Se) transformed from the amorphous phase was found to be monoclinic, which does not correspond to any known compounds in the Sb-Se system.
