CRYSTALLIZATION OF AMORPHOUS SB-SE THIN-F ILMS

The crystallization processes of amorphous Sb-Se thin films were studi ed in detail mainly by calorimetry and mean time for crystallization a t room temperature was estimated. Amorphous Sb100-x-Se(x) thin films ( X = 20 approximately 65 at%) were deposited on glass plate, and Polyme thyl-Methacrylate (PMMA) substrate using two-point electron beam depos ition and RF magnetron sputtering techniques. The crystallization proc ess of amorphous Sb-Se thin films have been investigated by X-ray diff raction (XRD) differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). An activation energy for the crystallizati on is estimated by Kissinger's plot and Johnson-Mehl-Avrami (J.M.A) eq uation. The crystallization temperatures were found to be proportional to the Se concentration (Se less-than-or-equal-to 60 at%) and those o f Sb40Se60(Sb2Se3) and Sb67Se33 (Sb2Se) films were estimated to be 220 -degrees-C and 195-degrees-C respectively by DSC measurements (heated at a scanning rate of 10-degrees-C/min). An activation energy for the crystallization in an Sb67Se33 (Sb2Se) film is estimated to be (2.85 /- 0.02) X 10(5) J / mol by Kissinger's plot (from the analysis of the DSC data on the continuous heating) and (2.78 +/- 0.02) x 10(5) J / m ol by J. M.A equation (from the analysis of the DSC data on the isothe rmal annealing) , and its reaction order is n = 5 approximately 6 and the frequency factor is v = 1.61 x 10(29) (s-1) . It was concluded tha t the amorphous Sb67Se33(Sb2Se) thin film is sufficiently stable at ro om temperature for practical use. The mean time for 10% crystallizatio n was estimated to be about 100 years at 100-degrees-C. The structure of the crystalline Sbr67Se33(Sb2Se) transformed from the amorphous pha se was found to be monoclinic, which does not correspond to any known compounds in the Sb-Se system.